Before proceeding I would urge anyone with an interest in energy to look at the post "Energy and Artificial Intelligence Expert Professor Sir David J.C. MacKay Has Died, Age 48" in particular the discussion of his book "Sustainable Energy - Without the Hot Air". He thought the topic important enough to post a free version of the little volume. Here's his Cambridge Uni -Cavendish Laboratory - webpage with some stuff from the days before the Queen made him a Regius Professor.
And for a quick look at the facts of electricity and charging away from home, Driving Canada's Motor Mouth column, October 6:
Motor Mouth: More inconvenient truths on banning gas engines
High-speed EV recharging stations on highways sound great – until you hear how much they would cost
Anyone who tells you that the electric car in your future will be just as convenient as the gasoline-fueled vehicle you’re currently driving is lying. If not overtly, then at least by omission. Nor can they plead ignorance, the calculations required to reach this conclusion hardly the stuff of graduate-level physics. Indeed, judging from the experts I’ve spoken with, plenty have been the warnings proffered to the politicians, policy makers and futurists advocating an all-battery-powered future.Now before you go all Tesla on me and start putting angry pen to paper, let me give credit where credit is due. In an emissions-free automotive world, the electric vehicle is king of the inner-city commute: the ability to recharge at home — during off-hours, minimizing the load on our grids — is convenient, their torquey motors perfect for the point and shoot of inner-city traffic, and their range more than what is needed by 90 per cent of commuters. I also trust that battery technology will get lighter and more energy dense so the 100+ kilowatt-hour batteries of the future won’t all weigh a thousand pounds. Nor is the tired old bugbear — “all that electricity is being generated by coal” — likely to be a problem in 20 or 30 years, the cost of renewables hopefully coming down to a manageable level.Instead, the problem for our all-electric future (now California is said to be following France and England’s banning of the internal combustion engine) is power transmission. More specifically, as one industry expert summed up the situation, “the bottleneck [clouding the future of the electric vehicle] is local distribution.” That bottleneck is going to be the highway service stations that will be required to service our 300 million now-electric cars for longer trips when we don’t have access to the convenience of our home chargers.Consider the following scenario: last Labour Day weekend, like so many holiday weekends, pretty much every fuel pump on the side of Ontario’s 401 was, er, pumping non-stop. That, for anyone thinking of following along with my calculus, is a station every 80 kilometres, each with up to 16 pumps. More importantly, each of those is capable of pumping about 30 litres of gasoline in a minute. In other words, discounting credit card transaction and unscrewing of gas cap, even the most ardent gas-guzzler can take in enough fossil fuel for 500 kilometres of driving in about two minutes.But consider this: an EV that can guarantee 500 klicks requires at least 100 kilowatt-hours of battery. Do the math and a similar two-minute recharge would require three megawatts. That, for those who don’t have an electrical engineering degree, is 3,000 kilowatts.Now for some perspective: current fast chargers boast about 50kW. Yes, essentially 1/60th of the charging capacity required to match the refueling rate of an everyday gas-powered car. If you’re reaching for your calculator, I’ll save you the trouble: Serving the same number of cars could theoretically require as many as 960 charging stations (and they’d still have to sit there for two hours to fully charge).But isn’t Porsche promising a 20-minute charge for 400 kilometres of range, you ask? Doesn’t that mean we’ll soon see EVs capable of matching those two-minute recharges?Well, yes, Porsche is making just such a promise. Unfortunately, however, that would seem to be the practical limit of how fast we’re going to be able to recharge these electrical behemoths. Indeed, The 350kW rechargers required for those promised 20-minute refueling is, according to the experts I spoke with, likely the upper limit of the equipment we humans will ever be allowed to handle. In fact, these 350kW rechargers generate so much heat, their amperage is so incredibly high, that the cables carrying all that current need to be liquid cooled. And anything that can recharge our batteries faster than 20 minutes will have to be automated, i.e., phantasmagorically expensive.How expensive? As I mentioned, you’ll need about 60 50kW rechargers to replace one fuel pump; about eight of the 350kW variety for every pump. That, as I mentioned, would mean 960 of the low-powered 50kW units at each rest stop and 128 of the high-tech 350kW versions. Have I mentioned that even those low-powered 50kW fast chargers cost about $40,000 apiece? One of those faster-charging 350kW items? About two hundred large. Faster-charging automated versions would cost upward of a half-million each.Even a more conservative estimate taxes one’s calculator. Factoring in the aforementioned credit card transaction and washing of windshield that might extend gasoline refueling to five minutes, it would still require 600 of those 50kW chargers for a roadside station to service the 2,000 cars those gas pumps could service in a busy 12-hour period. Even that conservative estimate would require a $24-million investment just for the cheapest rechargers.They’d also need about 30 megawatts of power. For those thinking that’s a sh%$-load of electricity, you’re right. Thirty megawatts, for perspective, is enough to power about 20,000 homes. In other words, powering these service stations of the future will require about the same amount of electricity as a city of 75,000. Oh, and by the way, all that electricity, unlike off-hour home recharging, happens during peak-usage daylight hours.In other words, all that extra power, at least for intra-city travel, will have to come from new — not existing — sources. At the most optimistic prices posited for the future cost of solar panels — about a buck a watt — that’s another $30 million. If you want to go the windmill route, you’ll need 10 of them, each costing roughly $4 million. Just as further reminder, that’s for each and every roadside station. And for those thinking there may be some breakthrough in the future that will allow faster recharging, know that while battery technology is in its infancy, electricity generation is a mature technology and the laws of power transmission are likely to remain pretty much immutable....MUCH MORE
