Solar and Wind as Distributed Generation Will Power Our Future Grid
Solar is available everywhere and wind (in more places than you thought) to supply distributed generation to power a more renewable grid.
The image above shows solar PV panels, wind turbines, and high voltage transmission lines in the same photo. We are on the path away from centralized generation plants feeding high voltage transmission in a kind of hub-and-spoke distribution system. The new description for this change is called distributed generation, meaning that the means of producing electric current (and transmittable high voltage) is spread among many locations within the grid. And in keeping with California’s regulatory policies, an increasing portion of this is to become renewable electric generation from sources like solar PV (photovoltaics) and wind turbines (33% by 2020).
The least dense and far-flung deployment of solar PV is individual rooftops on residences and other small buildings. The largest generation of electricity at the outer reaches of the grid (at least in California) has been utility or government-built hydroelectric generating stations that capture the kinetic force of water under gravity’s influence to spin hydro-turbines of various kinds. But most of the best hydro sites have already been built, and political and social resistance keeps more river canyons from being plugged with hydro facilities. You could attempt to make the same argument about locating wind turbines—almost.
That’s because the canyons and mountain passes with the best wind are already festooned with small-to-medium turbines. However, there’s a rich resource right off California’s coast, and offshore wind is already well developed in Europe and has now begun off the coast of Massachusetts.
On a summer day when the mid-day wind velocities inland are more than a bit lazy—look off the coast. Winds are uniform and very brisk, at up to five times the velocity of those inland.
Historically, we’ve focused inland because it was close and easy. Offshore is another matter. But it’s been accomplished by the setting of turbines in shallower ocean water with direct foundations, and by floating turbines anchored with line anchors in much deeper water. The turbines for offshore use have also gotten bigger. Much bigger. Six megawatt turbines (that’s six million watts) are becoming common and eight megawatt units have also become commercially available.
It’s always good to remember that winds are intermittent and the sun doesn’t shine at night or very well during storms, but industrial grid storage strategically located within heavy use points on the grid are erasing that problem at a brisk pace. It should also be remembered that geo heat pumps are the only technology that can heat and cool buildings and provide hot water by the use of increasingly renewable electricity and a connection with an underground renewable thermal resource.