Utilities and oil companies, among the biggest polluters, are using their market awareness to stay ahead of a climate race, maneuvering to own the most viable low-carbon technologies.
In addition, they are a natural magnet for government incentives as big emitters which have to drive cuts.
"They are sufficiently commercially and technically mature and their concentration makes action possible," said Chris Mottershead, head of research and innovation at King's College London and former climate change adviser to oil firm BP.
"There's an obvious conclusion: the big utilities, the international companies are the ones that are going to benefit in the first phase," said Copenhagen Climate Council director Per Meilstrup. "And that's quite a problem as I see it."
The council works with scientists and sympathetic industry to develop a green business voice and says governments must penalize carbon emissions more, to drive more investment in cash-starved, clean energy entrepreneurs.
The world is meant to agree a global climate deal at a UN-led December 7-18 meeting in Copenhagen. Negotiators may miss that deadline, say analysts who expect an agreement in 2010 which governments will craft into national policies to drive carbon cuts.
Big business is competing in a technology race by snapping up or partnering with smaller companies as these develop products, said Mark Kenber, policy analyst at The Climate Group.
That has been seen in wind power and in a technology to bury carbon emissions from coal plants called carbon capture and storage (CCS). In biofuels U.S. oil giant Exxon Mobil Corp announced in July $600 million plans to develop clean fuels from algae.
The dominance of high-carbon companies in cleantech is underscored by patent ownership. Exxon is the world's top holder of CCS patents, research by the UK thinktank Chatham House showed last month.
CCS is receiving billions of dollars but may take a decade to develop. It is popular with big corporates as a bolt-on to coal plants which may use depleted oil wells to store carbon dioxide. The European Union's executive Commission two weeks ago awarded 1 billion euros to 6 CCS projects.
Analysts at the investment bank Citigroup have identified a "watch list" of 181 publicly traded companies which could benefit in the long-term from strong targets to cut carbon.
Benefiting sectors included utilities and engineering companies in nuclear, hydro and wind power, and the natural gas industry following new reserve finds and favorable economics for the low-carbon fossil fuel.
Likely winners were mostly large and well established such as electronics firm Philips, engineering company Alstom, oil and gas company Gazprom and waste firm Suez Environment.
Not everyone is happy that oil firms, utilities and big engineering companies may hold the keys to a low-carbon future, and there is a worry that insufficient public funds are reaching start-up companies and entrepreneurs.
"If you are not in a lab in a big international company that can afford to develop ideas, demonstrate projects and market mature products, then it's really hard," said Meilstrup.
He added that "amazing" technologies were being missed for example to generate cheap household energy from waste in developing countries.
High-carbon utilities may also have an unfair headstart after winning windfall profits under Europe's emissions trading scheme, meant to penalize polluters. And oil companies continue to get subsidies, such as U.S. oil exploration tax breaks.
U.S. venture capital investors in cleantech start-ups needed the same tax breaks, argued Mungo Park, chairman of Innovator Capital, a specialist investment bank.
But a booming wind industry is proof that a low-carbon revolution will likely create new winners outside traditional sectors perhaps battery makers, expected to roll out mass production units in pure electric cars from next year.