Renewable energies have experienced exponential growth in recent years. Despite their success in generating electricity, one of the main challenges that they still face is their integration into the electricity grid. This is largely due to the intermittence renewable sources such as wind and solar energy, and their limited storage capacity. The future of renewable energy lies in overcoming these obstacles and developing efficient and affordable mechanisms to store the electricity generated.
The success of renewables and their role in decarbonisation
Renewable energy is not just limited to electricity production. It also plays a vital role in heat and fuel generation, offering a viable alternative to fossil fuels and mitigating the negative effects of climate change. Solar and wind energy, in particular, have proven to be able to compete in terms of costs with conventional energy sources in many markets.
In fact, 77% of new energy installations worldwide In 2015, renewable energy was the most common source of energy, with wind and solar energy leading the way. This has been made possible by technological improvements that have dramatically reduced the cost of generating electricity from these sources. For example, the cost of generating electricity from wind and solar photovoltaic energy is now lower than that of many conventional energy sources.
The challenge of storing renewable energy
Although the success of renewable energy to date is undeniable, the real challenge remains in finding efficient solutions for storage of the electricity generated. Unlike fossil fuels, which can be easily stored and distributed, the storage of renewable electricity is more complicated and is still difficult today. very expensive.
There are different ways to store energy generated by renewable sources. The most common ones include: mechanical storage, the thermal storage and the chemical storageEach offers advantages and disadvantages depending on the type of renewable energy used, and the cost and efficiency of each system varies considerably.
Mechanical storage solutions
Mechanical storage is usually represented by the pumped storage hydroelectric plants, which are a reliable and efficient technology. During times of low energy demand, the system pumps water into an upper reservoir, storing potential energy. When demand increases, the water is released, generating electricity through turbines. This type of technology represents more than 90% of Europe's energy storage capacity. Notable projects such as the Chira Falls in Gran Canaria are focused on this technology.
The advantages of this system are its great flexibility and efficiencyHowever, it requires large initial investments and its construction depends on the appropriate geography, which limits its expansion to all areas.
Thermal storage: concentrated solar energy
Thermal storage is key to harnessing solar energy more efficiently. This system allows the storage of heat generated by the solar concentrating technology, where the sun's rays are concentrated to heat a fluid, which can be water or molten salts. molten salts They stand out in this field for their ability to store heat for long periods of time, releasing it when demand requires it.
This system is used especially in the Concentrated solar power (CSP) plants, where stored heat is used to generate steam and ultimately electricity. This technology is crucial to overcome the intermittency of direct photovoltaics, which only generate power during sunlight hours.
Chemical storage: the great future of hydrogen
Undoubtedly, the hydrogen technology is set to play a central role in the future of renewable energy. This system consists of generating electricity from renewable sources, and then using it to split water into oxygen and hydrogen through a process called electrolysisThe resulting hydrogen can be stored and later used as fuel or to generate electricity again using fuel cells.
The call 'green hydrogen' It is a way of storing renewable energy for long periods of time. However, its production cost is still high and new technologies are being developed to improve efficiency and reduce costs.
Lithium-ion batteries in electrochemical storage
As for electrochemical storage, the lithium ion battery It is the most common technology due to its wide application in electronic devices, electric vehicles and now also in large renewable energy projects. These batteries allow the storage of excess energy generated during times of low demand and release it when the system needs it.
The main challenge of lithium batteries is their high costs y limited shelf life, which are compounded by environmental concerns arising from the extraction of the materials needed for their manufacture, such as lithium and cobalt. However, they can be an effective solution for the short-term storage of renewable energy.
In summary, the future of renewable energy will depend, to a large extent, on the ability to solve the challenges related to energy storage. Recent technological innovations offer promising solutions, but there is still a long way to go to make these technologies accessible and efficient. As renewables continue to advance, storage will become the pillar that will allow the full integration of these energy sources into the global electricity system.