Moving the country towards renewable power when coal remains a cheap fuel source has been a challenge, one that a number of states are addressing by setting hard targets for their utilities. Two of the states that will require their utilities to provide a fixed percentage of renewable power in the next decade or so, California and New Jersey, will be the site of some major solar power efforts, both announced this week. The projects are interesting because they demonstrate how renewable power can adapt to the geographic realities of each state. California's deserts will be the site of large-scale solar-thermal facilities, while the densely populated garden state will see a distributed network of photovoltaic cells.
First up: California, where Southern California Edison announced a deal with the solar-thermal company BrightSource Energy. All told, the deal will eventually lead to the construction of seven major facilities, which will provide a total of 1.3GW of generating capacity. The first of these, a 100MW facility, will be built in the southeastern part of the state, which is dominated by the Mojave Desert. As you can see from the picture below, there's not a lot else in the area, meaning the project is very unlikely to meet any resistance from the local populace.
BrightSource uses a fairly conventional solar-thermal approach, using an array of mirrors to focus sunlight onto a boiler filled with water, heating it to steam that drives electric generators. This doesn't have the advantages of some of the more exotic solutions, like liquid salt, where the heat can be stored to produce power well after the sun has gone down—its big plus is that all the technology involved is extremely well understood. BrightSource promises that the water used will be retained in a closed-loop system, allaying what would otherwise be a serious concern for a water-limited state.
This sort of project is also apparently old news for Southern California Edison. In a statement announcing the deal, the company claims that, in 2007, it bought more than 80 percent of the solar energy produced in the United States, an impressive figure. It's not clear whether there are existing transmission lines that make the location appealing for getting the power to the company's customers, but the utility appears to have experience with long distance power transmission, as it has contracts with companies that are generating wind power in Washington State.
On the other side of the country, New Jersey would hardly seem like a mecca for solar power. But the differences are less than one might expect; one speaker at a renewable power conference said that the difference in potential solar power between the Mojave and Seattle is only 50 percent, and New Jersey is significantly sunnier than the Pacific Northwest. One issue the Garden State does face, however, is one of the highest population densities in the nation. Its utility has responded with a plan that takes advantage of the densely-packed infrastructure it maintains to support that population.
The plans are an order of magnitude smaller—PSE&G will install 120MW of capacity—but the approach is a novel one. 40MW of the capacity will be what is being called "neighborhood solar." Photovoltaic panels will be installed on the utility poles and streetlights already maintained by PSE&G. Since these are already plugged into the grid and receive regular maintenance, it should simplify the ability of the utility to maintain the hardware. The utility will offer every town the opportunity to have panels installed on their municipal infrastructure, including schools, and will coordinate with the state's affordable housing program to put solar installations on new construction; its own facilities will also see panels installed.
By the time all that capacity is factored in, only 10MW of the total will wind up being dedicated solar facilities. The utility intends to target brownfield and other unutilized developed sites. The projects will come at a price, but the utility estimates that it will add only a total of 35� to a typical customer's bill once fully in place. At the same time, it will meet seven percent of the state's renewable energy requirements.
The radically different approaches highlight how there won't be a "one size fits all" solution to increasing the amount of renewable energy we produce. Wind may be the country's big success story, but it will have to be joined by a variety of other sources if we're to reduce our reliance on non-renewable energy. The projects suggest that, with a bit of government prodding, we're now entering an era of experimentation that may help us make more intelligent decisions about which approaches will most effectively meet our future energy challenges.