RWE’s eight-hour lithium-ion battery energy storage system (BESS) was the only successful project in NSW’s first long duration storage long-term energy service agreements tender process last year. With a planned capacity of 50+ MW and 400+ MWh, the Limondale BESS will support the energy transition by storing excess renewable energy and feeding it into the NSW grid when it is needed most. The project will be located next to RWE’s 249 MWac Limondale solar farm – which is one of Australia’s largest – and will connect to existing grid infrastructure.

Tesla has been selected as the BESS supplier, and Beon Energy Solutions as the delivery partner for the balance of plant, which includes the civil, structural, electrical and control works required to connect the battery to the existing 33 kV substation. Construction is scheduled to start in the second half of this year, with commissioning planned for late 2025.

NSW has set an ambitious roadmap to replace ageing coal-fired power stations with zero emissions generation and storage. The bipartisan policy is backed by a schedule of auctions for new renewable and storage capacity out to 2030. It aims to support the private sector to deliver at least 12 GW of new renewable electricity generation and 2 GW of long-duration storage.

RWE plans to expand its battery storage capacity to 6 GW worldwide by 2030, of which half is expected to be located in Australia.

New BESS to support UK’s net zero goal
On the other side of the globe, cleantech company Ameresco and Envision Energy have been chosen by Atlantic Green to build the Cellarhead BESS project in the UK. The 300 MW BESS will have a maximum energy capacity of 624 MWh and will be one of the largest in the country, according to Ameresco.

Connection to the electricity grid is expected at the end of 2026.

‘We believe that a continuous development of battery energy storage is a vital step in the UK’s journey to achieving net zero carbon emissions [by 2050],’ says Nick Bradford, Managing Director of Atlantic Green.

Some long-duration energy storage technologies set to ‘out-compete’ lithium-ion batteries
In other news, a new study from BloombergNEF (BNEF) suggests that long-duration energy storage (LDES) is rapidly gaining momentum, with some technologies already set to ‘out-compete’ lithium-ion (Li-ion) batteries on cost in some markets.

BNEF surveyed seven LDES technology groups and 20 technology types for the report, which finds that the least expensive technologies are already providing cheaper storage than Li-ion batteries for durations over eight hours. Thermal energy storage and compressed air storage, for example, had an average capital expenditure (capex) of $232/kWh and $293/kWh, respectively. For comparison, Li-ion systems had an average capex of $304/kWh for four-hour-duration systems in 2023.

Flow batteries and compressed air technologies have had the most commercial success so far, which could help ensure further cost reductions in the future, says the report.

BNEF expects the typical time it takes for energy storage assets to discharge or charge will increase as the technology displaces fossil fuel generators and is used to address the intermittent sources of renewable power. LDES technologies can add more energy storage without requiring more power conversion capacity, so they are seen as a contender to Li-ion batteries. Still, LDES costs are unlikely to fall as fast as those of Li-ion batteries this decade, as Li-ion batteries are extensively used in both the transport and power sectors.

Currently, China leads the way on cost-effectiveness for established technologies like compressed air energy storage, flow batteries and thermal energy storage. The average capex in non-Chinese markets is 68% higher for compressed air storage, 66% higher for flow batteries and 54% higher for thermal energy storage, according to BNEF.

Yiyi Zhou, BloombergNEF’s Clean Energy Specialist and co-author of the report, explains: ‘The significant cost disparity is largely due to China’s far greater adoption of LDES technologies. While other nations are still in the early stages of commercialising LDES technologies, China is already developing gigawatt-hour scale projects, driven by favourable policies. This is particularly true for compressed-air energy storage and flow batteries, where China has set new project size records in the past two years.’

However, despite China’s lower costs, LDES technologies may struggle to compete with Li-ion batteries produced in the country, which are the cheapest in the world. Only a few LDES technologies, like natural cavern-based compressed air storage, can outcompete Li-ion batteries in terms of per-unit capital costs today.

LDES technologies have a better chance of competing with Li-ion batteries in non-Chinese markets, where the Li-ion batteries are more expensive, suggests BNEF.