The way to go for large-scale storage of renewable electricity is “power to gas“, which means making hydrogen from water. Germany can store up to 200 TWh with the existing gas infrastructure, much more than the around 30 TWh needed in a 100% renewable electricity scenario. And hybrid wind power plants with the ability to store energy over hydrogen are already starting up.
Most existing projects are wind parks. But now SPIEGEL reports about a new technology for solar “power to gas”.
Researchers have developed a solar cell that is able to directly split water. It does not produce electricity in a first step and splits the water in a second step, but only has one step. Just like plants’ photosynthesis produces carbohydrates directly, this solar cell will produce hydrogen directly.
It beats photosynthesis (efficiency of about one percent) by a large margin, converting already 12.3% of the solar energy into hydrogen energy, even at this early prototype stage. And this solar cell uses no expensive materials, which means it will be even cheaper than photovoltaic solar cells.
In the short term, this will solve the remaining storage problems with a 100% renewable grid even cheaper than already existing alternatives. In the long term, this will replace oil.
Oil is ancient biomass. When storing the energy, the efficiency was only about one percent. Then it took millions of years and random geological processes to actually create the oil.
It is obvious that there is no way this could be competitive, except for the fact that we are burning oil that is already in the ground. Which can be done exactly once for each barrel.
Once peak oil becomes downhill oil and then gone oil, making our liquid fuel ourselves as opposed to burning through the reserves will be the only alternative anyway. It took 5.3 million years to build up the fossil fuel humanity burns in one year. There is no way this is sustainable.
So we will need to make our fuel, instead of burning the reserves. One-step hydrogen production from cheap materials is a big deal for doing that.
