The cost of protecting the West's Middle East oil supplies is about a dollar a gallon, a UK Government minister says.
Peter Hain, the Europe Minister, said this cost should be reflected in transport and other domestic policies.
Ultimately, he said, no amount of money could guarantee secure oil supplies, especially in the next few decades.
He urged a rapid effort to develop renewable and low-carbon replacement fuels.
In a speech to the Royal United Services Institute (Rusi) in London on energy security, Mr Hain said there were three clear priorities for action:
"Paid predominantly by the US, the costs of protecting our Middle East oil supplies are as high as $15-25 a barrel - that is about a dollar a gallon.
Double benefit
"We should factor these sizeable external costs into all our decision-making - for example in transport policy - rather than placing them in a separate box marked 'security'.
"Even more troubling in a divided world, there may be no amount of money we can spend that will guarantee the security of our oil supplies, especially their vulnerability to short- and medium-term disruption over the next few decades."
Mr Hain said reducing the use of oil as a transport fuel would boost other objectives, notably on air quality and climate change, in "convergent policy-making".
He said: "There is no area where the need for convergent policy-making is greater than in ensuring our energy security, especially in the field of transport."
Transport was the fastest-growing source of greenhouse gas emissions globally, and consumed a growing share of total oil consumption, he added.
Hope for Africa
New fuels would be needed, including biomass, wind and solar power, and wave and tidal energy, and also new transport technologies.
There would be another gain from the transition away from oil, Mr Hain said - "massive potential benefits for poverty reduction, particularly in Africa".
"I believe that renewable energy technologies have an important part to play in Africa's longer-term development, and could help define a new successful Africa of 'lion economies'.
"A combination of mobile telecommunications and solar and renewable power could bring affordable energy to all the people of Africa.
"We can shift the bounds of the possible if we can combine the political urgency we associate with our national security with the wide range of low-carbon transport fuel technologies. We must not be prisoners of our own time."
All must change
Mr Hain told BBC News Online: "The horrific terrorist attack in Bali, the attack on the French tanker off Yemen the other week - these threats are coming at the world from all directions.
"And you can't continue, though it's important to try obviously, to just keep erecting security and defence barriers all around you.
"We have a way of life, a set of consumption patterns, that are going to have to change - all of us.
"We have to recognise that without a major shift in the whole way we organise ourselves, our pattern of life is simply not sustainable."