Module 1: Text Versions
Below is the text version for the System Advisor Model (SAM) Introduction and Demonstration video.
Male: All right. Good morning, and welcome to the System Advisor Model demo webinar. We're glad to have you today. Before we get started, we're just gonna go over a few housekeeping items. If you're having any technical difficulties or you have a question you'd like to ask our presenters, just use the "Questions" pane down in the right-hand side of your screen. It should pop out of the GoToWebinar, and you can ask your question there. We'll be stopping at a few different points throughout the webinar to take questions, and we can also correspond with you by text if you're having any technical difficulties. All attendees are in "Listen Only" mode, and this webinar will be recorded, just so everyone is aware of that. All right. So, without further ado, we're going to get started, and we'll hand it over to Jenny Heder.
Female: Hi, everybody! Thanks for joining today. Before we get started with the demo, I just have a few updates on schedule and upcoming events. So, Module Four will be coming to you next. It should be ready in mid-April, and then, we'll have the Office Hours on April 25th.
If you're not already registered for that session, you can go ahead and click that link and get registered for that session. I also wanted to let you guys know about the US EPA's upcoming webinar, which will highlight their local government solar project portal. So, the registration link is there, and then, we can also go to the next slide for a little bit more detail on their upcoming program. So, we are working with the EPA – with their Green Power Partnership – with funding from the Department of Energy. And the EPA is developing this local government solar project portal.
The link is there on the right, and you can see a screen shot down below. But, basically, what they're doing is providing a platform for local governments to track their progress towards installing solar just as everybody in this program is doing already. So, they're encouraging folks to get some recognition for the work that they're doing and be part of this listing that's up on their website. They're also gonna be linking to some of our resources and providing extra resources for local governments going solar. So, check that site out and participate in the webinar to learn more about that.
So that's all I have. I will turn it over to our SAM expert to walk us through the tool.
Male: Hi, and good morning, everyone. My name is Nate Blair, and I'm here with Janine Freeman, and we are really excited to be here talking about our favorite product – the System Advisor Model, also known as SAM. The agenda today is to have a few slides. So, I've got some slides to talk about what SAM is, what the background is, maybe some of the more advanced features in SAM and how you could use those eventually. And then, I'm gonna turn it over to Janine.
She's gonna go through a demonstration of how to get started in SAM, kind of walk through the easiest path to get through SAM to do solar analysis. SAM can be fairly straightforward to use, or it has a lot of options, and so, you can make it as complicated as you want, but it doesn't have to be. So, that's our plan. And then, we're gonna stop for questions after that and see where everybody's at. And, along the way, we're gonna poll you with a few questions so we'll know who's paying attention and who's not. So, watch for those.
First, I wanted to sort of set the stage by talking about the various tools from NREL that you can use to do solar analysis, and then kind of – they're listed here. The FEMP DG Screening Tool, PVWatts, REopt lite web tool, and SAM – and they kind of go from more basic to more complex. And so, we're gonna talk today about SAM in detail, but I wanted to sort of set the stage as there are some tools – particularly, if you're at the feasibility stage of a project or even the pre-feasibility stage or if you're even just trying to get a handle on how much power you could get out of a PV system in your location or at your city. We've got some other options to use. And on the back end, all of these tools are using a consistent set of modeling capabilities, which is great.
So, they just allow you to do more or less in terms of the interface, and more or less things are assumed for you as you go through the process. So, we'll keep going. Oh, the first poll question has popped up. And so, the first question is – have you previously used REopt? And by REopt, I really mean REopt lite – the web-based version of REopt. This was released some months ago and helps you both size the PV system and/or battery for your location after you enter load data and utility rate data. And should we pause to see the first question?
Male: Yeah. We'll give people a few seconds to answer that.
Male: Okay. We need the Jeopardy music.
Female: All right. We've got 85 percent of folks having voted. 55 percent of you guys have not used either tool, 35 percent have used REopt Lite, and 24 percent have used SAM. So, about a quarter of folks have used SAM before this webinar.
Male: That's great. And hopefully, this webinar will raise the SAM number significantly. Thank you and we'll move on. So, when we talk about SAM, we're really talking about combining two different things together – one is a really detailed performance model – and again, we have presets for everything, so you can allow it to assume some of that detail for you – and then, we combine that with a detailed financial cash flow model. And so, you can see on the left side here, these are the inputs sort of – the key inputs – to the performance model weather data sets key, and if you're in the US, we have great hourly solar data for almost 20 years now available through NREL's NSRDB, and that's available through a 1-touch button in SAM.
You combine that with system specifications – and here, we have databases that have modules and inverters and so forth that allow you to pick the specific components that you want to use – system losses; again, here, you can look at shading in detail or assume some kind of average shading based on some of the work that we've done to look at that around the country. Combine all that together, you get electricity production, hourly – or sub-hourly – as well as annually and monthly. Take that electricity production, combine it with the cost of the different components in the system, compensation – in other words, do you have net metering? How are you getting paid for that energy or are you avoiding energy? How are you financing that system?
Is it a third-party ownership system? Is it a debt-based system? Are you just paying cash out right? And incentives, of course, are always a key piece for any solar system in the US. And then, you get a series of results, and Janine's gonna demo some of the results that you can see, but we have literally thousands of results that you can dive into, and we've got a couple of neat ways to look at some of that – particularly, hourly results. So, you can see some of these are a performance-based capacity factor output as well as then a financial based levelized cost of energy in the net present value payback and revenue.
The key thing about this slide is that I want to emphasize that this software is free. So, now, you can download it at this address here at the bottom – SAM.NREL.gov/download – and we do keep older versions available, and we have, obviously, the latest version. We release a new version about once a year, and then we have three-four patches in there. So, it's not quite as bad as your IPhone in terms of updates, but we do try to release things on a regular basis. What technologies are available in SAM?
We're talking primarily today about PV and that's obviously a place where we've invested a lot of resources and have a lot of capability in SAM, but we also have detailed models for wind onshore, and we represent turbines for offshore wind as well. Concentrating solar power – we are probably the best tool globally for concentrating solar power analysis of this type. Geothermal power, biomass, combustion power, and solar water heating – so, that's one that comes along with these other solar technologies. And it's a little bit of a different flavor, but could be really useful for certain cities if they're interested in looking at providing hot water for various uses. Financial models – we have them – they stretch across utility scale all the way down to residential models.
We have a couple behind the meter, residential, commercial, and third-party ownership, and those differ a little bit, and we have another slide on third party ownership. Residential and commercial typically differentiate themselves based on whether or not you're paying taxes, kind of default sizes, those kinds of things. You can have a loan or pay cash for either one of those. Power purchase agreements – these are typically more of a utility scale type plant financing system single owner. It's like, a utility buys a system, equity flips, and sale-leaseback.
There's some complex structures in here primarily to allow developers to use the investment tax credit that's available in the US. And then, simple LCOE calculator. That's very simple and helpful if you have no idea what kind of financing you're gonna have or you want to compare technologies.
Female: We got a question that just came in.
Male: Okay.
Female: "So, when you're talking about utility scale, are you using municipal utilities?"
