Sunday, October 9, 2016

Lifecycle emissions and electric vehicles

A common theme by denialists is that life-cycle emissions of EVs (electric vehicles) are greater than  those of petrol-engined cars because the power to run the EVs comes from coal-fired power stations.  They're wrong, even if the grid is 100% coal-powered.  The higher emissions of a coal grid are  offset by the greater efficiency of electric motors: petrol engines convert less than 20% of the energy in petrol into kinetic energy (motion), while electric motors convert 60%.  So still better to use EVs instead of ICEs, because coal produces twice as much CO2 per unit of energy as oil.

But what if you fill your EVs batteries from power from your solar panels.  Or from overnight power when demand is low, but base load power stations have to keep going whatever the demand?  Or from a 100% renewable grid.  This chart shows the numbers.  Grey shows conventional ICEs, purple shows hybrids, yellow shows EVs.  With a 100% green grid, EVs produce 1/4 to 1/3 of the life cycle emissions of an ICE car.

(Source)

No comments:

Post a Comment