As the world moves towards a more renewable and decentralised energy system, energy storage is becoming increasingly important. 

Energy storage technologies allow us to store energy when it’s available and release it when it’s needed, providing a range of benefits for the grid, businesses, and households.

One of the primary reasons efficient energy storage is crucial for the green transition is the need to manage variable energy supply. Renewable energy sources like wind and solar are intermittent and don’t provide a consistent energy supply. Energy storage can help smooth out these fluctuations by storing excess energy when it’s available and releasing it when needed.

As many renewable energy sources are becoming cheaper and cheaper, storing them and using them later can be very cost-efficient for society. 

Energy storage can also provide backup power during emergencies and help reduce peak demand, which occurs when many people use electricity simultaneously. 

By storing excess energy during off-peak hours and releasing it during peak hours, energy storage can help prevent blackouts and reduce the need for expensive infrastructure upgrades or reliance on fossil fuels.

Improving energy storage infrastructure and overcoming the issues posed by the intermittent renewable energy supply is essential to achieve decarbonisation targets and can drastically help eliminate our fossil fuel dependence. 

Thermal Energy Storage

Thermal energy storage (TES) is an innovative technology that offers a promising solution for storing and releasing heat energy. It allows us to leverage renewable energy sources such as wind and solar by utilising the energy they generate to heat a “thermal battery” that can store the heat for several hours or even days.

This stored energy can be used to generate electricity when needed, especially during periods when renewable energy sources are not readily available. This approach is a game-changer for renewable energy as it enables us to use it when it’s most cost-effective, which typically occurs during sunny or windy periods. 

As a result, the overall cost of electricity can be reduced, and the grid’s stability can be improved.

⚡️Renewables alone will not solve the current energy and climate crisis. Long-duration energy storage is critical to help the EU overcome today's energy challenges. We're pleased to see the inauguration of the EIB financed @bren_energy gigafactory for thermal energy storage. pic.twitter.com/X9kr0W8tp0

— EIB Global (@EIBGlobal) May 2, 2023

One of the main benefits of TES is that it offers a simple approach to energy storage. Thermal batteries are typically constructed from abundant materials that are cheap to assemble and maintain and can operate for many years.

For instance, a lot of TES companies, such as Antora Energy, use solid carbon, which is extremely cheap and highly accessible. The existing supply chain of solid carbon is over 30 million tons a year, 50 times the available quantity of lithium. 

The technology is also highly scalable, meaning it can be adapted to suit various applications, from large-scale power plants to smaller residential buildings.

Pumped hydroelectric storage

Pumped hydroelectric storage (PHS) is currently one of the most widely used forms of energy storage. PHS involves pumping water from a lower reservoir to a higher one during low electricity demand, such as at night, using excess electricity generated from renewable sources. 

During periods of high demand for electricity, the stored water is released to the lower reservoir which generates electricity by turning turbines. This process enables excess electrical capacity to be stored efficiently and inexpensively, allowing it to be released when it is most needed.

According to the International Energy Agency (IEA), the total installed capacity of PHS worldwide was around 160 GW in 2021, making it the most widely deployed grid-scale storage technology. 

Indeed, PHS accounts for over 90% of the world’s electricity storage, at approximately 8,500 GWh in 2020. 

The majority of PHS plants currently in operation provide daily balancing, ensuring a steady supply of electricity during peak demand. However, there is potential for PHS to be used in larger-scale applications, such as supporting the integration of intermittent renewable energy sources into the grid.

Scotland can more than double UK’s pumped storage Hydro capacity to 7.7GW, create almost 15,000 jobs, & generate £5.8 billion for the UK economy by 2035. https://t.co/Oo83qkQyVE

— Celtchar 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🏴󠁧󠁢󠁷󠁬󠁳󠁿 🇮🇪 (@Dubh_Doeltenga) May 10, 2023

The United States has the largest capacity of PHS, with many plants scattered across the country. The world’s largest PHS plant, the Bath County Pumped Storage Station, is located in Virginia, with a capacity of more than 3 GW, a 24 gigawatt-hour storage capacity, the equivalent of one year of electricity use for 6,000 homes. 

