In what could be a new sign that Apple (AAPL) is stepping up its efforts in so-called cloud computing, Data Center Knowledge reported Wednesday that the company has signed a long-term lease for several megawatts of critical computing power from a data center under construction in Santa Clara, Calif., less than 10 miles from Apple’s Cupertino headquarters.

The facility is being assembled by Dupont Fabros Technology (DFT), a major supplier of third-party server power to such clients as Yahoo (YHOO), Facebook and Google. The new center is scheduled to come online in two phases: 180,000 square feet this summer, and another 180,000 square feet sometime down the road.

When completed, the 360,000 sq. ft. facility would be nearly three-quarters as large as the 500,000 sq. ft. server farm Apple is building for itself in Maiden, North Carolina.

According to Wednesday’s report, however, the seven-year lease Apple has signed is for only 2.28 megawatts of power, about 1/8 of the capacity of the first-phase of the project.

Below: The description of the new data center that appeared in DFT’s 2010 annual report:

In May 2010, DFT commenced development of its SC1 data center. The facility will be built in two identical phases, each comprising 18.2 megawatts of critical load. SC1 will provide a new class of wholesale data center to this market. The building is designed identical to ACC5 which provides for a flexible and efficient design as tenants are able to lease one or multiple dedicated computer rooms each with independent redundancy and security. The building’s two phase scalable solution enables tenants to grow within DFT as their capacity needs expand. The building is designed to meet LEED standards. Phase I is expected to deliver in the third quarter of 2011.

Phase I Highlights:

• 18.2 megawatts
• 180,000 gross square feet
• 88,000 square feet of raised floor
• Currently pre-leasing