Electric cars.

Thinking of buying an electric car and saving the planet?

If you look at the diagram above (Sorry for the poor quality), you’ll see what is required to get the power for the car battery from the source.

Lets look at the efficiencies of the various parts of the diagram, starting with the generating station first. Even a non CO2 emitting nuclear plant is at best 30% efficient due to the lower steam temperatures employed. That’s a start down the slope.

Next comes the step up transformer. Ever wondered why they have to be oil cooled? Using a step up transformer to increase the voltage does not give you something for nothing. As the voltage goes up, the current goes down by the same proportion. The power equation shows that the overall power remains the same.

P=V x I  Power = Voltage x Current

In reality, the power output is always less than the power input because the changing magnetic field in the core creates currents (called eddy currents) which heat the core.  This heat is then lost to the environment, it is wasted energy. It’s actually not too bad at 2%. But 2% never the less.

Now we come to transmission of this power. This is usually transmitted at voltages of around 133kv in the UK for long distances. Here again we lose energy. Estimated at approximately 6%.

Of course we now have to transform it down again to a realistic voltage for consumers to use. Another 2% lost.

Bearing in mind  charging the batteries of your electric car is going to involve turning that AC voltage into a DC voltage and step down to a voltage that will be suitable for your battery, the efficiency falls further. Lets say another 2%.

Overall by my reckoning that makes the whole jiggery pokey to have you on the road is about 58% efficiency overall.

Contrasting that to a modern common rail fuel injected diesel engine at 50% efficiency,  the efficiency is not vastly better.

Of course you have to buy the car first before you can drive an electric vehicle on the open road. Now the agony really becomes real. Even with a generous government subsidy (£5,000), a Nissan Leaf is going to set you back a whopping £25,990.

And for that price you only (On a good day) get a mileage of 109 miles between charges.  

And finally the cost of a replacement battery will set you back over £5,000. (Conservative price. Some sites have reckoned it could be as high as £8,000).

Still want to buy one? Me. I’m sticking to my diesel powered car, which has a range of 350 miles even when my heater is on in the winter. I don’t want to take 3 days to visit my son. (And three days back) After all, who would feed the cats?

What a Bufhuhne

I’m talking about our Energy Secretary here.

The proposed motorway speed limit increase to 80mph should only apply to electric vehicles, according to energy secretary Chris Huhne.

He certainly hasn’t done any research has he? To find the info below took me five minutes

Speed and Performance - electric cars can cover the full range of speed performance, from neighborhood electric vehicles that only get up to 25 mph to high perfomance cars like the Tesla Roadster which can reach 85-90 mph.  However, the average electric car available in the UK will comfortably reach 50-55 mph.  This is lower than even a small 1.1L petrol car although arguably in the city this more than adequate for the top speeds you will be legally allowed to do.

The cheapest Tesla you can buy is expected to sell for £40,000. And that would include the electric car grant.

So we’re not going to see many cars doing 80 mph on the motorways. And the ones that do will most likely be parked on the hard shoulder with flat batteries, due to the fact that charging points are few and  far between.

Nice one, Mr Huhne. Now go to the back of the class.

Electric cars

It would seem that our American cousins like to throw money down the drain faster than us

The federal government has figured out how to save $116,000 per year … and it only costs $4 million to do it! The pilot program in San Diego and four other American cities will take no more than, oh, 39 years for the savings to pay back the cost of the vehicles:

San Diego will be one of five cities in which the federal workers will test plug-in cars for government use.

The General Services Administration said Tuesday it plans to buy 116 plug-in electric vehicles, including 101 Chevrolet Volts and 10 Nissan Leafs.

It will put 13 Volts and four Leafs with San Diego workers, and will also install charging stations to serve them. The cars will go to workers with the Navy, the Marine Corps, Veterans Affiars and the Department of Transportation. …

The purchases announced Tuesday are expected to cut gas usage by almost 29,000 gallons a year, saving taxpayer an estimated $116,000 and reducing greenhouse gas emissions by 257 metric tons, said GSA administrator Martha Johnson.

I’ll give the financial analysis a whirl:

101 Volts at $38,500 equals $3,888,500. Add to that 10 Leafs costing $33,000 and you get $4,218,500. Now add 5 EV’s at $32,500 and the grand total is $4,508,500. At a savings of only $116,000 a year in petrol it would take 39 years to offset the costs of the cars.¹

Doesn’t make much sense to me? The battery life of these cars will not last more than ten years (And that’s a conservative estimate. There are some quotes of only half that.), the last time I checked.So the costs of buying new “green” cars will never be offset.

Oh and not withstanding the cost  of all those charging points they are going to install.

Makes you wonder what world those people live on.

¹ I’d convert to sterling if I could be bothered. But I’m sure you’ll get the picture.