Sunday, January 11, 2009


[Photovoltaic panels] are great at capturing the sun's energy. But Languell says it takes more energy to manufacture and transport a panel "than it is ever going to produce over its useful life."
Read more in Housing industry a good environment for eco-friendly claims.


  1. I don't think that's true - even in 2000, the "payback period" was only around eight years - see this paper, and I believe it's got shorter since. Ecogeek says this is a myth probably started by solar panels created for NASA.

  2. Rebekka is correct. I hadn't realized how much more efficient the production of PV has become.

    However, as the paper in her link explains, PV systems degrade more quickly in maritime climates. Maritime climates, such as ours, are also cloudier and the panels will produce less energy.

    Even if it were a wash energetically and economically, I am inclined to install them on our house just so that we have a source of electricity when LA experiences summertime rolling blackouts or we have a disruptive disaster.

    Solar thermal makes both economic and environmental sense. I am surprised so few new homes have them. I am also surprised that the governator wants to require new homes to have PV but not solar thermal or clotheslines. That's another case where people are more infatuated with technology than the tried and true.

  3. Anonymous07:30

    The author of the LAT piece is guilty of "overbalancing", I think. Insulating foam is great, he says, "but no mention is made of the fact that it is fossil-fuel-based", as if this were some great journalistic gotcha. The fossil-fuel content to retrofit an entire house with blown-foam insulation is measured , I'd estimate, in gallons, or at most tens of gallons. To recover the labor costs of getting foam put in your house might take a few years, and as for health effects of volatile fumes in your house while the final drying takes place, I'm agnostic (but if the installation at the beginning of open-window season in your climate, you can have several months of volatile-free drying.) One thing for sure, though, is that the fossil-fuel payback time for retrofit foam will be only months, or even weeks, once the weather turns harsh.
    The net effect of aggressively "balanced" articles like this one is to leave the uniformed with the impression that there's no point in doing anything, ever, because at the end of the day, everything sucks.

  4. Eric also makes a good point. But, certain individuals with chemical sensitivities may not be able to tolerate the off-gassing from blown foam insulation.

  5. Usually if you have a grid-connect system it won't work during blackouts, as the inverter shuts down to stop things being damaged - you'd need battery backup to keep the power on during blackouts, and that makes a system much more expensive.