Energy storage technologies: enabling grids to transition to decarbonized electricity

As a key driver to move away from fossil fuels, which are a massive source of CO2 emissions, renewables are an essential part of the future of energy. In this context of race against time to combat climate change, a growing emphasis is put on decarbonization of electricity.

The transition to renewable energy on a large scale is reliant on energy storage technologies. Energy storage is an essential part of the transition to clean energy and the foundation upon which the decarbonization of today’s grids must be built. Due to the intermittent nature of renewable energy - mainly wind and solar - grid operators must rely on energy storage systems to balance supply and demand. This interdependence means that storage is integral to grid resilience and reliability.

It is projected that by 2030, global energy storage installations will reach a cumulative 411 gigawatts (GW), according to the latest forecast from research company BloombergNEF - an increase of 15 times the storage online in 2021.

Other significant factors driving energy storage growth are government policies aimed at curbing increasing energy prices, meeting peak demand, and energy independence. In 2022, the Inflation Reduction Act (IRA) bill was signed into law, representing the U.S.’s largest investment to fight climate change.

Energy storage challenges: the need for widespread grid-scale technologies

A major challenge facing the industry today is the need for widespread grid-scale storage technologies. Today, the most viable solution is pumped-storage hydropower, which generates electricity by pumping water into a reservoir and then releasing it to generate electricity at a different time. Unfortunately, this technology can only be applied in specific locations. As such, grid operators must resort to fossil fuel energy sources to meet peak demand periods.

However, in recent years, advancements in storage technologies are now providing new opportunities for the potential to meet energy fluctuations in energy demand without resorting to fossil fuels. Thus giving grid operators the ability to store excess renewable energy and, to some extent, help balance in real-time energy demand to meet peak periods.

Five renewable energy storage technologies ensuring a reliable power supply

Proper energy storage ensures a reliable power supply as the electricity grid becomes more dependent on variable renewable energy (VRE) sources. What often differentiates technologies are their storage capabilities, reactivity, scalability, and application requirements.

1. Battery storage: increasingly safe and cost-effective

Battery storage is increasingly vital in solar and wind applications as it can be easily installed and provides a cost-effective solution. In recent years, newer battery technologies, alternatives to traditional lithium-ion batteries, have made their deployment safer and more cost-effective. For example, zinc batteries provide a viable alternative due to their superior stationary storage capability, non-flammability, and stable supply.

2. Thermal energy storage: a viable alternative for commercial buildings

The emergence of newer thermal energy storage (TES) technologies is making it a viable alternative in commercial buildings. TES systems can store heat or cold to be used later and are divided into three types: sensible heat, latent heat, and thermochemical. When installed in a building, a TSE solution allows the building itself to act as a thermal battery - storing renewable energy in tanks or vessels to be used when needed.

3. Hydrogen energy storage: leveraging electrolysis for a stable and reliable carbon-free energy

Hydrogen energy storage is an ideal carbon-free fuel that can lessen reliance on fossil fuel backup power plants to match supply and demand. Its high-energy storage capacity makes it attractive for grids integrating larger shares of variable energy. Because energy sources like wind and solar are variable, hydrogen storage enables any excess renewable energy to be converted into hydrogen through electrolysis. This surplus hydrogen, stored in fuel cells, ensures stable and reliable carbon-free energy.

4. Superconducting magnetic energy storage: for an instant and efficient release of energy

Superconducting magnetic energy storage (SMES) stores energy in a magnetic field. Because it can release stored energy instantaneously, it is considered ideal for grid applications requiring fast reaction time. Due to its negligible energy losses, there is increasing interest in finding a way to use it in large-scale energy storage applications. A few prototypes are currently in service, mostly under investigation, and they are beginning to be identified as a possible cost-effective solution.

5. Mechanical energy and pumped hydro-storage: ensuring grid reliability at scale

Mechanical energy storage encompasses a wide range of technologies, including pumped hydro-storage (PHS), flywheels, compressed air energy storage (CAES), and liquid air energy storage (LAES). Today, the technology most widely used in large-scale energy storage is PHS, considered the ideal form of clean energy storage for electricity grids reliant on wind and solar energy.

Absorbing surplus energy, PHS technology releases energy when demand spikes, thus ensuring grid reliability at scale. The International Hydropower Association (IHA) estimates that PHS projects worldwide store up to 9,000 gigawatt hours (GWh) of electricity, accounting for over 94 percent of installed global energy storage capacity.

What is the future of energy storage?

New materials and the development and supply of storage batteries for surplus renewable energy are quickly evolving to meet maturing requirements. Newer power electronics can convert stored energy into electricity to provide low to zero-impact solutions.

Nexans contributes in several ways to the energy transition, of which electricity storage is a key element, starting with the supply of transmission and distribution grids for the collection of renewable energy—wind and solar—at the source. It is crucial to collect electricity where it is generated (e.g. offshore wind farms) at an acceptable cost. The integration of storage sites is based on the same connection capacity, whether on a high-power scale or more widely distributed over a region.

Integrating variable renewable energies into smart grids will require an ever-increasing ability to monitor real-time usage requirements alongside automated systems in order to balance demand and supply loads. Faced with the need for greater flexibility, Nexans has developed new services accordingly.

For electric mobility applications, which are highly dependent on the technical and economic performance of electricity storage, Nexans supplies proper cable connections and protections, as for charging stations of electric vehicles, through specific safety functionalities to ensure safe energy storage.

Nexans has also acquired worldwide expertise and leadership in electrical and fire safety, that can be extended to the new applications of storage, such as vehicle batteries as they are becoming increasingly crucial.

The Group has been innovating for decades with industrial cryogenic and superconducting systems, such as with the development of a cryogenic transfer system of liquefied natural gas and hydrogen. As liquid hydrogen is very likely to play a key role in storage, Nexans will continue to innovate with breakthrough technologies to design tomorrow’s electricity grid.

Progress in energy storage technologies is vital to the transition to clean energy and the decarbonization of electricity. In the future, large-scale energy storage technologies will evolve and thus provide smart grids with the ability to reach their full potential. Diversifying and strengthening the supply chain of the new equipment for a massive deployment is a major challenge, especially for critical raw materials in a tense geopolitical context. Innovating by recycling materials used in end-of-life products is already a key driver, for which Nexans has prepared and positioned itself particularly well.