Gravitational energy storage – how it works and is it the future of electricity storage?

Gravitational energy storage – what it is and how it works

The use of gravitational energy as a power source relies on employing large, heavy weights that are lifted upward during periods of solar energy overproduction. When energy becomes scarce, the weights are released and, as they descend, generate kinetic energy, which is then converted into electricity. These weights are usually made of concrete blocks, water-filled containers, or compressed earth masses, though other materials can also be used. Gravitational energy storage has already been developed in several different forms.

Of course, for a gravitational energy storage system to store and release electricity, it must first receive it. For this reason, such installations are typically connected to renewable energy sources, such as solar farms, wind farms, or hydroelectric plants. This setup allows for the production of clean, green energy to power large-scale economic operations.

Types of gravitational energy storage

There are different types of gravitational energy storage systems, each operating on slightly different principles, though the ultimate goal is always to store generated electricity.

Pumped-Storage Hydropower

A pumped-storage power plant pumps water from a lower reservoir to an upper reservoir during periods of energy surplus. Then, during peak electricity demand, water is released back down to drive turbine blades and generate power. Its key advantage is the ability to start up quickly, reaching full efficiency in just 3–4 minutes. Global pumped-storage capacity is estimated at over 180 GW. The main drawback is that these plants can only be built where suitable water reservoirs exist. Their efficiency is around 80%.

MGES (Mountain Gravity Energy Storage)

Another method is Mountain Gravity Energy Storage, used exclusively in areas with significant slopes. This technology involves building two cranes—one at the bottom and one at the top of a slope—that operate cable cars to haul sand or gravel upward. Electricity is generated during the upward movement. When electricity is scarce, the cars descend, driving a power-generating turbine.

The steeper the slope, the cheaper the electricity production. Recommended locations for MGES include the Andes, Himalayas, or Alps. However, this infrastructure is particularly suited for isolated areas where other types of infrastructure are not feasible, such as Hawaii. In general, MGES systems have lower efficiency than pumped-storage plants, rarely exceeding 60–70%.

ARES (Advanced Rail Energy Storage)

Yet another technology is ARES, developed by the company of the same name. It uses specially designed, multi-ton rail cars that are hauled uphill by a powerful winch when excess electricity is available. During periods of energy shortage, the rail cars are released, descending and driving energy generators. This solution is ideal as a supplementary energy source for industrial processes, helping maintain key electrical parameters such as voltage and frequency.

According to the manufacturer, this technology is resistant to explosions and ignition, easy to implement, and can maintain maximum efficiency for about 40 years.

Gravitricity

Another gravitational storage technology is Gravitricity, which makes use of abandoned mine shafts. Massive blocks are suspended inside the shafts using special winches and are raised or lowered depending on the availability of electricity in the system. The infrastructure is estimated to have a lifespan of over 50 years, and the system can deliver full energy output in less than a second.

The cost of implementing Gravitricity on an industrial scale is lower than that of conventional lithium-ion batteries, and the system generates no downtime costs.

Other innovative gravitational solutions include Energy Vault towers with suspended concrete blocks and the Gravity Power Module, which uses pressurized water inside a special cylinder. The range of available technologies is already broad, and further advancements in gravitational energy storage can be expected.

Can gravitational energy storage work at home?

Because the infrastructure can be relocated and scaled, gravitational energy storage offers significant flexibility. Unfortunately—for now—it is not a technology suitable for households. The limitation comes from the fact that gravitational storage systems are large and costly structures, so they are primarily adopted by industrial enterprises. However, it is not impossible that in the near future, such technology could be adapted to secure electricity supply for individual consumers, much like today’s solar farms. Given the risks of blackouts and recurring power grid failures, this would be a highly desirable development.

Even if a company operates on too small a scale to implement its own gravitational storage system, it is certainly worth considering partnerships with green energy providers under a Power Purchase Agreement (PPA).

Are gravitational energy storages the future of sustainable power?

At present, gravitational storage methods are not as common as traditional battery systems for solar power. Nevertheless, they are developing rapidly, and within the next decade they may begin to replace or coexist with other technical solutions. Currently, the biggest drawbacks of these technologies are their high upfront costs and the need for large areas to accommodate the infrastructure. For now, batteries remain more space-efficient, though not necessarily more effective.

Gravitational energy storage systems are already gaining traction in countries like Malaysia, where many abandoned mining shafts provide ideal conditions.

On the other hand, gravitational storage offers something solar and wind energy cannot—inexhaustibility and constancy. Gravity is a universal physical phenomenon, omnipresent on Earth and entirely independent of time of day, weather conditions, or geophysical factors.