More than 70% of the planned spending on projects in the Treasury's "infrastructure pipeline" is on schemes that will help move the economy away from fossil fuels, including railways and wind power, analysis from think-tank Green Alliance said.
Taking into account the announcements in the latest spending review, some £180 billion is scheduled to be poured into low carbon infrastructure between now and 2020.
The figure is around four times what will be spent on high carbon schemes such as roads, airports and gas power plants, according to the research by Green Alliance, backed by Greenpeace, WWF-UK and Christian Aid.
But a perception the UK is not fully committed to a shift to a low carbon economy is putting that investment at risk, the think tank is warning.
The Government has been accused of sending out "mixed messages" to investors by backing sectors such as shale gas and failing to set a target to slash emissions from the power sector by 2030, at the same time as supporting renewables.
A clearer commitment to low carbon development from the Government could unlock the huge potential of private sector investment, making the economy cleaner and more prosperous, the think tank urged.
Matthew Spencer, director of Green Alliance, said: "This research shows that the UK's biggest infrastructure investment over the next few years should come from the low carbon makeover of our energy and transport systems.
"Unfortunately the big beasts of British politics have been largely silent about this opportunity, and investor confidence has dropped as the perception has grown that the UK is not fully committed to its current low carbon direction. This is perverse."