Despite its benefits, PHS does have some limitations, including the need for suitable topography and access to large amounts of water. Nevertheless, PHS remains a key technology for energy storage and has enormous potential to help accelerate the transition to a more sustainable energy future.

Green hydrogen 

The production of green hydrogen through electrolysis powered by renewable energy sources like solar and wind offers a promising solution for long-term energy storage. 

Hydrogen produced from this process can be stored and converted back to electricity when needed, providing balancing power for the grid. Most importantly, it can be burned when required without releasing any GHG emissions.

One of the significant advantages of hydrogen is its ability to be stored for months without losing power through discharge, making it an attractive option for long-term energy storage. In comparison, lithium-ion batteries can only store energy for a couple of hours.

On the other hand, the “power-to-gas-to-power” process required by green hydrogen has a high energy storage capacity, but it is less efficient and more expensive than other storage technologies. 

Indeed, converting the power to gas and back to power has an efficiency of 18%-46%, according to the Massachusetts Institute of Technology. To put that into perspective, pumped-storage hydropower has an efficiency closer to 70%-85%

Despite being a promising option for energy storage, the logistics and infrastructure to scale up its production are not yet developed enough. 

Bringing production costs down and at a larger scale could provide a significant step towards reducing carbon dioxide emissions and even creating a circular economy. 

Many projects are already in the works as more industry leaders, such as John Ketchum at NextEra Energy Resources, see green hydrogen as a “really long-term solution.” NextEra is already working on 50 potential green hydrogen projects. 

In the EU, many projects have been implemented, such as the Green Skills for Hydrogen, an EU-backed skill conversion and training program aimed at equipping workers with the necessary tools and skills to adapt to the new technology. 

Gravity Batteries

Gravity batteries are a new form of energy storage technology that leverages the power of gravity and regenerative braking to send renewable energy to the grid. 

The batteries work by using renewable energy to lift a heavy object into the air or to the top of a deep cavity in the ground, and then lower the weight when energy is in high demand. The movement of the cables to bring the object up and down will produce electricity on demand, thus overcoming the issue posed by inconsistent energy production.

Unlike conventional batteries such as lithium-ion, gravity batteries do not experience self-discharge, meaning they can store energy for months or even years.

Researchers have discovered that abandoned mines worldwide can be repurposed to store energy, providing a unique solution for excess energy generated during good weather conditions.

One of the significant benefits of using abandoned mines for energy storage is the ability to use existing infrastructure. 

Mines are already connected to the power grid, reducing the cost and complexity of implementation. 

A recent study by the International Institute for Applied Systems Analysis (IIASA) suggests that these decommissioned mines could provide up to 70 terawatts of energy storage, which is enough to match the entire world’s daily electricity consumption. 

With an estimated 550,000 abandoned mines in the U.S. alone, this technology has immense potential.

Some companies are already building gravity batteries that don’t require mines and can be dropped anywhere. This technology would make energy storage more accessible, affordable, and scalable, opening up new possibilities for renewable energy.

In the UK, a trailblazer project, Gravitricity, has been testing a gravity battery in Edinburgh by using a 15-meter steel tower to bring the heavy weight up and down using solar power. 

Although the project operated only for 10 seconds, it demonstrated that the theory could be put into practice. 

Jill Macpherson, the project’s senior test and simulation engineer, elaborated on the successful experiment: 

“The demonstrator was rated at 250kW – enough to sustain about 750 homes, albeit for a very short time. But it confirmed that we can deliver full power in less than a second, which is valuable to operators that need to balance the grid second by second. It can also deliver large amounts more slowly, so it’s very flexible.”

The promise of such batteries is unmatched, as they can be implemented all around the world, including in Africa; as said by Gravitricity’s founder, Charlie Blair: 

“If this technology is one that really makes a difference it’s going to make a difference globally. It’s going to keep the lights on in Africa, as they build the grid, just as much as it will in Europe.”

Building holes specifically for these gravitational batteries in Africa could allow them to go as deep as 2 km. In Africa, integrating these batteries into the network could drastically improve access to electricity. In Europe, it could provide an efficient solution to storing renewable energy. 

