A study by the University of Delaware and Delaware Technical Community College suggest a well-designed combination of wind power, solar power and storage in batteries and fuel cells would nearly always exceed electricity demand at costs comparable to today's electricity expenses, a university release reported Monday.
"These results break the conventional wisdom that renewable energy is too unreliable and expensive," University of Delaware researcher Willett Kempton said. "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."
A computer model considered multiple combinations of renewable energy sources and storage mechanisms, testing each with four years of historical hourly weather data and electricity demands, the researchers said.
The findings suggest a very large electric system can be powered almost entirely with renewable energy, they said.
"For example, using hydrogen for storage, we can run an electric system that today would meeting a need of 72 gigawatts, 99.9 percent of the time, using 17 gigawatts of solar, 68 gigawatts of offshore wind, and 115 gigawatts of inland wind," said study co-author Cory Budischak, an instructor in the Energy Management Department at Delaware Technical Community College.
One gigawatt -- a gigawatt is a measure of electricity generation capability -- is the capacity of 200 large wind turbines or of 250,000 rooftop solar systems and can power 75,000 to 100,000 homes for as long as that generation rate is maintained, the researchers said.
A typical home uses 11,000 kilowatts per year.