Estimating the CO 2 Impacts of Wind Energy in the Transition Towards Carbon-Neutral Energy Systems

In this study, the CO 2 reduction benefits of wind energy in the transition towards a carbon-neutral energy system are explored. The marginal benefits of wind energy in replacing CO 2 emissions in electricity generation are gradually declining as carbon-emission-reduction targets are fulfilled. However, there is still the potential to reduce emissions by replacing fossil fuels in other energy sectors via electrification. Using the Finnish TIMES-VTT energy system model, this study simulates the impacts of different wind energy scenarios between 2030 and 2050, analyzing the effects of adding or removing 5 TWh of wind energy on power generation. Our findings indicate that the reduction benefits of wind energy vary over time, stemming initially from the generation of electricity but they are increasingly being driven by electrification through lowered electricity prices, and fuel switching, like the replacement of bioenergy in heating and fuel production. Between the years 2030 and 2050, an average marginal emission reduction of 180–270 gCO 2 eq/kWh was seen, rising to 250–320 gCO 2 eq/kWh if the impact on reduced carbon sinks through wood chip use was taken into account. Issues using marginal, substitution impacts from simulations are discussed; however, no straightforward methods for capturing the cumulative benefits of assets over their lifetime exist. In transitioning towards a net-zero-carbon energy system, other issues like costs, land use, and social aspects will become more relevant than emission substitution.