[simonh]

You said:

>Imagine power plant stack exhausts channeled through this technology

What's I'm saying is, if you have spare energy available to power the converter, you're better off reducing the hydrocarbon power plant output and replacing that output with your 'spare' energy supply. Doing so would be dramatically more efficient.

The only case this doesn't apply is if there is no way to substitute your spare available energy for the output of the hydrocarbon plant, but I can't think of such a situation, at industrial scale, off the top of my head.

[ossie]

Ok, I understand where you're coming from, and its a logical argument. However, a lot of fossil generators (esp coal) are baseload plants that stay running for system reliability. They might stay running during off-peak hours when the output is barely needed, just to ensure availability during on-peak hours. In those cases, you can't tweak output to match variable renewable energy output.