UPDATE 2-First Solar, SoCal Edison plan big solar projects

* Two projects with capacity of 550 megawatts

* To supply 170,000 homes, completion seen in 2015

* No near-term boost to First Solar results (Adds analyst comment, details, changes dateline pvs NEW YORK)

LOS ANGELES, Aug 18 (Reuters) - First Solar Inc (FSLR.O) and utility Southern California Edison said on Tuesday that they would build two photovoltaic solar projects that will provide enough power to supply 170,000 homes.

The combined 550 megawatts of projects in the California counties of Riverside and San Bernardino are expected to be completed in 2015, the companies said.

The announcement is the latest move by U.S. utilities to increase their production of electricity from renewable energy sources to meet stricter state environmental rules and as the United States moves closer to regulating greenhouse gas emissions from fossil fuels.

The projects are also a sign that financing for new solar installations might be starting to recover after a year when many major banks abandoned the industry because of the meltdown in the credit markets.

First Solar is the one of the world's largest producers of photovoltaic cells, which turn sunlight into electricity. Its production costs are the lowest in the industry, although its thin-film cadmium telluride cells are not as efficient in capturing the sun's rays as the more traditional silicon-based cells.

First Solar will engineer, procure and construct the projects -- a 250-megawatt installation to be called Desert Sunlight near Desert Center, California, and a 300-megawatt project to be called Stateline in northeastern San Bernardino County. The plants are each roughly the size of a small natural gas-fired power plant.

Raymond James analyst Pavel Molchanov said the deal ties the record for the largest photovoltaic contract in the United States -- the other is also held by First Solar -- but would not provide a near-term boost to First Solar's results.

"The only 'catch,' so to speak, is timing," he wrote. "Construction isn't expected to start until 2012/2013, with completion coming only in 2015."

Southern California Edison, owned by Edison International (EIX.N), delivered about 65 percent of solar energy produced in the United States last year.

Pending approval by state regulators, construction will begin on Desert Sunlight in 2012 and on Stateline in 2013.

First Solar shares rose 1 percent to $134.38 on Nasdaq, while Edison International shares rose 1 percent to $31.97 on the New York Stock Exchange. (Reporting by Matt Daily and Nichola Groom; Editing by Lisa Von Ahn, Bernard Orr)