Interacting policies in power systems: Renewable subsidies and a carbon tax

Without careful planning and design, energy policies like carbon taxes and renewable subsidies like production tax credits undercut one another in unanticipated ways. We examine how a carbon tax interacts with PTCs by simulating an electricity market using the IEEE RTS model with a carbon tax of $38/tonCO2e and a PTC of $23/MWh. The results show that PTCs work against the carbon tax by both lowering average energy prices and altering the generator dispatch.