We already discussed the pioneering work Younicos is doing to cut fossil fuel spinning reserves and backup plants out of the energy mix, but Younicos is just aiming to take over the primary electricity regulation market (backup for intervals up to 15 minutes in length). Beyond primary regulation and Younicos, battery storage on the whole is perhaps useful up to 24 hours. After that, however, it really gets uneconomical. Eventually, another technology will also need to tackle longer-term storage. The only really viable option, at least in Germany, seems to be power-to-gas technology. (For new storage capacity, that is.)
Another stop on our jam-packed trip around Germany* was a visit to the 1st wind-to-hydrogen-to-electricity system of a megawatt scale in Germany, and probably the only such project of that scale worldwide. It’s still very much a pilot project, but it’s a step forward.
The system uses excess wind electricity to split water and create hydrogen. The hydrogen is stored until needed, which, in this pilot project, is basically just when the wind turbines are not turning and creating enough electricity for their basic heating or operational needs, which is rare. (About 5% of a wind turbine’s rated capacity is needed for its own operation.) When the wind turbines need electricity, instead of receiving it from the grid like normal, the hydrogen is burned in order to spin a turbine and create electricity. The closed-loop system is also what makes this project quite unique.
The efficiency of the hydrogen production is 65–75%. Combined with the internal combustion engine for the re-electrification, an overall electrical efficiency of 20-25% can be reached. It is not ideal for normal use, but it is a demonstration project showing how excess wind (or solar) electricity could be stored in the longer term. To be fair, the 20-25% is merely the electrical efficiency. The heat that accrues in the process is currently only partly used for the heating of the facility. If the heat was fully used, the overall efficiency of the systems could be increased significantly.
The 150 MW wind farm connected to the hydrogen storage facility is actually special in itself. It uses 7.5 MW wind turbines!! None of us on the trip even realized that wind turbines that large were being installed on land (other than myself, there were the editors of two other clean energy outlets & magazines as well as Roy on this trip).
These massive wind turbines were one of the coolest sites on the trip, with huge fronts on the nacelles that made them look like characterizations of normal wind turbines. The pictures and video I took really don’t do them justice, but here they are:
The capacity of the water-splitting system for creating the hydrogen is 1MW, and 50,000 kWh can go into or out of the compressed air storage where the hydrogen then goes.
Depending on policy and changes in the electricity market, this system could even be competitive for secondary regulation or storage by 2020.
*Disclosure: My cleantech tour around Germany was sponsored and organized by Germany Trade & Invest.
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