PHOENIX - From a block away, the house was hardly visible, hidden by a dense stand of native mesquite and palo verde trees and tall clumps of prickly pear cactus. Close up, you could see the concrete block structure, built a half-century ago when acres of citrus groves were broken into parcels and replaced by homes.
Turning the site back into desert took some work, Brock Tunnicliff explained, standing outside his house on a typical September morning in the Sonoran desert, temperatures in the mid-80s under a nearly cloudless sky. It also took some courage, because desert landscaping isn't popular in Phoenix. Most people here still prefer a lawn out front and a swimming pool in the back.
For Tunnicliff, who works in natural resource management, adopting native landscape was a logical choice in a desert climate. Bolted to his roof was another rational choice: a solar photovoltaic system that supplies most of his family's electricity needs. He installed the system even though he estimates it will take 12 years to break even on the investment.
That is the future of energy, he said, pointing to the dark blue panels on his roof.
How far in the future is anyone's guess, however. Four years after Tunnicliff installed the system, a satellite image reveals no other solar panels in his neighborhood. In America's sunniest and driest big city, swimming pools still outnumber solar panels by a thousand to one. In fact, Germany - which receives only half as much sunlight as Arizona - has four times as much solar power installed per capita as the Grand Canyon state. Compared nation-to-nation, Germany's advantage is even more lopsided: This darker, cloudier central European country has 23 times more solar power per capita than the United States.
The primary reason for the renewable energy gulf between the United States and Germany can be summed-up in one word: policy. In 2000, Germany's Renewable Energies Act went into effect, and power generated from the sun, wind and biomass soared. In 2012, U.S. politicians are still wrangling about whether global warming is a hoax.
For a time, the United States led the world in developing renewable energy. At one point the Carter administration's Solar Energy Research Institute (SERI) made the dream of a renewable energy economy so real that it set off alarms in the oil-rich countries of the Middle East.
The big powers are seriously trying to find alternatives to oil by seeking to draw energy from the sun, Saudi Arabia's oil minister Sheikh Ahmad Zaki Yamani warned his colleagues. We hope to God they will not succeed quickly because our position in that case will be painful.
Four years later, Jimmy Carter was defeated by Ronald Reagan. The new administration considered SERI a prime example of what it derided as solar socialism. The budget of the world's leading solar institute was slashed and before long it was back to (oil) business as usual.
A generation of Germans picked up the renewable torch that the Reagan administration tossed aside and bought up SERI-produced patents at fire-sale prices. The renewable energy revolution didn't end. It moved overseas and was renamed die Energiewende.
Can the American renewable energy revolution be restarted? William Reilly, the director of the U.S. Environmental Protection Agency in the George H.W. Bush administration, thinks so. We're going to get there, one way or another, he said during a 2009 interview about his solar-powered home.
Indeed, optimists look at recent energy figures and see evidence that a seismic shift has already begun. In the past three years, 3,700 megawatts of solar power have been installed in the United States - nearly twice the amount that existed in 2009. More wind power (4,728 megawatts) was added to the U.S. electrical grid in the first three quarters of 2012 than the total generating capacity from wind just a decade ago (4,687 megawatts). All told, over the last four years the percentage of our electricity generated by renewables (not including hydroelectric) has doubled.
Still, energy expert John Farrell warns that it's too early to celebrate an America renewable energy renaissance along the lines of Germany's Energiewende. The U.S. electric grid is poised for a transformation, said Farrell, a senior researcher with the Minnesota-based Institute for Local Self-Reliance. But we're not there yet.
The numbers support Farrell's caution. Renewable energy's share of the total American electrical pie is pitifully low - just 6 percent. Germany gets a full 25 percent of its electricity from renewable sources - and has its sights set on a goal of 30 percent by 2020 and 80 percent by 2050. Hans-Josef Fell thinks Germany can do even better, reaching 100 percent renewable energy by 2050.
This is an excerpt from Davidson's book Clean Break: The Story of Germany's Energy Transformation and What Americans Can Learn from It. InsideClimate News is a nonprofit, non-partisan news organization that covers clean energy, carbon energy, nuclear energy and environmental science.