"For the first time we are doing an overall audit to take stock. We don't have a tally of our carbon footprint. That's what we are trying to assess -- how to reduce our carbon emissions," a Buckingham Palace spokeswoman said on Tuesday.

"This is to pull everything together to see what is working and what is not. It will cover everything from changing light bulbs to looking at travel," the spokeswoman added.

But she stressed the Queen, who is known to wander the royal corridors switching off unnecessary lights, was not just following in the carbon footsteps of her son Prince Charles, a fervent environmental campaigner.

"The management of energy has been an integral part of royal households for many years and we are now taking a look at where we are at," the spokeswoman said.

Boreholes are going to be used this year to cool the royal wine cellars in Buckingham Palace.

Plans are being developed for a turbine in the River Thames to generate electricity for Windsor Castle.

Two royal Bentley and two Rolls-Royce limousines have been converted to be more fuel efficient.

Elizabeth's husband, Prince Philip, drives around London in a gas-fuelled taxi cab.

Their eldest son Charles has long been an impassioned environmentalist, promoting organic farming and a sustainable approach to agriculture.

The heir to the throne has pledged to exchange private planes and helicopters for public transport and biodiesel cars. Wood-burning boilers, bicycles for his London staff, more energy efficiency at his country homes -- all are on his green agenda.

"We are consuming the resources of our planet at such a rate that we are, in effect, living off credit and living on borrowed time," the future king has warned.

So how best can the House of Windsor try to save the planet?

"Some of the quick routes are things like changing light bulbs. It becomes more tricky when you look at things like transportation," said Ashok Singha of the Stop Climate Chaos Coalition, an environmentalist umbrella group.