Male: What I'm talking about – good question. When I'm talking about utility scale, I'm talking about the actual – typically, the actual size of the system – so, something north of 5 to 10 megawatts for a PV system. And so, that could be a municipal utility; it could be a large investor of utility.
Female: Another quick question. It may be coming later, but Eric Hemple wants to know if we will provide some information on using local weather in SAM to estimate production.
Male: Yes. Yeah. And Janine will demo the weather page in SAM and show exactly how you can enter your address. And we are – I would just add, we're linking to the National Solar Radiation Database here at NREL, which is a grid cell every four kilometers now, and SAM will just pick the closest grid cell to you. So, what can you do with SAM?
I think I talked about a couple of these already. And one of the things we do here at NREL is model a variety of technologies in a consistent platform. Often, we're interested in what's the levelized cost of wind versus solar for kind of a similar location or making sure that the assumptions are consistent and people aren't using vastly different financial assumptions, which could skew it. Looking at financial metrics in different markets – so, a lot of times, state to state, there's quite a variation in incentives. There's quite a variation in even cost.
And so, looking at those consistently. We'll talk more about this, but we have capabilities to do parametric, stochastic, uncertainty analysis. We have a reporting function, so you can view and export model results. So, we have a lot of users that are providing reports to clients or developers or cities and saying, "Oh, well, I ran 50 different sites through SAM and here's 50 reports for each of those locations." And then, we have a lot of help, tutorials.
We have how many webinars now? 30?
Female: Close to 100.
Male: Close to 100. Okay. So, we have a lot of – you can spend a lot of time on YouTube, if you'd like, with us, if you're having trouble sleeping. So, globally, we track, because the Department of Energy's interested in this as well to make sure they're making a good investment. We track when people start up SAM; we don't track anything else about their usage.
And globally, SAM is started once every two and a half minutes. We have about 65,000 active users – that's the webinar one there. We have a lot of major firms in the US – solar and utilities – that are using SAM for solar analysis. In the lower left, we track how many papers use SAM. We have a lot of students using SAM, a lot of researchers using it, and then, in the lower right, you can see just over half of the users are from the US, and then, we have kind of a smattering of other users around the globe that are using SAM as well.
Good. We're onto the next poll question. Do you anticipate buying PV directly or through third-party owners at this point?
Male: All right. We'll give everybody about 15 more seconds to answer.
Female: Great. Thanks, everybody, for answering. We still have a bulk of folks who are not sure what they're gonna do, so that's a good piece of information for this webinar. I think that folks need some help deciding between those two. So, 48 percent of folks not sure, about 30 percent are gonna be purchasing directly, and 23 percent – third party ownership.
Male: Okay. Great. Well, and as I said before, we can look at both of those, and so, we'll talk through how that works. And, in fact, we'll talk through it right now. But Janine will show it, actually, in the model in a little bit.
So, the third-party ownership – what we've done in – so, I have another slide which I'll start talking about, but for years, we've had kind of a residential ownership model and a commercial building ownership model where these people owned the buildings. One of the things that's tricky about third-party ownership is that it's very hard to know the inner financial workings of Solar City, for example. I'm sure lots of people would love to know how that works on the inside or Sun Run. And I think the idea is that in a traditional SAM analysis, they would own the system and we would take the perspective of them and decide if them putting a system on your roof is a good deal for them or not. And, what we really want to know is if you're owning the building and you get an offer from a third-party owner, is that a good deal for you as the building owner?
And so, it says here, this is from the perspective of the building owner. So, you put in the building owner's discounted rate, et cetera, what else could you do with your money other than do a solar system, and then, you enter the offered PPA or lease offer. So, unlike our PPA models which calculate the PPA price that you would need to get from a utility to make your system work, this model you need to enter a price or a PPA offer from a Solar City or from a Sun Run. Once you get that offer from them – or, if you have an idea of what offers in the area are going for – once you get that offer, you enter that in here. You enter in your load data and your utility rate data for your location, whether you have net metering or not, whether you have time of use, whether you go with solar, you're on a different utility rate – all those questions can be examined – and then, what this does is then calculate the net present value to you as the building owner.
So, if it's a positive net present value, then you say, "Oh, look, I'm making money by buying this third-party owned system." Or, you can set up two cases in SAM – one where you own the system and one where you're doing third-party ownership – and you can compare, "Oh, I'm making more money if I do third-party ownership than not." And for a city which can't take advantage often of the tax credit, this is a tricky question for the next couple of years. It will likely be that it is more beneficial to have a third-party owned system because that company can take advantage of the tax credit, and they can pass those savings onto you. They can also take advantage of bulk buying and some other procurement things that maybe a city doesn't have access to or is perhaps more difficult for a city.
So, we're seeing in a lot of cases where maybe third-party ownership is a real advantage, but, on the other hand, there are a lot of cities where maybe there isn't a third-party ownership option available to you as well. So, those are some of the things. And we're trying to enable those comparisons.
Female: Before you go on, we got one – actually two questions coming in. The first is just asking if we'll address the differences between the three distinct forms of PPA analysis available in SAM – such as leaseback structures.
Male: We can definitely talk about those. We weren't gonna delve into a lot of detail on that in today's webinar, but I'm happy to get to that. And I think the best place to get to that is during the demo.
Female: Okay. Great. Another question – "Does this also compare PPA with the virtual net meter package from a utility as in Solar Farm?" Which maybe that's comparing a subscription to a community solar project. I'm not sure, exactly, Lisa, what you mean there.
Male: We don't have that option explicitly modeled at this point, and I'm not sure what the details are on the financial side. I would think that we could work with you to figure out if the inputs that we have and the calculations are appropriate, depending on the details of what you're trying to do, and we'd be interested in that. There is another community solar analysis spreadsheet that is available from NREL. Yeah. I think it's Community Solar Spreadsheet.
I'm not sure actually. But we can probably send that information out separately after the webinar to people if you want to delve into that. And that helps look at some of the issues specifically to community solar. It walks through some of those aggregating finance options. So, we don't compare that.
I would say that rule of thumb would be that that's a large, freestanding system, not on a rooftop – probably a lot cheaper cost initially, because you're not hauling it up to a roof and you've got a larger system, typically. So, what I've read is that a lot of these community solar systems are financially, a pretty good deal.
Female: Yeah, Lisa, why not – this is Jenny. Why don't you send me a note with a little bit more detail about what you're looking for and I can help get you some other resources to answer those questions. So, I think we're good, then, to move on.
Male: Okay. Great. The next couple slides I really want to emphasize – maybe make your head hurt a little bit – the complexity that you can get to with SAM. And then, I think when we do the demo, we're gonna kind of go back to kind of a little more of a simpler approach to make sure that you don't think it's too complicated to get through here. And emphasize some of the more recent additions that we've had.
So, we've had a lot of people who have looked at SAM sometime in the last 12-13 years and said, "Oh, I know what SAM is." But, in reality, we've continued to have several people developing new features for this whole period, and I think – I just want to kind of tell a little bit of a story here about what kind of detailed analysis you could do, and then, we'll switch over to the demo. So – and I'll start that by talking about one of our newest capabilities that we added about a year and a half ago, which is our battery model. And what's unique about this battery model – one is, it's designed primarily for behind the meter analysis at this point. We're also working to make it available sort of in front of the meter or on the grid and a couple of other options.
