Former US Vice-President Al Gore has been accused of hypocrisy for apparently guzzling energy while he lectures the world on climate change.
A former aide suspects a campaign by Mr Gore's opponents
A Tennessee-based free market think-tank said Mr Gore's home used more than 20 times the national average of gas and electricity.
A spokeswoman for Mr Gore said he was trying to reduce his carbon emissions by using sustainable energy sources.
Mr Gore's climate change documentary An Inconvenient Truth won an Oscar.
The Tennessee Center for Policy Research said utility bills obtained from public records indicated that Mr Gore's 20-room house and swimming pool in Nashville used nearly 221,000 kWh in 2006, compared with a yearly average of 10,656.
The centre's president Drew Johnson said the Gores had a heated swimming pool, natural gas lanterns and an electric gate.
"As the spokesman of choice for the global warming movement, Al Gore has to be willing to walk the walk, not just talk the talk, when it comes to home energy use," a news release from the think-tank said.
In An Inconvenient Truth, Mr Gore calls on Americans to reduce energy consumption at home.
Mr Gore's spokeswoman Kalee Kreider did not deny the figures, but said that both Mr Gore and his wife Tipper worked from home, implying that they were therefore likely to use more energy.
The family was trying to reduce carbon emissions by getting energy from a local programme which generated energy from renewable resources such as solar and wind power instead of fossil fuels, she told ABC News.
They were also in the process of installing solar panels and low-energy light bulbs to reduce consumption from the grid, she added.
A former aide said he suspected a campaign by Mr Gore's political opponents.
"Considering that he spends an overwhelming majority of his time advocating on behalf of and trying to affect change on this issue, it's not surprising that people who have a vested interest in protecting the status quo would go after him," he told ABC.