WERLTE —For all the talk about the imminent end of the oil era, nearly 99% of the cars, trucks and planes currently operating are still petroluem-powered. German Chancellor Angela Merkel has insisted that change is on the way: in 2011 she predicted that as many as one million electric cars will be in use on Germany's roads as early as 2020. And yet, as of Jan. 1, 2015, there were only about 19,000 electric cars registered in the whole of Germany, according to the Federal Motor Transport.

There are a couple of reasons this. For one thing, electric cars don't have the kind of mileage range drivers prefer. Also, Germany lacks the infrastructure necessary to charge electric cars at regular intervals. The state hasn't even agreed on a universal standard for electric fuel stations.

It is thus hardly surprising that companies are looking for alternatives to electric cars. One of the most promising options so far is the so-called gas or fuel-cell car, which is powered by "windgas." Superfluous eco-electricity from wind turbines and solar panels can be used to produce hydrogen and relatively simple organic compounds, such as methanol and methane, which can then be used to power cars, either in a combustion engine, or with the use of a fuel cell to transform the materials back into electricity.

This is precisely the alternative Audi has been exploring for the past two years in Werlte, Lower Saxony, where it commissioned Etogas Ltd. to build the planet's first and largest power-to-gas plant. Power-to-gas is the process by which wind and solar power are transformed into hydrogen and methane, a technique that took years to develop at the Centre for Solar Energy and Hydrogen Research (ZSW) in Stuttgart.

The term "largest" is relative in this case. All that can be seen of the plant are a few intersecting pipes that connect silos and tanks. Any chemical plant of middling size would have more to show. Nevertheless, the Werlte facility produces a fair amount of power: 6 megawatts (MW), enough to power 1,500 Audi A3 g-trons, the first gas powered mass-produced (and mostly climate-neutral) car.

Audi spokesperson Oliver Strohbach says the cost of running an Audi A3 on "windgas" (purchased at petrol stations) works out to roughly $.06 per mile. Customers who buy or lease one of the vehicles also have the option of paying a flat monthly rate of $16 for the fuel. "This would not be dependent on a certain mileage," Strohbach explains.

The range of a windgas-fueled car is comparable to that of a petrol or diesel car, and thus outdistances the 93-mile range of an electric car. The only restriction is the limited availability of windgas petrol stations across the country. Right now there are only about 1,000.

Either way, a look at the reality of renewable energies demonstrates how important the conversion of excess renewable energy to "windgas" could become. At the end of 2014, according to the German Wind Energy Association, the country had 24,867 active wind turbines generating a total of approximately 38,000 MW, equivalent to 9% of the electricity Germany needs.

But the numbers hide the true state of wind energy. Output from wind turbines is notoriously unstable. Weather conditions might keep them idle for days or weeks. At other times, they work full tilt, even at night, when electricity consumption is way down. In that case, electricty can be wasted. The power surplus can also lead to network collapses, another reason it's so important to figure out ways to store or recycle wind power.

Audi's anwser is to save that electricty "chemically." Power that would otherwise be wasted is used first to transform water into hydrogen through the use of electrolysis. Hydrogen and carbon dioxide (also produced on-site in an organice gas plant) are then synthesized into methane.

The gas network offers what the electricity network lacks, namely sufficient storage capacity. Whereas electricity can only be stored in batteries or "storage lakes" for later use, the gas network works quite differently. "Windgas" can power cars and trucks or can be burned to produce power.

Power-to-gas technology represents a real opportunity. The car industry seems to have made note of this already. Toyota's "Mirai" — meaning "future" in Japanese — is the first hydrogen powered mass-produced car. It will be available in Germany next autumn. Daimler, in conjunction with Nissan and Ford, has been developing its own model for years and hopes to launch it in 2017. But the necessary infrastructure to support these cars is still missing. Currently, there are only 17 public hydrogen petrol stations across Germany.

Natural gas powered cars are a different story. There are more than 15 million registered worldwide, with 3.5 million in Iran alone and three million in China. The technology is so well-developed because it only requires a combustion engine connected to a gas tank. There are plenty of gas petrol stations to be found. And methane is much more environmentally friendly than petrol or diesel — even more so if it is produced through wind or solar energy — which make it essentially climate-neutral. These are the basic equations that could transform an entire industry, and help save the planet.