Edward Norton's $9,000,000,000 Housing Project (that's $9 Billion)

The data from Solar Neighbors were a start, but they wouldn't be extensive or rigorous enough to convince investors, so the Enterprise team put together a Green Communities checklist of mostly mandatory specifications covering construction, materials, and design -- the first nationwide green criteria for residential construction -- and set a goal of building 8,500 residential units in five years. Michelle Moore, the senior vice president for policy and public affairs at the U.S. Green Building Council (USGBC) -- which expanded its LEED standards to residential building only in 2007 -- marvels at what Enterprise has accomplished. "Their data really appealed to us because they're focused on affordable housing," she says. "We can't let a green home or school be 'eco-bling.' It's great to demonstrate that a green lifestyle is not just something celebrities can afford. We've learned a lot from them."

Enterprise met its 8,500-unit goal two years ahead of schedule. Showing an analytical fortitude that would make Silicon Valley proud, Bourland is leading the charge to crunch the resulting data and determine what it costs to integrate Green Communities building criteria and what savings can be harvested. By 2008, she says, it was clear that "water savings are 20% above baseline. Energy is pretty close to that. Those are stunning figures." The team also learned that asthma in children could be reduced for a tiny expenditure. "It's a database that exists nowhere in the world," she says.

Those data are driving financial innovation. Enterprise is introducing its first Green Communities Retrofit Fund, which will work with energy-services companies, or ESCOs, to provide affordable-housing operations with in-depth assessments of energy efficiency, construction plans, and loans based on the expected operating savings. Williams says the fund could grow into a stand-alone ESCO, staffed with its own auditors, trained in energy efficiency and home building, and generating green jobs. For the Chicago project that Mayor Daly announced in September, says Williams, "basically we'll be making low-interest-rate loans that will finance the retrofit of affordable-housing developments. We plan to prove that, for the first time, we can scale this across the country."

Perhaps the most ambitious new product is the Green Communities Offset Fund, which plunges Enterprise into the controversial world of carbon trading. Again, the data drove the financial innovation. "We can now look at numbers by region and project type, and know specifically what each improvement costs and what carbon benefits they provide," Bourland says. "And we can sell an offset because our data are measured and verified and real." Developers apply to the fund for financing; once the project is approved, the fund sells credits in the voluntary market, based on the amount of carbon that will be saved by building to Green Communities standards.

The fund is at an early stage. It has raised nearly $500,000 and made its first transaction, for a new apartment building in Albuquerque, New Mexico, for low- and middle-income tenants. Because the fund lives within the nonprofit part of Enterprise, future investors can offset their own carbon-rich lifestyles and get a tax deduction. (In a nice karmic nod, the USGBC plans to offset the carbon associated with its own annual shindig.) With banks and investment banks struggling to regain their footing, "it may very well be that Enterprise will become a major player in the carbon market," says Garry Hattern, a vice president at Deutsche Bank and creator of its community-development financing group. (Over the years, Deutsche Bank has participated in more than $120 million in tax-credit funds.)

Enterprise is also using its green-building expertise to reenergize its tax-credit operations, which have provided about $700 million in capital each year to affordable-housing efforts across the country. Under the rules administered by the Internal Revenue Service, the federal government allocates low-income-housing tax credits to all 50 states based on population. Developers make proposals to the state housing agencies, which review and award credits based on the size of the projects. "Then," explains Werhane, "the developer takes the credits to people like us, and we syndicate it to investors." The marketplace sets the dollar value of the credits.

Most tax-credit investors have been financial institutions with plenty of profits to offset and a comfort level with complex markets. Harvey recalls the first big commitment, from Hugh McColl at NationsBank, later CEO of Bank of America: "Hugh said to me, 'You can invest in these areas and make money doing it? I don't believe it.' He checked with his CFO and came back in and said, 'We'll take a billion.' " Today, with banks in disarray, the value of the credits has fallen -- from about 90 cents on the dollar last year to as little as 75 cents in some regions today -- leaving developers scrambling to make up the shortfall or postponing new projects.