Friday, October 9, 2009

It’s the Batteries, Silly

There was an article on Reuters a couple of days ago about Dow’s new photovoltaic roofing shingles. On the one hand, this is pretty cool. I mean, putting the means of production (of electricity) into the hands of the people is a pretty revolutionary concept if it can be done with sufficient efficiency and cost-effectiveness to make it a true improvement over (or addition to) the current system (get it – the current system? Ha! I’ve got a million of them. Well, no, mostly I just have that one.). But it’s not without its challenges.

For starters, the new Dow system is currently even less efficient than the traditional photovoltaic plates we’re used to seeing, and those are only around 15-20% efficient to begin with. In the physics world, efficiency is all about waste (or lack thereof). If you have a 100% efficient system, it converts energy from one from to another with no waste. On the one hand, you might argue that we “waste” the sun’s light and heat energy all the time, and we usually “waste” all of it by not converting any of it into a more useful energy. So by that logic, converting even 10% of it is a vast improvement. But it still strikes me as a technology that’s ripe for dramatic improvements, probably fairly soon. At which point, early adopters are likely to wish they had held off a bit.

Next, this technology isn’t for everybody. You need an unobstructed view of the sky, and preferably a direct southern exposure. If you’ve got trees or telephone poles or a neighbor’s house or a hill between your roof and the sun, solar power becomes a pipe dream pretty fast. Though surprisingly it can still work reasonably well even in places like Syracuse where the skies are often overcast and the roofs are often covered with snow. I mean, no it doesn’t work so well when the roof is actually covered in snow, but that doesn’t truly happen all that often for most people, or last that long.

No, the biggest issues I found with this system were retaining the charge and maintenance. Both were complex and expensive and scared me off of a $22k+ investment that might (or might not) have achieved ROI in 5-10 years. The system can’t necessarily be maintained by a layman, or even by an electrician who isn’t totally well-versed in solar-cell technology. So now you’re beholden to one of the (relatively few) solar-power contractors whenever your system needs service or routine checkups. But the biggest challenge I saw with photovoltaic technology as it exists today occurs if you really want to go “off the grid” either temporarily or permanently.

For me, I really wanted solar power to just reduce my electric bill 99% of the time by generating power and “selling” it back to my local power company to be used as “credit” when I bought back electricity from them. If I produced more than I used, they’d actually pay me money for it. But for that other 1% of the time, I wanted solar power to keep my lights on and my electronics running during a power outage. And for that, you need some way to store your electrical charge locally so you can draw off it when the sun is down. That way, until somebody invents another one, involves batteries. Lots of them. Big ones. And they don’t necessarily hold their charge all that long. A couple years isn’t an unusual lifespan for these batteries, I was told. Maybe you’d get 5 years out if them if you’re lucky. But as part of your regular maintenance on the system, those batteries need to be replaced when they’re no longer working well. And that entails ongoing expenses I wasn’t happy with.

Which is why I keep coming back to batteries. Batteries, batteries, batteries. The key to human technological evolution is going to be in how we store and release electrical power. Batteries need to get smaller, they need to hold more, they need to cost less, and they need to do all of this reliably for a long time without that annoying tendency they have of gradually losing capacity until they won’t hold a charge at all. Electric cars and solar homes all need good batteries before they really come into their own. I think it’ll be a great day for humanity when that happens, but I fear it’s not as close as it sometimes seems.

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