I agree that this is a great idea. Promoting your service to an organization should be the easy part since it will help promote their brand/company as an eco-friendly one. To help answer some questions I've been curious about: How do you charge for event planning in general? Does the company pay you for all materials required for the event? You're defintily on to something. Just keep a close eye on how this green trend evolves/fades and make adjustments accordingly. Oh yeah, it wouldn't hurt to drive a hybrid to your events :-p