🇩🇪 Excited to announce we've been contracted by Geiger Gruppe to investigate storing energy in a decommissioned mine shaft, near Halle in Germany.

🏗️ If the initial study is positive it could lead to a full-scale gravity energy storage plant.

Details 👉 https://t.co/3sUDFLvVd4 pic.twitter.com/YP5u7PtCnV

— Gravitricity (@gravitricity) April 26, 2023

While gravity batteries are a promising technology, there are still many barriers to adoption. Cost is a significant concern, as is the need to optimise the technology for different environments and use cases. 

Further research and development are required to improve the efficiency and reliability of these batteries. Nonetheless, the potential of gravity batteries to provide long-term energy storage using existing infrastructure is a compelling reason to explore this technology further.

Developing efficient and large-scale technology for energy storage will help society overcome one of the most prominent issues with using renewable energy — the inconsistencies in supply that are unable to match peaks of demand. It is thus crucial to keep progressing in energy storage research worldwide and collaborate to achieve a long-term solution. 

Editor’s Note: The opinions expressed here by the authors are their own, not those of Impakter.com — In the Featured Photo: Electric Towers Featured Photo Credit: Anja van de Gronde

Beyond Batteries: Most Efficient Energy Storage 2023

ByGuest@HuaweisolarBlog

Leveraging technology for a sustainable future and choosing the most efficient energy storage plays a crucial role in shaping the energy landscape. This article focuses on these systems, offering a comprehensive list and discussion of their attributes, advantages, and real-world applications. We will delve into how these storage systems interface with renewable energy, the benefits they bring, and how they might shape the future of energy storage.

Most Efficient Energy Storage

Here are the most efficient energy storage devices of 2023:

Lithium-Ion Batteries

Arguably one of the most popular energy storage technologies in today's market, Lithium-Ion batteries excel in terms of energy density and charge/discharge efficiency, enabling them to deliver a remarkably high return of energy. Their compact size, light weight, and longevity makes them ideal for diverse applications including electronics, electric vehicles and renewable energy systems. However, their critical drawbacks like the potential for overheating and high cost remain concerns.

Thermal Energy Storage

Thermal energy storage methods store energy by heating or cooling a storage medium, which is later used for applications like power generation or heating/cooling purposes. Examples include sensible, latent, and thermochemical TES, each with varying efficiencies and applications. TES can operate at varying scales, making it flexible and ideal for applications from industrial to residential.

Pumped Hydro Storage

Pumped Hydro Storage (PHS) is a large-scale, long-duration energy storage technology wherein energy is stored in the potential energy of water. During times/periods of low electricity demand, excess energy is utilized to pump water to an upper reservoir. When electricity demand increases, this stored water is released to produce power. PHS's high efficiency (70-85%) makes it one of the most efficient large-scale energy storage solutions currently available.

Liquid Air Energy Storage

Liquid Air Energy Storage (LAES) stores electric energy by cooling and liquifying air, then storing it under pressure. When power is needed, the pressure change causes the liquified air to expand and drive a turbine. LAES is scalable and can deliver a long-duration energy storage system, with the potential for 60-70% round trip efficiency.

Compressed Air Energy Storage

Similar to PHS, Compressed Air Energy Storage (CAES) uses off-peak electricity to store energy. However, in this case, the energy is used to compress air and store it underground. Upon demand, this compressed air is expanded in a turbine to generate electricity. Despite its complex setup, CAES is advantageous for large-scale, long-duration energy storage systems, with efficiencies ranging around 40-70%.

Flow Batteries

Flow batteries utilize the principle of reduction-oxidation reactions to store and discharge energy. This energy storage container is distinguished by its capacity for almost unlimited energy storage, separate energy and power scaling, and long cycle life. Though their round-trip efficiency (65-75%) is slightly lower than traditional batteries, their extensive longevity and scalability for grid storage make them notably efficient for certain applications.

