ComputerWorld has an article where Enterprise-Rent-A-Car is the main reference customer and discusses the deployment of thin-clients.

Environmental impact: IT sees the light on green computing
For some organizations, reducing the energy consumed by IT equipment is becoming a selling point with customers and even potential new hires.
By Patrick Thibodeau
June 30, 2008 (Computerworld) This version of the story originally appeared in Computerworld's print edition.
When Enterprise Rent-A-Car Co. completes a move from PCs to thin clients this summer, as part of the rollout of a new rental transaction system, it expects to cut internal energy consumption by 5 million kilowatt-hours.
That will save about $500,000 annually while reducing the company's carbon dioxide emissions by 6.5 million pounds each year, according to Enterprise officials. Energy costs and consumption were considerations when planning for the new system began earlier in the decade. But they have grown in importance for Enterprise -- so much so that the company issued a press release in April to let the public know how its shift to thin clients would help the environment.

Here is the enterprise press release, and an environment web site for Enterprise, National and alamo rental cars.

And, it was nice to see Enterprise IT staff has seen Green Computing as a way to make its company stand out in recruiting IT staff. This point is missed by many who don't understand how much pride people take in working on Green solutions for the data center and IT.

Meanwhile, Enterprise isn't just touting its green computing exploits to the general public. The committee that's evaluating the environmental impact of new technologies includes a representative from the human resources department. Miller said the company has found that green computing is a strong selling point in attracting IT job prospects, and it wants HR to know what it's doing in that area.