Abstract:
Wind and solar generation are rapidly expanding around the globe as their costs come down and societal pressure to reduce greenhouse gas emissions rises. To supply a high fraction of electricity demand with variable sources, different types of storage are needed to balance daily, weekly, seasonal, and interannual weather fluctuations. Battery storage can bridge several hours of low solar and wind feed-in. However, if wind and solar penetration rises to cover all demand in the absence of other generation technologies, longer duration energy storage becomes necessary to supply multiple days or weeks of dark wind lulls and seasonal variations in supply and demand, as well as to bridge years of low renewable production. While the term long-duration energy storage (LDES) is often used for storage technologies with a power-to-energy ratio between 10 and 100 h,1 we introduce the term ultra-long-duration energy storage (ULDES) for storage that can cover durations longer than 100 h (4 days) and thus act like a firm resource. Battery storage with current energy capacity investment costs of 100–200 €/kWh would be too costly for these long periods. Simulations show that for renewable systems to be competitive with dispatchable low-carbon technologies, ULDES would need to cost at most around 10 €/kWh.2 (Note that all costs are given in 2020 euros, while all fuel energy units and efficiencies refer to the lower heating value.)
Brown, T., & Hampp, J. (2023). Ultra-long-duration energy storage anywhere: Methanol with carbon cycling. Joule, 7(11), 2414-2420. https://doi.org/10.1016/j.joule.2023.10.001 and PDF
