The production of Electricity from wind and solar power plants fluctuates sometimes stronger, sometimes weaker, depending on the weather. In order to adapt the changing supply to a relatively inflexible demand and to keep the power grids stable over the course of the year, larger storage in the future asked. Here is often from hydrogen the Reason.
However, Austria is in the fortunate position of having the necessary landscape relief for pumped storage power plants to dispose. Couldn’t all renewable energy simply be stored in the form of water, which is pumped up and then released via turbines and generators when needed? If it weren’t more efficient converting water into hydrogen as electricity by electrolysis and then converting it back into electricity in fuel cells?
What comes out at the end
When it comes to the question of efficiency, it is usually the efficiency downtown. It indicates what percentage of the electricity that is put into a storage facility comes out again when it is converted back into electricity. At pumped storage power plants this proportion is comparatively high. “Our oldest systems achieve between 70 and 75 percent, modern systems 80 percent and more“, explains Martin Schrott, head of the technical planning department compoundthe largest operator of such power plants in Austria.” hydrogen will, however 50 to 60 percent achieved, explains Alexander Trattner, head of the hydrogen research center HyCentA.
There are some losses with hydrogen, because they are relative many conversion steps are required. Apart from electrolyser and fuel cell, there are also at the warehousing of hydrogen losses. There are a variety of methods here. For example, if you need a compressor to compress the gas to 1000 bar, that costs money 7 percent from the energy content. If you want the hydrogen on minus 253 degrees Celsius cool and liquefy, you lose up to 30 percent the energy. In addition, hydrogen can be converted into methane or methanol. This also reduces the efficiency. According to Trattner, however, research into these technologies is progressing rapidly and there are constant improvements. In addition, in electrolysis and in fuel cells warmth created that can be used.
Energy from the other side of the world: A tanker with liquid hydrogen on board
© REUTERS / YUKA OBAYASHI
Location-independent and scalable
The big advantage of hydrogen is that you can build anywhere also closer to wind farms or solar parks, so that losses during power transmission are minimized. Generation technologies are tried and tested and scalable. In addition, no special topography is required for this. The existing one is ideal for the future distribution of hydrogen natural gas network at. This is already 90 percent ready for hydrogen transport. Hydrogen is advantageous for Austria’s energy supply, which will continue to be heavily dependent on imports in the future. It’s fine transport on shipsfor example from countries where there is plenty of solar or wind energy.
Immediate delivery of high performance
Pump storage is currently the only solution for storing large amounts of electricity. Losses are caused by transformers, motor generators and the friction of the water on the walls of the huge tunnels. 22 power plants with a power over 10 Megawatt are according to the electricity industry association Austria’s energy currently available in the country. According to Schrott, they can if necessary Cover 36 percent of the highest electricity loadwhich appears on average in the year (annual peak load).
The great advantage of pumped storage power plants is that they are flexible enough to generate large amounts of electricity in the short term and save. Usually will during the day and week Balanced load differences in the power grid. If a lot of electricity is produced by photovoltaics at midday, water is pumped into higher-lying reservoirs. In the evening and in the morning, the water is drained again to help cover the increased electricity demand. Electricity generated at the weekend is stored for the coming week due to reduced demand.
Save for the winter
What is difficult to do with pumped storage, however, is the seasonal transmission of electricity, i.e. storing solar energy, which is harvested in abundance in summer, for the winter. “If the expansion targets are met, there will be a surplus of 10 to 11 terawatt hours (TWh) give. The total volume of all large storage facilities (storage and pump storage power plants) is included 3 TWh. So you need much larger storage volumes.” The fact that many additional pumped storage power plants with new, large basins are built is unrealistic. “So it also needs other technologiesapproximately hydrogen.”
The question of efficiency alone is so not crucial for which electricity storage technologies will be needed in the future. Instead of a competitor, one can rather choose one necessary supplement speak.
