Manufacturing firms are appealing to ministers to match a European grant scheme that subsidised the cost of installing renewable energy.
Under the EU system companies were able to claim up to a third of the cost for installing solar panels, biomass boilers or double glazing.
European funding has run out and there were no plans to replace it with a British scheme, the government said.
Instead, ministers said there would be tax breaks for green investments.
In Gloucestershire the programme was administered by Severn Wye Energy, an independent charity, which handed out nearly £500,000 of EU funds.