"The industry has a very short space of time in which to meet challenging targets. There are still gaps and anomalies that need to be addressed with fresh polices."
The REA said it was pleased the government had gone beyond its usual focus on power generation to look at the potential of renewables in heat, transport and buildings.
But ministers are expected to say on Thursday up to half of the target will still have to come from the electricity sector, meaning a third of Britain's power will have to come from renewables - which some in the industry say is unrealistic.
"The engineering challenges inherent in delivering a vast uplift, particularly in offshore wind, are immense and totally underestimated, if accounted for at all, in the government's thinking," said Sue Ion, vice president of the Royal Academy of Engineering.
"The consultation document almost acknowledges failure as it is printed by admitting that there are only three manufacturers in the world currently able to make the turbines, that there are not enough vessels to deploy or skilled workers in the sector."
Long standing critic of energy policy Greenpeace hailed the plan - which could see millions of homes topped with solar panels and a boom in electric cars - as visionary but said the government had failed to meet previous promises.
"If the government actually means it this time then Britain will become a better, safer and more prosperous country," Greenpeace executive director John Sauven said on Wednesday.
"But it won't happen without real government action."
Britain gets less than 5 percent of its electricity from renewables and is expected to be required by the European Commission to get 15 percent of all its energy from environmentally friendly sources by 2020.
