Have we ever wondered what happens to photovoltaic energy at night or to wind energy when there's no wind? Why are electricity bills so volatile and how do they significantly impact our wallets? The key lies in storage.
In renewable energy production, there are periods when no energy is generated (off-peak periods), as well as other periods of very high production that often saturate the grid. It is during off-peak periods that reservoirs capable of accumulating energy during periods of high production and releasing it when demand is high or power generation is low must be considered. This ensures a constant and controlled energy supply. In addition to improving the stability of the electrical grid, energy systems contribute to efficient management of charging and discharging, which significantly reduces losses in transmission and distribution.
When renewable energy production declines due to insufficient sun or wind, gas fills the gap, and the bill rises. Solar and wind energy have proven to be the cheapest renewable energies; the idea is to free ourselves from dependence on gas. This green dawn will bring new sources of employment, lower electricity costs, and combat the climate crisis, positively impacting pollution.
Focusing on the basic principle of energy, which states: "Energy is neither created nor destroyed, it is only transformed," very novel and curious ways of storing energy have been achieved. The most efficient and ingenious ways that will solve the problem are described below:
Gravity storage:
It is a method of energy storage whose principle is based on the relationship between potential energy and kinetic energy, when there is energy production, gigantic blocks of concrete are raised to a tower, here the energy is stored in the form of potential energy, when energy is needed, the crane uses a system of pulleys that generate kinetic energy, lowering the blocks and letting them fall, resembling a gigantic, cheap battery with a very high efficiency of more than 85 %. There are already numerous plants in development, the principle is adapted to a tower or a gigantic industrial warehouse that with the same principle stacks and drops blocks for the storage and release of energy, another similar way is by means of wagons on a hill, where the wagons are raised and then allowed to fall freely
The most impressive example is the gravity-powered battery facility built in China, in an industrial park that operates on the same principle.
Reversible water pumping stations:
The same principle of relating kinetic energy to potential energy is used, but with water. A gigabattery is formed by two dams, separated from the supply network. The first is located at a higher elevation and the other below. Water is pumped to the upper reservoir when there is low demand for electricity, and then lowered to the lower dam when energy is needed. This water, stored in the form of potential energy, is transformed into kinetic energy when released. Turbines are located at the end of the section, the purpose of which is for the liquid to move the turbines, generating energy.
Classic drums:
This is currently a field being studied based on conventional lithium batteries, whose price has fallen by 89% in ten years and for which there are already gigantic parks, the most significant of which is located in California, with the capacity to supply 150,000 families for 24 hours.
Batteries are currently being manufactured with cheaper, more abundant materials with a lower carbon footprint, such as sodium-sulfur, aluminum, sodium, calcium, silicon, zinc, magnesium, and, most notably, the iron battery, whose storage system is 10 times larger than conventional lithium batteries and has very high efficiency, storing electricity for days.
Solar thermal with storage:
It consists of an obelisk surrounded by solar panels that reflect all the energy toward the top of the obelisk. This concentration of light generates electricity by melting salts stored in a silo, storing energy for days and feeding electricity into the grid at night. Spain is a global leader in solar thermal energy, with more than 50 plants in operation.
Heat Storage in Mass:
Heating rocks, sand, bricks to very high temperatures that are located in special tanks or underground, that energy is stored in the form of heat and can be for months with very high efficiency, being able to be used to heat water, for district heating or for heavy industry furnaces, we have the example of the largest sand battery in the world located in Finland, supplying hot water to the local heating service supplied to homes in the city of Vatajankoski
Compressed air:
Compressed air storage occurs in two phases: First, during periods of energy production, the air is compressed and stored in special containers. In the second phase, when energy is demanded, the compressed air is released into a chamber, expands, and drives a turbine, producing electrical energy. The world's largest plant operating under this principle is located in Alabama and has been operating since 1991. Its storage capacity is 2.86 GWh, equivalent to the energy consumed by more than 300,000 homes in 24 hours.
Fly Wheel:
Using the same principle as wind-up cars, but with a huge steel or carbon fiber disc in a vacuum container with magnetic levitation, the winding process creates energy storage. This is a widely used technology that has been on the market for years. The International Space Station operates under this principle, with an efficiency of 95 %.
Using the law of conservation of energy, supported by basic physical principles, green energy is stored and injected into the supply grid to meet the demand of all users when necessary, regardless of their production.
Energy storage appears to be the key to ensuring a constant and reliable supply in an energy system powered by renewable sources. Through these innovative technologies, we are getting closer to eliminating dependence on fossil fuels, stabilizing the electricity grid, and significantly reducing energy costs. These actions will not only drive the transition to a cleaner future but also generate job opportunities in a growing sector.
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