It was a hot and sunny month. … No, this isn’t the opening line of a bad novel; it’s a story about electricity and climate change, and our backyard solar array.
July was indeed hot, which means it was a costly month for electric generation. When the heat index pushes over 100 degrees, and homes and businesses run their air conditioning full tilt, utilities have to purchase more expensive power, from less efficient generating stations, to meet the higher demand. Their costs, and the costs for every consumer, go up.
But here’s the good news. It was a sunny month, which means all those solar arrays at farms and businesses and in people’s back yards were generating power at a great rate. The recently installed array at our home generated 1,749 kilowatt hours of electricity from late June through late July. That was 510 kWh more than we used, for which we received a $14 credit from the utility. (When I use more electricity than I generate, I pay over 12 cents per kWh for the extra; when I generate more than I use, the utility pays me 2.8 cents per kWh.)
But all of that electricity we generated meant that the utility needed to purchase 1,749 kWh less power from the grid, power that was more expensive than average. That savings equates to about the amount of electricity used by two average residential customers in a month.
In the last session of the Iowa Legislature, MidAmerican Energy pushed a bill that would allow them to charge an extra monthly fee to future solar generators, people pretty much like us. That fee would have been enough to make installation of solar unattractive to many, which in turn would have devastated the growing solar installation industry in the state. Their rationale: People like me aren’t paying their share of costs for using the utility’s transmission facilities to sell our home-generated power back to the utility.
Every month I pay a $13.50 “facility charge” regardless of our usage or solar generation. The Iowa Utilities Board, which has to approve all changes in rates proposed by Iowa regulated utilities, is scheduled to undertake a study to see if these kinds of facility charges appropriately reflect the utilities’ cost of accommodating solar generation. But MidAmerican’s proposed bill would have pre-empted the normal rate-setting process with the utilities board and imposed the new fee by legislative fiat before the study was even undertaken to see if any fee was justified.
In pushing their bill, the utility or some unidentified group, sponsored TV advertising to try to get the average Iowan riled up by convincing them that they are subsidizing solar users.
But here’s the thing: Iowa is a summer peaking state. Despite the longer winter heating season, the summer air conditioning season is when electricity usage hits its daily or hourly maximum. All utilities use their most efficient, lower cost generating facilities first, and bring the higher cost facilities on line only when needed. So those high-cost facilities are brought into use just when solar power is doing its thing, when the hours of sunshine are greatest. That reduces the need for that high-cost power, which helps all utility customers.
More importantly, those summer peaks are likely to get worse as climate change worsens. Solar power not only saves on current generation of high-cost power; it reduces the need for future generating capacity by helping to reverse the trend of global warming. That is good not just for electricity consumers, but for the planet and for our grandchildren.