A million scenarios to identify conditions for robust bioenergy carbon capture in Sweden

• We apply robust decision-making theory to 113 retrofits of bioenergy carbon capture. • Conditions for low capture costs, biomass use, and energy penalties are identified. • Plant utilization, heat recovery, steam availability and electricity prices are key. • Non-predictive scenarios expose decision trade-offs and robustness to uncertainty. • The method enables decision-maker deliberation and robust carbon capture strategies. Large-scale bioenergy carbon capture and storage (BECCS) could be realized without escalating biomass use - under the right conditions. We apply robust decision-making theory to frame carbon capture as a decision problem. We then search for conditions of low costs and energy penalties by modelling the capture decision across a million scenarios of already-existing plants in Sweden. Mining the scenario data reveals that annual plant utilization, heat recovery via heat pumps and electricity prices constitute key conditions for combined heat and power plants. For pulp mills, key conditions are site-specific, but the availability of low-pressure steam and electricity prices are generally important. A sensitivity analysis supports these findings, but also identifies capture rates as key. About 19 MtCO 2 could be captured annually from the 113 plants studied while combusting zero additional biomass. Under the identified conditions, this would entail reduced power and district heating generation of 5.1-7.9 TWh per year – a modest penalty relative to the 220 TWh generated annually in Sweden.