The business case for Battery Energy Storage Systems (BESS) in Europe is determined by revenue stacking, ie the ability of operators to obtain revenues from different sources and markets. While long term capacity remuneration helps provide investor certainty, it is revenues from frequency response ancillary services (AS) that have proven to be critical drivers of BESS investments. Of particular importance to the value proposition is the capability of BESS to deliver extra fast response times (sub 2 seconds). This Insight looks at such fast response AS in more detail and concludes that they constituted up to 40% of revenues for BESS operators over recent years. This makes the treatment and remuneration of these services an essential component to consider for system operators, regulators and policymakers when designing BESS investment frameworks. READ ECA’s INSIGHT HERE