When you buy 40 litres, it won't actually be 40 litres. Let's talk about equivalent litres—the equivalent amount of energy in natural gas.
Last year we checked the price at the pumps in Toronto, and it was 69¢ per litre. If you multiply that by 40, that gives you your price at the pump. We made a calculation that if you had your own home refuelling, at 25¢ a litre, that would basically be $10 for your fill-up. That's what drives the payback. The cost of fuel is a lot lower.