Solar array on MassDOT Highway Division office property in Northampton, MA. MassDOT photo
George Harvey
All solar photovoltaics (PVs) have one very special characteristic. While they only produce electricity during daylight hours, they also produce at just the time electricity demand is at its highest. This is particularly important because they replace the most expensive electricity we have with the cheapest electricity available. But also, small, “behind the meter” (BTM) solar power also reduces the peak load of electricity transmitted during a year, and that reduces the transmission costs for all of New England’s electricity customers, all the time, day and night, all year. This part of the energy mix includes any PV system that is grid-tied but does not participate in the grid market. The owners of such systems are called “prosumers” because they produce and consume grid electricity. They use their own power much of the time instead of sending it to the grid, so usually there is no record of how much was generated.
These savings, as important as they may be, are not the end of the story. Solar power replaces grid power that would be generated from fossil fuels, and that reduces societal costs, such as those relating to healthcare and climate change. BTM solar plants increase the tax bases for some communities, saving other taxpayers money. And they offer employment, an additional benefit.
Because of these savings, everyone benefits from the addition of BTM solar PVs, whether they go on a factory rooftop or in someone’s back yard. The big question a lot of people might have is, “How much?”
The cost benefits of BTM solar power are not easy to calculate. It would be hard to guess how much solar power has reduced costs in the New England states, but now we have a resource that explains it. Synapse Energy Economics (SEE) has published a report, “Solar Savings in New England,” which examines the effects of BTM solar power in the six New England states over a six-year period, including the years 2014 through 2019 (). The savings are impressive.
Just from BTM solar power alone, New England electricity consumers saved $1.1 billion during the six-year period. Of course, the largest share of that went to the owners of BTM systems. But as we have seen, these systems reduced grid costs and transmission charges during peak periods, so a significant share of the savings went to every ratepayer.
The SEE report breaks down the cost savings for each state over the six years. Connecticut saved $260 million. Maine the least, at $68 million, and Massachusetts saved the most, at $513 million. New Hampshire saved $83 million, Rhode Island saved $58 million, and Vermont saved $79 million.
While the savings for states varied to a degree by population, they also varied according to the amount of BTM solar capacity installed. We note that the greatest saving per person was for the state of Vermont, where savings came to $126.60 per person over the six years. If that seems a small amount, remember that this is not utility-scale solar, it is BTM solar, largely on people’s rooftops and in back yards. Also, it represents the average of all savings, including everyone who does not have a PV installation. In other words, the small solar systems a few of us own are creating a significant positive impact for everyone. And that is a big story.
Another aspect of all of this is that the benefits of PVs do not end with the prices for electricity, and BTM systems save in ways that are not represented in the data we just saw. The SEE report addresses these in its coverage of two important areas. One is healthcare. Based on data from an EPA assessment of healthcare impacts during the same six years, the SEE report concludes that BTM solar saved New England residents $87 million during that time.
Savings from offsetting carbon emissions are much harder to calculate. We can take any of a number of costs of these emissions. The SEE report makes this clear, and cites three numbers for savings. They range from a low of $515 million to $1,948 million.
Combining these numbers still does not tell the whole story, but it does put a value on the modest solar arrays we see around us. Taking the lowest savings values, they are pushing $300 million per year for New England. With the highest values, they would be worth well over of $520 million.
Generally speaking, BTM systems are small. But taken together, they are significant in big ways.
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