At Nanosolar, we believe very much that meaningful scale for solar will come foremost from utility-scale solar power plants, in particular from municipal solar power plants of 2-10MW in size. These are rows of solar panels mounted onto the ground of free fields at the outskirts of towns and cities, feeding power directly into the municipal electricity grid.
A 2MW municipal solar power plant requires about 10 acres of land to serve a city of 1,000 homes - that’s acreage generally easily available at the outskirts of any city of such size in even the most developed countries. Similar for a 10MW plant for a city with 5,000 homes: This would require five such lots.
Solar panels are mounted onto rails above the ground in solar power plants so that grass and flowers can continue to grow in between and below the panels, protecting the local ecosystem. Care is taken that rainwater can flow in between adjoining panels to nourish the flowers and organisms below.
Municipal solar power plants integrate very naturally into the existing landscape as well as the existing electricity grid. By feeding power into the grid directly at municipal voltage levels (typically 20kV), they even avoid the expense of a substation for down-transforming power from high (multi-100kV) transmission voltages as required by conventional power. Furthermore, the solar power plants utilize power inverter electronics with increasingly intelligent features which enlightened utilities around the world are now recognizing as a very good way to improve grid power quality especially at the outer branches of the electric grid where power quality is hard to manage otherwise.
In any region with a decent amount of sunshine, there is no more economic way of reliably providing municipal power during the day than through a municipal solar power plant.
Ground-mounted solar power plants are installed in industrially streamlined ways, with specialized tractors deploying standardized substructure components according to standard system block designs to achieve optimal cost efficiency.
While rooftops are surely a good application too for solar panels, it is a business that’s difficult to scale rapidly in a truly meaningful way. Crawling onto rooftops and mounting solar panels in compliance with building codes is fundamentally always a somewhat more expensive proposition.
Municipal solar power plants can be deployed at a different level of efficiency and speed. This is just not yet known very well to the public, particularly in the United States and California (where we have California Solar Incentives which are adminstered by the state utilities and which presently rule out this most cost-efficient form of installing solar).
But towns and cities throughout Europe and Asia have already proven the concept, and more and more - increasingly entire counties in fact - are now implementing plans to go 100% renewable based on a mix of solar and biofuels. It works, it is economic, and it is possible now. (Any U.S. utility executive who desires to learn more should join this trip.) It is a silent revolution going on that the press rarely reports about.
A good exception is an article today in our local newspaper – “Local communities reach for power over energy” (SF Chronicle) – describing how Marin County in California is wrestling with going for local renewable power. We salute their effort. It is well timed, smart, and with a lot of foresight. They are on the right track based on what we see happening in our own industry and in energy overall. In a few years, they will have less expensive power than it is available in the rest of PG&E territory.
The amount of activity going on behind the scenes in readying technologies, sites, and financings for such is tremendous, and this will become very visible to the public in many locations in the United States in 2010. There is a reason why one of the world’s largest power producers invested in Nanosolar.
Municipal solar power plants are an avenue for delivering a GigaWatt of local power through one solar farm each in a few hundred cities - local to where the power is needed - as opposed to constructing a new coal-fired or nuclear plant. They can also be deployed very rapidly. (It takes 10-15 years to get a new coal plant done; a solar plant can be done in 12 months - provided no administrative blocks exist).
But now is the time for cities and counties to lay the adminstrative foundation for having their own power, 100% renewable, if they care to make a difference by then.