johnwalker 13 Jan

nagle:
Two islands with four chargers each can charge eight cars. Charging stations may be able to replace gas stations on the same real estate.

Current standards for electric vehicle charging stations have the following maximum power delivery:

• SAE J1772 DC Level 2 — 400 kW
• IEC 61851-1 — 80 kW
• Tesla NACS — 250 kW
  (Again, these are maxima under the standards: many installed charging stations are lower power. A typical Tesla V2 Supercharger provides 120 kW.)

Plans for future higher power charging standards include the Megawatt Charging System 1 (MCS) with a rating of 3.75 megawatts (3000 amperes at 1250 volt DC).

Let’s compare this to a gasoline pump. A typical filling station pump in the developed world delivers around 50 litres per minute (38 l/min in Safetyland), and gasoline has an energy content of around 7500 kcal/litre depending on its formulation (around 5000 kcal/litre for pure ethanol and 8600 for #2 diesel). Plugging these into Units Calculator, we get:

 (50 litres/minute) * (7500 kcal / litre) = 26.15 megawatt

so even the proposed MCS (which is primarily intended for large commercial vehicles and buses) delivers only around 1/7 the power of a gasoline pump.

Now, even getting installation of five megawatt electrical service is a pretty big thing in most places (that is the consumption of a very large office building), so it looks like building out an infrastructure which will allow electrical vehicle charging times competitive with gasoline filling will require very substantial upgrades to the power grid and local distribution facilities.