If I remember my Real Estate 101 correctly, the goal is to rent out as much square footage as possible at the highest price, maximizing revenue for a building. But what about all of that wasted space above your head, on the roof? There's got to be a way to monetize that space right?

That is becoming a more viable option for REITs around the country as utilities and solar developers make business models that are palatable to the real estate industry. In one example AMB Property Corporation (NYSE: AMB) is leasing out roof space to Edison International (NYSE: EIX) subsidiary Southern California Edison for a 1 MW pilot facility. For AMB this is gravy because they're getting paid to lease space that would otherwise go unused with zero capital investment. Sign me up for that deal.

Developers Diversified Realty Corporation (NYSE: DDR) is also on the bandwagon signing a deal with MEMC Electronic Materials (NYSE: WFR) subsidiary SunEdison to deploy solar on 200 shopping centers in the U.S.

The biggest hindrance to widespread adoption for now is the lack of a consistent business model. Solar initiatives vary state to state, and developers are not yet equipped to handle the capital expenditures that REITs would want them to handle for solar installations. SoCal Edison did take a big step with their 250 MW distributed generation rooftop program, which it will own and operate. SunPower (Nasdaq: SPWRA)(Nasdaq: SPWRB) won 200 MW worth of the project -- the company's panels will be installed on otherwise unused rooftops all over southern California.

Manufacturers like LDK Solar (NYSE: LDK) and Canadian Solar (Nasdaq: CSIQ) are counting on greater U.S. demand in the future, and REITs may be a big piece of that puzzle. As I look out of my downtown highrise window I can see a lot of wasted rooftop space that could be generating electricity on this sunny spring day.

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Fool contributor Travis Hoium owns shares of SunPower. You can follow Travis on Twitter at @FlushDrawFool, check out his personal stock holdings or follow his CAPS picks at TMFFlushDraw.