Plug-in hybrid electric vehicles as a mean to reduce CO2 emissions from electricity production

In this study we have investigated the consequences of integrating plug-in hybrid electric vehicles (PHEV:s) in a wind-thermal power system supplied by one quarter of wind power and three quarters of thermal generation. A fleet of PHEV:s with an electricity consumption corresponding to 3%, 12% and 20%of the total electricity consumption has been integrated to the system (i.e. the total electricity consumption remains unaffected while the non-PHEV consumption is 97%, 88% and 80% in the three cases). Four PHEV integration strategies, with different impacts on the total electric load profile, have been investigated by means of a mixed integer model which can model the effects of the new load profiles on the dispatch of the units in the system and, thus, on the CO2-emissions from the system. The study shows that PHEV:s canreduce the CO2-emissions from the power system if actively integrated, whereas a passive approach to PHEV integration (i.e. letting people charge the car at will) is likely to result in an increase in emissions compared to a power system without PHEV load.The model simulations give that CO2 emissions of the power sector are reduced with up to 4.7% compared to a system without PHEV:s. If the reduction in emissions is allocated to the electricity consumed by the PHEV:s, the emissions from generation of this electricity are reduced from 588 kg CO2/MWh (windthermal system without PHEV:s) down to 367 kg CO2/MWh (PHEV:s actively integrated). Under the assumption that electric mode is about 3 times as efficient as standard gasoline operation, emissions from PHEV:s would then be less than half the emissions of a standard car, when running in electric mode