Hey Mr. Green,
I've contacted my power company and switched to 100 percent renewables. Is it still important to keep up with other energy-saving practices in my home? --Kelly in Sussex, Wisconsin

Mr. Green answers:
Darn right you should keep saving energy, for three very simple reasons: First of all, even if an energy source is renewable, that doesn't mean it has zero environmental impact. Windmills and solar panels require all sorts of potentially polluting industrial processes (and energy) to manufacture. Some windmills can also mangle birds and bats, hydroelectric dams drown big tracts of land, and growing crops to use as biomass can have serious drawbacks in the heavy demands it makes on the soil. So it makes sense to use these more benign sources as efficiently as you can.

Second, signing up for renewable energy doesn't necessarily mean that wind-powered current is actually buzzing from some turbine in the boondocks straight to your digital toys. Even though you've agreed to pay the utility company the extra money it needs to buy renewables, which cost more than conventional power, those more virtuous electrons might be going someplace else on the grid.

Finally, since it will be a long time before we have a surplus of kinder current, we should spare as much as we can for other concerned enviros. Oh sure, some economic wizards will probably claim it's good to squander renewable power because it'll increase demand, unleashing free-market forces that will spur power companies to invest more in renewables, blah, blah, blah. But since it was exactly such enthusiasm for squandering that got us into our energy mess in the first place, you may safely ignore such arguments.