Techno-economic study of hybrid biomass-fossil power plants with and without CO2 capture

Abstract

To address climate change, decreasing CO2 emissions during electricity production, a major source of greenhouse gases, is necessary. One option is the co-utilization of nearly carbon-neutral biomass with fossil fuels at power plants, which has the added advantage of potentially achieving negative emissions if CO2 capture is applied. The techno-economic feasibility of biomass usage along with fossil fuel or as a dedicated fuel for combustion and gasification-based power generation, with and without CO2 capture in Australia is investigated. Sensitivity analyses are undertaken to evaluate jurisdictional variations in economic parameters on power plant economic viability. Simple analytical or graphical tools are also developed to evaluate the economic incentives required to make each bio-power technology viable. The results show that for biomass-coal co-firing, higher quality biomass is preferred as plant performance is not significantly affected. For biogas-natural gas co-firing, higher heating value biogas is preferred as it requires minimal modifications to plant equipment. The breakeven carbon price required to make each bio-power technology cost competitive with the same technology without biomass and/or capture ranges between 37 – 97 $/t CO2. Including other incentives such as Renewable Energy Certificates, and low biomass to fossil fuel price can make bio-power technologies economically viable at low carbon prices. A multi-criteria analysis compares deployment opportunities for bio-power technologies based on the CO2 emission reduction potential, cost of electricity, biomass consumption rate, electricity output, and technology maturity. Using biomass in auxiliary units to provide the energy for capture at existing coal plants and supplementary biomass firing in existing NGCC plants (with and without capture) are the highest-rank options. These options provide relatively low cost emission reduction, are technically mature, and can alleviate electricity output loss due to capture. Dedicated biomass plants (with and without capture) are the lowest-rank option due to the high cost of electricity, high biomass requirement, and significant output loss for capture. Currently, using low to medium levels of biomass in combustion-based plants is a feasible method to reduce CO2 emissions. Deeper reductions could be achieved by increasing the R&D commitment for biomass conversion and CO2 capture technologies, introducing policy incentives, and increasing biomass supply.