Solar photovoltaic generation, known as PV, like wind power before it, is coming into the mainstream — at great environmental benefit.
Based on comparative life-cycle analyses of power sources, “PV electricity contributes 96 percent to 98 percent less greenhouse gases than electricity generated from 100 percent coal and 92 percent to 96 percent less greenhouse gases than the European electricity mix,” said Carol Olson, a researcher at the Energy Research Center of the Netherlands.
Photovoltaic generation offers several additional environmental advantages, Ms. Olson said in an interview.
“Compared with electricity from coal, PV electricity over its lifetime uses 86 to 89 percent less water, occupies or transforms over 80 percent less land, presents approximately 95 percent lower toxicity to humans, contributes 92 to 97 percent less to acid rain, and 97 to 98 percent less to marine eutrophication,” she said. Eutrophication is the discharge of excess nutrients that causes algal blooms.
Toward the end of last year, installed global photovoltaic generating capacity passed the milestone of 100 gigawatts — enough to meet the energy needs of 30 million households and save more than 53 million tons of carbon dioxide emissions annually, according to a recent report by the European Photovoltaic Industry Association, E.P.I.A., a solar power industry lobby group.
“Right now, today, the world has installed 130 gigawatts of PV, up from 1.4 gigawatts in 2000,” Wolfgang Palz, a former manager of the European Commission’s development program for renewable energies, told a conference organized by France’s National Center for Scientific Research, CNRS, in Paris last month.
Europe alone now has 80 gigawatts of installed photovoltaic capacity, of which 35 gigawatts is in Germany, the European Union leader, providing about 7 percent of the country’s electricity, he said.
Some regions of Germany are even further ahead: “If you buy an Audi today, manufactured in Bavaria, 10 percent of the electricity used to produce it is PV,” Mr. Palz said in an interview.
With large-volume installation, economies of scale have substantially reduced unit costs.
According to a report by the E.P.I.A., the European solar industry’s lobby group, photovoltaic costs have dropped 22 percent with every doubling of production capacity.
Going back 10 to 15 years, “we had to fight to find some crazy people who would install solar panels for $70 per watt on the rooftop,” said Eicke Weber, director of the Fraunhofer Institute for Solar Energy Systems, in Freiburg, Germany.
“We had to find some market support systems for the first thousand-roof program,” Mr. Weber said. “That became the 100,000-roof program — and then the million-roof program.”
Now, “the number that should be broadcast is that, in Germany now, we are able to put PV systems on the rooftop for one euro per watt,” or $1.34, “with the back-up system, with the inverter, and with the cost of installation,” Mr. Weber said. An inverter is a device that converts the direct current electricity produced by solar generation into alternating current that can be fed into the electrical grid.
“In other countries, in the United States, it’s about a factor of two to three more expensive,” he added.
The rapid expansion of renewable energy generation in Europe has been driven by policy, and specifically by the provision of relatively high guaranteed prices for renewable energy sold into the transmission grid — known as feed-in tariffs.
Ahead of the 2009 United Nations climate change conference in Copenhagen, the European Union adopted a set of targets committing it to a 20 percent reduction in its greenhouse gas emissions below 1990 levels; an increase in the renewables’ share of E.U. energy consumption to 20 percent; and a 20 percent improvement in energy efficiency — all by 2020.
Since then, feed-in tariffs have been one of the main drivers of cuts in greenhouse gas emissions. The other has been reduced industrial activity resulting from economic recession. Between them, they appear to have been remarkably effective.