A Sneak Peek of the National Grid on Renewables
A government research facility uses a megawatt-scale simulator and supercomputer to test futuristic grid technologies without disrupting today’s grid.
Renewable sources of energy can help combat climate change, and reduce U.S. dependence on foreign petroleum.
A new $135 million research facility aims to solve a puzzle: how can countries prepare for an energy system that relies heavily on renewable energy? It can also test ways to improve reliability under stress, for example when demand soars in the summer as the air-conditioning load taxes the grid.
Because wind and solar energy supply power intermittently, they create challenges for grid operators. Other new energy technologies are coming online, too, including electric vehicles, energy storage, efficient buildings that cut power use during peak times, and small-scale natural-gas generators and fuel cells. Integrating these technologies on a large scale presents challenges to grid operators.
The National Renewable Energy Laboratory (NREL) in Golden, Colorado, created the Energy Systems Integration Facility (ESIF) to understand how to best operate the pieces of a more diverse energy system. Drawing on a supercomputer and power equipment that can create a megawatt-scale mini-grid within the facility, product engineers and utilities can simulate the impact of new technologies without causing problems to functioning grids.
Regions with a high percentage of wind and solar now rely on daily forecasts and stand-by fossil-fuel power plants to maintain reliable service. But once renewable energy is more than 20 percent of capacity, grid planners need more sophisticated tools, says Benjamin Kroposki, director of energy systems integration at NREL. “We saw this big shift. If we are successful in reaching cost targets for individual technologies, then what? You need to start doing systems integration,” he says.
An NREL analysis published last year found that, with a more flexible system, the U.S. could get 80 percent of its electricity from existing renewable energy technologies by 2050 (see “The U.S. Could Run on 80 Percent Renewable Electricity by 2050”). Germany and Denmark already have about 20 percent renewable electricity and Germany plans to achieve around 80 percent renewable energy, in both electric power and transportation, by 2050.
ESIF is unique in that it has 15 different labs that allow scientists to test how the electricity grid integrates with the fuels and heating infrastructure, Kroposki says. It also has an on-site supercomputer to aid research. One could design an experiment to see how effectively a new type of fuel cell would provide both electricity and heating to buildings. Or, in a more futuristic scenario, excess wind and solar power could produce synthetic gas from hydrogen and waste carbon dioxide—grid operators would then use the natural gas infrastructure to store that energy, he says.
The simulation tools are designed to accelerate adoption of energy technologies. Utilities are wary of deploying untested products on their networks, a long-standing business problem for smart-grid startups that target utility customers. ESIF can create a detailed model of a utility’s specific network and then test the performance of actual hardware products against that data.
For example, the municipal utility in Sacramento, California, has a housing division where most of the houses have rooftop solar panels. It has distributed storage units to compensate for voltage dips when clouds pass over. By using a detailed computer model of that circuit, engineers at ESIF can test whether less-expensive solar inverters could address the issue. “You don’t have to go out and build a full-scale replica and integrate with a real system before you get a lot of the bugs figured out,” says Kroposki.
The supercomputer at ESIF will do complex analyses, such as simulating the placement of wind turbines in thousands of locations, as well as advanced visualizations. The facility has an immersive display where a scientist can stand within a three-dimensional image to, for example, examine the chemical bonds in novel photovoltaic materials or change the pitch of an array of wind turbines to optimize energy capture. “Being able to move around and interact with your data allows you to get insights that you may not be able to see on a flat screen or simple graph,” says Steven Hammond, the director of the computational science center at NREL.
Transitioning to a national electric system powered mostly by renewable sources will likely take decades and big changes in utility regulations (see “Will Utilities Embrace Distributed Energy?”). In the nearer term, a facility like ESIF can test distributed grid products on local or regional grids. For example, it could test the impact of a large number of electric vehicles and rooftop solar panels in one neighborhood.
The first user of the lab, Colorado-based Advanced Energy, began testing its utility-scale solar inverter there in June, and the U.S. Department of Defense also has plans to test systems for reducing fuel.