I don't buy diesel, but I seem to recall it's about 85p a litre, which is about $6.00 for one of your gallons or about $6.90 for one of ours. Most "alternative fuels" (in particular biodiesel and LPG) are also taxed. Hydrogen will also be taxed when it is available for use in cars. It's hard to tax domestic electricity, because people use it for other things. But "put not your trust in princes" - they'll find a way to tax EVs if they get popular!
In London you pay UK5 (about $9) a day just to drive your car into the centre of town. This is the famed "congestion charge" - which incidentally resulted in our prime minister getting over 1000 pounds in fines. That charge is waived for electric cars, which is another temptation.
All our systems are 230v, and most domestic supplies have a "company fuse" the other side of the meter which allows between 50A and 100A to be drawn. Our largest single-phase receptacle is a 30A one, which is the normal limit for a single spur using UK wiring (normally called a "cooker point"). The only wiring that requires more than this is typically an electric shower, and electric shower manufacturers advise you to check with the utility company to make sure your fuse is up to it.
The "overloading the grid" fear is valid: here in Britain at least 30% of the nation's energy goes on transport. If everyone switched to electric cars, the electricity requirement for the nation would double. Cheap rate electricity is at least part of the answer. Here in Britain electricity costs about 6p per kWh, but only 2.5p per kWh between midnight and 7AM. That is because the generators have spare capacity. The solution is to time the charge cycle to begin at 1AM, when you're not driving the car because you're asleep, and let it be mostly finished by 7AM. (I'm not worried about "finishing charging", which is only done to improve cycle life and capacity - it is the bulk charging that sucks amps.) That saves money, but it also saves the grid, since nobody else wants the electricity anyway.
The biggest cost of a BEV is battery wear. Since the batteries are normally quickly and deeply discharged, they'll typically deliver between 300 and 1000 times their total storage capacity before they're junk. They're hit hard: at 75mph my Quantum needs between 15kW and 25kW to push it down the motorway, depending on wind and slope. For a 180v system that's up to 140A. When I stamp my foot on the go pedal at the lights, I'm expecting the peak current to reach 1200A.
They also (almost by definition) spend a large amount of their time partly discharged, since here in Britain I'll drive to work, park the car away from power at 30% discharge for nine hours, then drive home, and leave it 60% discharged for another six hours while I wait for the cheap rate electricity to start. It's a hard life being an automotive traction battery. I know that in the average "home power" setup the batteries would last for a decade or more, but if I get three years out of these batteries, I'll have won.
Slow charging is a non-starter, I'm afraid: if you charge at C/20, it takes nearly a day to recharge your batteries. The charging algorithms are going to have to be of the bulk then finish variety, or the car can only be driven every other day. One recommended (by the manufacturer) algorithm for the Optimas is to charge at C rate (so maybe 15kW) until the temperature rises to 50C! As I said, it's a hard life being an automotive traction battery.
The Trojan batteries that are the mainstay of home power systems are flooded, and don't belong in a moving vehicle. Optima "yellow tops" deliver 1000 times their total capacity when discharged to 30% DoD each cycle, and 400 times at 80% Dod - Thunder Sky lithiums deliver 750 times their capacity at 50% DoD and 400 times at 80% DoD. That could maybe be improved with clever charging algorithms, but in the end it provides a limit - and it's a part of the "total cost of ownership" that can't be ignored. If you think that my simulations are expecting about six miles per kWh at 40mph and four miles per kWh at 75mph; Optimas cost about $310 per installed kWh and Thunder Sky about $420 per installed kWh, you can see what they cost per mile (Optima $0.05 to $0.19, Thunder Sky $0.09 to $0.26). Add on to that the cost of electricity in your region, adding 10% to 20% for charging losses.
Now engines and gearboxes wear out too, but they are not as expensive as replacement batteries. Fortunately I bought my battery for UK250, which will make battery wear negligible. But I'm going to be saving that money I'm not spending on petrol so I can afford to replace the battery when it wears out after three years' usage. Interestingly, the batteries I'm replacing will probably be fine for an off-grid system, since they'll still have about 50% of their capacity and they'll probably recover when float charged for a few months. So the change-over to EVs may have spin-offs for the home power people, in the form of lots of batteries available for skip-divers. :-)
For comparison, the hydrogen powered buses they're using in central London have a fuel cell that brings the total price up to somewhere around the $200,000 mark. Modern fuel cells use precious metals (platinum for instance) which makes them very expensive. Since they're prototypes, nobody really knows how long they'll last, or what the effects of impurities in the fuel or air will be. But you could buy a lot of diesel for $200,000 even at our prices.
In summary, even with petrol at our price, BEVs make sense only if you have the right batteries. The lithiums are marginal. The alternative SAFT lithiums are about five times the price, and so are completely uneconomic. Fortunately there is a government scheme to subsidise the cost of new electric vehicles (it's called "Powershift", and no, it's not available to home constructors) but even then things are barely competitive.
The driver for alternative energy cars will be fuel prices. When the oil runs out, everyone will be paying for motoring about the same way the British are now. Before that happens, for most of the world BEVs will not make economic sense.
Neither will the other alternative technologies.