99.9% of a large electric grid could be powered by renewable energy sources by 2030, while keeping the costs as low as electricity costs of today, new research from the University of Delaware and Delaware Technical Community College has found.

By utilizing an efficiently designed mix of solar power, wind power, battery storage, and fuel cells, energy demands would almost always be exceeded while still keeping costs very low.

“These results break the conventional wisdom that renewable energy is too unreliable and expensive,” said co-author Willett Kempton, professor in the School of Marine Science and Policy in UD’s College of Earth, Ocean, and Environment. “The key is to get the right combination of electricity sources and storage — which we did by an exhaustive search — and to calculate costs correctly.”

The researchers created a computer model to analyze 28 billion different mixes of clean energy sources and storage methods, which were then tested using “over four years of historical hourly weather data and electricity demands. The model incorporated data from within a large regional grid called PJM Interconnection, which includes 13 states from New Jersey to Illinois and represents one-fifth of the United States’ total electric grid.”

Image Credit: Marika Krakowiak
Image Credit: Marika Krakowiak

In contrast to most previous studies, this model’s focus was on keeping costs low, rather than the approach that has typically been used, matching generation to electricity use. What the researchers found was that it was cheaper to generate the peak amount of electricity needed the majority of the time, rather than store a lot of energy to be used only during peak hours.

One of the primary findings of the new research is the confirmation that large electric systems can be powered almost completely by renewable energy.

“For example, using hydrogen for storage, we can run an electric system that today would be meeting a need of 72 GW, 99.9 percent of the time, using 17 GW of solar, 68 GW of offshore wind, and 115 GW of inland wind,” said co-author Cory Budischak, instructor in the Energy Management Department at Delaware Technical Community College and former UD student.

Solar power plant using Yingli solar modules. Image Credit: Yingli Solar
Solar power plant using Yingli solar modules.
Image Credit: Yingli Solar

The research helps to provide an image of what an electric system composed primarily of renewable energy would look like. Because of the natural variability in wind speeds and sun exposure that occurs seasonally and because of weather, something needs to be done to improve reliability. For this research, that necessary reliability was gained by “expanding the geographic area of renewable generation, using diverse sources, employing storage systems, and for the last few percent of the time, burning fossil fuels as a backup,” the University of Delaware press release noted.

“Aiming for 90 percent or more renewable energy in 2030, in order to achieve climate change targets of 80 to 90 percent reduction of the greenhouse gas carbon dioxide from the power sector, leads to economic savings,” the authors note.

Source: University of Delaware
Image Credits: Photos by Lisa Tossey and Jonathan Lilley and courtesy of Cory Budischakw