N.H. solar power is still on the light side


Spring is here and the sun is shining – well, mostly – so let’s talk about solar power.In a way, there’s a lot of it to talk about. The state’s net-metering program, which basically lets homes sell any excess power from wind or solar systems back to the utility, has 265 photovoltaic installations (making electricity from sunlight) with an installed capacity of 787 kilowatts. Combined with a scattering of projects completely off the grid, plus a handful of bigger arrays, that puts New Hampshire’s total solar power close to the magic megawatt level — a psychological mark that indicates we’ve moved beyond the hobbyist level.another viewpoint, however, that’s not much to talk about. New Hampshire used a peak load of 2,241 megawatts last year, so solar power handles, at best, less than a 20th of 1 percent of our needs.The problem isn’t our climate. Massachusetts isn’t exactly the Gobi Desert, yet that state’s solar rebate program has issued awards for 23 megawatts in the past two years, and recently boosted its net-metering law so it can handle large systems.While New Hampshire is doing OK adding small photovoltaic sites, usually 5 kilowatts or less on a single rooftop, it lacks big ones. The 51-kilowatt array on PSNH’s Manchester headquarters and 50-kilowatt array on Stonyfield’s headquarters are the biggest we’ve got, but they’re puny compared to the Brockton Brightfield, a 425-kilowatt site built two years ago on an abandoned “brownfield” in Brockton, Mass., or the 500-kilowatt array that Harvard University just opened atop a former factory in Watertown, Mass.Those will be eclipsed soon by several megawatt-level arrays in Massachusetts, including one built by an electric utility next to its own transmission station, avoiding expensive power lines, and several planned by municipal governments.All those require subsidies from local, state and federal governments because solar power is still far more expensive than power from coal or natural gas plants. Even though fuel is free and maintenance is minimal, solar panels remain so expensive that photovoltaic power is still two to four times the dollar cost (although not environmental cost) of burning fossil fuels.That’s partly because it’s inefficient. On average over the course of a year, due to nighttime, clouds and the like, New England photovoltaic panels can expect to produce 13 percent of their maximum theoretical output, compared to at least 60 percent and usually 80 percent or more for traditional power plants. Nuclear plants often top 90 percent.This means you need at least four times as many kilowatts in a solar array to match the overall power produced by a similarly “sized” hydropower dam, wood-fired power plant or natural gas or coal plant.Solar hot waterIn real-world applications, photovoltaic arrays can do even worse. PSNH’s headquarters facility, which went online last July, produced a little over 9 percent of its theoretical output between August and March, including almost nothing in December.“Much of this likely was due to the fact that the panels were snow covered in December and January. We did not clear the snow (that was never intended),” wrote PSNH spokesman Martin Murray in an e-mail response to my query.PSNH certainly would clear snow off the large array it wants to build atop the closed Manchester landfill. This site would at least double the state’s total solar power in one fell swoop, producing between one and five megawatts, but is controversial for financial rather than environmental reasons. PSNH wants to use some of the money it is supposed to add to a state-controlled renewable energy fund, where it would be available to any company.Opponents say this would choke off a major source of money for the alternative energy industry while PSNH says it’s the best way to get utility-scale solar power going quickly. The state legislature is pondering a bill giving PSNH access to $5 million worth of funds for it.Meanwhile, there’s the other type of solar power: using the sun to heat water, which is far more efficient than using it to create a stream of moving electrons.The state has just begun offering rebates for solar hot water systems through its Renewable Energy Funds, to go along with the rebates it has long offered for solar photovoltaic systems. The rebates run from $600 to $900, depending on size, plus there’s a federal $750 rebate that has long been offered.These systems cost much less than photovoltaic arrays – as little as $2,000 – so rebates can really make a difference.The state hopes to make rebates available for larger “commercial-scale” renewable energy systems this year, a move that could help boost our photovoltaic profile.And while we’ll never be the Northeast’s version of Arizona, I look forward to the day when glassy boxes on rooftops, whether heating water or creating electricity, are so ordinary we don’t notice them. — DAVID BROOKS/THE TELEGRAPH