From a theoretical perspective, tradable credits may be the next best thing if we cannot have full internalisation of external costs, but what price theoretical elegance? In most of Europe, municipal waste and landfill gas combustion are the cheapest renewable energies and it would take some time before their deployment was limited by the size of the resources. Wind energy would only be developed on a large scale in countries with the very highest wind speeds. Germany might not see much action, for example. Even if there were a percentage specifically for wind energy it would have a devastating effect on diversity -- unless it was sub-divided between offshore, small scale projects, community developments and larger onshore projects. Moreover, the sheer complexity and long gestation period involved in developing international legislation is a fundamental obstacle.
Planning permission has been the limiting factor in the deployment of wind energy in the UK. This is not likely to be alleviated if planning committees are considering the benefits of projects needed to meet the obligations of far off utilities elsewhere in Europe.
Finally, putting the obligation on "all suppliers" also seems a recipe for massive bureaucracy. The NFFO places an obligation on utilities whose continued existence is guaranteed by statute. If early experience with gas is a guide, there will soon be many more suppliers, some wholesale, some retail, some robust, some frail. In other words, the obligation would be chasing a fast moving target -- and would be very difficult to monitor.
The BWEA has been debating these issues in detail for over a year now. The Rolling Programme (Windpower Monthly, October 1997) was actively chosen as the best option, and it can be implemented without major legislative upheaval. The NFFO has been tremendously successful in bringing the price of renewable energy down and as a result is being emulated worldwide. The BWEA cannot advocate replacing it with something infinitely less sensitive and much more complicated.