Are Power Grids Ready for Solar?
G.E. and Arizona’s biggest electric utility are working together to answer a crucial but sometimes overlooked question concerning the future of solar power, even renewable energy in general – how the power grid can be prepared for more and more electric capacity that is not produced from fossil fuels.
In a pioneering effort, G.E.’s researchers and the Arizona Public Service Company will study how grids are affected by huge volumes of solar power fed into the electricity distribution network.
With four other partners, G.E. will then identify methods and technologies to optimize grid reliability and efficiency as it experiences higher concentration of distributed solar generation.
“Much of the focus has been on new [solar] cell developments and system improvements to make solar more cost competitive,” said Kathleen O’Brien, project leader for G.E. “But the larger question is how to reliably integrate the higher penetrations of solar power expected.”
In Flagstaff, Arizona, 1.5 megawatts of solar energy sourced from different types of solar installations will be integrated into the local distribution area.
About 600 kilowatts of that capacity will come from residential photovoltaic rooftop installations. Five hundred kilowatts will come from a utility-scale solar park, and 400 kW will be from solar units on commercial business properties.
The study will use G.E.’s solar inverters that convert D.C. electricity to A.C. and its suite of solar plant monitoring and control devices that will coordinate the operation of the entire solar system so that they could perform like a single conventional power plant. A full report of the study will be released in 2013.
The study is timed with a generally positive outlook for solar within the entire energy market. According to New Energy Finance, demand for solar energy has grown by about 30 percent per year over the past 15 years, while demand for traditional sources of energy has grown by less than 2 percent yearly.
The trend is expected to continue as the industry’s cumulative annual growth rate is projected to rise as high as 41 percent through 2012, nearly double wind power’s 22 percent.
In the United States, solar installations are expected to exceed 6,000 MW by 2010, more than triple the country’s installed capacity two years ago, said the Department of Energy. Sunny Arizona is one of the country’s leaders in terms of solar growth.
As solar power, still largely a novel energy source, along with other renewable energy sources gain traction in the energy market, it is expected to put more strain on the world’s power grids. The reliability of future power grids is crucial for renewable energy sources to make a much bigger contribution to a country’s overall energy portfolio.
Concerns over solar electricity’s effects on the grid could not have arisen had there been no growth in the sector. Previously, it was the enormous power capacity from the wind sector that was a concern for the grid.
This has happened in China, where the Inner Mongolia Power Company has warned that its renewable electricity generated by wind is being wasted due to insufficient grid capacity. G.E., in fact, originally designed the inverters it will use in the Arizona study to be capable of integrating large amounts of wind power capacity.
Tian Shuping, the company’s development and planning director, said that the pace of construction of the power grid simply could not keep up with the growth of wind power in the region.
Wind turbines in Inner Mongolia presently have a capacity of 7.05 gigawatts, while an additional 3.25 GW are under construction. However, less than 2 GW of wind power goes into the power grid, while the remaining 8.3 GW of wind power is yet to be connected.
Si Jun, Inner Mongolia wind power project manager of China Datang Corporation, said a power grid must have more than five times the capacity of wind power generated to avoid overloading due to the unpredictability of wind conditions.