A community center in Würrich, Germany with solar panels on its roof (wikimedia commons)

We live on a spherical world, tilted slightly askew. And we have weather. Although we do not think of them now, preconditions such as these will have a profound impact on the way solar energy is implemented in this century, with corresponding impacts on the shape of our future economy. It’s currently imagined that a solar economy would leave the world as is, just with solar panels on the roof. But a meaningful shift from fossil fuels to solar power will require economies of scale—economies likely not offered by the small installations promoted by many current solar boosters. A solar-powered society may involve alterations to the Earth’s surface as dramatic as those caused by the industrial revolution.

The world’s most aggressive solar advocate is also one of the least likely: cloudy, high-latitude Germany. The German government subsidizes renewable power through the use of a feed-in tariff, which requires electric companies to buy power from solar panels at an above market rate for twenty years. This assures the installer of the system that they will make a profit, leading to a rush for the most expensive of the renewables: photovoltaics (solar panels). The result has been a solar power boom, with Germany generating over half of the world’s solar electricity.

There are two main modes for generating solar electricity. The centralized model operates much like a conventional power plant, setting aside a space for a solar panel farm (or mirrors to focus heat on a working fluid to run the generator) and distributing the power from there. A good example of this is a mammoth eighty-megawatt one planned for a former German Democratic Republic army base.

The other method, distributed generation, consists of small-scale solar installations, mostly on rooftops, all linked together by the grid. Germany’s feed-in tariffs have been incredibly successful in distributed generation, and similar incentives for solar power have already been implemented in Ontario and the city of Gainesville, Florida.

Since public utilities have to pay more for renewable energy under feed-in tariff systems, they pass on these costs to consumers. In Germany, this adds about an extra euro to each month’s bill—not a large amount, but the projected growth of renewables in Germany could lead to a monthly increase of two to eight euros, with figures in the higher part of that interval now being favored due to the trendiness of costly photovoltaics.

Also, there are also political-economic reasons for German investments in photovoltaic technology, though. By driving up demand for solar panels, the feed-in tariffs form something of a subsidy for the German solar panel industry. Photovoltaics are seen as a next-generation export, and the ability of manufacturers to generate high-paying industrial jobs is at least as to the German government as using solar power to generate electricity.

This does raise the prospect, however, that if Germany wants to run its economy from the sun it will likely have to pay much more for its energy. This is not entirely surprising—Germany’s abundant coal deposits fueled its rise to an industrial power. Germany might have the will to switch to solar power, but overcast skies at high latitudes mean they have to install more photovoltaics to extract the same amount of energy as another array in a sunnier climate. Switching to renewable power and remaining an economic power may well be contradictory aims.

There is a strong ideological component to distributed energy’s appeal. As Governor Jennifer M. Granholm of Michigan put it, with distributed solar “every homeowner, every business, becomes a renewable energy entrepreneur.” Granholm uses the rhetoric of opportunity to sell distributed solar power, making small rooftop installations seem distinctly American. Distributed power also has sort of a Web 2.0 vibe. Rather than having to buy electricity from a big corporation, you can make it yourself.

Even if distributed generation fits well with the contemporary zeitgeist, economies of scale still present an issue. It is simpler to construct one big solar farm than a large number of installations on existing rooftops. In all likelihood, it is also a more financially viable option. Furthermore, at high latitudes like Michigan’s, today’s technology does not allow most consumers to generate electricity to make a profit, so Granholm’s statement is worse than rhetorical—it is disingenuous.

Nonetheless, solar cells have retained high levels of popularity, resulting in massive production, which in turn has caused retail costs to fall. Now China intends to cut prices even more — according to Reuters, US solar entities as well as German solar firms Conergy and Solarworld are becoming more concerned about China’s efforts to grab a larger share of the renewable market by cutting costs in order to compete. The US faces the task of trying to encourage consumers not to purchase the cheaper solar energy products made in China. Needless to say, there has been much speculation about trade barriers.

But is this truly the best way to establish a solar-powered economy? Solar projects have boomed because installers are guaranteed returns on investments, but such guarantees have forced Spain and Gainseville to restrict the number of new installations each year, while Ontario has had to temporarily shut down the program altogether. Just as fostering a photovoltaic industry has been instrumental in protecting Germany’s feed-in tariffs, in the United States job growth is a major argument for the promotion of distributed solar. Even in more favorable environments, these programs may not be financially sustainable.

A solar farm at Nellis Air Force Base in Nevada

This is well illustrated by the centralized-distributed debate going on in Nevada. Distributed power is seen as more conducive to job growth. Danny Thompson—the treasurer for the Nevada chapter of the US’s largest union federation, the AFL-CIO—told the Las Vegas Sun that a centralized solar power plant would be a mere “flash in the pan” in terms of job growth. The incremental installation of photovoltaic panels on rooftops would provide more jobs over a longer period of time. This also means it will cost more. The great danger in sacrificing efficiency for current job growth is that it leaves our solar policy more exposed to changes in energy policy. Should feed-in tariffs drive up electricity costs too much, they will become an easier political target here than in Germany.

Even considering the ideal solar farm located in a sunny environment with its photovoltaics (or mirrors) positioned to maximize insolation, we would need to cover large swaths of desert with solar panels in order to really start replacing fossil fuels. “[The] Sahara could supply all of Europe, the Gobi could power China, and the Chihauhuan, Sonoran, Atacama and Great Victoria Deserts could electrify entire continents,” the Guardian’s George Monbiot dreams in his book Heat. Nicolas Sarkozy tossed the same idea around while proposing a Mediterranean Union. A solar economy would rework the Earth’s surface to save the atmosphere.

The scale of this inspires a certain awe: pyramids and Great Wall, look at how much bigger our civilization’s solar farms are! It also inspires fright—some conservationists are beginning to line up against schemes to cover the Mojave Desert with mirrors and photovoltaics, as is California Senator Diane Feinstein. If the damming of western rivers serves as any guide, though, the possible profits from paneling the deserts will likely prevail eventually.

As convenient as the sun has proven for four billion years of life on this planet, harnessing it to power our more recent inventions is a challenge. Our current technology has achieved neither the ease of nature nor the economy of fossil fuels, but our reckless use of the latter is forcing us to alternatives. The prevailing policy in Europe and the United States is not so much a solar policy as a jobs policy that involves photovoltaics. Despite enthusiasm over green jobs, we have to face the prospect that the path an environmentally sustainable economy may not be the one that creates the most jobs. Furthermore, a real plan for shifting our civilization to solar power would probably employ economics of scale to an unprecedented degree, opening up paradoxes about what a saved planet would look. Sunlight may be free, but we should not trick ourselves into thinking it can be harnessed effortlessly.

A version of this article first appeared in the Spring 2009 print edition of Diskord, and has been updated.