I'd like to know how we could expect an aging and already insufficient power grid to take on the added load of charging automobiles. Places like California have had to resort to rolling blackouts for a long time now. Places with seasonal demand for home air conditioning (like New England) are starting to have issues all summer. What is going to happen to the grid when people start plugging cars in to charge overnight? Cities and states don't want to spend the money to ramp up the grid because it is invisible capital expense but if they don't get on this soon all these plug in electrics are nothing more than a pipe dream.
What happens when we have a power outage? Your internet and VOIP phone are dead as are your refrigerators and possibly heat/cooking. You have limited time on your cell phone. Now we're talking about being unable to drive because we can't charge the car? Are we going to start keeping gas tanks on site specifically for backup generators to charge the cars we no longer want running on gas?
The grid in the USA could handle a reasonable number of people charging their electric cars at night. Electricity discounts during off hours are available to residential customers in many regions already and have been standard (and even required) for commercial customers for years, so you could take advantage of this, and it would naturally encourage people to charge their cars at night, which they'd probably largely do anyway, when there is excess capacity available.
The grid is already a little strained in the day especially during peak heating and cooling seasons; this is a known problem. It will need upgrades no matter what, and programs to do so are in place. There are also some nifty ideas being floated around about using the battery capacity in electric vehicles (since it's actually pretty huge) to offset peak (and I mean PEAK - like for less than an hour during the day) electricity demand. And before someone runs off on a tirade about how that means your car may not be fully charged, participation would be optional and encouraged via compensation, and the amount of draw-down on the batteries we're talking is only a few percent. It's enough to make a huge difference when you've got several hundred thousand cars to do it with, but it's so little that you'd barely notice.
As for what to do when the power is out, well, you should have at least 100 miles on a charge (that's CURRENT vehicles - it's only going to go up). I get 350-400 on a gas tank, but I'm not likely to fill it up every evening like I would be apt to plug my car in since filling up a gas tank requires a trip to the gas station while I can plug my car in to charge at home. If I had to guess, I'd say I average about 200-250 miles "reserve" on my tank at any moment and that's only because I rarely let it get below 1/3 full; I know many many people who don't fill up until the light comes on, so their numbers would be lower. Given that the gas station's pumps are unlikely to work in a city wide power outage, I'm not sure that's something worth throwing a fuss over.
Electrics aren't great for everyone. If you routinely drive more than ~75 miles in one trip where you would be unable to charge, they're probably not a good option for you right now. I realize this describes a good chunk of the population. The other chunk is also quite sizable. There's a reason we already have several types of vehicles (small cars, vans, light trucks, big trucks, busses, etc.). Electric passenger cars just augment the selection.
And yes, heat engines (especially those running an otto cycle i.e. gasoline engines) are generally woefully inefficient. The saving grace is that gasoline is cheap and extremely energy dense, so you can waste a lot of its energy as heat and still get a lot of useful energy i.e. propulsion. Diesel cycles are a bit better.
The cycle that is run in a heat driven power plant (coal, solar thermal, nuclear, some natural gas) can be a bit better (look up a rankine cycle). The real gains are caused by economies of scale, especially in the waste product (e.g. environmentally hazardous gasses): it's practical to put some amazing pollution controls on a commercial scale power plant, but economically impractical to do so on a car.
Electric cars also enable you to decouple the generation medium from the vehicle. That is, you can have a "nuclear powered car". Obviously nobody would ever put a nuclear reactor on a car, but nonetheless you can have most of the benefits of a nuclear power plant when it comes to powering your car. Right now, petroleum fuels are so cheap in the USA that this isn't a huge deal, but if the cost of oil keeps going up, it could become quite nice. Coal is plentiful, available in the USA, and cheap (if environmentally questionable).
Once the electricity is produced, the distribution and battery storage is reasonably efficient all the way to the motor of e.g. a car. Typical losses in battery charging/discharging, conversion, and motor heat loss should add up to around 25-30%, assuming a reasonably efficient motor and VFD, giving you an efficiency of ~70-75% excluding grid transmission losses which will vary heavily with where you are and grid load. These losses have been trending down for the past 20-30 years. I remember designing SMPSes just ~10 years ago and having literature tell me that 70% efficiency was good. Now, if I'm not hitting 85%+ at design load, I'm a little unhappy if there isn't some oddball factor causing it.
Oh, and those of you in the states? relax, price of gas there is still heaps less than most other places in the world. I just noticed today that 98 octane here in Brisbane, Australia is $1.65 a litre. That's $6.27 a gallon...
Am I reading this right? 98 octane!? The highest octane rating you can get here in CA is 91. I think they only sell 98 octane at racing places.
Europeans use a different system of measuring the "octane" rating of gasoline than we use here in the states. There are two established methods. One gives a higher number (RON) than the other (MON). In the states, we average the two results: the (R+M)/2 method you see referenced on labels. The Europeans use the higher number only. 98 octane in Europe should be about like 93 in the states, which I can get at any quality gas station in the Midwest. CA numbers are sometimes lower due to pollution control additives.
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Topic: GAS PRICES....WTH :angry: (Read 9858 times)
