Business leaders are watching Copenhagen climate talks, which might launch new, bigger carbon markets and help drive investment in green technologies.

Following are views of chief executives of green and clean companies attending the conference.

Ditlev Engel, CEO Vestas Wind Systems

We need a price on CO2 and we need it now. Renewable energy needs exactly the type of long-term visibility and planning that you had in the oil and gas industry, in that once you understand the possibilities, you make sure the regulatory framework is there. For the political decision that needs to be taken here, it's important that there is a unity across renewable industries.

Tom Knutzen, CEO Danisco

Even though we will not have the technicalities in place at this meeting, if we produce a binding agreement that is executed in the short term, then I will applaud that.

If the summit talks collapsed then Danisco would go ahead with its present bioethanol business plans but it may take longer for these to grow and to develop new projects, said Krutzen. We will go on. We will do what we do right now.

Jan Hylleberg, CEO Danish Wind Energy Association

Our hope is, of course, that no matter what kind of a deal they agree on on Friday, that it becomes as ambitious as possible.

My concern is that, in a worst-case scenario where we don't have a climate deal, then we could have a setback in relation to how fast we (the wind industry) would otherwise recover from the current financial crisis.
Denise Bode, CEO American Wind Energy Association (AWEA)

We would like to see an agreement on carbon. We are excited that the U.S. is here and that (Obama) is coming at the end of the conference, which indicates to us that the president wants to make a strong statement on behalf of the U.S.

We just need to have that long term policy in place.

Tulsi Tanti - Founder, Chairman and Managing Director, Suzlon Energy

We need very clear, long-term visibility from Copenhagen. Without a deal, the wind industry could supply 20 percent of global energy by 2030.

With a deal, that could grow to 30 percent, and that would cut global emissions by 10 percent. In having long-term visibility, we can develop the required resources like capital expenditures, human resources and geographic distributions.

Ian Mays, CEO, Renewable Energy Systems

We need investment, and that investment needs stability. Mechanisms supported by significant and binding emissions targets agreed here will provide that. They would have to be met with renewables playing a substantial part of the solution.

We can, by 2020, reduce carbon emissions by around 10 billion tonnes if we have a challenging but achievable programme for renewable energy. That will need a very strong message from Copenhagen, a trigger for policy action at the national government level.