What are the Current Energy Storage Systems Used For Renewable Energy?

solar panel under blue sky

Renewable energy power plants like solar power and wind farms are a growing resource but storing excess energy has always been an issue getting in the way of its potential.

Fortunately, we’ve recently made a lot of headway in renewable energy storage solutions. Many options show a lot of promise for helping us move away from toxic batteries and reducing humanity’s carbon footprint on the planet.

Electrical grids are complex systems requiring a significant balancing act to ensure that supply and demand are equal, and viable renewable energy storage solutions will be essential to maintaining that balance and delivering greater reliability and flexibility.

Check out a few trending renewable energy storage solutions that show potential for ensuring a steady flow of power to the grid.

Pumped Hydro

A pumped hydro system borrows many principles used in traditional hydroelectric power generation wherein stored water is released through turbines to generate energy.

However, instead of building large dams that devastate the local ecology, pumped hydro uses excess electrical energy to power pumps that push water into an uphill reservoir. During peak demands, or when green energy is not available, the water is released to flow downhill through turbines until it reaches a downhill reservoir, where it is stored, ready to be used for the next excess energy cycle.

According to the International Energy Agency, hydropower, which includes pumped hydro, will continue to be a key player in reducing carbon output.

Pumped hydro faces many challenges, such as cost and geographical limitations on where it is feasible. The reservoirs need to store significant water volumes at height, limiting this system to a particular type of landscape.

Thermal Energy Storage

Thermal energy storage has proven helpful for industrial complexes and buildings. Excess energy, usually from renewable resources like waste heat, is stored for later use.

There are a few different types of thermal energy storage systems in development, including:

Sensible Storage – Heat energy is stored in a medium while keeping it in a solid or liquid form. The term comes from the ability to ‘sense’ a temperature change in the medium. Energy is recovered by allowing the medium to cool. Materials used to store heat include oil, rocks, water, air, and molten salts. 

Thermochemical Storage – Thermochemical storage systems absorb heat energy that causes the absorbing compound to split into two different chemicals. Releasing heat by reversing the process can be used to generate power.

Phase Change Storage – Phase change storage systems store energy by changing a medium from solid to liquid. Phase change materials absorb heat energy when cooled and released when heated.

Battery Energy Storage

Lithium-ion or lead-acid battery banks convert stored chemical energy into electrical energy. Batteries have been around for a long time, explaining why battery energy storage systems are so prevalent in renewed energy storage systems.

The Tesla Powerwall is a popular lithium-ion battery configuration used as a backup power supply for homes capturing solar energy. However, advances in battery technology have enabled grid-scale battery facilities to deliver renewable energy sources to entire communities 24/7. For example, the Moss Landing Energy Storage Facility in California in the US stores up to 300-megawatts in a 4,500 stack of lithium-ion batteries.

Research into battery technology is ongoing, and more grid-scale applications for batteries are planned around the globe. But are batteries the solution for a carbon-neutral world that needs to rely more on green energy solutions?

Unfortunately, the manufacture of batteries imposes enormous costs on the environment. Lithium mining is responsible for pollution at a scale that has the potential to destroy the local ecosystem unless carefully managed. Recycling spent batteries is expensive and complicated, so most lithium-ion batteries will continue to find their way into landfills.

Kinetic Energy Storage

Kinetic energy storage is an emerging technology that uses a spinning flywheel to store energy.

Excess energy spins up a heavy flywheel, and a few clever engineering principles are employed to ensure the stored kinetic energy is accessible for hours afterwards.

Magnets support the flywheel inside a vacuum chamber, reducing friction to almost nothing and eliminating wasted energy through heat and noise. When the flywheel energy storage system switches over to generator mode, it can return power to the grid when green energy is unavailable or during peak demand.

Why Kinetic Energy Storage is One of the Most Promising and Exciting Solutions

Out of all the new technologies for green energy storage, flywheel energy storage has the most promise of all renewable energy storage systems.

Unlike pumped hydro or compressed renewable energy storage solutions, flywheel energy storage units can be installed anywhere that needs a large-scale energy storage strategy.

They are also manufactured from 100% recyclable materials, have a service life of many decades, and require very little maintenance after installation. Compare that to batteries that use toxic chemicals, require careful management of recharge and discharge cycles, and will need replacing every 5 to 10 years, depending on the type and configuration.

Amber Kinetics – Spinning Up Power for a Carbon-Free Future

Amber Kinetics is a kinetic renewable energy storage solutions company pioneering the way towards a carbon-free future.

Their flywheel energy storage solution is the first commercially available product using advanced technologies to deliver a four-hour-discharge cycle of 32 KWh of energy.

Individual flywheels can be scaled up to tens or even hundreds of megawatt capacities, making flywheels a viable solution for powering the modern grid at cheaper rates than other renewable energy storage solutions.

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