Much of the economic theory of “Green Growth”^{[1]} Green Growth, https://en.wikipedia.org/wiki/Green_growth [2019-10-07]. is predicated on the notion that we can continue enjoying a Western lifestyle without destroying the atmosphere if we replace the energy we use from fossil fuels with renewable sources. Straightforward calculations reveal that this will be easier said than done^{[2]} Vaclav Smil, Energy Transitions – Global and National Perpectives, Praeger (2016)..

For example, in late 2018 the British Columbia (BC) government announced that all cars in the province must be solely electric-powered by the year 2040. The question is, how much green power will this initiative need?

The current (2019) population of BC is five million and its residents own about three million cars. If we assume each car is driven a typical 20,000 km per year, with an average fuel economy of 10 L/100 km, and that the enthalpy of combustion of gasoline is 34 MJ/L. How much extra power will the province need to produce to run all these cars solely on electricity? There are inefficiencies (energy losses) in both running gasoline engines and powering electric motors, so let us assume for the purposes of approximate comparison and simplicity that these inefficiencies are the same.

**The Calculation
**

The volume of gasoline used per car per year is 2000 L.

The total distance driven is 6×10^{10} km/year and thus the total volume of gasoline is 6×10^{9} L/year.

The total power requirement is thus 2×10^{11} MJ/year.

Converting this power to more understandable units (there are 31.5 million seconds in a year) gives **6.5 GW**.

**How big is 6.5 GW?**

BC does not have any well-developed sources of wind or solar energy, but the province does have large hydro-electric dams. These dams are fully used but only one new dam is under construction, and this is the controversial Site-C dam^{[3]} Site C dam, https://en.wikipedia.org/wiki/Site_C_dam [2019-10-07]. in northern BC; its installed capacity is **1.1 GW **with an expected average electrical output of **0.58 GW.**

**Created (CEW) 2019-10-07**