Globally, the first 10 000 MW of geothermal generation was able to take advantage of pristine, high-temperature resources at relatively shallow depths. For the next 10 000 MW and beyond, we will need to find new ways to improve generation economics in lower-temperature, marginal systems. Hybridizing geothermal generation with bioenergy is one approach for topping up resource enthalpy while also adding new revenue streams that increase project cash flow and shorten capital payback. In this paper, we present order-of-magnitude calculations of the energy, economic, and emissions benefits that may be realized through bioenergy hybridization. Our analysis is centered on a generic flash plant and considers the incremental performance gained from a unit of biomass combustion. We use a thermodynamic-financial-carbon model of the total power cycle to quantify the additional mass or enthalpy of produced steam as well as the production rate of green CO2. We then calculate revenue from net electricity generation and carbon removal sales of green CO2, and compare these against globally-sourced CAPEX and OPEX rates. We find that incorporating bioenergy-boosting into a geothermal energy cycle is mainly favorable for lower-temperature, marginal geothermal resources. A plant design that includes biomass heating of produced geofluid prior to separation produces a larger steam fraction for turbine dispatch, and this was found to be more effective than a hybrid that uses direct heating of the separated steam. Both biomass and carbon removal pricing are key factors in project cost, but we find that bioenergy hybrids are likely to outperform standard geothermal plants under reasonable price ranges ( less than 140 USD/tBio and greater than 50 USD/tCO2). Importantly, by offsetting project costs with new green revenues, we predict that total reserves of developable geothermal could be substantially increased. This is because systems that would otherwise be classified as marginal or uneconomic under other plant designs, have lower costs under hybrid schemes. Finally, geothermal-bioenergy hybrids with CO2 removal have high rates of negative emissions at low to medium temperatures, exceeding -1000 gCO2/kWh, which helps contribute to climate goals beyond decarbonizing the electricity system.

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