grid-scale

Grid-Scale Gravity Energy Storage | Earth Wise

September 19, 2023 By EarthWise Leave a Comment

As wind and solar energy play a growing part in our energy system, the need for grid-scale energy storage is growing as well. An historic form of energy storage and still the largest in installed capacity is pumped hydro storage, which makes use of the potential energy contained in having water sitting at a higher elevation where it can be released downward to operate turbine generators. This is an effective system but is limited to places where geography cooperates.

For the past five years, a company called Energy Vault has been developing a system that uses the same principle to generate electricity but instead of pumping water to a higher elevation, it uses mechanical devices to lift heavy objects such as concrete blocks to an appropriate height. Lowering the blocks back to the ground drives generators.

To date, Energy Vault has only built demonstration systems with a fraction of the storage capacity needed for grid-scale operation. Their EV1 Tower in Switzerland was successfully grid interconnected in 2020 and demonstrated round-trip efficiency (the fraction of the energy stored that was produced by the generators) above 75%. Their improved EVx system is expected to do better than 80%.

This year the company, along with partners Atlas Renewable and China TIanying, is now in the first phases of commissioning a grid-scale system located outside of Shanghai, China. The 25-MW system is built adjacent to a wind farm and a national grid interconnection site

This is the first grid-scale gravity energy storage system and is expected to be fully online in the fourth quarter of this year. A second, similar system is now under contract to be built elsewhere in China.

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First grid-scale gravity energy storage system undergoes commencement in China

Photo courtesy of Energy Vault.

Earth Wise is a production of WAMC Northeast Public Radio

Cutting The Cost Of Energy Storage | Earth Wise

September 9, 2021 By EarthWise Leave a Comment

The cost of both solar and wind power continues to drop making the two renewable energy sources the cheapest way to make electricity in more and more places. Given the virtually inexhaustible supply of both wind and sun power, these clean electricity sources can in principle meet all our energy needs. The hang up is that both of them are intermittent sources – the wind doesn’t blow all the time and the sun doesn’t shine all the time.

The solution to the intermittency problem is energy storage. If energy produced by wind and sun can be stored so it can be made available for use at any time, then the goal of having 100% clean energy can be realized.

Energy storage technology has continued to improve over time and to get cheaper. The Department of Energy recently announced a new initiative aimed at accelerating both of these trends.

The new program – called Long Duration Storage Shot – has the goal of reducing the cost of grid-scale, long-duration energy storage by 90% within this decade.

Long-duration energy storage is defined as systems that can store energy for more than ten hours at a time. Such systems can support a low-cost, reliable, carbon-free electric grid that can supply power even when energy generation is unavailable or lower than demand. With long-duration storage, solar-generated power can be used at night.

The program will consider multiple types of storage technologies – electrochemical (that is: batteries), mechanical, thermal, chemical carriers, and various combinations thereof. Any technology that has the potential to meet the necessary duration and cost targets for long-term grid storage are fair game for the program.

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DOE announces goal to cut costs of long-duration energy storage by 90%

Photo, posted October 16, 2017, courtesy of UC Davis College of Engineering via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Grid-Scale Battery Storage is on the Rise | Earth Wise

February 4, 2021 By EarthWise Leave a Comment

Driven by steeply falling prices and improving technology, grid-scale battery storage systems are seeing record growth in the U.S. and around the world. Battery storage is a way to overcome one of the biggest obstacles to renewable energy: the cycling between oversupply when the sun shines or the wind blows, and shortage when the sun sets or the wind drops. Storing excess energy in battery banks can smooth imbalances between supply and demand.

In California, a 300-megawatt lithium-ion battery plant is being readied for operation with another 100 megawatts to come online in 2021. The system will be able to power roughly 300,000 California homes for four-hour periods when energy demand outstrips supply. It will be the world’s largest battery system for a while until even larger systems in Florida and in Saudi Arabia come online.

Nationwide, a record 1.2 gigawatts of storage were installed last year and that number is projected to jump dramatically over the next five years to nearly 7.5 gigawatts in 2025.

The price tag for utility-scale battery storage in the U.S. has plummeted, dropping nearly 70% just between 2015 and 2018. Prices are expected to drop by a further 45% over the next decade. Battery performance has continued to improve dramatically with increased power capacity and the ability to store and discharge energy over ever-longer periods of time.

Favorable energy policies including renewable energy mandates coupled with continued price drops will drive the widespread expansion of battery energy storage.

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In Boost for Renewables, Grid-Scale Battery Storage Is on the Rise

Photo, posted November 17, 2016, courtesy of Steve Ryan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.