A full tank for 2 euro

Filling up at the gas station will cost around 50 €, and loads about 450 kWh of energy into the tank. A combustion engine will convert this energy into approximately 100 kWh of mechanical energy, to be used for propulsion, on-board electronics and airconditioning. Consuming this amount of fuel emits over 150 kg of CO2.

But now, electric vehicles are entering the market with battery charges of 25 - 30 kWh. This is still about a quarter of what a combustion vehicle has available. But the performance of electric vehicles can become similar or even better, bridging the gap through regenerative braking, the different torque-speed characteristic of the electic motor, and its very high efficiency to convert electric into mechanical power. And 30 kWh of electricity requires only 75 kWh of primary energy, and emits only 15 kg of CO2. This is a factor 6 improvement in primary energy use, and even a factor 10 in CO2 emissions. At night tariff, 30 kWh of electricity will come at about 2 euro.

These vehicles come with a high price tag, as well as a long waiting list, so it'll be a while before these cars acquire a large user base. Average driving over 4 years will save a user only 10,000 euro, insufficient to earn back the initial investment. Also, the infrastructure to charge vehicles in parking lots away from home is largely missing.

But thinking ahead, electric cars at today's volume can be expected to go through a steep learning curve - after all, only a factor 2-3 price reduction is needed. And Europe's daily electricity consumption is 6.8 TWh. A fleet of 150 million cars would add 0.8 TWh daily to this, while eliminating 13.5 TWh equivalent in oil consumption (over 7 million barrels per day). Such a fleet offers 3.8 TWh of stored electricity, i.e. 50% of total daily consumption, allowing virtually unlimited hosting capacity of intermittent renewables in the electricity network.

A factor 6 in primary energy, factor 10 in CO2 and factor 25 in the cost of a fuel tank seems more promising that the marginal improvements reported for hybrids, if only we can make the economics work.

However, in this scenario, governments will also loose about 25-30 euro per fuel tank of tax revenue, that will need compensation in some manner.