The transition to a more environmentally friendly energy model that we have embarked on as a society poses great challenges. And also big questions. Renewable energies aspire to play a leading role in a future energy ecosystem that will pursue minimize polluting emissions, but its intermittent nature entails some challenges that need to be resolved.
Some experts, such as Alfredo García, best known on Twitter for his alter ego @Nuclear Operator, advocate a model in which nuclear energy is postulated to act as support for renewables in those moments in which its intermittent nature does not allow to sustain the production of electrical energy. However, in Spain this model is currently not an option. And it is not because nuclear power plants have an expiration date.
As nuclear reactors are shut down and the burning of fossil fuels is no longer an option, we will need an efficient electricity storage infrastructure
The nuclear blackout planned by the Spanish government establishes that the last Spanish nuclear power plant that will remain active, Trillo, will cease in 2035. As nuclear reactors are permanently shut down and the burning of fossil fuels is no longer an option as As a result of the commitment we have made at the United Nations Conference on Climate Change (COP26), we will need to have a storage infrastructure of efficient electricity. And getting it ready is not easy.
Its purpose will be to act as a complement capable of storing the surplus produced at times of maximum power generation capacity from renewable sources. to deliver it when they cannot contribute. It is currently unclear which technology, or combination of technologies, will ultimately establish itself as a renewables traveling companion, but fortunately there are several promising options that could take on this responsibility in the future.
These are some technologies that aspire to work hand in hand with renewables
Fortunately, there are several solutions that can go hand in hand with renewable energies to act as that complement capable of store surplus energy whenever necessary. Here are some of the most promising electricity storage technologies:
- Batteries: the technology involved in its tuning is developing significantly thanks to the push of the electric car. Tesla already offers us its Megapack, a modular and scalable storage solution with a reasonably promising future. The cost of large lithium-ion batteries is falling, but they suffer from limited lifespan and discharge capacity, so other technologies, such as redox flow batteries, end up moving them in this usage scenario.
- Hydroelectric pumping or reversible plants: they fit very well in mountainous countries because they allow us to take advantage of uneven terrain to move large bodies of water between two reservoirs or reservoirs at different heights. The surplus energy can be used to pump water from the lower reservoir to the upper one using a hydraulic pump, and to recover that energy it is only necessary to drop it back into the lower reservoir from the upper one so that it drives a hydraulic turbine. It is one of the most efficient large-scale energy storage systems.
- Hydrogen generation: green hydrogen, or renewable hydrogen, is obtained from renewable energy sources using procedures with zero or very low polluting emissions. The most popular method of obtaining it is the electrolysis of water, but there are other options, such as steam reforming of biogases or organic waste, thermolysis of water or photocatalysis, among other options. The challenges posed by the electrolysis of water still need to be resolved.
- Compressed air: This system has been used for decades, but the energy transition has caused some companies to refine it to use it as a complement to renewable energy. In a very succinct way, this solution consists of using the energy surplus to compress an air pocket that is stored in a natural or artificial reservoir. Later, when it is necessary to recover that energy, the air expands, which drives a high-performance turbine and delivers the energy that can be contributed to the electrical grid.
- Thermal energy storage: storing heat is simpler than safeguarding electricity, so this strategy proposes just that: storing thermal energy. Solar thermal power plants use solar radiation to heat a fluid (usually molten salts), so that this thermal energy can later be transformed into electrical energy using the same thermodynamic procedure used in classic thermoelectric installations.
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