Bioenergy with carbon capture and sequestration (BECCS) is critical for stringent climate change mitigation but is commercially and technologically immature and resource intensive. State and federal fuel and climate policies can drive first markets for BECCS in California. We develop a spatially explicit optimization model to assess niche markets for renewable natural gas (RNG) production with carbon capture and sequestration (CCS) from waste biomass in California. Existing biomass residues produce biogas and RNG and enable low-cost CCS through the upgrading process and CO₂ truck transport. Under current state and federal policy incentives, RNG-CCS can avoid 12.4 mmtCO₂e/year (3% of California's 2018 CO₂ emissions), of which 2.9 mmtCO₂/year are captured and sequestered. It simultaneously produces 93 PJ RNG/year (4% of California's 2018 natural gas demand) with a profit maximizing objective, resulting in profits of $11/GJ. Distributed RNG production with CCS can potentially catalyze markets and technologies for CO₂ capture, transport, and storage in California.

Low carbon fuel and waste management policies at the federal and state levels have catalyzed the construction of Californias wet anaerobic digestion (AD) facilities. Wet ADs can digest food waste and dairy manure to produce compressed natural gas (CNG) for natural gas vehicles or electricity for electric vehicles (EVs). Carbon capture and sequestration (CCS) of CO2 generated from AD reduces the fuel carbon intensity by carbon removal in addition to avoided methane emissions. Using a combined lifecycle and techno-economic analysis, we determine the most cost-effective design under current and forthcoming federal and state low carbon fuel policies. Under many scenarios, designs that convert biogas to electricity for EVs (Biogas to EV) are favored; however, CCS is only cost-effective in these systems with policy incentives that exceed $200/tonne of CO2 captured. Adding CCS to CNG-producing systems (Biogas to CNG) only requires a single unit operation to prepare the CO2 for sequestration, with a sequestration cost of $34/tonne. When maximizing negative emissions is the goal, incentives are needed to either (1) fund CCS with Biogas to EV designs or (2) favor CNG over electricity production from wet AD facilities.

Carbon capture and storage (CCS) is a strategy to mitigate climate change by limiting CO2 emissions from point sources such as coal-fired power plants (CFPPs). Although decision-makers are seeking to implement policies regarding CCS, the consequences of this technology on water scarcity have not been fully assessed. Here we simulate the impacts on water resources that would result from retrofitting global CFPPs with four different CCS technologies. We find that 43% of the global CFPP capacity experiences water scarcity for at least one month per year and 32% experiences scarcity for five or more months per year. Although retrofitting CFPPs with CCS would not greatly exacerbate water scarcity, we show that certain geographies lack sufficient water resources to meet the additional water demands of CCS technologies. For CFPPs located in these water-scarce areas, the trade-offs between the climate change mitigation benefits and the increased pressure on water resources of CCS should be weighed. We conclude that CCS should be preferentially deployed at those facilities least impacted by water scarcity.