We're also working to tie it to wind, but we haven't gotten that working yet. What's interesting about this is that you can pick from a bunch of different battery chemistries. So, a lot of times, the battery model is very simple, and we had a simple one in SAM years ago where it's just basically, you're putting charge in, and then later, you're taking charge out. And that doesn't answer all the questions people want answered today, because it doesn't address things like RAMP rate, dispatch issues – like, how fast can it charge? How fast can it discharge?
History uses over time – batteries tend to degrade over the years. And depending on how many times you charge and discharge them, that impacts how long their lifetime is and when you have to replace them. So, there's a lot of detailed questions in here on that certain battery manufacturers kind of gloss over when they're giving you their marketing pitch. So, we want to be able to get at some of those questions. So, we have a battery model, and, as Janine will demo, we have a very detailed PV model.
And again, there's – one of the things we try to do at NREL is provide several different modeling options, provide the latest, greatest models coming out of the laboratories. So, you can see here, we have a simple efficiency model. So, that's, as it says, simple. You just put in the efficiency of the module. Single diode model – that includes the CDC database or data sheets.
So, this is the easiest way to get through SAM is to use the single diode model and pick a module. IEC61853 is a new way of testing modules and getting performance data, and then, the Sandia model is an older model. And so, we have several different module actions. We have several inverter options, and then, we have a couple of ways to look at degradation over the years. And so, you can really delve into a lot of detail.
If you're building a big utility scale farm, some of these questions get to be really important. If you're looking at a single rooftop of a commercial building, these questions probably are gonna be in the noise on a lot of these variations. But, this is a really detailed capability. We also have the ability to do detailed 3D shading. This is fully integrated into SAM.
As you can see here, you can drop your lollipop type trees all around your solar panels and you can look at the impact of shading around you. You can pull in a Google image underneath. And this can take a while to learn and figure out, but is quite capable. And then, complex utility rates – we work with a group here at NREL that builds the utility rate database, which we have several people populating most of the major urban areas for utility rates. We're not as up to date as some other people that provide utility rate data, but we have wide coverage, and it's a great starting point that you can download the utility rate that you think you need, and you can check it against the latest data sheet to see – and you can see when it was last updated and that kind of thing.
So, you can get really complex rates out of this, and we've been continuing to update that. So, you're not looking at just a single rate. You can have tier rates and ratchet rates and time of use rates, and you can have a time of use tiered ratchet rate and you can have all kinds of complexity. Lastly, I'm gonna talk about load data. You can enter load data for your building.
If you have a residential building, you can kind of have us generate some load data and then maybe scale it based on your monthly bills. Or, if you have a commercial building, we have some pre-processed loads for that. There's a couple of ways to get out load data. Obviously, the best way is if you have your own historical load data for your building. That would be the best.
But, if you don't have that, we can help create some synthesized data for you. So, then, you put all this together and so, if you really want to look at a complex analysis, you can look in the upper left here. We have a dispatch strategy for a particular battery system. You can see here in the upper right – you can see when the battery is meeting part of the load, when the battery is charging, when the battery is discharging. You can see all that in detail, hour by hour.
On the lower left, you can plot things like how fast the battery is degrading. So, you can see effective capacity over a number of cycles. So, the battery starts to go bad or not be as effective, and then, in the lower right, you can see, "Oh, in year 12 now and in year 23, I have to replace the battery." And so, that's the kind of question that you can start to get at. Like, "Geez, if I use the battery all the time and I avoid, I'll have this dispatch and I'll have this battery replacement and I'll have this project value versus if I use the battery less, I maybe don't have to replace it, but I won't save as much money."
So, this is the kind of – this is kind of on the complex side of analysis that you can do with SAM. This is some of the stuff that we do or maybe grad students do that ends up in a paper somewhere looking at dispatch strategies and optimal dispatch strategies. So, I just wanted to put this out there to tell you, hey, there is a lot of capability here, and we're gonna calm you down here in a minute talking about an easier way to get through it. Extending SAM – we have a bunch of stuff in the desktop application – parametrics, stochastic analysis, P50 P90. We have a built-in scripting language, which is a great way to try and do some extra stuff.
Macros are a script that we've written that we've kind of included in SAM, and then lastly, we have a bunch of ways to get at it if you are a programmer. So, you can use SAM in other code. We do that internally. PVWatts has an API web service, and then, we have open sourced all the SAM code as well. That just happened last fall. We're pretty excited about that.
We've got people really starting to pick that up and use the open source code themselves. So, I assume we don't have a lot of developers on the phone, but I wanted to make sure that we covered that in case you wanted to go that direction. Okay. We're at our next poll question. Do you anticipate using SAM in a way other than via the desktop tool?
Female: I actually do have some folks who think they might be doing something other than the desktop tool – so, about 14 percent of folks. So, maybe touching on those capabilities a little bit?
Male: Well, that would be great. I would be happy to talk people through that. I think a good place to start for that also is our website where we have a bunch of stuff dedicated to the software development kit and some other options. So, that's pretty exciting. Actually, the number is higher than I expected. I expected it to be like, "No, we're not doing that."
How to interact with the SAM team – we have, as I just said, a website. We have a support forum where we've got a lot of questions that you can search through that have already been asked and answered, and we have someone dedicated to supporting the support forum. YouTube channel – we have a bunch of demo videos going back quite a ways that are either broad, or we also have a number that are really specific on particular capabilities. That's also a good place to start. Twice a month we host a live webinar type session like this where people are able to log in and ask questions to the entire SAM team, and then, we have e-mail support, too, as well – more traditional support.
That's a great place to get started on some of these things. And we have – on the website, for example, we have a lot of sample scripts, which are a great place to get started with scripting as well. So, I think we've covered most of this. I would just add, on this page, that we have done quite a bit of validation of SAM against other software, tools, as well as against actual real world measured data. That's a question that comes up a lot of times with people when they're trying to make decisions using SAM.
So, we have done quite a bit of validation – particularly around PV. And so, now, we're gonna go into the live demo.
Female: All right. Cool. Well, thanks, Nate, for a really great overview. And we're just gonna switch presenters real quick here.
So, next, we'll sort of back it off, and – like Nate promised – we're gonna make your head hurt less with the live demo and go through some of the simpler options. And I'm gonna cover sort of basically almost two points in potential progress – thinking of the perspective of cities looking to put solar on municipal buildings. So, first, we're gonna go through sort of before – maybe you've issued a request for proposal, you're still at the feasibility stage. You're thinking about what type of system might make sense and maybe how to finance it. And so, I will walk through that, and that's where I'll touch on, looking at a couple of different financing options for all of those people who answered that they weren't sure whether they want a third-party owned system or to buy it directly.
Then, the second system I'll walk through is gonna be a little bit more detailed, so it's maybe after you've received bids for a system from contractors or third parties, et cetera. We'll walk through the model. It's a little bit more detailed how you can maybe verify some of those bids and maybe check out – say, you're getting different PPA offers from third party owners; we'll check out how to look at that analysis as well. So, without further ado, I'm just gonna jump right into the tool. So, this is the home screen that you see when you open up SAM.
