Liquid Air Energy Storage Could Save The Day For Offshore Wind

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Offshore wind fans have been getting a reality check of late, bedeviled by high costs and market uncertainties. Nevertheless, long duration energy storage could come to the rescue. The leading wind developer Ørsted, for one, is banking on a new high tech “liquid air” energy storage system, and they have reportedly seen good results from an initial analysis.

Liquid Air For Long Duration Energy Storage

Lithium-ion battery arrays have been doing much of the heavy lifting for renewable energy storage, but their job is mainly limited to daily cycles lasting a few hours. A cap of about 4-6 hours is the rule of thumb, though systems lasting up to 8 hours are beginning to emerge.

Long duration energy storage systems of 10 hours or more — including days, weeks, months, or whole seasons — are needed in order to shunt more wind and solar energy into the grid.

Large scale, long duration systems are already in use today, but mainly in the form of pumped  hydropower systems. Their application geographically limited. Now the hunt is on for more portable alternatives.

Back in 2011 CleanTechnica caught wind of one such energy storage system, a “liquid air” battery under development by the UK firm Highview Power. The R&D road has been a long one since then, but it looks like all that hard work is paying off. In 2019 Highview announced a long duration system partnership in the US state of Vermont, though the US will have to wait for its liquid air system to materialize. In 2022 Highview sidelined the Vermont storage project to focus on several others, including its first full scale storage plant, under construction in the UK with a £10m assist from the UK government.

Highview’s liquid air battery literally uses liquid air as a storage medium. The system deploys electricity to supercool ambient air down to -196 C, at which point it becomes compressed as a liquid. There it stays in a cryogenic state until electricity is needed, when heat is applied to restore the liquid to a gas, which is goes through a turbine to generate clean kilowatts.

“None of this makes any sense in a fossil fuel scenario, because cooling air into a liquid takes a lot of energy,” CleanTechnica noted back in 2020. “However, in today’s world of renewable energy, liquefied air can add value to a lot of expensive equipment that may otherwise be idled during periods of low demand.”

Ørsted Eyes Liquid Air For Co-Located Offshore Energy Storage

Ørsted and Highview fostered a ripple of excitement though the Intertubes last April, when they announced the start of a joint analysis aimed at strengthening the investor case for offshore wind in the UK. They anticipate that co-locating energy storage systems with offshore wind farms would put idled wind turbines to good use during periods of low demand.

“Storage systems will play a crucial role in supporting the stability of the power network and improving the efficiency of wind farms, encouraging future investment in renewable energy that will boost the UK’s energy security and cut consumer bills,” Highview explained in a press release.

In written testimony submitted to Parliament in September, Ørsted made the case for Highview’s storage system in particular.

“Some [long duration energy storage] technologies which are based on synchronous generation such as [liquid air energy storage] can provide advanced system services beyond electricity arbitrage, including grid stability, inertia, and dynamic response,”  Ørsted testified. “These services will be especially important to support a high renewables system as the proportion of traditional thermal generation capacity (that would normally provide such services) reduces.”

Ørsted also underscored the value of co-location.

“Siting both technologies together can help mitigate the impact of curtailment events, where offshore wind operators are asked to turn off generation at times of low demand or transmission constraint (which effectively wastes the potential to generate green power),” the company explained.

“Curtailment increases costs to consumers and generators,” they added. “Consumers not only forgo the lost generation of curtailed assets, but will face the cost of the payments made to those generators to curtail.”

As for co-location specifically, Ørsted also noted that long duration energy storage “supports the operation of the electricity system, in which local system stability is an important requirement, and precisely where co-located solutions can deliver benefits.”

A Second Chance For Offshore Wind

The main point of Ørsted’s testimony was to make the case for unblocking unfavorable UK policies standing in the way of investor confidence in long duration energy storage projects.

“The Government should ensure there is a long-term roadmap for the contribution of LDES in the energy system to provide confidence to investors. This will also provide positive signals to renewable investors as the additional storage will have a positive impact on constraint and curtailment events,” Ørsted summarized.

If the US takes similar steps, it could help turn the tide on the US offshore wind energy, which has been running into some headwinds of late. The Biden administration’s efforts to lease new offshore wind areas in the Gulf of Mexico last summer received barely any bids, and Ørsted caused an uproar when it pulled the plug on not one but two major offshore wind projects in New Jersey. Meanwhile, New York has been struggling to keep its offshore wind developers to their promises.

As of this writing, New Jersey is still forging ahead with new offshore wind solicitations next year, and New York is also committed to pursuing new wind energy opportunities.

A more clear definition of the benefits of long duration energy storage would help make their case, and that appears to be forthcoming. Earlier this week, multiple news organizations reported that the joint analysis project between Highview and Ørsted is now complete, and the findings are being submitted to the UK government.

CleanTechnica is reaching out to Highview for more details. In the meantime, it appears that the analysis has contributed to the business case for co-location.

If so, that finding is of a piece with other technologies at work in the offshore wind area, where co-location has become something of a buzzword. In addition to the potential for co-locating long duration energy storage systems with wind farms, offshore stakeholders are also looking to combine forces with green hydrogen, wave energy, and solar energy as well as seaweed farming and other forms of aquaculture.

Another element at work is the floating wind industry, where a cascade of innovative new designs aims at cutting costs while opening up new sites for development.

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Image: The investor environment for offshore wind farms could benefit from co-locating storage systems based on supercooled liquid air (courtesy of Highview Power).