The Budge Prime Minister David Cameron, when he was leader of the opposition, is trying

to get elected. He wanted to convince people that he was a soft-carrying guy and he installed

a little windmill on his house.

Tim Hartford is an economist and writer who lives in London. His first book was called

the Undercover Economist. His latest is Adapt and it's about how success often starts

with failure. Now it turns out wind power can be pretty effective but you need a really

really big windmill and a really windy location to be efficient. These little windmills, especially

in an urban environment where you don't get a consistent flow of wind, they generate

an incredibly small amount of energy, really really ineffective. Indeed there's a fantastic

example from the British physicist David McKay, who points to building top windmills in

Japan that actually have little electric motors in them to keep them spinning around. Because

otherwise they would look really stupid on top of the building and not actually moving.

These windmills actually cost energy.

From APM American Public Media in WNYC, this is Freakonomics Radio. Today, hey baby,

is that a Prius you're driving? Here's your host, Stephen Dupner.

You will know that David Cameron did get elected Prime Minister of the UK. Now whether

is little windmill had anything to do with it? Tough to say. But while it may not always

be easy being green, these days it's certainly attractive. Roof top windmills, those I am

not a plastic bag, reusable shopping bags, and a certain make of automobile.

That's from the TV show South Park. Poking fun at how some people get a little sanctimonious

when they start driving a hybrid car. In this episode, the car is called a Pius. A little

bit like a Prius maybe. The message is clear. Helping the planet is nice, but being seen

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