This german project features home based distributed cogeneration, excellent! It replaces a home furnace and hot water heater with a generator burning natural gas. The waste heat from the engine does the home heating. Electricty is generated in each home and sent onto the grid. Honda has developed a system like this as well.
Still it goes better with distributed storage, battery storage in homes, factories, buldings, and on farms that offsets demand and renewable supply peaks. this also provides emergency power and can store rooftop generated solar power.
Distributed cogeneration like this would really rule with a 50% efficient solid oxide fuel cell to convert the natural gas or biogas to electricity. There are a few breweries that use these to produce electricity now from biogas made from brewery waste. The breweries use the waste heat from the fuiel cells to make steam for use in cleaning, cooking, and heating.
But the waste heat at 800 degrees can also drive a turbine generator to extract another 25% of the energy in the gas. The remaing waste heat can still heat domestic hot water and buildings.
That's a total electrical conversion efficiency of 75%, about 4 times the efficiency of the VW gas engine driven generator. 1/4 the fuel for the same amount of electricty/heat. That makes even natural gas cost competitive with coal.
The problem with the lower efficiency design employed in the german design is that hot water and building heat supplemented with ground source heating and solar cogeneration (heat and electricty from the same solar collectors) does not need nearly the heat energy to back it up. This system supplies too much heat and 1/4 the electricty.
They ought to go back to the drawing board and install simple battery storage and ground source heating and solar cogeneration in most buildings. Then in larger buildings, farms, and factories install the solid oxide fuel cell/turbine cogeneration in say evety 50th building as backup for the rest of the community grid.
Larger buildings, farms, and factories can more easily utilize the waste heat from this form of cogeneration. Renewable energy works better together, with a smart grid, and distributed cogeneration and storage.
Why no attempt at superconducting electromagnetic energy storage yet? Europe is lagging behind our local utility here, they have employed SMES on a small scale for decades.
With large scale storage coupled directly to a 500 kilovolt DC super grid, a region would have it's own combination renewable energy transportation and storage. These syutems linked across continents would make fossil fuel power and nuclear power completely obsolete.
