I'm pleased to say that this blog has been listed as one of the 50 Best Patent Blogs on the Guide to Online Schools site -- though sadly only as one of the "rest of the best" rather than among "our favourite five".
One of the favourite five was new to me, the Green Patent Blog®, by Eric Lane, a San Diego patent attorney. Its strapline is "covering intellectual property issues in clean technology". Understandably he focuses mainly on litigation rather than on the use of patent documents as blueprints for green innovation.
I was very interested in his post on Green patent policies and initiatives, where he discusses recent work. New to me was WIPO's IPC Green Inventory, a tool to assist finding patent classifications in the area. Once you have the right class, what do you do then ? I suggest my posting on using patent classifications is a good start if you are unsure.
I knew about the European Patent Office's final report Patents and clean energy: bridging the gap between evidence and policy, which has a lot of statistical analysis of trends in green patenting.