Google Inc and Citigroup are investing another $204 million in the Alta Wind Energy Center in Southern California's Tehachapi Mountains, bringing their total combined investment in the project to $314 million.

The additional funds will be split evenly between the two companies, according to Terra-Gen Power, which is building what is expected to be the nation's largest wind energy project.

The new investments specifically finance the Alta V Project, which is projected to generate 168 megawatts of electricity. Google and Citi had previously jointly invested $55 million in the nearby Alta IV phase of the project.

Terra-Gen Power, the project developer, is an affiliate of ArcLight Capital Partners and Global Infrastructure Partners.

The AWEC site is currently generating 720 megawatts of power, according to Terra-Gen Power.

By year end, another 300 megawatts of power are projected to be online, Terra-Gen says, bringing the facility up to 1020 megawatts.

The wind project is expected to generate 1550 megawatts of power upon completion. Edison International utility Southern California Edison has a contract to purchase all of the power generated by the site.

We are particularly excited about AWEC because it will be one of the largest wind energy centers in the world, wrote Rick Needham, Google's director of green business operations, in a statement on the company's Web site.

This project is a national model for the economic viability of large scale renewable energy projects, said Citi's managing director of environmental finance and stability, Michael Eckhart, in a statement. We hope it will encourage further investment in the space as we work to expand the clean energy economy in the U.S.

Google has invested more than $780 million in clean energy, with over $700 million of those investments occurring this year, according to the company.

(Reporting and writing by Mary Slosson; editing by Gunna Dickson)

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