And so, we start right up here with the "Start a New Project" option. And you'll see the first thing you're presented with is long lists – like Nate mentioned – of all the different technologies that we have in SAM. So, for this group of folks, we're gonna be looking primarily at these two photovoltaic models, and you'll see we have the two different options. The difference here is basically PVWatts, which you may have heard of – it's also available online as a very simple web tool – we have it encoded in SAM as well so that you can combine the very simple PV system analysis with financial analysis, which you cannot do on the website. And then, the second option is the much more detailed photovoltaic model.
So, this would be where you would actually be picking what type of panel, what manufacturer, what manufacturer of inverter – a little bit most specifically, the sizing. So, it basically lets you enter some more details of the system, which – depending on where you are in the process – you may or may not know. So, that's why I said I'll walk through sort of the two cases. So, we'll start, and we'll assume that you're sort of in the feasibility stage, and at that point, it's a great time to just use the simple PV model, 'cause you don't have to know tons about how the system is actually going to look to evaluate whether financially it makes sense or not. So, once I click on PVWatts, you'll see all the different financial model options come up.
Like Nate mentioned, these ones are basically what we call "Behind the meter". So, that means that you are already an existing utility customer, you have a meter, you may a monthly bill for your electricity, versus these options --- which are – you are selling directly to the utility. These are less common for municipal and city type installations – although not unheard of it. But these, for the sake of our demonstrations, are probably not gonna be what the majority of you are gonna be looking at. And then, within these, the different options are basically how you're structuring your debt.
There's more detail on that on the website that we can maybe go into at the end if there's still some interest in that. And then, as Nate mentioned, there's the simple method that just calculates the levelized cost of energy and that's about it for you. So, assuming that we're in that sort of feasibility stage and you're looking at whether or not a system might even make sense, we would probably want to pick one of these behind the meter ones for your system. So, I'm gonna go ahead and start with the commercial model. So, this would be for a building that it is owned by a commercial institution, which, in a lot of cases, might encompass sort of a municipally owned building as well.
And then, I'll just go ahead and click "Okay" and it goes ahead and creates a case. So, when you first open SAM, it can be a little bit overwhelming. There's a lot of data that you can look at here, and so, that's why, this demo, I'm gonna sort of show the quickest path/the easiest way to get through. Just to orient ourselves in the tool, you'll see along the left here we have different tabs, and these basically group inputs with like inputs. So, this allows you to step through the system with different pieces of information and sort of breaks up what it is that we need from you.
Across the top, we have what, in SAM, we call "Cases". They're sort of like tabs in Excel, and I'll show later why this can be useful, but it's primarily helpful when you're trying to compare system types. So, we'll do that. And next, we just dive right in and start with the actual inputs for our system. So, as Nate mentioned on that one slide showing what the steps were for modeling renewable energy, you have to have the weather data or the resource data for your location.
And this page has a lot of information on it, but I promise – there's actually only one thing you have to do on this page. This first button here lets you download what we call a typical meteorological year file for a location in the Americas. And it's all of North America and about half of South America, which is why _____ the Americas. So, if I go ahead and click that button, I'm gonna create a system, and let's say I'm gonna look at it on NREL's campus. So, I'll type in that I'm in Golden, Colorado and click "Okay".
And what this does is it just automatically downloads a file for the location I typed from the National Solar Radiation Database – so, that's this acronym here, the NSRDB. And you can see it downloaded the file for Golden, Colorado, which is what I typed in, and it set everything up for me. So, now, I don't have to touch anything else on this page. That's it. I've set my weather data. I'm good to go, and I can move onto the system design.
So, because I picked the PVWatts model, the design of the actual PV system is fairly simple. It's got – you know, it looks like maybe about 20 inputs, but it's actually about eight that are important, and several of these have defaults. So, that's one of the things about SAM – is that we try and make sure all of the inputs are pre-populated with reasonable default values. So, if you don't know what should go in a particular box for the system you're looking at, you can leave it as a default value, because we've gone through and picked something that makes sense for a lot of systems. So, to start, one thing that you would probably want to know is about what size system you're looking at – and I understand you guys had the REopt Lite webinar already, so that might be one way to look at what size system you'd be interested in.
So, let's say maybe I'm interested in about a, I don't know, 50-kilowatt system. I would just enter that there, and then, we have a couple of details that you may or may not know. Module types – this basically lets you select whether you're interested in the sort of widely available, what we call, standard modules. Premium modules would be really high efficiency ones, so that might be something you'd be considering if you're looking for a really high efficiency system, but have very limited space on a roof, for example. And then, thin film, which is sort of the opposite.
They're a little bit lower efficiency, but they can also be cheaper, and so, they can be a consideration sometimes. But, if you don't know yet, you might just stick with the standard panel, 'cause that's represents sort of the average. DC to AC ratio basically refers to the size of the DC part of the system – so, the actual module – versus the AC part of the system, which is your inverter. And those aren't necessarily one to one. Can be for a lot of different reasons.
But, that's one of the things you might not know in the feasibility stage. So, 1.2's a pretty reasonable default, and I'm just gonna leave it at that. The same with the inverter efficiency. 96 percent is average for inverters that were released in the last 5 years or so, so we're gonna leave it there. Things I do know, for instance – I might actually be interested in putting this system on a roof.
So, instead of the fixed open rack option, I'm gonna say, "Okay. I have a 50-kilowatt system going on a roof, and I know that the tilt of that roof is, say, 10 degrees and the Azimuth – which is basically referring to sort of the heading, the bearing of the system; you can see in our little diagram here – I happen to have a building that is perfectly facing South, which is this 180 degrees." So, I will leave it that way. I consider myself fortunate to have a building already facing south. And then, the last step is to set the losses, and this is one of the things where it looks like a lot of input, but we have sort of tuned these losses to be representative or a good starting point for a lot of systems.
So, if you don't know anything more about your system, this gives you a good place to start, and I'm just gonna use that default. Two of the biggest ones that might be something you'd want to look at but may be more in the actual design stage would be the shading. So, for instance, if you have a building that has another building right next to it and you're not gonna get any afternoon sun, that might be something you'd want to up, and then snow, depending on where you are in the country. There can be different snow losses for your PV system. And we do have a report available about that.
It gives you sort of average starting points for different locations in the country that I can point you to at some point in the future. But, at this feasibility stage, I'm just gonna go with the defaults here. So, that's it for designing the system in the PVWatts model. It can be very simple. Then, I move onto sort of the financial pieces.
So, the first step of that is just cost. What we have here are a lot of different buckets for costs. So, the ones we would expect – like module and inverter – there's cost for batteries – if you have a battery, which in this case, I don't. And then, there's also these balance of system, installation, permitting, engineering – that type of thing. And the primary reason all of these buckets are here is to basically remind people that they have to account for those in the cost of the system.
But, again, what we've done is we've taken basically the averages for different sectors of the market. So, because we picked the commercial model, this is going to populate with the default cost for a commercially sized system. So, that's sort of a large rooftop system. And that is for the US market, so that's the data that we've gotten from US. And so, again, because I don't have better information on this because I'm in the feasibility stage, I'm gonna leave this at the default.
