The bi-annual report ranks the top 40 countries on how attractive they are for renewable energy investment.
It takes into account economic stability, clean energy gaps, political stability and support systems, ease of market access and the potential for renewable technologies, including wind, solar, biomass, geothermal, small hydro and marine energies.
China and the US retained the top two places once more, while India replaces Germany in third spot as it nears its solar PV target.
EY said the ongoing geopolitical instability, including mounting trade wars between the US and China – which has affected imports of solar panels – means the two markets are "in a holding pattern".
Ben Warren, RECAI chief editor at EY, said: "An uncertain political climate — particularly the continuing trade disputes between the US and China among others — compounded by the increasing scarcity of subsidies, presents a challenging backdrop to the maturity of the renewables sector.
"However, oversupply will provide a short- to medium-term boost to the price competitiveness of renewables, while also likely to drive some consolidation upstream.
"In the longer-term, increasing demand for power from the mobility and heating sectors provides something other than trade disputes for policymakers to focus on," Warren added.
New entrants to the rankings were Uruguay (37th) and Saudi Arabia (39th). The Saudi government has been making numerous noises about strongly growing renewables deployment. It is targeting 3GW of renewables by 2020, and 9.5GW by 2023.
In July, the Renewable Energy Project Development Office (REPDO) and the Ministry of Energy, Industry and Mineral Resources (MEIM) received bids of between $21.30/MWh and $33.86/MWh for the 400MW Dumat Al Jandal project.
Among the big movers was Argentina, which entered the top ten for the first time, having only been included in the list since May 2016
EY said the Argentine government was demonstrating political support for renewables.
In September, undersecretary for renewable energy, Sebastian Kind, revealed plans of a 350MW tender for wind and solar capacity as part of a third round of RenovAr auctions, alongside a tender for transmission.
Egypt meanwhile, boosted its rankings by five places to 15th, following the country’s ministry of electricity and renewable energy "making strides towards implementing wind energy in a big way, with plans for wind schemes up to 1.8GW and total capacity expected to expand by 3.3GW by 2027".
Greece also climbed six places to 28th on the list as it moves to a tender-based system.
"Greece looks to auction 2.6GW worth of wind and solar projects, aiming to hit its EU-prescribed target of 18% renewables by 2020," EY said.
The rebounding Spanish market also sparked a seven-place jump to 17th overall, as it "embarks on a subsidy-free journey".
EY said Sweden was "a victim of its own success" after falling ten places on the rankings to 32nd.
EY said the influx of onshore wind has caused "future prices in power and green certificates to decline".
South Korea was another of the big fallers, slipping five places to 31st, being leapfrogged by the likes of Greece, South Africa and Taiwan.
EY's Renewable Energy Country Attractiveness Index:
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