The Chancellor should announce funding for making homes more energy-efficient and new renewable power subsidies in the upcoming autumn statement, experts have urged.
Measures such as more efficient boilers and insulation in homes and offices could cut the energy needed to heat indoor spaces by 30% to 50% by 2050, researchers from the UK Energy Research Centre (UKERC) said.
But there is a policy vacuum since the flagship "green deal" to improve home energy efficiency was abandoned as a failure, and resources to fill the gap were needed.
There also needs to be clarity on the money that will be made available to support renewable power after 2020, through the "levy control framework", or investment will go elsewhere, the experts warned.
There should be a level playing field for more mature technologies so that emissions can be cut at the least cost, instead of the current situation where the cheapest options, solar and onshore wind, have been excluded.
The experts also suggested there should be clarity on developing technology to capture and permanently store carbon emissions from industry and power plants, without which gas cannot stay in the electricity generation mix in the longer term.
But Chancellor Philip Hammond should avoid announcements on shale gas, which provokes local hostility to central government and is a "distraction from the other things that need to be done now", UKERC's Prof Mike Bradshaw warned.
As Mr Hammond prepares to make his first autumn statement and the Government draws up its industrial strategy and emissions reduction plan, UKERC has reviewed the UK's energy policy.
If the Government does not act now, the chances of the UK meeting its legally binding targets to cut greenhouse gas emissions by the late 2020s are "pretty low", UKERC director Prof Jim Watson warned.
"But if the Government acts further, there's no reason we can't meet them. The acting now is really important," he said.
The review of energy policy calls for a co-ordinated, cross-government approach to energy, warning that: "An offshore wind factory and a new nuclear power station do not make an industrial strategy for energy. It needs to be much more systematic."
The experts also warned that while the costs of solar and wind were tumbling, and would continue to fall, the new nuclear power plant given the go-ahead at Hinkley Point, Somerset, was "likely to be very poor value for money for consumers".
The report makes a series of recommendations, including a new white paper on heat and energy efficiency, and an approach to gas that ensures its place in the energy mix is compatible with cutting emissions.
The experts also called for demonstrations of technological solutions such as district heating and injecting hydrogen into the gas grid to see what works in which contexts, engaging people and communities in the energy transformation, and tighter emissions standards for vehicles.