The Dane, Bjorn Lomborg is a well known, and respected climate sceptic.......or he was. I recall reading that he was now accepting of climate change, but the following article does call into question the economic pathways most suitable to achieve a lot' with using renewable energy. Especially the economic policies used to achieve take up of the concepts.
He seriously questions the role that renewable energy systems can play in reducing fossil fuel use, and ultimately carbon emissions. Particularly the economic costs of using renewable energy such as wind and solar. Many others might agree directly with this view, and others strongly support the same general view by suggesting that carbon capture and storage must be made to function, as coal will need to play a role in stationary energy production, including electricity, for many years yet.
Here in Australia, a monster user and producer of coal, there has been a degree of support for the develpment of the zero emissions stationary energy plans developed over the past several years and formalised in a document available here -http://beyondzeroemissions.org/zero-carbon-australia-2020
I would agree they do seem economically and conceptually feasible, but significant changes must be implemented in regard to distribution networks for example. And more investment is now going into that area, but not necessarily to meet this concept plan. Lack of vision is a serious impediment to implementation of this concept. Spain has been investing in base load solar systems successfully, as shown in the photo.
Many would argue that nuclear energy will be needed around the world to meent energy needs. And that is low carbon emissions. Recent events eg Fukishima in Japan, will affect ideas on that too.
The Chinese are moving to develop thorium nuclear reactors. They have several notable features that could lead to wider interest. They do not generally have self sustaining fission- ie need some nuclear fuel to keep them going, and they produce very modest radioactive level and relatively short half life waste products [a strong point]. Curiously, Australia has a lot of thorium resources, and even more curiously it can occur with rare earth minerals and Chinese are investing in some of the mines with rare earth/ thorium resources too. Is this coincidence??