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Energy Systems Integration News

A monthly recap of the latest energy systems integration (ESI) developments at NREL and around the world.

August 2016

Read the latest ESI news from NREL.

Photo of a visualization screen showing power grid modeling scenarios

Study Shows Eastern U.S. Power Grid Can Support Upwards of 30% Wind and Solar Power

Using high-performance computing capabilities and innovative visualization tools, NREL's newly released Eastern Renewable Energy Integration Study (ERGIS) shows that the power grid of the Eastern United Statesone of the largest power systems in the worldcan accommodate upwards of 30% wind and solar/photovoltaic (PV) power.

The U.S. Department of Energy commissioned NREL to perform the scenario-based study of four potential wind and PV futures and associated operational impacts in the Eastern Interconnection. The results give power system planners, operators, regulators, and others the tools to anticipate and plan for operational changes that may be needed in cleaner energy futures.

Key findings include:

  • The operation of traditional power sources (such as coal, natural gas, and hydro) changesturning up or down more quickly to accommodate seasonal and daily variations of wind and PV. In addition, traditional generators would likely operate for shorter periods of time as wind and solar resources meet more of the demand for electricity.
  • Flows of power across the Eastern Interconnection change more rapidly and more frequently. Meeting 30% targets under the study assumptions sometimes requires coordinating operations from Montreal to Miami and as far west as New Mexico.
  • Regulatory policy changes, market design innovation, and flexible operating procedures are critical to achieving technical potential. ERGIS shows that the power system can meet loads with variable resources like wind and PV in a variety of extreme conditions. However, achieving the technically feasible depends on incentives for transmission and generation operators to provide the necessary ramping, energy, and capacity services.

Learn more about ERGIS.

NREL Power Systems Researchers Present Latest Work at Recent Conferences

Researchers in NREL's Power Systems Engineering Center shared their expertise at several industry meetings in July.

