
The report is expected to say that the Carbon Reduction Commitment, a government efficiency scheme, could reduce CO2 emissions by 11.6m tonnes.
This would be the equivalent of taking four million cars off the road.
The study says the government and businesses have more potential to cut energy use than originally estimated.
Main tools
There has been long-standing scheme to force heavy industries to reduce emissions, but the little-known CRC is the government's new attempt to spread the effort more broadly across business and services.
It will cover around 5,000 large organisations including construction, food, manufacturing and local authorities.
The Environment Agency report says hotels, restaurants, shops and government departments have huge potential to cut energy use - even more potential than originally estimated.
The main tools are better management of heating, air conditioning and lighting.
The study quotes the example of Kings College London, which carried out a refurbishment which allowed its buildings to use natural ventilation rather than air conditioning. Window shutters - another important insulation measure - were also added as part of the project.
As a result, the report says, the college is saving around £96,000 per year on its energy bills.
The study also points out that by simply turning lights off in areas that are not being used, businesses could shave 15% off their energy bills.
Under the CRC, organisations will be required to buy CO2 "allowances" for each tonne of CO2 they emit.
The revenue raised from selling allowances will be "recycled" back to participants according to the progress they make in reducing emissions.
Those doing best will get more money back than they put in - and those doing worse will lose out.