[Retric]

what infrastructure will be useful in 20 years

I expect we will still have wind in 20 years and using infrastructure to turn wind into electricity seems obvious. The other real advantages to wind farms is you get energy sooner and it is simpler to scale exponentially. AKA 1billion wind farm = 50 mil profit and next year you have 1.05 billion wind farm which makes a 5.25 million profit so you now have a 1.125 billion wind farm next year... You can do similar things with debt financing, but that's higher risk.

Not to mention a smaller Not In My Back Yard problem. I consider oil mostly a done deal, we are going to burn most of the cheep oil because it's just so useful. But there is far more coal luckily it's far simpler to replace coal power plants than oil in cars / boats. We are also close to the tipping point where the free market is going to switch to wind on it's own, because it's cheaper.

[nazgulnarsil]

if "green" energy was profitable why would you need to subsidize it? people would do it voluntarily.

[Retric]

The profit from "green" energy needs to exceed the interest on the loan it takes to build it. Today the loans are still slightly more costly than the profit. It's like 5.9% profit vs 6% cost of a loan. The math get's complex as you need to take into account inflation, the rate of depreciation of your assets, and taxes.

This magnifies the amount of wind farm you can build today. If you had a billion and wanted to donate it to "clean energy" then you could get a loan for 5 billion in wind farms and use your billion to make up the difference. By the time the loan was paid off you would still have some money, but far less than if you had invested it well.

If on the other hand you a billion dollars and built a wind farm without borrowing money then you can keep expanding indefinitely. You would still have less profit but there would be little risk.

PS: With subsidy it is profitable today which is why we are building so many wind farms, but that's just the government handing out money.