Green Hydrogen

Green hydrogen, also known as renewable hydrogen, stands as one of the most efficient energy storage solutions (ESS Solution). It refers to hydrogen produced through electrolysis powered by sustainable energy sources like solar power. This process splits water into hydrogen and oxygen, with the former being stored and used as needed. It produces zero greenhouse gases and, when used as fuel, only water is emitted. Green hydrogen has the potential to be utilized for various applications, from fuel cells in vehicles to a utility-scale energy storage solution. Because it can be produced during periods of excess renewable energy production, it effectively addresses the intermittent issue associated with renewable power sources.

Flywheel Energy Storage

Flywheel energy storage is a mechanical battery that stores kinetic energy in a rotating mass. The flywheel spins rapidly and the energy is stored in the system as rotational energy. It's known for its high efficiency, long operational life and ability to deliver power quickly. This energy storage solution efficiently converts and stores energy that would otherwise be wasted, and its primary function involves load-leveling to smooth out power delivery. Flywheels can also deliver stored energy instantaneously, which is beneficial in instances requiring immediate power, such as power quality applications and grid stabilization.

Power-to-Gas Systems

Power-to-Gas (P2G) systems provide a promising means of large-scale energy storage by converting electrical energy into gas (usually hydrogen or methane) that can be stored in the existing natural gas grid. Energy is stored in the gas form for later use when the demand for electricity exceeds the supply. P2G systems are highly beneficial for their large capacity and long-duration energy storage capabilities.

Gravity Energy Storage Systems

Gravity energy storage systems are a form of gravitational potential energy storage. They essentially work on the principle of storing energy in an object positioned high above the ground. When there is a surplus of energy, like during the day with solar power, energy is used to raise a massive object. When energy is needed, this object is allowed to fall, and the kinetic energy generated is converted back into electrical energy. These advanced energy storage technologies are advantageous because they can store energy for long durations with minimal losses, have low maintenance requirements, and are environmentally friendly.

Lead-Acid Batteries

Lead-Acid batteries are the oldest kind of rechargeable batteries. They consist of lead (anode) and lead dioxide (cathode) with a sulfuric acid solution acting as an electrolyte. The chemical reaction between these components allows the storage of electrical energy. They are often used in vehicles and in power storage for solar panels and wind turbines. While not as efficient or long-lasting as some modern battery technologies (like lithium-ion), they remain popular for their low cost, reliability, and well-understood recycling process.

Conclusion

Wrapping up, breakthroughs and progressive developments profoundly characterise the landscape of the most efficient energy storage. The potential held by these technologies, like FusionSolar, not only guarantees a sustainable future but also highlights potential solutions for energy concerns we face today. These advancements reaffirm the vital role efficiency plays within the most efficient energy storage, paving the way for further innovations thus instilling optimism towards our global green energy goals. Join FusionSolar, the forefront PV solution provider, in shaping the future of energy storage and sustainability.

FAQ

Here are some commonly asked questions about the most efficient energy storage.

Are Flywheels Better than Batteries?

Choosing between flywheels and batteries really depends on the specific application. Flywheels are effective for storing large amounts of energy, particularly for short durations, offering instant power with less deterioration over time and tough environmental conditions. They excel in high-cycle applications where rapid charging and discharging occur, such as in grid balancing. Batteries, on the other hand, are more efficient and versatile for portable applications and longer-duration energy storage. They are also more established and have a wider range of technologies (lithium-ion, lead-acid, solid-state, etc.) catering to different uses.

What Is the Cheapest Energy Storage?

Pumped Hydro Storage is usually considered the cheapest form of large-scale energy storage. It uses two water reservoirs at different heights to store and generate power. When demand is low, excess energy is used to pump water to the upper reservoir. When demand is high, the stored water is released to generate electricity. The affordability of Pumped Hydro Storage is largely due to its maturity and deployment scale.

What Is the New Type of Energy Storage?

One of the newest types of energy storage is Gravity Energy Storage Systems. This latest energy storage technology employs the potential energy of an elevated mass. When energy is available, a large weight is lifted. The stored energy is recovered when the weight descends, turning a turbine connected to a generator. New developments are occurring in this field, with approaches like Energy Vault's concrete-block gravity battery gaining attention.