So, this is just the US average for the commercial based system. And you'll also see there's some inputs for operations and maintenance costs down here that again, we have populated with sort of the average for commercial systems, so I'm gonna leave it there. Next, we move onto the lifetime and this basically allows you to specify degradations. So, the modules don't perform exactly the same as they did on day 1 in year 15. And again, we have a pretty standardly assumed degradation rate throughout the lifetime of the system, so you can leave that alone as well.
So, basically, you should start to be noticing a pattern here where there's a lot of inputs you don't have to touch, and that's what I'm trying to convey. So, like Nate said, there can be a lot of detail, but there's a lot of it also that we can basically take out of the equation for you with the default. Next, we move onto the financial parameters. So, this would be where you might start to explore how you want to finance your system. And so, you'll remember, I picked the commercial model.
This is where you're either buying the system outright in cash or taking out a loan for all or part of the system. And so, you might look at that as an option, for instance. Let's say with this one, I know that I'm going to be taking out 100 percent of the cost of the system as a loan and I'm going to get a 25-year loan and I'm getting a screaming deal on a loan rate at just 4 percent interest. So, I'll go ahead and change that. My inflation rate?
Yeah, probably about two and a half percent. And then, discount rate – so, basically, what else could you be doing with the money? What is the value of that money to you? Which I'm gonna go ahead and leave at five and a half percent. That sort of depends a little bit on your organization.
It might be lower for a lot of municipalities; it might be higher. I don't really know. And then, you fill in some information about your tax and insurance rates, because this will affect, basically, how some of the income is treated, whether or not you're taxed on things. And finally, some depreciation options. So, this is basically one way to get a little bit more bang for your buck out of the system as these advanced depreciation options.
The five-year macro is a pretty standard one, so I'll go ahead and leave that there, but you might be eligible for some different depreciation schedules, especially at the state level. So, I just wanted to point out that that's there. And then, you move on to incentives. Again, this is sort of an overwhelming page because there are so many different types of incentives available. But basically, on this page, you'll probably only enter one or two different incentives that apply to your system, and you just have to find the right boxes that they line up with on this page.
So, for instance, the one that's the default for PV systems is the federal ITC – Investment Tax Credit – which is 30 percent of the price of the system. So, that one's on by default, but you could also add investment based into other investment incentives – either from a state level, maybe from your local utility, from your municipality. You can look at capacity-based incentives – so, these are $1.00 per watt bases rather than just dollars – and there might be production-based incentives, which is sort of a third way to think about it. So, that's $1.00 per kilowatt hour that you produce. So, that one, obviously, got to produce something before you get the incentive money.
So, basically, just a lot of different ways to enter incentives. And then, of course, there's also the main production tax credit. So, there's the – cash incentives are slightly different bucket than credit on your taxes, so these are basic two ways to do that that are most common. ITC usually for solar; PTC production tax credit is pretty commonly applied for wind projects.
Female: Can you talk about which incentives are available to municipalities generally?
Female: That one tends to be pretty specific by state and municipality. And so, there used to be – there still is, sort of, a database that looks at what incentives are available depending on where you are in the country – so, by state and by county, even. Unfortunately, that database hasn't been updated very regularly lately, so it's maybe not as useful as it once was, which is why we no longer link to it on this page.
Male: Well, I think I would – so, that's the DSIRE database – D-S-I-R-E-US.org or something?
Female: But there's no dash.
Male: There's no dash. Okay. But anyway, be careful what you type in,'cause Desire.com is a different thing. I think the website itself is being maintained and they are putting the data in. We used to have a machine-readable version of the data that we could link into SAM and so, you could download those incentives. They still are pulling incentive updates out from a legislation for each state – so, particularly for states which are just now kind of implementing in RPS or have some state incentives. Those might be available for municipalities. I think if you are not paying taxes, the federal incentives generally go away, and a lot of the state incentives go away as well, and that's what makes third party ownership more attractive. So, we can't say, for sure, for any individual city, but by far the biggest is typically the 30 percent investment tax credit from the federal government, which obviously, if you're not paying taxes, is a different thing. There used to be a federal grant program as well, but I believe that's long gone.
Female: And just one more resource that I will send out after this session. NREL has developed some state policy pages from mid-scale solar systems. Those are state by state pages. They don't go into every single utility incentive that may be available, but it is a good place to start. And just generally, since we know DSIRE is not up today, the state policy pages are not always up to date, we advise folks – check with your utility.
Check with your state energy office to make sure you're getting the latest information about those incentives, and especially when they may be timing out or when you would need to apply to them before they may no longer be available.
Male: And a lot of times, the solar developers are up on the latest incentives as well.
Female: Yep. And we will be talking more about incentives in the next month, so stay tuned for more.
Male: Real good lead in.
Female: We did that on purpose. All right. So, once you finish filling in incentives for your system, you move onto sort of the way that this starts to make sense for behind the meter systems. Because you're not selling directly to the utility in your area, the way that this system is going to monetarily make sense is that you are avoiding electricity costs in the building that you're putting it on. So, for that reason, we have to know something about both what you're paying for the electricity you're using, but also, what type of electricity you're using.
So, we call that the building load. Again, these pages can be sort of overwhelming, but I'm going to show you the shortcut through them once I move the little GoToMeeting things out of the way. Here we go. So, again, this is helpful. We have this one button option.
As Nate mentioned, we hook up with the United States – and it's actually even broader now; it has some international rates as well – but the Utility Rate Database. And you can just search for rates that apply to you. So, for instance, you might know the name of your local utility or you might just search it by zip code. I happen to know that for our system in Golden here, our utility is Xcel, and there it is. So, I filtered, and now, I have Xcel Colorado.
Perfect. There we go. And because I picked a commercial system, it is showing me the rates for commercial entities. If I had picked the residential system, it would show me the rates for residential properties. And you can switch within this window as well, but I'm gonna stick with the commercial rate.
And this one can be a little tricky to figure out exactly which one you have right now. It might be one to check with whoever is in charge with communicating with the local utility. You can also call your utility if you're not sure. So, we'll assume that I'm on some type of time of use rate here, and then, all I do is download and apply utility rates. So, that automatically gets that information and it changes all of the inputs on this page to reflect what my utility rate actually is.
So, you'll see here is where it lists the energy charges. There's one tier that has two different periods in it, and you can see the periods here. We're mostly in period one, but there is a peak period from about noon to 8:00 during the summer on this rate – so, you pay more for energy at that point in time. And then, that's it. That's all I really have to do.
The one other input to take a look at on this page is basically, the metering options. So, you may have heard things like net metering, and there are starting to be some different flavors of those. I would say that this first option is still the most common and it's the one that we tend to think of when we think of net metering, and a lot of utilities do still offer net metering for solar PV systems. There are some other options as well. This one basically is like net metering, but instead of rolling over any excess energy in kilowatt hours, you roll it over in dollars at a particular sell rate.
And there are a few different options, and I'm not gonna dig too much into for the sake of time, but we have some other resources on those, and we can come back to them if we need to. So, last up, I want to take a look at the electric load page, and this is actually the time for the last poll question of the day to see if I've lost how many people are so far. So, we have a couple of options. I'm not sure if they're all showing on the screen, but what type of load data you have for your building. So, if you don't have any load data, that's also fine.
