The "Cleaner, Smarter, Cheaper" report suggested renewables could provide at least 61% of Europe's electricity by 2030 if lawmakers seize all the available opportunities while negotiating proposals for post-2020 climate and energy policy.
This would include measures at the national level to push forward with decommissioning coal-fired power plants, and measures enabling demand response, where consumers are rewarded for moderating their electricity consumption at times of insufficient generation output.
The report only foresaw a limited role for gas as a less dirty 'transition' fuel.
"Even where coal is considerably reduced, we are still seeing gas-fired generation reduced by about half, driven by low-cost renewables and flexibility resources," said Jonathan Gaventa of the think tank E3G, which collaborated on the research.
The 61% renewables share goes beyond the forecast results for a 'current plans' scenario — based on proposals in the European Commissions clean energy package — that the report suggests would lead to an increase from 29% in 2015 to 55% by 2030.
The report was commissioned by the "Energy Union Choices" platform, which includes the European Climate Foundation (ECF), E3G, the WWF and other and environmental pressure groups and think tanks.
The European Commission is currently finalising its own report into the cost of renewables, after complaints from MEPs that the assessment used as a basis for current proposals assumed far higher prices than those seen recently following sharp falls.
Citing preliminary findings, the Commission's vice-president for energy Maros Sefcovic said the cost of meeting a 30% overall renewables target for 2030 would not be "that much different" from the proposed 27%.
"From the cost perspective this is achievable and I would underline once again that in our proposals we were always talking about 'at least' 27%," Sefcovic said.
The fall in renewable energy costs has led to an unprecedented situation where "less ambition will cost us money", said Dries Acke, who heads the ECF's energy union programme.
European environment ministers are expected to adopt their position on proposed reforms to the Renewable Energy Directive on 18 December, with the most recent indications being that they plan to stick to the 27% proposal.
The European Parliament's industry and energy committee will adopt its position on 28 November, and lead negotiator José Blanco López has proposed an overall goal of 35%.