Is the green energy future big or small?
Should the taxpayers and utilities be investing hundreds of billions in new heavy-metal infrastructure to transmit renewable energy to big cities from massive centralized installations in the windy Midwest and the sunny Southwest?
Or does a real green energy future look a lot more locavore , with a patchwork of publicly financed rooftop solar, small-scale wind, microhydropower, wave buoys, biogas and battery power, woven together with sophisticated software management, allowing each region to be self-sufficient?
The answer probably falls somewhere in between. But this is just as much a political debate as a straight-up technical policy question. Basically, existing utilities, which have regional monopolies and make money from transmission as well as generation, want to borrow more money to build thick lines and big green power plants, and then have the public pay it off for years in their electricity bills. State governments like Arizona and Kansas are into this idea too because they want to sell their power to other states.
Yesterday, the folks who control the Midwest grid released a proposal  that put the cost of sending Midwestern wind power to Northeast cities at $50 to $80 billion. But Northeasterners aren't so sure this is a great idea. They might buy wind from Canada instead. And the Midwest still produces a lot of coal power too, which the Northeast doesn't want (once you get electrons pumping through the grid, it's hard to separate them out by origin.) Basically, they want local control over future decisions about their regional power mix, which is hard to do once you start investing in huge facilities.
Consumers should have a say in this debate too. Not everyone wants to go off the grid and produce all their own juice. But as we move toward a low-carbon future that relies on multiple, variable energy sources, we should be wary of sinking big capital into single-source projects that look an awful lot like the old "fires and wires" model.
Image: A 3KW Micro-hydro-turbine from Run of River Hydro Power.