If you know the monthly usage, that's pretty common. And some buildings might actually know the hourly or even sub-hourly usage about their buildings. So, well, it looks like a lot of the answers are coming in. About 70 percent so far, so, we'll give people another couple of seconds to vote. But, it looks like overwhelmingly, people definitely know the monthly usage for the most part, so that's good.
Some people have hourly or sub-hourly data and some people do not have any data, which is fine. So, the good news is that for all three of those, we have a way you can move forward in SAM, and I will go ahead and show you that.
Female: Can we take just a second and go back to the electricity rates tab? So, question is about under that _____ accounting of excess generation. What about sale back at utility avoided cost? Would that be the last option?
Female: Sale back at utility avoided costs. Is that a certain – like a specific sell rate, I'm assuming, is what they're asking about, so, it isn't necessarily net metering, which gives you the rate you would actually be paying at that point in time. Yes, that would be this last option here. So, basically, anything that you sell – anything that you're not consuming on site – is at a specific sell rate. So, you can specify that here. Typically, that's lower than the buy rate, and then, anything that you have to buy from the grid that you're not offsetting with PV is at this rate that you've _____. So, yes, that's correct.
Female: Okay. Great.
Female: So, skipping back to the electric load page, we'll start with the people that have the most data, I guess. So, that's people who have either hourly or sub-hourly utility data. You can actually just enter that here on this page. So, we have an "Edit Data" button. You can paste in, say, from Excel or something like that.
You can import and export files. This is just populated with sort of default, at the moment. So, that's the way to input the data if you have a lot of data. So, hourly – if you need it to be sub-hourly – like, say you have 15-minute data – you would just say, "Instead of a 60-minute data period, I have 15-minute data." And then, you would enter that here.
So, that's option number one. Option number two, for people who have monthly data – and I'm gonna go mostly for commercial buildings here – there's basically two ways to do it if you have monthly data, but for commercial buildings, there's sort of only one. We're gonna take a dip into the advanced features world of SAM, and down here, you'll notice we have something called "Macros". If I click here, you'll see I get a new interface that has a list of what we call "Macros" and these are sort of like macros in Excel, so these are using the scripting language that's built into SAM, but you don't have to see or interact with this scripting language; you just have to click "Run". And this is one of the ways that we help people extend SAM.
So, it provides some extra features that don't necessarily make sense in the core user interface but provide something helpful nonetheless. And so, what we have – you'll see the first one here – is "Download Electric Load". If I click on that – because I'm in a commercial model, this gives me a bunch of different options of commercial buildings. And so, these are basically – they're coming from a website called "Open EI" and these are typical load profiles for buildings of these types for each weather station location in the US that we have data for from the Team _____ Three data set, which is a little bit older than what we're using now, but it still has about 1100 locations throughout the US, so, it definitely has a location near you somewhere. So, what you would want to do is pick the type of commercial building that's most similar to what you're putting your PV on.
So, I would imagine for a lot of municipal buildings, it might be something like a medium office. People are there during the day, not at night – that type of thing. So, I'll go ahead and pick that one, and then, you'll see – the "Run Macro" button is a little bit hidden up here, but that's all I have to do is click "Run Macro". It's downloading the data, and then, it tells me, "Success" – it downloaded the data for the medium office building for a location in Golden, Colorado, because that's where I specified my weather file up on this page. So, it will automatically make those two choices for me, and we're gonna call that a pretty good starting point for load data.
It may be not perfect for my building, but it's – on a daily perspective, probably fairly helpful. And, if I go back to the electric load page, you'll see its populated these boxes, but then, what I can do – since I have monthly data – if I don't have any data, I can just stick with that and call it a day, but if I have monthly data, I can actually normalize that load that I downloaded to my monthly bills. So, I would get my usage in kilowatt hours from each of my monthly bills, and it will scale those profiles for me. So, it helps sort of tune that information better to your building if you have just monthly data.
Female: Question on the building types. So, for cities, most of our buildings are used by the public and do not fit on the list – like an ice arena or an indoor park. What do you suggest using for that and will there be data that will come out on those types of buildings that maybe don't fit into one of these categories?
Female: I don't think that they plan on adding the link types, unfortunately. And that is sort of a good question. It may be – so, what's really important here is to think about when people are in the buildings, and maybe what they're doing in the building. So, for instance, some of the indoor parks, it might be more like a retail space where there's people in and out from morning until 8:00 or 10:00 or whenever the park closes – that type of thing. So, that would be one of the ones – it is a little bit of a judgment call on which building type you think is most similar if you don't have data.
But, again, one thing that I'll point out is that most of you did have at least monthly data. So, if you're doing that and you download the load, that just gives you what the daily profile looks like – so, how much it changes throughout the day. If you're scaling that to your monthly data, it's still gonna get you, what we would call close enough to give you a good idea of how this system may or may not make sense.
Male: I would also add that I think if you have some of the building types, it might be worthwhile just letting us know and we can, at least, communicate with our building modeling team here at NREL. We have a really _____ capability there and see if they're aware of kind of other sample loads that – or some of these more unusual buildings and structures – like ice arena's a good one, actually. Or, if that's something we want to submit for future funding to kind of go into it if there's enough requests.
Female: Just a follow-up comment – "Ice arenas would be great – heavy loads with large groups."
Male: Yeah.
Female: There you go.
Female: Makes sense. All right. Well, so, that sort of gets us through all of the input for our PVWatts commercial system here. So, next, I'll go ahead – and I'm just gonna click "Simulate" down here. This is our "Go" button.
And you'll see the first thing that pops up is our automatic graphs and metrics. So, these are pretty common things that people are interested in knowing. For example – what your first-year energy is going to be, capacity factors, if you're familiar with that, the LCOE – we have nominal and real dollars – and really, you can look at whichever one interests you as long as you're looking consistently across different things, your comparing might not matter. It'll give you an idea of net present value. This is another one that can be important.
So, you'll see in this case, our net present value is actually negative, which means the system I set up was perhaps not a good choice. It's not going to make me money in the long run. And then, the payback period's another common one that people are interested in – so, how long will it take me to recoup these costs. And again, because I set up not a great system, the payback period actually does not occur within the 25 years that I set up for the analysis to be. So, it probably occurs after that.
So, this maybe isn't the best system in the world that I've constructed here. But that gives me an idea of outputs that you could be taking a look at. There are, across the top here, a bunch of other ways to look at outputs that I won't get into too much detail on just for time reasons, but as Nate mentioned, we have thousands of outputs. I'm not sure if it's thousands, but definitely at least hundreds, and you can search for those if there's particular things you're looking at. You can create your own drafts.
You can look at the cash flow for the system for year to year. You can look at things on a time series basis. So, for instance, I'll look at what my DCRI is doing throughout the year. You can zoom in on these and take a look at what a couple of days might look like – sort of a clear day, and here's a moderately cloudy day. So, there are a lot of different ways to slice and dice the data you're looking at.
