The US Department of Energy’s (DOE’s) Office of Electricity has published a comprehensive report on different options for long-duration energy storage (LDES) costs, with flow batteries having the best rate between costs and performance.
The 51-page document (Achieving the Promise of Low-Cost Long Duration Energy Storage) contains cost comparisons between 10 LDES technologies, from electrochemical energy storage to chemical energy storage, mechanical energy storage and thermal energy storage.
The 10 LDES technology areas evaluated span several energy storage families: Flow batteries (FB), lithium-ion batteries (LIB), lead-acid batteries (PbA), hydrogen storage, sodium-ion batteries (NAIB), electro-chemical double layer capacitors (Supercapacitors/EDLC), zinc batteries, compressed air storages (CAES), pumped storage hydropower (PSH) and molten salt storage (TES).
Flow batteries have the best rate between costs and performance according to today’s technological status, as low as $0.06/kWh, which is close to DOE’s $0.05/kWh target. Lithium-ion batteries hold the second place with $0.07/kWh, followed by zinc battery varieties, e.g. ZnMnO2, with $0.08/kWh and the first ever rechargeable battery, the lead-acid battery with $0.09/kWh.
Sodium-ion batteries are still in an early stage with $0.26/kWh, but their commercial potential is high when new electrolytes and even anodeless batteries are developed, according to the report. Supercapacitors suffer from low energy density and high self-discharge rate. From a cost-point perspective they are expensive at $0.34/kWh.
The DOE established the Long Duration Storage Shot in 2021 to achieve 90% cost reduction by 2030 for technologies providing 10+ hours duration of energy storage.
It has also evaluated the top three potential innovations for each technology to reach the $0.05 level and the costs for R&D for 10 years. The range stretches from $90 million for supercapacitors to $1 billion for lithium-ion batteries.
On average, the top 10% of innovation portfolios can reduce LCOS by 12–85% to $0.03/kWh–$0.26/kWh across storage technologies, the report stated. New materials, electrolytes, membranes and other components must be ramped up quickly to production to achieve critical mass and to reduce overall system costs targets. Standardisation is a key element to reducing development and deployment costs for lead-acid, flow and zinc batteries.
Photo: Invinity VS3-022 flow batteries in Soboba, California. Invinity
