As a bit of a primer on open data, the foreword to the Government's White Paper on Open Data is a good starting point, along with the glossary that follows it.
In response to much better availability of government open data, AMEE, a company that helps businesses become more energy efficient, has analysed governmental supply chains for their environmental impact. Their infographic is a great example of using open data to highlight opportunities to influence emissions, and their brief blog gives more detail.
A great source of open data on energy efficiency is the NEED database, which collates data on energy usage and efficiency measures across the UK, down to local level. It's worth having a quick nose around the site to see what parameters are included within the data. Data is also available on renewable energy generation across the UK, which enabled this website, Low Carbon Councils (still in development).
The Open Data Institute is a key player working towards better use of open data, and have worked with NESTA to run a series of open data challenges. Community Energy Manager is one example of a service that they have helped to kickstart. Carbon Culture is another.
The US is also driving change through open data, and could well offer some examples for us to follow. This article rounds up some of the promising startups and initiatives being launched across the pond.
Hope that gives a bit of a taster of what's going on around open data, and I look forward to some good discussions at the next meeting! Feel free to post further links in the comments below.