2016 IEEE Power & Energy Society General Meeting

  • Sudipta Chakraborty presented a poster based on the paper titled Cyber-Physical Test Platform for Microgrids: Combining Hardware, Hardware-in-the-Loop, and Network-Simulator-in-the-Loop. Chakraborty also co-chaired a panel session on Implications of DG Interconnection Requirements. In that panel, Sudipta presented an overview of IEEE Std. 1547 and 1547.1, including the current revisions of those two standards.
  • Emiliano Dall'Anese gave a presentation on Optimization of Multi-Energy Systems. This talk discussed core optimization challenges in integrated electricity, water, and gas systems, as well as the development of efficient distributed optimization algorithms that strategically decouple the solution of multi-energy system optimization problems across actors.
  • Fei Ding gave a presentation on PV Hosting Capacity Study. This presentation discussed a photovoltaic (PV) hosting capacity study completed for 15 utility distribution feeders under multiple scenarios, and also showed the tool that was developed to implement all studies. Fei Ding also gave a presentation on Distribution Feeder Reconfiguration with Distributed Energy Resources. This presentation discussed an hourly feeder reconfiguration study based on a three-phase unbalanced distribution system model, and showed the methodology to determine optimal location and operation status of distributed energy resources in order to minimize energy losses. Ding also presented a paper on Event-Driven, Automatic Distribution Network Reconfiguration in a poster session. The paper presented an event-drive approach developed to realize automatic network reconfiguration based on data collection and event detection and location.
  • Brian Johnson gave a presentation on Transitioning from Grid-Following to Grid-Forming Control Strategies as part of a panel session on Challenges to Operate a Large Transmission Grid with Minimal or No Connected Synchronous Generators Going Towards 100% Penetration of Power Electronics-Interfaced Generation. The talk outlined next-generation inverter control strategies for power electronics-based power systems.
  • Venkat Krishnan gave a poster presentation on The Impact of High Spatial Resolution in Long-Term Capacity Expansion Models. The poster was based on the Regional Energy Deployment System (ReEDS), NREL's flagship U.S. electric sector capacity expansion model that represents the U.S. electric system with high spatial resolution. It demonstrated how spatial aggregation of available resources and their costs in lower-resolution models impacts the relative competitiveness of renewables, and how higher levels of aggregation led to lower projections of solar PV deployment.
  • Ben Kroposki gave a presentation on Microgrid Design Considerations. This talk discussed the Continuously Optimized Reliable Energy (CORE) process that NREL uses to design microgrids and current examples of projects. Kroposki also gave a presentation on Microgrid Resiliency, which focused on understanding criteria for resiliency and how those could be applied to microgrid projects. In addition, Kroposki gave a presentation on PV Module and System Testing and Certification. This presentation discussed the current status of international standards for module performance and reliability as well as how new standards are being developed for full system certification.
  • Barry Mather presented as part of a panel focused on Distribution Simulations at Varying Time Scales. His presentation compared the study process of static model-based PV impact assessments and quasi-static time-series (QSTS) simulations of PV impacts. Initial findings from NREL and Sandia National Laboratories' joint project on advanced QSTS PV impact analysis, a project focusing on enabling QSTS as a tool for use by utilities completing PV impact studies, was presented. Mather also gave an opening introduction to a panel session titled New England Innovating Technology and Standards for Grid Integration of Distributed Energy Resources and Microgrids. This presentation focused on the role of IEEE P1547 and the 2030 series of standards, and how they are enabling the adoption of distributed PV and microgrids across the New England region.
  • Bryan Palmintier gave a presentation on Integrated Models for Transmission & Distribution. This talk described ongoing research with the NREL-developed Integrated Grid Modeling System (IGMS), while also describing other efforts to link traditionally distinct modeling types: unit commitment in capacity planning and large-scale QSTS modeling with PHIL simulation. These examples were then used to provide general guidance and lessons-learned for such linked modeling approaches. Palmintier also gave a presentation on Distribution System Planning for Uncertain DER Futures using Adaptive Dynamic Programming (ADP). This talk introduced the emerging class of ADP algorithms, and described ongoing efforts to release an open-source ADP toolbox and apply these approaches to forward-looking distribution planning for distributed energy resources (DERs). Dr. Palmintier also gave a presentation on PHIL for Advanced Inverter Testing. This talk, prepared with Sudipta Chakraborty, described a wide range of power hardware-in-the-loop (PHIL) testing projects NREL has undertaken for advanced inverters.
  • Annabelle Pratt gave a presentation on Including Consumer Asset Models in Power Systems Analysis as part of a panel session on Modeling and Simulating the End-User in CPS-Based Power Systems Analyses. This presentation discussed the importance of developing building and building load models that are compatible with power system simulation tools. Pratt also gave a presentation on Buildings' Role in Modernizing the Grid as part of a panel session on The Future of Smart Building Technologies. This presentation focused on the impact that building technologies, including energy-efficient building materials, rooftop PV, and home energy management systems, can have on future grid operations.
  • Qin Wang gave a presentation on Wind Power Integrations. This talk analyzed the impacts of increased wind power on the operational efficiency of electricity markets. The paper written by Wang and Bri-Mathias Hodge on this topic received the Best Conference Papers Award on Planning, Operations, & Electricity Markets.
  • Hongyu Wu gave a presentation on EV Aggregators' Optimal Bidding Strategies. This talk focused on using game theoretic approach to analyze the competition among the aggregators with financial risk management.
  • Rui Yang presented a poster on Coordinated Optimization of DERs and Smart Loads in Distribution Systems. This poster focused on developing a coordinated optimization approach to actively manage DERs and smart loads in distribution systems with respect to system operator's control objectives.

Other Conferences

  • Emiliano Dall'Anese presented at the 2016 American Control Conference for a special session centered around control and optimization of power systems. The presentation focused on distribution networks featuring inverter-interfaced DERs, and discussed the design of distributed feedback controllers that continuously drive the inverter output powers to solutions of AC optimal power flow problems.
  • Barbara O'Neill traveled to Sint Maarten to speak at the 2016 Caribbean Electric Utility Services Corporation (CARILEC) Engineering Conference & Exhibition on the Puerto Rican demonstration project NREL completed last year on active power control, as well as NREL's collaboration with the Hawaiian Electric Companies on several advanced inverter projects.
  • Bryan Palmintier gave a presentation on Cyber-Physical Systems for Energy Research at NREL at the 2016 National Science Foundation Cyber-Physical Systems (for Energy) Workshop. This talk discussed the wide range of NREL research that brings together the cyber (i.e., computation, information, communications, not just cybersecurity) and physical domains that are increasingly intertwined in modern energy systems.

NREL Teams With LiquidCool Solutions on New Approach for Cooling Computers

NREL is partnering with LiquidCool Solutions, Inc. (LCS) at the Energy Systems Integration Facility to demonstrate and characterize the performance of LCS's liquid-submerged technology for cooling computers and servers. Although air cooling currently dominates the computing industry, the approach is reaching its limits as new compute racks become denser and generate more heat. Liquid cooling, including the LCS technology, offers a more energy-efficient solution that also allows for effective reuse of the heat rejected by the computer.

