BOSTON, Sept. 3, 2020 /PRNewswire/ — The electricity grid is undergoing its first evolution since the invention of the power transmission system, and energy storage devices, particularly mechanical energy storage devices, will play a solid role in this evolution.

Decarbonization, renewable energies, and energy storage devices are all factors involved in the current evolution of the electricity grid. In the last decades the integration of renewable energies, pushed by the necessity to decarbonize the electricity sector, led energy storage devices to become increasingly important to stabilize the electricity grid.

The increased adoption of variable renewable energy led the electricity grid operator to adopt energy storage systems to smoothen the variability of renewable sources.

Li-ion batteries, currently dominating the storage sectors in all of its aspects. From portable electronics to MW scale storage systems, Li-ion batteries will struggle in the future to address the MW scale power and daily storage duration, when Mechanical Energy Storage systems will enter the market.

In the brand-new report “Potential Stationary Energy Storage Technologies to Monitor,” IDTechEx has investigated these emerging technologies. With a simple working mechanism, Mechanical Energy Storage systems are addressing the bigger spectrum of the energy storage devices: large power output, and long storage time.

This new class of storage systems include older and newer technologies. It includes elderly technologies like compressed air energy storage, already installed in the 1980s, and some of the younger gravitational energy storage, like in the case of Highview Energy, and Energy Vault recently backed with millions of dollars.

These interesting devices are now entering the electricity market with demonstration projects, to prove the technical concept. The constant integration of variable energy sources will require additional storage devices to stabilize the electricity grid, where the Mechanical Energy Storage device could play a fundamental role.

The US industry deployed 168MW / 288MWh of energy storage in the second quarter of this year, the second highest quarterly figures on record, according to Wood Mackenzie Power & Renewables.

The market research and analysis firm has just issued its latest quarterly US Energy Storage Monitor, produced in cooperation with the national Energy Storage Association industry group. The figures are up on Q1 2020’s 98MW / 208MWh of installations and are second only to the record-breaking final quarter of 2019, when 186.4MW / 364MWh of deployments were made.

Wood Mackenzie noted that one single grid-scale project in California made up two-thirds of the total deployments for the quarter: the state is leader in all three segments of the US market, from front-of-meter (62.5MWh in Q2), residential (66.1MWh) to non-residential including commercial and industrial behind-the-meter (32.1MWh).

Other states to lead the market segments included Hawaii (26.2MWh residential and 15MWh non-residential), Massachusetts (23.7MWh non-residential and 14MWh front-of-meter), Oklahoma (20MWh front-of-meter) and Arizona (3.5MWh residential).

Firm revises annual deployment forecast downward slightly
While Wood Mackenzie had earlier in the year issued a forecast for the annual market to total 7.2GW in size and US$7.2 billion in monetary terms by 2025 in the US, the latest Monitor predicts that US deployments will reach “nearly 7GW” annually by 2025, worth about US$6.9 billion.

Nonetheless the growth forecast is still a significant jump from the 1.2GW of expected installations in 2020, which the analysis firm pointed out still meant the market crossed the US$1 billion threshold despite the COVID-19 pandemic’s impacts.

Finnish technology group Wärtsilä has secured an engineering, procurement, and construction contract from Duke Energy for three battery storage facilities in the US.

In North Carolina, Duke Energy’s Asheville (8.8MW) and Hot Springs (4MW/4MWh) facilities will receive battery storage facilities under the contract. These are part of the company’s $2bn grid modernisation programme in western North Carolina.

The third energy storage facility is Duke Energy’s Crane project, located in Indiana. All three storage project sites are expected to be commissioned during 2020 and 2021.

A Wärtsilä spokesperson said the company would use its GEMS energy management platform in the projects. It will also use the software for planned battery sites and solar assets across six energy distribution areas.
The company said this will enable North Carolina facilities to dispatch energy, provide emergency backup power and balance the local grid.

Wärtsilä energy storage and optimisation vice-president Andrew Tang said: “Duke Energy is specifically utilising the GEMS Fleet Director and GEMS Power Plant Controller to monitor, assess and optimize deployments across multiple regions in real-time and integrating GEMS as a data source for their specialised algorithms and analytics.

“GEMS will be customised for Duke Energy’s deployments to increase grid resilience at sites that require energy storage backup and to ultimately facilitate the first-ever entry into the Midcontinent Independent System Operator market.”

As renewable energy generation grows, so does the need for new storage methods that can be used at times when the Sun isn’t shining or the wind isn’t blowing. A Scottish company called Gravitricity has now broken ground on a demonstrator facility for a creative new system that stores energy in the form of “gravity” by lifting and dropping huge weights.

If you coil a spring, you’re loading it with potential energy, which is released when you let it go. Gravitricity works on the same basic principle, except in this case the springs are 500- to 5,000-tonne weights. When held aloft by powerful cables and winches, these weights store large amounts of potential energy. When that energy is needed, they can be lowered down a mineshaft to spin the winch and feed electricity into the grid.

Gravitricity says that these units could have peak power outputs of between 1 and 20 MW, and function for up to 50 years with no loss of performance. Able to go from zero to full power in under a second, the system can quickly release its power payload in as little as 15 minutes or slow it down to last up to eight hours.

To recharge this giant mechanical battery, electricity from renewable sources power the winches to lift the weights back to the top. In all, the system has an efficiency of between 80 and 90 percent.

Ultimately, this kind of system should be able to store energy at a lower cost than other grid-scale energy storage systems, such as Tesla’s huge lithium-ion battery in Australia. The concept sounds very similar to the one behind Energy Vault, which uses a crane to hoist concrete blocks into a tower.

That said, Gravitricity seems to be further ahead in development. The company is now in the early stages of constructing a demonstrator facility to test out the concept next year. The tower will stand 16 m (52.5 ft) tall, lifting and dropping two 25-tonne weights in order to generate 250 kW.

Agreements to deploy 1GWh of novel aqueous zinc battery energy storage in Texas and 500MWh in California have been struck by technology provider Eos Energy Storage, marking a massive scale-up in expected installations for the systems.

Eos Energy Storage said in a press release yesterday that its long duration zinc hybrid cathode batteries, which are best suited for 4-6 hour discharge but have the flexibility to go to higher power and longer run-times through de-rating power, have been ordered by ‘technology agnostic’ power producer International Electric Power for 1GWh of projects to be connected to the grid run by the Electricity Reliability Council of Texas (ERCOT).

A second customer, Carson Hybrid Energy Storage (CHES), has ordered Eos’ zinc batteries for the full capacity of a 500MWh energy storage facility in the Los Angeles Basin. CHES will use the zinc batteries to store surplus solar that otherwise would be curtailed and unused, while also easing congestion on transmission lines. The project will be preceded by a 1MW pilot to be constructed next year.

CHES president Peter Reardon said that the fire safety of Eos’ technology was a big factor in their selection, as was the ‘Made in the USA’ tag that accompanies the battery systems – Eos has partnered with US nuclear technology company Holtec to create a manufacturing joint venture (JV) called HI-POWER. Alongside the order announcements, Eos said Holtec has invested a further US$10 million into the JV on top of an initial US$12 million it put in last year.

Eos not only makes and supplies the batteries but also the integrated AC Battery Energy Storage System (BESS) that the customers require to connect them to the grid and to other energy resources such as solar and wind. The company claims its battery systems are non-flammable as well as made from widely-available, recyclable materials and as far back as 2017 was claiming solar-plus-storage with 4-hour discharge could be possible for as low as US$0.10 per kWh using the technology.