Utilities’ networks usually do not store power due to high cost; this necessitated the use of additional fossil fuel burning stations to intensify or decline as needed to meet the market demand. However, these plants caused significant environmental pollution from burning fossil fuels, leading to the emergence of the concept of energy storage as an enabling technology that helps save consumers’ money, improve reliability and flexibility, integrate generation sources and, most importantly, reduce the environmental impacts of combustion.
In this article, we discuss the concept of energy storage with its many implications for society, as well as the most famous methods of energy storage and its most important usage. If you are interested in this matter and looking for detailed information on it, this article is for you.
What is energy storage?
The concept of energy storage refers to the simultaneous assembly of energy produced for subsequent use in order to reduce the gap between energy demand and production. Energy storage involves converting them from forms that are difficult to store into forms that are more convenient or more storable. Some technologies provide short-term storage of energy, and others store for longer.
History of energy storage
In 20th century plants, electric power was largely generated by burning fossil fuels, meaning that the less energy needed, the less fuel burned. In contrast, hydropower has spread as a way of storing mechanical energy on a wide scale for centuries.
Large hydropower dams have been sites for energy storage for over a hundred years, but concerns about air pollution, energy imports and global warming have led to the growth of renewable energy such as: solar and wind energy that is sustainable but not available consistently due to weather conditions and others. This has led to increasing interest in energy storage from these intermittent sources as the renewable energy sector emerges to generate a larger portion of total energy consumption.
Benefits of energy storage
To avoid pollution, States are moving towards converting energy consumption into less environmentally polluting forms of energy the foremost among which are solar and wind power in the market, and they have become cost-competitive in a large number of areas. In the field of power generation, they have been steadily expanding their share in various places worldwide, including Germany and parts of the United States.
However, owing to the unsteady availability of these resources, there was a need to store them for later use. Energy storage is important for the entire grid in terms of it increases resources from wind, solar and hydro to nuclear and fossil fuels. Here are the 3 most important benefits energy storage achieves:
Save Money
Energy storage may save operational costs regarding operating the grid, as well as electricity consumption in homes and businesses. Furthermore, Energy storage can also offset consumer costs by storing low-cost energy and using it later during peak periods at higher electricity rates. Using energy storage during short outages, companies can avoid costly disruptions and continue normal operations.
Improve reliability and flexibility
Energy storage may provide emergency backup power at the personnel, building, or network levels. Storage provides the grid to ensure the availability of continuous energy for consumers. As the cost of outages continuously rises, the value of enhanced reliability and flexibility improvements increases.
Reduce environmental impacts
Energy storage provides energy, reflecting on the creation of power grid competencies and capabilities – including the ability to reduce greenhouse gas emissions (GHG). Energy storage also helps to improve grid efficiency — increase the current resource capacity factor- and offset the need to build new peak power plants emitting new environmental pollutants.
Usages of Energy Storage
The uses of stored energy are multiple and can be summarized in the following uses:
Mills
Prior to the industrial revolution, waterways were the primary way to process grain or operate machines, and Complex reservoir and dam systems had been built to store water and release it with its potential energy when needed.
Homes
Household energy storage is expected to become common given the growing importance of renewable energy generation, especially photovoltaics, because of increasing energy consumption in buildings. For example, to achieve 40% self-sufficiency in a home equipped with photovoltaic cells, storing energy is needed. So, many manufacturers produce rechargeable battery systems to store energy to retain surplus energy from solar or wind generation. Currently, Li-ion batteries are preferred over lead-acid batteries to store household energy due to their high efficiency.
Electricity grid and renewable energy plants
Hydroelectric dams are the first and largest source of renewable energy; A large reservoir behind the dam can store enough water for the river’s average annual flow between dry and dry seasons. Because the hydroelectric dam does not store power directly from unstable sources, it balances the grid by reducing its production and retaining its water when generating power by solar or wind power. If wind or solar generation exceeds the region’s hydroelectric power, additional sources of energy are needed.
Air conditioning
Thermal energy storage can be used in air conditioning. Commercial air conditioning systems were the largest contributors to peak loads of electricity. In 2009, thermal storage was used in at least 3,300 buildings in more than 35 countries.
Transportation
Liquid hydrocarbon fuel is the most common form of energy storage used in transportation, but the continuous supply of electricity through renewable energy is considered a challenge, so photovoltaic systems installed on the rooftops can be used to operate public transport networks during periods of increased demand for electricity which is not readily available through access to other forms of energy.
Electronics
Condensers are widely used in electronic circuits to block the direct current while allowing the alternating current to pass. For example, electrical power transmission systems stabilize both voltage and power flow.
How has the modern energy grid been adapted to renewable energy and other changes?
The most significant adaptation to date has been the rapid deployment of wind and solar energy storage, driven by low prices, government incentives and climate changes with predictions that global wind and solar will surpass gas and coal by 2024.
