Imagine that a chunk of coal's got 100 units of energy. Out of those 100 units, 98 get lost on the way to powering your light bulb. A whopping 2 end up as light. Not exactly efficient. So what happens to our theoretical energy units?

Well, 62 get lost before they even leave the power plant, 2 are lost in transmission, and another 34 are squandered as heat cast off from your light bulb. Which means, essentially, we're using a crapload of coal to get a teensy bit of light.

This approximation explains a lot, and is highly effective in pointing out the shortcomings of our current energy infrastructure. The figures come from the Galvin Electricity Initiative's book Perfect Power, and they illustrate how ineffective our current combo of inefficient coal plants and inefficient light bulbs really is.

Bottom line is, we're wasting a lot of electricity, and pumping a lot of carbon into the atmosphere. And even though coal companies fight the prospect of climate legislation tooth and nail, there's a lot coal companies could be doing to retrofit their plants with more energy efficient technology to bring their pollution levels down and productivity levels up?without even immediately ceding to renewable energy technology.

And as for us—we can be buying more efficient compact fluorescent light bulbs to help bring down the 34 units we're responsible for.

Thanks to the tip from Dave Roberts.