Roger Harrabin reports on the Chinese car maker BYD, which is about to release a vehicle capable of revolutionising the world of motoring, if its claims prove correct.
A look at a battery-powered car that can travel 400km on one charge
BYD says that its new E6 electric car due out before the end of the year will do 250 miles (400km) on a single charge.
This is a very big number. The Tesla electric sports car does almost as much, but has little room for anything else in the car but the battery.
The E6 is roomy with space for five passengers and a good-sized boot. The battery tucks under the back seat.
It needs 7-8 hours with a domestic plug to charge the car but BYD - it stands for Build Your Dreams - says a specially developed fast charging point with a lead the diameter of a fire hose will fill up the car in just one hour.
You can get half a charge in only 10 minutes.
If these claims are accurate and if BYD can persuade either the Chinese government or a Chinese city to install a network of the fast chargers, then this large hatchback could be the vehicle that makes the breakthrough for electric cars.
Let us look at the accuracy of the claim first. BYD is already the world's number two in rechargeable batteries, and for the E6 it is using a ferrous battery it has developed itself.
There is a reputational risk in exaggerating the claims of a product. And that could be translated into a legal risk if people buy shares in the publicly quoted company as a result of misleading information.
For the E6 to succeed, the company will need a network of fast chargers
The green group WWF has just appointed the Chinese energy expert Dr Yang Fuqiang as its head of global solutions. He told BBC News that he would reserve judgment on BYD's claims.
"If they are true, this is an extraordinary step which will prove highly significant," he said.
So what about the other question about support for a network of charging stations?
The Chinese government has spent more than any other on its green fiscal stimulus and there is supposed to be support for electric cars.
But BYD's Rebecca Wang said that although BYD hoped for co-operation, none was yet forthcoming.
The E6 will sell for £30,000 and is aimed initially at the eco-conscious California market. When the price comes down with mass production, it'll be rolled out properly in China.
Whether the claims are accurate to the letter or not, the E6 is a marker that China expects to dominate energy storage technologies - which could become much more important if the world makes a significant shift towards renewable power.
Even if they are run on coal-fired power, electric cars still produce fewer greenhouse gas emissions than a petrol car because they are inherently more efficient, according to the UK's chief energy scientist David MacKay.
This efficiency is increased if you can run an automobile fleet on either off-peak electricity at night or on intermittent power from, say, wind farms.
I chanced to share lunch recently with the CEO of a major European car manufacturer. He told me that China intended to become the world leader in battery technology. "And if that's what [China] wants, it will happen," he said. Simple as that.
But the question remains if China has the cars to match its batteries.
As a car maker, BYD is very much at the "functional" end of the Chinese market - a farmer's car, my Beijing producer Jasmin called it.
There may be a risk that BYD's batteries could be undone by poor build quality.
The ability to attract top entrepreneurs into this field can only be good for China
Yu Jie, The Climate Group
BYD's chief executive Wang Chuan-Fu is certainly ambitious, and money is certainly not a limitation.
Following a huge investment by Warren Buffet, he has just made it to the top of the Forbes Rich list for China. He is joined at the top table by another green billionaire, Shi Zhengrong who made a fortune from the Suntech solar PV firm in just four years.
There is such a buzz about the Clean tech gold rush in China at the moment that some analysts warn of the possibility of a bubble.
The Climate Group is an international non-profit organisation that works with governments and businesses with the aim of building a low carbon economy.
It is keen to dispel such pessimism. Yu Jie, its head of research in Beijing, told BBC News that if the bubble popped, it would only deflate slightly.
"Everybody wants to get into clean energy at the moment," she said.
"It can only be for the good. And the ability to attract top entrepreneurs into this field can only be good for China, which has often depended on other people's technology in the past."
When we arrived at the BYD plant, the workers were on holiday so there was no activity to film. And the E6 itself was nowhere to be seen.
But we eventually managed to persuade our hosts that, having travelled all the way from the UK, we deserved a sneak preview, and the E6 itself was unveiled.
My cameraman Al implied this negotiation might have been part of the company's publicity strategy. We will see.
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