I'm always genuinely shocked to read about how much electricity appliances consume when they're off but still in "standby" mode—TV sets, especially, which stay undead after you turn them off so that they can be clicked back on with a remote. Here are some numbers from this Wall Street Journal piece: In Europe, unused appliances in standby mode account for 10 percent of total energy use (about $9 billion per year, down the drain); in California, it can reach 26 percent in homes with a disproportionately high number of TVs, DVD players, printers… All told, about 1 percent of global greenhouse gas emissions come from machines that aren't being used.

Trouble is, much like killing a vampire, it's tough to truly turn an appliance off—usually you have to unplug it, and even people aware of how much they can save by doing so either forget or just succumb to laziness. And, sure, TV makers could easily produce sets that switch off for good, but most people like the convenience of remote controls and not having to wait for an appliance to go through its start-up routine every time it's used (also, some appliances, like set-top boxes, need to be running continuously to work). So now European governments are trying to put in place standards on how much power standby appliances can consume, but, even more promisingly, one Spanish inventor claims to have "definitively" solved the problem by devising a new chip that can be placed in appliances to essentially emulate standby mode without using any power. It's still unproven, but it would be an elegant solution if it works—and an easy way to knock off a whole bunch of emissions.

--Bradford Plumer