Also, it is expected that the demand for grid electricity will grow significantly, with electric vehicles replacing petrol cars. However, offshore wind energy still remains a largely untapped resource given that it meets much of the additional energy demand. Until then, we need a variety of options for long-term energy storage.
How has the energy storage sector evolved?
Ten years ago, none solar nor wind, as well as were widely seen to be practical solutions due to their High prices. Today, they have become highly competitive with traditional coal and gas alternatives to basic energy.
How to store renewable energy
It is known that renewable energy from solar panels and wind power with wind turbines is not always available, and it does not provide surplus energy when the demand is low. Therefore, to reduce the impact of inconsistent energy generation from renewable sources, scientists and engineers are developing ways to store surplus energy.
Here are the six best ways to store renewable energy.
1- Batteries
Batteries are probably the most common way to store energy whereas they are used in all electrical devices, from smartphones to cars. Lithium-ion batteries are a common type that are used in small devices and also account for more than 90% of battery storage on the global electricity grid, according to The Institute for Energy Studies at Western Washington University
Batteries work by connecting the negative end of the battery to an electrode called the anode and connecting the positive end to another electrode called the cathode. An electrolyte (a liquid material of electrically charged ions inside the battery) combines with electrodes to produce a chemical reaction that generates an electric current. In lithium-ion batteries, anode and cathode store lithium, according to the United States Department of Energy. The electrolyte carries positively charged lithium ions from the anode to the cathode to power something and vice versa when charging the battery. The same process could be done by using renewable energy.
Lithium-ion batteries become less efficient and more likely to fail over time; furthermore, the cost of manufacturing them is high due to the difficulty of extracting the raw negatively environmental impact materials needed to make them. These Batteries also do not retain all the energy placed in, with efficiency ranging from 85% to 95%, according to the World Energy Council‘s Report 2020.
2- Pumped Storage Hydropower
Pumped hydropower storage systems are built on or beside rivers along with hydropower production, or by using ocean seawater such as the pumped hydropower storage system on Okinawa Island, Japan, where seawater is drawn from the ocean and sent through a pipeline. The system then relaunches the water back through the tube to power the turbines and generate electricity.
3- Pumped Thermal energy Store
Pumped Thermal energy Storage includes the use of electricity generated from renewable sources to heat gravel or other easily accessible material easy to prepare, and then keep heat inside an insulated tank for generating electricity when needed. The range of pumped thermal electricity storage efficiency is between 50% and 70%.
4- Gravity Energy Storage
A British company called Gravitricity is developing technology to take full advantage of gravity. This technology uses electricity to lift the weights on the crane for subsequent re-release to transform the generator and restore most of the power used to lift it. This equipment is built in abandoned mine poles to drop about 13,200 tons (12,000 metric tons below a column more than 2,620 feet (800 meters) deep, according to the Guardian in 2019. The efficiency of this technology is estimated to be from 80% to 90% according to the same company.
5- Compressed-Air Energy Storage
Compressed-air energy storage systems pump air into an underground room to increase pressure in order to be launched upon request to operate gas turbines. It is not recommended to produce energy by burning natural gas in high-pressure air because it causes CO2 emissions. System efficiency is between 70% and 89%, according to the World Energy Council’s Report 2020.
The two most important compressed-air energy storage centres are distributed in Huntorf, Germany, and in Alabama.
6- Hydrogen Storage
Hydrogen is used to store chemical energy in accordance with the principle of converting electricity into hydrogen through a process called electrolysis, which is the splitting of water into hydrogen and oxygen components, and then hydrogen is stored as a fuel for generating electricity or operating hydrogen compounds so that it reduces greenhouse gas emissions.
The efficiency of this technology in energy storage ranges between 35% and 55% according to the World Energy Council Report 2020. But hydrogen fuel cells are very expensive due to the expensive needed materials like Platinum.
Future of Energy Storage
Energy storage takes new forms ranging from next-generation batteries to chemical energy carriers, as well as thermal storage (by using steam or molten salt), and gravity storage (where heavy materials such as rock or cement are lifted, descend to store and release energy).
It is important to have the ability to easily convert energy between electricity, heat, mechanical movement, and chemical bonds. For example, converting electricity into green hydrogen by electrolysis, or converting hydrogen into electricity in fuel cells or combustion turbines
With the instability of renewable energy sources such as wind and sun, greater attention is put on the gravitational power for generating power through what start-ups such as Gravitricity are working on to develop sophisticated systems with a simple principle: lift and descend heavy weights for energy storage and release.
To conclude, the storage of renewable energy is a key step in reducing dependence on fossil fuels such as oil, and coal that produce carbon dioxide and other greenhouse gases leading to climate change. In addition, countries are moving towards an energy transformation on alternative energy sources and storing the energy generated for use when needed. What do you think of this move, and do find that energy storage generated by renewable sources is a viable solution to the growing demand for energy around the world?
