March 14, 2009

How expensive is the wind power needed to eliminate coal??

In my previous post, I said we could build enough wind capacity to replace coal for $400 billion. Coal supplies half our electricity - can we really do that?

Sure. Here's how I came up with that number:

The US generates about 50% of our electricity from coal, which amounts to an average of 220 gigawatts. Wind, on average, produces power at 30% of it's nameplate rating, so we'd need about 733GW of wind. Wind costs about $2/W, so that would cost about $1,466 billion. Transmission might raise that about 10%, to about $1,613 billion.

Now, roughly 50% of coal plants need to be replaced in the next 20 years, so about 50% of the $1.6T coal replacement investment is needed anyway; new coal plants are just as expensive per KWH as wind, so that half, or $800B of the investment can be eliminated from our considerations.

Coal plants cost about $.035/KWH to fuel and operate, which is about 50% of the cost of wind. That's an expense that we'll have either way, so we can eliminate 50% of the remainder, which is about $400B: all told, we can discount the wind investment by 75%!

Wind's intermittency is often raised as another source of cost: I address that here.


So, that gives us a cost of roughly $400B, or $40B per year for 10 years. That's about 5% of US manufacturing (less than the currently idle manufacturing capacity!), and .3% of GDP.

A bargain.

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