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Long Term Energy Storage Will Impact The Future Of Renewable Energy

Updated: Jul 9


long term energy storage

As the world transitions to renewable energy sources, the issue of intermittency must be overcome. If renewable electricity sources, including wind and solar power, can completely phase out the use of coal and natural gas, we will need to have energy around the clock. Sometimes, wind and solar farms produce surplus power when demand is low, resulting in waste. Therefore, long term energy storage is essential for slowing climate change and ensuring a stable energy supply.


Although lithium-ion batteries in utility-scale battery storage systems are great for short-term energy storage, they are not currently cost-effective for long periods of time, and they can experience issues with thermal runaway. Advancing long-duration energy storage (LDES) technologies is critical to the decarbonization of energy by providing system flexibility and managing fluctuations in energy supply and demand. Let’s explore this topic to gain a greater understanding of how LDES can help decarbonize energy in a reliable and cost-effective manner.


What Is Long Term Energy Storage?

LDES technologies include mechanical, thermal, electrochemical, and chemical storage systems that can store energy economically for days or even weeks. Ideally, these technologies will use low-cost and readily available raw materials and have high energy densities. However, there is currently no clear leader among long-duration energy storage technologies, but there are several promising options.


The United States Department of Energy defines LDES as energy storage systems capable of providing electricity for durations of 10 hours or more. The Bipartisan Infrastructure Law appropriates $505 million to develop LDES demonstrations “to validate new technologies and enhance the capabilities of customers and communities to integrate grid storage more effectively.”


According to Greentech Media, the five most promising LDES technologies are:


This involves pumping water from a low to a high reservoir. When electricity is needed, water is released and generates electricity at hydroelectric power plants. Once built, these long term energy storage projects are inexpensive to operate. However, few sites are suitable for this application, because they disrupt ecosystems, and projects can cost billions of dollars.


The first use of PSH dates back to the 1890s in Switzerland and Italy, and it was first used in the United States in the 1930s. There are currently 43 PSH plants in the United States, and there is the potential to double the pumped storage hydropower capacity for long term energy storage.


Stacked Blocks

long term energy storage
Energy Vault Project in Switzerland

Like pumped hydro, this technology involves converting electricity into potential energy through the use of heavy blocks. However, it doesn’t have many of the same challenges and can be deployed in a wider range of locations.


The Swiss company Energy Vault creates stacked block energy storage systems that power crane motors to move concrete blocks up a tower. Then, the crane motors can go in reverse when lowering blocks, creating electricity in a process that is about 85% efficient. Energy Vault was recently selected for a 440-mWh long term energy storage system in Nevada.


Liquid Air Energy Storage (LAES)

This long term energy storage technology involves storing electricity in the form of liquid air or Nitrogen at temperatures below -150 degrees Celsius. A charging device uses off-peak electricity to power a liquefier, which produces liquid air held in an insulated tank at low pressure. A power recovery unit re-gasifies liquid air to power a turbine to generate electricity. Unlike pumped hydro, there aren’t geographical constraints for this long term energy storage technology, and it uses components in other commercial applications.


Highview Power specializes in cryogenic energy storage and is based in the United Kingdom and the United States. It has numerous projects in various stages of development that utilize LAES technology, including two existing pilot projects.


Underground Compressed Air

This concept uses excess electricity to pump compressed air into a cavern. Releasing the compressed air powers a generator to produce electricity as needed.


Although this approach to long term energy storage has geologic constraints, the Canadian company Hydrostor is trying to overcome this by using purpose-built caves or mine shafts. It has a variety of projects in development or operation in the United States, Canada, Chile, and Australia.


Flow Batteries (Redox Flow Batteries)

This electrochemical cell provides chemical energy from two chemical components dissolved in liquids pumped through the system on separate sides of a membrane between two electrodes. Most batteries contain two tanks of liquids that circulate in their own respective spaces.


ESS is a publicly traded company based in the United States that produces flow batteries with a liquid electrolyte containing dissolved iron. It has a deal with the Sacramento Municipal Utility District in California to provide 200 MW of its products for long term energy storage.


The LDES Council

The LDES Council is a nonprofit, executive-led organization with over 60 members in 19 countries. It is dedicated to accelerating long term energy storage technologies and applications. The council provides guidance on LDES systems to governments, utility providers, and large electricity users, and its members include technology innovators, investors, and energy users.


The LDES Council is dedicated to the wide-scale adoption of long-duration energy storage to accelerate the use of clean energy, replace fossil fuels, and achieve carbon neutrality. It provides member-driven, fact-based guidance and research to help achieve net zero for energy grids by 2040.


Benefits Of Long Term Energy Storage

There are many benefits of being able to store energy for long durations.

  • Grid Stability and Reliability: Long-term energy storage helps balance supply and demand, reducing the risk of blackouts and ensuring a steady energy supply even during peak usage times.

  • Renewable Energy Integration: It allows for the effective integration of intermittent renewable sources like solar and wind, storing excess energy generated during peak production times for use when production is low.

  • Environmental Benefits: By enabling greater use of renewable energy and reducing reliance on fossil fuels, long-term storage helps lower greenhouse gas emissions and mitigate climate change.

  • Economic Savings: It can lower energy costs by storing cheap, off-peak energy and releasing it during expensive peak periods, as well as reducing the need for expensive grid upgrades.

  • Energy Security: Enhances energy independence and security by reducing the need for imported fuels and providing a reliable backup during emergencies or natural disasters.


Challenges Of Long Term Energy Storage

Long-term energy storage faces several significant challenges, which include technological, economic, and regulatory hurdles.

  • Technological Challenges: Many storage systems, such as advanced batteries or hydrogen storage, are still in the developmental stages, with issues related to efficiency, energy density, and lifespan yet to be fully resolved.

  • Economic Hurdles: The high initial investment costs and the uncertainty of long-term financial returns pose substantial barriers to widespread adoption.

  • Regulatory Issues: Regulatory frameworks often lag behind technological advancements, resulting in a lack of clear guidelines and incentives for integrating long-term storage solutions into existing energy grids.

  • Environmental and Safety Concerns: These also add layers of complexity, necessitating rigorous assessment and management practices to mitigate potential risks.


Long Term Energy Storage Puts Climate Goals Within Reach

About 20% of the electricity produced in the United States in 2021 was from renewable sources, primarily wind, hydropower, and solar, according to the Energy Information Administration. However, to slow climate change, it is critical to phase out the use of fossil fuels as quickly as possible. The advancement of LDES is essential for curtailing greenhouse gas emissions while ensuring a reliable and cost-effective power supply.


Several companies are constructing long term energy storage systems, including Energy Vault, Highview Power, Hydrostor, and ESS, and the Bipartisan Infrastructure Law is allocating $505 million for LDES demonstrations. As more LDES projects are constructed, it will be easier to evaluate which technologies are the most promising for large-scale deployment for the power sector.


Want to learn more about solar energy? The GreenLancer blog has articles about utility-scale solar and microgrids.

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