<rant>I posted this twice to the storage section. It was deleted twice from the storage section. I don't know whether the editor who keeps deleting it has stocks in battery companies or is just determined to relegate wind power to niche applications, but it's getting old.
</rant>
I made up a little spreadsheet to calculate the optimum mix of battery/hydrogen/methanol storage for various price points and usage scenarios.
Basically, the idea is that, while hydrogen and methanol come with large losses, it is cheaper to build more windmills to make up for those losses than it is to buy batteries. Also, since hydrogen and methanol production have high fixed capital costs, cost-effectiveness goes up with capacity. Methanol, for instance, can be cost-effective as a long term storage medium when also used for transportation. With cheaper hydrogen storage methods, hydrogen can be as well.
This calculation makes a couple of assumptions for simplicity, like 100% battery efficiency, dual-fuel (hydrogen/methanol) backup generators, readily available water for hydrogen and CO2 for methanol production, and averaged windmill output. I put in some values for what I think will be my typical uses. I'm sure you guys can come up with more realistic prices and usage scenarios than I can, so here it is:
http://www.deesconsulting.com/personal/methanol_storage.xls
