Forget zero-energy homes, which produce their own power and are carbon-neutral.

The Germans are taking green building to the next step with so-called “triple-zero” homes, which both create enough energy to power themselves and have enough energy left over to send back to the grid.

German architect and engineer Werner Sobek’s triple-zero homes are entirely energy self-sufficient, produce zero emissions and are made entirely of recyclable materials like glass, according to a recent article in Scientific American.

So far, Werner Sobek’s firm of engineers and architects has built six of these homes, all in Germany, with a seventh planned for France.

The first home, a one-story glass home, is like a “tiny power plant [which] feeds electricity into the public grid,” said Sobek during a lecture on his recent work.

Since the building industry is responsible for about 35 percent of the world’s energy consumption and carbon emissions, Sobek believes that planners, builders and policy makers should be working to reduce the environmental impact of buildings in addition to making efforts to reduce impacts by other industries, such as the automobile industry.

Though Germany is known for its passive houses, which maintain comfortable living temperatures without the use of active heating and cooling systems, Sobek feels that these homes, with their scant number of windows and super-thick insulation, can feel like living in a “Styrofoam box.”

That’s why he invented “active houses” that have windows that are triple-glazed for superior insulation.

"I invented the so-called 'Aktivhaus' [or active house] — buildings which open your soul, which open your mind, which open your heart," said Sobek.

To help minimize the use of steel and concrete while keeping his buildings lightweight, Sobek’s engineers developed a technique to inject bubbles into the concrete, which reduces the overall amount of concrete needed for the structure. In addition, Sobek cut down on steel use by employing thin steel frames in his homes.

But the truly unique and environmentally friendly aspect of Sobek’s homes is not what the buildings are made of, but rather how they’re held together. Sticking pieces of a house together with toxic glue makes it all that much harder to take it apart, which means that most torn down houses often end up in landfills.

"This is nothing but a toxic waste," Sobek said. "Nobody will ever sort those materials so the result is that you put them in a waste dump and hope that the next generation will not find them."

Instead, Sobek's engineers and architects use stainless steel bolts to put together their triple-zero houses, which have proven to be as safe as putting buildings together the conventional way.

Though having triple-zero homes in the states is still a long way off, some communities in the U.S. are taking a big first step by designing “eco-communities” that will hopefully inspire others to take green building as far as it can go.