I recently spoke with someone in Alameda County and they shared a few great case studies. I think that one that we must keep in mind is that going green is simply the 'right thing to do' - but there are real financial benefits to doing so!
An example of installing lighting and occupancy sensors. With incentives, the payback is less than one month! Even without incentives the payback is under 8 months. (http://sfenergywatch.org/pubs/JordanHousingCaseStudy.pdf)
An example of changing out metal halide lights with CFLs. With incentives, again under one month! If your area doesn't provide incentives at this time, the payback will be fully recognized in under 3 months. (http://sfenergywatch.org/pubs/TheWatermark.pdf)
These types of easy improvements are wins all the way around, renters are happier, operating costs are reduced, and more eco-friendly.