In the feasibility stage, you're probably gonna be sticking with metrics in this table. So, now that we've done the simple PV model and the trickier financial model, let's switch over and say [Inaudible]. How about I take a look at what the same system would look like, but under a third-party owned scenario? So, you'll notice I clicked on the right-hand side the name of my case here, and I have a bunch of different options. So, I can create a report for the case – like Nate was mentioning, this just creates a PDF with some of the inputs.
I can also duplicate it, which is what I'm going to do here. So, I'm going to create a second case, but this one, instead of being my commercial, I'm gonna look at third-party owned and I'm gonna rename it, just so I keep it straight here. And then, what I'm gonna do is I can actually change the model. So, that brings me back to this first stage, and instead of picking commercial, I'm gonna have that same PVWatt system, but with a third-party ownership model and click, "Okay." So, that will do is all the pages that are the same between the two will keep the same inputs that I already set up.
So, you'll see that this is still saying my location is Golden, and I still have my 50-kilowatt system here, so, I'm comparing the same system, but my financial parameters page is different and a lot simpler for the third-party owned option. So, now, I can compare the two. So, we're gonna say that I'm gonna take a look at leasing this system, for example, and let's say I know that roughly for a 50-kilowatt system – and I am totally making this up, so we're gonna see how this turns out – maybe it's a $500.00 a month lease payment and it's gonna be a 25-year agreement. Again, I have to enter my inflation rate and my discount rate to do the net present value, and that's it. So, that's a lot simpler from the financial perspective.
Still keeps the same electric rate and electric load that I had before, because again, I'm offsetting what I would have been using. This system is gonna make sense for me. And so, I go ahead and simulate this one. Turns out, that's maybe too high of a monthly payment, because my net present value is even worse that for the other systems. So, you can tell I'm not super up on what third-party ownership lease agreements would be for a 50-kilowatt system in Golden.
So, I'm assuming these numbers will come out a lot better for those of you trying these tools. But now, I can compare the two. So, I can look side by side. This one – it would actually make more sense for me to buy the system outright if these were the true financial metrics, which they're definitely not – than it would for me to lease the system from a third party in a very, very, badly set up case. So, that sort of walks you through the simple version.
So, we're using PVWatts. This is sort of your feasibility stage – investigating different financial options and what those could look like. And the last thing that I want to just quickly talk through is the detailed option, and I won't spend too much time on this. I think we've been sort of taking questions throughout, but I want to leave some dedicated time. So, I would select "Detailed" and let's say, that's a third-party ownership system, because I've gotten a bid from the third-party for this system.
I'll skip over the page you're already familiar with – so, this would be downloading my location – and I'll just come to the module. Like I said – the detailed model, you would know a little bit more about what your system would actually look like. This might be coming off of the bid that someone has given you, so they might be telling you exactly what module and what inverter you're looking for. So, let's say, in this case, they came back with a [Inaudible] module. All I'm doing is searching up here and it shows up in this list.
And on this module page, that's all I really have to do – is select the right module model off of the list and I'm good. I'm golden. So, there's a lot of information, but again, not a lot of things you have to necessarily change. Same thing with the inverter. I just come back.
Let's say that they did quote me this SMA inverter rate – I'm gonna use it. I move on to system design. So, here, there's two ways to do it. If they tell you exactly what the system layout looks like, you can enter that here, but more likely, they're just gonna be telling you what size. Maybe they give you a 50-kilowatt system.
And SAM can automatically size the modules with, again, the inverters for you. So, how many of that specific module, how many of that specific inverter, how they're wired together. That's probably gonna be most common in you're evaluating a bid that someone's giving you. And everything in blue is calculated value for your reference. So, it might be useful to look at, but it also means you don't have to input something in those boxes.
They're not quite as scary. Same thing – I have my fixed tilt system, I'm saying my building has a 10-degree tilt, and that's all I really have to do is set up the system size and whether it's fixed or not, what the tilt is, et cetera. You'll see that in the detailed model, we have more detailed models for shading and for snow – a snow model. Although, with the snow model, unfortunately it does not work with the NSRDB data that we downloaded, because that doesn't have snow depth data in it. So, that is maybe not as useful, unfortunately, for this scenario.
There are different ways to enter shading. We actually have some webinars on those. I'm gonna leave them alone for now. Unless you have a building that's pretty heavily shaded, you can maybe ignore that. We still have losses.
The page looks a little bit different, but it has some of the same buckets and some of them have a little bit more detail. Again, these are reasonable defaults, so I'm gonna go ahead and leave those. And the lifetime page, again, is similar, and this is where a little bit more information on battery storage – so, right now, there's no battery set up, but these blue boxes at the top here are how I change models. And, if you click this, you can see that you can enable the battery for the system, which I won't do, but just wanted to point out that that's where it is. And then, you'll see the same financial parameters page as we had before.
Same electricity rate page, same electric load page – so, you've already mastered those. So, we're pretty much good to go ahead and simulate this system. This one – look at that – because I didn't make as many changes and set up a system that doesn't make any sense, we have a positive net present value, so that's awesome. But, this is the same type of thing. So, you could look for some of the outputs that you might be interested.
Maybe you're looking for monthly energy. So, if I search for energy – that's not the right key – oh, no. Maybe it is the right keyword. There we go. "System energy" energy under our "Monthly data" here.
Now, I can look at what it's producing each month, 'cause at this point, maybe I'm looking for a little bit more detail, that type of thing. So, that's sort of the overview of the different ways to run through PV systems in SAM. I'll quickly point out, as Nate mentioned, we do have some advanced features. They're mostly located under the "Simulate" button. So, we have a parametrics interface that allows you to sort of quickly take a look at a couple of different options. So, in this case, if I'm looking at maybe different lease prices and I'm – let's see.
Third party ownership. Here we go. Oh, apparently, I can't [Inaudible] that. Well, if I want to look at different, maybe, agreement periods – so, maybe one person has given me a 20-year contract; someone else has given me a 25-year contract, but otherwise, they're the same – I could set that up here, which I'll do real quick, and just say, "I'll star with the 20 and 25 year contract." And I want to look at the LCOE for an output. [Inaudible] none of my things showing up right now.
Well, what should I look at? Annual energy instead?
Female: Maybe some sort of financial metric?
Female: Yeah. Looks like that. Electricity bill with system, for instance, which [Inaudible] 'cause it's the same system, it's going to be the same. And it's data, so here it is. Here's my electricity bills.
Again, sort of a bad system – or no, good system, 'cause they're negative, so they're paying me every month. So, like, as you can see, I did not set up a real system here, but this just gives you an idea of a quick way to run multiple simulations. So, the typical example we use is you have buildings maybe with different tilts or with different Azimuths and you want to look at a bunch at once fairly quickly, this is one way you can do that fairly quickly. We also have the ability to look at things stochastically, which probably won't apply in this scenarios you guys are mostly looking at. The macros I've already touched on a little bit.
You can look at different weather files with the P50P90. So, those are just some of the advanced features we have in the tool that might be useful to you down the road as you start to maybe look at more and more systems or do more analysis.
Male: Didn't you want to show the report?
Female: Oh, yes. Let's do that. So, as Liam mentioned before, the case menu here for this specific case – click on "Create Report" – it will go ahead and generate a PDF for me. So, I will save it, and this gives me basically a summary of all of the inputs that I picked for that case, and some of the outputs as well. So, here's the net present value listed here – a couple of pages here so you can see.
