The Big Green Challenge is a two-year program with three stages: Stage 1 deadline is February 29, 2008 for initial submissions. Stage 2 invites up to 100 groups to submit detailed plans. Stage 3 has up to 10 finalists implement their ideas from October 2008, receiving advice and up to £20k each. To qualify, ideas must achieve carbon savings through innovation, demonstrate sustained community commitment for durable impact, and be replicable at scale.