The Cheapest Long-Term Power Banks: The Scientific Research
09 November 2021
The main disadvantage of using the renewable energy sources (first of all, of the wind and sunlight energy) is their instability. This is why the more the part of the “green” electricity on the market becomes (for instance, in Germany it is about 40%, and in California it rose beyond 55%), the more critical the problem of balancing the energy supply system becomes: how to compensate the lack of electric energy when the generation falls?
Power Banks: Which Ones Are the Most Efficient?
Currently the basic methods of managing the periodic nature of renewable energy sources are thorough forecasting of generation volumes of sun and wind electric stations (however, it is often very inaccurate), flexible load management and using switching capacities (in Ukraine, those are thermal power stations). At the same time, using electric power banks is an efficient method of compensating the lack of generation.
A group of American scientists performed a research of efficiency of using the electric energy storage systems on the basis of the data of the U.S. Department of Energy and prospective developments of scientific laboratories. The main task of it was determining which technology is going to ensure the lowest cost of accumulation, storage and reverse generation of electric energy:
- For the short periods of storage (up to 12 hours), the most efficient were the systems based on compressed air (pneumatic accumulators), as well as the pumped-storage units. Large losses during the transformation are compensated with very low cost of construction and operation of such systems.
- The systems based on lithium-ion batteries follow them, but if the current tendencies of reduction of cost of lithium batteries continue, they will become the most cost-effective for the medium-term electric energy storage (for up to 36 hours) in the meantime.
- For the long-term storage of electric energy (for up to 120 hours), the hydrogen systems will be the most optimal; during the excessive generation they will produce hydrogen stored in underground storages. This is a very prospective technology, but currently there are great difficulties related to its practical implementation. But even in case of improvement of the technology, it will not be able to compete with the lithium-ion storage systems if short-term storage is required, and this very mode is basic for the systems where the generation systems based on renewable energy sources prevail.
