A large solar array in Westboro, who knew?
I am now an expert on solar power. A few nights ago I listened to a few talks about it, so there. Here are a few things I now think I know.
Solar panels cost has declined, sure. But what about other costs? Not so much. There are lots of other costs: framing, the installation, permitting, financing, site selection, the transaction costs to move power back into the grid, getting your tax rebate, political uncertainties, maintenance, the control electronics, the power-inverters, etc. etc.
For example there was a period a few years back when the price of panels rose, people who built arrays during that interval are a bit cranky about that. For example in my state the tax credit pool is draining out so the current boom is coming to an end. I was quite amused by one person’s complaint about how hard these projects are to get past a New England town meeting. That’s was principally about risk and financing.
So, coordination and other harder problems have come to dominate the industry. The cost decline of these systems is leveling off. This is why you see these efforts to build arrays using robots.
All that makes large projects much more effective v.s. small ones. We have done a lot of projects here in Massachusetts over the last few years, and it’s employed a lot people. But reading between the lines I get the impression that many of those jobs were on little projects where the costs were disproportionately in the coordination costs.
Hot water? It was interesting to see the experts react to a question about solar water heating. They sort of did a collective sigh. Apparently a system that has moving parts and fluids is a pain. I guess that goes to explain why they are so rare. Most of my neighbors have little solar garden lights, none of them have solar heating of any form.
And yet, I look forward to steam-powered garden gnomes.
The first use of solar power is getting off the grid. That’s why solar garden lights are a good idea. But that doesn’t tell you anything about photovoltaics and water heaters. And I don’t think your neighbors are good evidence about what is cost-effective. People install photovoltaics because they are cool, not because of a cost-benefit calculations.
Yes, plumbing makes water heaters difficult, but everyone already has to deal with plumbing. I wish there were more detail about this. But people don’t have to deal with plumbing on the roof.
My uncle looked into using solar heating for his pool, because he has a spare roof near it. It’s inessential, so if it broke he could put off going on the roof. And he wasn’t going to throw out the old heater. I think the main reason he didn’t was that would require more precise pH control to avoid leaching copper. He’ll probably do it with PVC eventually, but it will be a lot less efficient.
I recently heard the claim that photovoltaic + heat pump is more energy efficient than solar water heating. I rather doubt it’s a better investment at this time. But if it, and everything else I’ve heard about heat pumps is true, why don’t people use them for their hot water, rather than burning gas?