What is an electrolyzer
What is an electrolyzer
Electrical, mechanical, or thermal energy can be obtained from hydrogen, with high performances and zero CO2 emissions.
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Energy storage
Energy storage
Keys for a more sustainable future
Keys for a more sustainable future
In a world in full development of technologies related to renewable energies, progress in electrical energy storage systems plays a fundamental role. This development accompanies the promotion of sustainable energy sources and makes it possible to optimize the use of each megawatt generated, contributing to the balance of grid systems.
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What is energy storage?
What is energy storage?
The process of storing energy has a fundamental purpose: to capture and retain it for future use.
Energy storage is essential to support the efficiency of renewable energies and ensure their maximum utilization in energy systems. Key functions in terms of energy storage include:
- Balancing supply and demand, ensuring that there is always electricity available when needed.
- Integrating intermittent energy sources, such as solar and wind, by storing excess energy during periods of high generation and strategically releasing it when production is limited.
- Improving the efficiency of power plants by reducing the need to keep them in constant operation and prevent the waste of renewable energy.
Energy storage systems
Energy storage systems
Energy storage systems are essential for energy management in a variety of applications, from household appliances to large-scale energy generation.
Energy storage systems help to overcome obstacles related to energy generation from renewable sources that vary in their availability, such as solar and wind. They are capable of storing energy at times of high production and releasing it when demand is high or generation is low. This not only ensures a constant and secure power supply, but also reduces the need for backup non-renewable energy sources.
As well as improving the stability of the power grid, energy storage systems contribute to the efficient management of charging and discharging, which reduces transmission and distribution losses.
When users store energy, they can be an active part of distributed generation. Instead of relying only on large, distant power plants, there are now several nearby points that generate power, such as solar panels on nearby buildings. By storing excess energy, either from renewable sources or during periods of cheaper electricity rates, consumers can harness that stored energy. This reduces direct dependence on the conventional power grid and encourages greater energy independence.
Electrical energy storage is achieved through several procedures. The choice of method depends on factors related to the capacity to store electrical energy and generate electricity, as well as the efficiency of the system.
There are several types of energy storage, such as capacitors, which are devices that accumulate energy in electric fields. Although they are efficient, their capacity is limited. Another device is the supercapacitor, which, compared to capacitors, allow energy storage on a larger scale. They are ideal for applications that require fast charging and discharging. Finally there are batteries, which convert energy by storing it as chemical energy during charging and releasing it as electricity during discharging. They should not be confused with capacitors and supercapacitors, as the latter are energy storage devices with different functions.
Solar energy storage involves capturing the energy generated by solar or photovoltaic panels and storing it in batteries for its subsequent use, as this type of energy is intermittent and isn't always available when needed.
The generation of solar energy starts with the conversion of the sun's rays into direct current (DC) electricity, using solar panels. Later, an inverter converts this DC into alternating current (AC) for common use.
The energy can be stored in batteries, where it is stored in the form of chemical energy for future use. For this purpose, efficient and safe charge controllers and solar energy storage management systems are used to ensure its availability when required.
Contracting solar energy is increasingly more accessible for any home, representing a significant contribution to both the energy transition and use of renewable energy sources.
Hydropower storage is achieved through the use of reservoirs or elevated bodies of water. During periods of high hydropower generation, excess electricity is used to pump water from a lower level to an upper reservoir, converting the electricity into potential energy stored in the form of high water. Then, at times of high electricity demand, the water is released from the upper reservoir, flows down through the turbines, and is converted back into electricity.
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Wind energy storage is essential to make the most of the energy generated by wind turbines, as the wind speed is variable and doesn't always coincide with the electricity demand.
Wind turbines capture the kinetic energy of the wind and convert it into electrical energy by rotating their blades. In this way, the electricity generated is converted from alternating current (AC) to direct current (DC) using rectifiers, which facilitates storing the electricity in batteries. After this process, the electrical energy is stored in batteries designed to accumulate large amounts of energy.
As well as batteries, there are other kinds of energy storage. Offshore wind energy is especially relevant in this context, as it makes the most of the stability of offshore winds to optimize the use of natural resources.
When there is a lot of wind onshore, water is pumped from lower to higher levels. Then, when electricity is needed, the water is released from the higher position, which generates energy. Although this process is not directly linked to offshore wind turbines, as it is usually done on land with reservoirs, it is still an efficient alternative to manage changes in offshore wind power generation.
Other ways of storing electrical energy
Other ways of storing electrical energy
Hydrogen emerges as a versatile solution for energy storage. Its capacity to store excess renewable energy and its use as a raw material in the production of synthetic fuels make it an efficient option.
Water electrolysis, a process that separates water into oxygen and hydrogen using electricity, is key when using renewable energy. On days with excess renewable energy, this electrolysis harnesses that surplus to produce hydrogen. This hydrogen is stored and used when more energy is needed, creating an efficient solution for managing peak energy production and demand.
Energy storage in decarbonization
In our firm commitment to the decarbonization of society, we recognize that energy storage plays an essential role in the transition to a more sustainable and highly efficient energy system.
At Repsol, we strive to align our operations with more environmentally friendly practices. We work to create energy plans that adapt to the needs of consumers and maximize the use of renewable energy sources, such as solar and wind.
