The mushrooming growth of rooftop solar systems is a good thing for the environment and for the overworked electric grid. However, in places like California, where there are now an estimated 150,000 such systems, utilities face a new kind of problem.
California’s rooftop solar arrays amount to a generating capacity of 2.7 gigawatts, the equivalent of several nuclear power plants. For utilities, this is like several large power plants they don’t own and can’t even monitor. For the most part, the only information the utilities receive is the net flow (in or out) from the customers’ meters, which depends on what they are generating as well as what they are using at the time.
This situation creates problems for utilities who need to plan for distribution, allocate resources, and perform upgrades to local facilities as needed. With a growing fraction of generation resources out of their control and out of their sights, this becomes more difficult.
Right now, California utilities are making use of various solar forecasting services to try to get a handle on what is likely to be produced by the solar installations in their region. But this modeling can only predict the generation on an average basis. It is not real-time data.
In Germany, where solar installations have been a major enterprise for years, the solution has been to use smart inverters, which report production data directly to the utilities. With more and more people generating their own power, our utilities will need new tools to manage the grid.
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Web Links
California’s Invisible Solar Problem
http://www.renewableenergyworld.com/rea/news/article/2013/07/californias-invisible-solar-problem
Photo, taken on September 27, 2011, courtesy of Flickr.
Earth Wise is a production of WAMC Northeast Public Radio. Support for Earth Wise comes from the Cary Institute of Ecosystem Studies in Millbrook, NY.