Lithium-ion based batteries are still dominating the stationary energy storage sector but a rising number of companies try to develop different technology types. Among the Li-ion batteries competitors, the Redox Flow Battery (RFB) system – based on flowing two liquids as electrolytes across the electrode – is seen as an attractive approach.
Unlike rechargeable lithium-ion batteries, flow batteries use large tanks of liquid to store energy which has made the technology “prohibitively expensive” because it relies on pricey electroactive metal salts. Researchers at the MIT are working on alternative approaches that use less expensive electroactive materials derived from organic compounds.
Technical advances in energy storage metrics accelerate the attractiveness and roll-out of battery storage to balance rising volumes of intermittent renewable energy supply to the grid. In the United States, the utility-scale battery fleet is operating with an average monthly round-trip efficiency of 82% – more than the 72% efficiency of pumped-storage.
Scotland’s Shetland Islands are relying on Wärtsilä to provide grid balancing services and reserve power through an energy storage system. Once operational, the system will deliver 8 MW/6 MWh of electricity and will be managed by Scottish and Southern Electricity Networks (SSEN), part of the UK’s largest utility SSE.
South Korea’s conglomerate SK Group has decided to invest $1.5 billion in the hydrogen fuel cell provider Plug Power as the two South Korean companies enter a strategic partnership. The aim is to provide full cells, hydrogen fueling stations, and electrolysers to the Korean and broader Asian markets.
Toshiba has developed an aqueous rechargeable lithium-ion battery in a bid to realise the world’s first large-scale battery that can operate at -30°C. The high durability battery has over 2,000 charge- and discharge-cycles and by using water as aqueous electrolyte, it is safe even if exposed to fire.
Energy capacity cost of utility-scale battery storage in the United States has rapidly decreased from $2,152 per kilowatthour (kWh) on average in 2015 to below $625/kWh in 2018, falling further since. Long-duration batteries are cheaper and costs vary by region, coming in at just $947/kWh in Hawaii.