We have the monthly generation. We have your bills with the system/without the system, what your savings are, et cetera. So, these reports are sort of an idea of what the losses are in the system. These reports just sort of give you an easy, quick summary of what you set up in that case that's easy to share with someone else or for someone else to share with you. So, another feature that we do find people think is useful – especially when you're looking between multiple parties.
So, with that, I think maybe we can switch to questions that people didn't ask throughout.
Female: Yeah. We've got a couple of questions. We do have a little under 10 minutes left, so you guys feel free to ask a few more questions if you have them. The first question is on the losses. So, the question is, "Are the defaults in losses regional based or more US East based?"
Female: So, the losses are sort of country wide. They're not – the default ones. They're not regionally specific. They're meant to be at least roughly representative of any area in the country. The ones that I mentioned that will vary the most regionally are probably snow.
And if we go back to my PVWatts case here and look at the system design, snow is definitely gonna be your biggest one. Soiling could also change. So, that refers to basically how dirty the panels get typically aside from snow. So, if you are right next to a farm that kicks up a lot of dust, your panels might get a little dirtier than if you are in an area where it rains every morning and cleans them off. The rest of them are fairly competent across the country, and snow is such a big one.
I'll just pull up the SAM website real quick and see if I can't, on the fly here, find that snow report for you live, but it gives you an idea of throughout the country, of what your default snow loss is – or a starting snow loss might be. So, this is the SAM website. It might not look the same to everyone, 'cause I was logged in, but there we go. And so, across the top, we have a lot of the different resources I was talking about, but you can also search. So, if I search "snow", I can get some of the questions that people have already looked at about snow or some of the questions that people have asked, and I can also go to "Resources" and see if I can't find it, because now that, of course, I'm doing it live, it may or may not actually – is it performance or is it here?
We're also in the process of reorganizing our whole website 'cause we're not crazy about the current organization, so, look forward, to – in the next couple of months – a drastically improved SAM website. We are definitely looking for it. All right. I'm gonna do this differently instead. I'm gonna Google, because I know what the report is, and then, perhaps it's something we could send out so that people have some information.
Female: Yep. We can definitely send it out and release it on their platform.
Female: Perfect. Then we can make it more obvious we're on the same website, 'cause I'm sure it's there somewhere.
Male: In the "Help", it also often will point to where the documents – where we get our defaults – and I would say that some of the default losses have gone down over time as more research has been done and system installation has improved, and soft costs have dropped. And so, you'll see periodically – and each time we do a big release, we go through the default values for things like DCAC ratio and some of these design considerations and talk to people in the field and try to figure out what's the most typical number for the US at this point. It also applies to cost data. So, we tie our cost data to whatever the latest NREL document is at the time of our release. And NREL has several periodic PV cost reports that come out.
So, it's often lagging behind the industry, but we do our best and we always want to have a reference for our default cost data, in particular.
Female: So, this is the snow map that we can send around, but you'll see there's sort of – oh, my. My computer is just going crazy at the moment. Too much live demo, I guess. This is a – just annual loss percentage depending on where you are in the country for a tilt _____ 20-degree system. So, that would be higher for flatter systems, lower for more tilted systems, but this can be sort of a starting point for what you might want to put in that snow loss box for your system depending on where you are.
Male: And again, this assumes you are not cleaning off your system when it snows.
Female: Correct.
Female: Great. We have another question about entering electricity rate and load data. So, Karen says, "If you're looking at solar for groundwater pump and treat system or other non-building applications and have detailed electricity rate and load data, where would you input this data?"
Female: Okay. Well, it is great to have detailed data. That would also go on the same electricity rate and electric load page. I might point you to some of the webinars where we've talked a little bit more in depth about what exactly all these values on the electricity rate page are, but the quick summary is that for the rate, you would enter your energy charges in whatever number of tiers and periods you have, and you can specify those on weekdays or weekends, and again, we do have webinars that go through it in a little more detail. And then, you can also do the same thing for any demand charges that may apply under your utility rate, which I know can be common for some larger buildings.
And then, with the electric load – again, with that detailed load data, you would probably just want to input it directly – either on an hourly or sub-hourly basis into this box right here. And then, you don't have to normalize it or anything. You're just all set for that.
Female: Great. Another question – so, you mentioned you might want to use some values from an RFP process and put them in here. Can you talk about – is that common that you would need to double check what developer submit if you're an RFP or why would somebody be doing that?
Female: So, that's a great question. There's a variety of reasons you might, and it's not that you wouldn't trust your developer, because you shouldn't be getting bids from someone you wouldn't trust. But, one thing – it might just be A – either a good set of practice for you to sort of understand how they arrived at their number – so, we do find people sort of using it as a learning situation almost where they're looking at the inputs and sort of understanding how those might affect the annual energy output so that they can ask questions, "Why did you choose this module? Why did you choose this tilt?" That type of thing.
Another reason that we find people might put them in is if they get two bids and they are very different. So, if, for instance, the lease price is really different or the annual energy that they're saying you can produce is very different, it would be helpful to understand why they're so different. So, that's one reason that we would see people doing that.
Female: Okay. Great. We've got one last question – I think it's probably a good concluding question, unless there's anybody else with a burning question they have – but the comment and question is, "We've used Map Swell and PV Sketch Ups for initial screening of site and potential size of the system. What does SAM offer that these commercially available options don't?"
Female: That's a great question. I'm not as familiar with either of those two tools specifically, but generally, one of the things that we find people are using SAM the most for is a lot of those detailed financial options. So, a lot of tools don't have as many different – you know, your commercial options with or without debt versus your third-party owned options or even looking at some of the residential or utility options, depending on who you are. So, that's one thing that we find people really are using SAM a lot for the evaluation of – that might be particularly relevant to this group.
Male: I'd also add that I think it depends on what kind of questions you're asking. For example, if you want to compare premium sun power modules and their costs versus lower cost tree _____ panels, for example, that maybe don't have as high of an output, I think – and I'm not sure on PV Sketch Up, but we have interfaced with the Sketch Up team previously. And so, I think there's definitely options there. We're also in connection with teams like Helioscope and some of the other teams that are out there – Aurora, Google Sun Roof has a tool as well. And I think what SAM allows you to do is just really get under the hood and really tweak all the knobs that you want to with some of those.
So, if those tools are answering your questions, then I think that's completely fine. And we haven't compared SAM against those two particular tools, so I can't speak to how accurate they are or anything, but I think that's why we talked at the very beginning about the breadth of tools that we have, and there are a whole lot more tools available out there.
Female: Great. Thank you, Nate and Janine. I think we are at time, so I'll go ahead and wrap up. I do want to remind folks that we will be posting a recording of the webinar, so if you need to go back and review some things, that will be available – we'll put that on Litmus shortly. And we will also pull out the slide deck so that folks can click on some of those links in Nate's presentation and make sure they're able to get to all of that information.
Do you have anything else? No? Okay. Well, thank you, guys. We'll be in touch next month with our next Office Hours, but before then, poke around on SAM and let us know if you have any questions.
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