Solar Power for Home Use: The grid connection
There was a big push recently in several Connecticut towns, including the one where I live, to encourage residents to install rooftop photovoltaic systems. The program, called Solarize Connecticut, involves a coordinated marketing, education and outreach effort along with a pricing structure that reduces the cost of the systems based on the number of people who sign up. Installing solar had been on my “must look into” list for some time, so I attended an informational session with about 30 other people to find out more.
Aside from the financial structure of the program, many of the questions raised by residents dealt with the relationship of their PV system to the local power grid. They wanted to know how it was connected, whether they would still be able to use power from the grid, how much money they might save, and whether they could count on their solar system to keep the lights on and the refrigerator running when the grid went down. (The answer is no, by the way.)
Those questions prompted me to look into the workings of grid-tied photovoltaic systems in the June/July issue of Fine Homebuilding. Grid connections are a big part of what has made solar power for home use practical-and increasing popular-in the last few years. (The other factor is the declining price of solar components, making it a near no-brainer for those with a serious commitment to energy efficiency.) Tying a home solar system to the grid eliminates the need for expensive storage batteries and, with net-metering arrangements, makes it financially viable for a homeowner to produce some of his own electricity.
But the economics of grid connections are getting tricky. Utilities are complaining that net-metering forces non-solar customers to bear a larger share of costs associated with maintaining the grid that all customers rely on to some degree. As a result, net metering arrangements have been altered in some states and surcharges added in others. Still other localities are experimenting with a “value of solar tariff” (VOST) model that sets a specific value for solar-generated electricity that’s sold back to the utility. But the path here is not clear, either. Minnesota adopted a VOST in April; within a month, the state’s largest utility asked the state to reconsider the move.
The disparity in home-solar adoption rates between areas that allow net metering and those that don’t makes it clear that how home solar power is valued has everything to do with whether it is embraced. If the rules continue to change, that will make efforts to convince homeowners to adopt solar power for home use all the more difficult.
Drawing: John Hartman