A bright poster, with a picture of a sunflower, on the forecourt informs drivers: "This site uses energy generated by solar panels." Britain's first solar-powered filling station taps the sun for electricity to pump fuel into customers' cars.
It testifies to the commitment of BP, owners of the station near the intersection of the A6 and the Bedford bypass, to solar power. The company, which already has a tenth of the world market in tapping renewable energy sources, is investing $1bn over the next 12 years.
Not to be outdone, Shell is spending pounds 500m on alternative energy over the next five years, seeking a 10 per cent market share.
Shell, with the car giants Ford and Daimler Benz, is investigating hydrogen as an alternative fuel. The first mass-produced cars running on the non-polluting gas are expected to be in showrooms within five years. The race for the sun signals that renewable energy is coming of age, moving from the commune to the boardroom, from the beards to the suits. And the firms insist it makes good business sense.
Shell and BP have set up special companies to exploit renewable energy and both say this is one of the fastest growth areas. BP Solar's turnover rose 33 per cent last year.
Shell believes that many renewable sources are following "similar paths" to oil in its early years of development, and expects the market for solar cells to be worth $6bn by 2010. The company predicts that burning of oil and gas will peak by 2020 and that clean sources may provide half the world's energy by 2050.
Both companies believe that the prospects for renewable energy will steadily improve as the world clamps down on the pollution that causes global warming.
And their initiatives offer hope of faster action to tackle the climate change, as business tends to move faster than government when it sees the opportunity to make money.
"These are exciting times," said Jim Dawson, president of the newly-formed Shell International Renewables Company. "We are sure of the potential, now we have to make it work in practice."
Anna Stanford, renewable energy campaigner for Friends of the Earth, said the Shell and BP initiatives were "very important in terms of the message they send".
BP has 17 solar-powered petrol stations around the world and is about to open its second British station in Milton Keynes. The sun provides only part of the power needed to run them, so they are also connected to mains power.
BP is supplying 500 solar power units for the athletes village at the Sydney Olympics, has provided lighting for the Ford Motor Company's factory at Bridgend, Wales, and is helping to build a "solar suburb" in the Netherlands.
Shell has equipped one of its oil rigs off Brunei with solar panels, is working with the Dutch government on solar buildings in the Netherlands and has established a series of "sun stations" which generate electricity from the sun and from burning wood in developing countries.
Drawing on its experience with oil platforms, the company is also investigating windmills in the North Sea in response to a government drive to encourage offshore wind power.
Shell is carrying out research into hydrogen, which produces only water as waste, to replace petrol. The project also involves Daimler Benz, Ford and Ballard Power Systems, a Californian company which produces hydrogen fuel cells.
Daimler and Ford have had prototype vehicles on the road, while the Californian company says it is "moving towards mass production" and plans to have hydrogen cars on sale within five years.
Meanwhile, a British company, Zevco Limited, has already built a hydrogen- powered London taxi and plans to put 150 vans powered by the gas on the road next year. The chief executive, Nicholas Abson, said the company could produce the vehicles at a "very low cost" and that a taxi would save pounds 20,000 in running costs over its lifetime because the fuel was so much cheaper.
He said there were no technical barriers to a hydrogen economy and no need for government subsidies.