Lab results thus far show a minimum outlet water temperature of 120F, with potential for 140F water, depending on the coolant temperature and heat exchanger specifications. These water temperatures are suitable for building applications such as forced-air heating, radiant heating, and domestic water heating.

Learn more about the partnership, which is part of the Wells Fargo Innovation Incubator (IN2) program.

Register by Today for Devices and Integrated Systems Workshops at NREL September 1314

Join us at a series of three workshops related to the Devices and Integrated Systems technical area of the U.S. Department of Energy's (DOE's) Grid Modernization Initiative on September 1314 at NREL's Energy Systems Integration Facility.

The Grid Modernization Initiative was launched in early 2016 with a series of six regional workshops designed to solicit stakeholder input on DOE's grid-related research and development (R&D) strategy and the grid-related technical challenges of regional and national policy initiatives. Stakeholder feedback from these initial workshops is shaping DOE's Grid Modernization Multi-Year Program Plan and the R&D work of the national laboratories. But in order for the labs' R&D efforts to be the most effective and useful, continued collaboration with stakeholders from all sectors is vitaland these workshops aim to foster that dialogue.

Register by today to secure your spot at one or more of the workshops to participate in this continued collaboration.

NREL Contributes Deep Expertise to New Solar Forecasting System

Researchers from NREL's ESI team recently contributed solar forecasting expertise to the development of the new Sun4Cast system, a U.S. Department of Energy-funded project with the National Center for Atmospheric Research (NCAR) and researchers from other government laboratories, universities, and six public utilities. The Sun4Cast system will allow utilities to deploy solar energy more reliably and inexpensively by significantly improving daily forecasts of clouds and other atmospheric conditions such as atmospheric pollution that influence the amount of energy generated by solar arrays.

For the project, NREL researchers used their deep expertise in solar radiation to develop a fast radiative transfer model and integrated that model into the Weather Research & Forecasting (WRF) model. To validate the forecasting process, NREL worked with Florida Power and Light to collect and process measurements from a large photovoltaic plant in DeSoto, Florida.

NREL researchers developed and provided aerosol data for the WRF model to improve the accuracy of solar radiation computations and provided support in the development of benchmarks for forecast validation.

For more information on the project and NREL's solar forecasting capabilities, contact Manajit Sengupta.

NREL Collaborates with Industry to Develop International Radiometry Standard

Members of NREL's sensing, measurement, and forecasting group chair two ASTM International standards subcommittees on Radiometry and Statistics, and recently led the development of the new standard ASTM G214-16 "Standard Test Method for Integration of Digital Spectral Data for Weathering and Durability Applications."

The standard was developed by Subcommittee G03.09 on Radiometry, which is part of ASTM International Committee G03 on Weathering and Durability. The subcommittee has national and international participation from organizations like 3M, Q-Lab, Atlas Material Testing Technology LLC., the National Institute of Standards and Technology (NIST), Lawrence Berkeley National Laboratory, German Aerospace Center DLR, and others.

The standard specifies a single method to integrate digital or tabulated spectral data. This provides greater consistency and comparability of photovoltaic test results between various exposure regimes, means of calculation of material properties, and laboratories with respect to numerical results that depend on the integration of spectral distribution data.

There are numerous mathematical techniques for performing numerical integration. Each method provides different levels of complexity, accuracy, ease of implementation, and computational efficiencyand, of course, resultant magnitudes. Thus, a standard integration technique simplifies the comparison of results from different laboratories, measurement instrumentation, or exposure regimes.

In Case You Missed It: More ESI Highlights

  • A paper by NREL Senior Engineer Emiliano Dall'Anese on distributed controls was the second most popular article in IEEE Transactions on Power Systems for July 2016. The paper, Photovoltaic Inverter Controllers Seeking AC Optimal Power Flow Solutions, discusses future distribution networks featuring inverter-interfaced photovoltaic (PV) systems, and addresses the synthesis of feedback controllers that seek real and reactive power set points corresponding to optimal power flow solutions.
  • A thermosyphon device from Johnson Controls has been installed in the Energy Systems Integration Facility to evaluate the technology as an energy- and water-efficient cooling solution for data centers. Stay tuned to upcoming issues of this newsletter for more information on the project.
  • Catch up on the latest webinar recordings from our ongoing Smart Grid Educational Series, including recent presentations on video surveillance system security and the North American Electric Reliability Corporation Critical Infrastructure Protection plan.

Read Up: More New ESI Publications