- Category: Renewables
11 Dec 2012
- Published on Tuesday, 11 December 2012 07:47
- Hits (2933)
Renewable energy could supply power to an entire large electric grid, according to a new research by the University of Delaware and Delaware Technical Community College.
“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 U.D.’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,” he stressed.
When wind energy, solar energy and fuel cells are combined, they could deliver power as far as 99.9 percent of the time by 2030, at costs similar to today’s electricity costs.
“For example, using hydrogen for storage, we can run an electric system that today would [meet] a need of 72 gigawatts, 99.9 percent of the time, using 17 GW of solar, 68 GW of offshore wind, and 115 GW of inland wind,” said study co-author Cory Budischak, instructor at the energy management department of the Delaware Technical Community College.
A “gigawatt” is a measure of electricity generation capability and 1 GW is equivalent to the capacity of 200 large wind turbines or 250,000 rooftop solar photovoltaics. “Renewable electricity generators must have higher gigawatt capacity than traditional generators, since wind and solar do not generate at maximum all the time,” the researchers noted.
A computer model was developed to test 28 billion combinations of renewable energy sources and storage mechanisms over four years of historical hourly weather data and electricity demands. According to the researchers, this model incorporated data from within a large regional grid called the PJM Interconnection, which covers 13 states from New Jersey to Illinois and represents one-fifth of the United States’ overall electric grid.
Significantly, it focused on reducing the costs instead of the conventional approach of matching generation to electricity use used in other studies.
From this, researchers found that producing more electricity than needed during average hours – in order to meet needs on high-demand but low-wind power hours – would be cheaper than storing excess power for later high demand. Storage is relatively costly given that storage medium, batteries or hydrogen tanks, must be larger for each additional hour stored, they noted.
The study used technology costs projections in 2030 without government subsidies, comparing them to current costs of fossil fuels generation in wide. The cost of fossil fuels includes both the fuel cost itself and the standard external costs like human health effects brought by power plant air pollution. Moreover, the estimated capital costs for wind and solar in 2030 are nearly half of their costs at present, while maintenance costs are estimated to be more or less the same.
“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,” said authors of the study. – C. Dominguez