Energy Systems Integration Newsletter December 2018

NREL Wins Sustainability Award, Sheila Hayter Testifies Before Canada House of Commons, and ESI Course Featuring NREL Is Now Open

NREL Garners Top Sustainability Honor at Data Center Dynamics Awards

NREL won the prestigious 2018 Data Center Dynamics (DCD) Data Center Eco-Sustainability Award, bolstering the lab’s status as a world leader in data center efficiency and sustainability. Referred to as the Oscars of the data center industry, the annual DCD Awards event recognizes the industry’s top data center projects and people. An independent panel of data center experts selected finalists from hundreds of entries from organizations around the world. This year’s winners—among them NREL Computational Science Center Director Steve Hammond—received their trophis at a gala held on December 6 in London. Read more about NREL’s international achievement as an energy-efficient and sustainable data center.

NREL’s Alicen Kandt Inspires the Next Generation of Engineers

People take different paths to get to NREL, paths that often begin in school, sometimes as early as junior high school. NREL researcher, Alicen Kandt, is reaching out and giving back to young students, volunteering to do her part to influence the next generation of engineers, who might even become her colleagues one day. Read more to find out what Kandt is doing to become engaged and involved in numerous activities to support students as they contemplate their academic and professional futures.

NREL’s Sheila Hayter Testifies Before Canada House of Commons

Canada is well on its way to creating economic opportunities for energy-efficiency and building performance. NREL’s Sheila Hayter is contributing toward this effort. Currently serving on special assignment as the 2018–2019 president of ASHRAE, last month Hayter was asked to testify before the Canada House of Commons Standing Committee on Natural Resources. Read more about the topics Hayter covered in her testimony.

Q&A with Mike Callahan: Modernizing Energy Systems

Mike Callahan is the group manager for the Applied Engineering team, a new group at NREL that supports projects in the areas of resilience, microgrids, building systems, and new technology testing and evaluation. In his nine years at NREL, Callahan's work has taken him around the world, helping partners develop and implement energy and water security initiatives and integrate cost-effective large-scale energy storage and renewable energy projects. Callahan shared some stories about his international experiences as well as details on what his new team at NREL is working on.

Improving Grid Edge Control with NREL's Advanced Distribution Management System Test Bed

Millions of new devices are now connected to the electric grid. Although many of these devices provide grid services that can help improve reliability, it is difficult for grid operators to have visibility of such devices and their control systems. Advanced distribution management systems (ADMS) help utilities gain that visibility and monitor devices to more effectively coordinate their operations for improved efficiency and reliability.

With support from DOE's Office of Electricity Delivery and Energy Reliability Advanced Grid Research program, NREL researchers are developing a vendor-neutral ADMS test bed, aiming to accelerate industry adoption of ADMS technologies for the next decade and beyond. An ADMS can be a significant investment for a utility, and the NREL test bed allows industry partners to evaluate unique ADMS features in a controlled laboratory environment at low risk and low cost.

This capability offers a multi-timescale simulation environment that can be interfaced with actual grid hardware. It also provides integrated data collection and real-time visualization capabilities, allowing researchers to more effectively observe experiments as they are executed and store data for further analysis. Learn more by viewing a capability video on ADMS research at NREL.

Energy Systems Integration: A Trend or Revolution?

Register now for the online course featuring NREL experts Mark O'Malley and Ben Kroposki on energy systems integration and the evolution of electric grids. With support from EIT InnoEnergy and the Energy Systems Integration Group, the KU Leuven course, "Energy Systems Integration: A Trend or Revolution?" is now live and open for students from around the world to register. The course looks at energy systems from the perspective of five disciplines: the overarching value of energy systems integration, energy policy and regulation, the impact of electromobility, the future of electric power systems, and the psychology behind consumer behavior. The class is designed to benefit engineering students as well as professionals in the energy sector to help understand how energy systems integration impacts everyday life, business, and research in the field.

New ESI Publications

A New NREL report titled 2018 U.S. Utility-Scale Photovoltaics-Plus-Energy Storage System Costs Benchmark establishes NREL's first benchmark of photovoltaics- (PV-) plus-storage costs. The study models the costs of several stand-alone lithium-ion storage and PV-plus-storage system configurations.

The study found that co-locating the PV and storage subsystems produces cost savings by reducing costs related to site preparation, land acquisition, permitting, interconnection, installation labor, hardware, overhead, and profit. The cost of the co-located, DC-coupled system is 8% less than the cost of the system with PV and storage sited separately, and the cost of the co-located, AC-coupled system is 7% less. Read more about this and another PV cost benchmarking study.

A Multilevel DC-to-Three-Phase-AC Architecture for Photovoltaic Power Plants The cost and maintenance of utility-scale photovoltaic (PV) inverters has driven manufacturers to investigate alternative PV inverter architecture that is more cost-effective and reliable. To achieve these goals, this article presents a new PV inverter architecture that is composed of stackable DC-to-three-phase AC converter blocks. These blocks are connected in a series structure—made possible by a quadruple active bridge DC-DC converter that provides isolation between the PV and input and each of the three AC-side phases within each block—to obtain transformerless medium-voltage AC interfaces for PV power plants. The proposed architecture was validated in a simulation of a medium-voltage 13.2-kV system and in a scaled proof-of-concept experimental prototype comprising three 250-W block modules. The article concludes that the converter structure and distributed controls enable a modular and scalable system architecture, thus making this new architecture much more resilient than other utility-scale PV inverters.

Estimating Ultraviolet Radiation from Global Horizontal Irradiance Terrestrial ultraviolet (UV) radiation is a primary factor contributing to the degradation of the efficiency and reliability of PV modules over time. The necessity for knowledge regarding terrestrial UV on the surface of PV materials drove this study to develop a simple method to estimate the clear-sky terrestrial UV irradiance from total irradiance data. The goal of the study was to be able to provide reliable estimates of the UV received by samples from a variety of impactful conditions.

The model was validated using ground-measured total UV, with data pulled from seven high-quality locations representing various climatic conditions. The finished results showed that the proposed model can be applied to estimate the total UV irradiance from total solar irradiance under all-sky conditions, and the necessary input data can be obtained from actual measurements, satellite-derived time series, or typical meteorological year data files.