DUBAI, May 16 (Reuters) - Abu Dhabi Water and Electricity Authority (ADWEA) has invited bids from construction companies to build a 350 megawatt solar plant in the emirate, state news agency WAM said on Monday.

The plant would be the Abu Dhabi power utility's first foray into renewable energy -- it currently has 11 gas-fired, independent water and power projects -- and comes as the emirate, which has huge oil reserves, seeks to produce around 7 percent of its power from renewables by 2020.

Construction firms which had been pre-qualified by state-owned ADWEA after expressing initial interest in the project have been asked to submit proposals for the scheme, including the cost of generating power and financing its development, by Sept. 19, the report said.

The project will be situated at Sweihan, around 120 km east of Abu Dhabi, the capital of the United Arab Emirates.

A source told Reuters in December that the chosen developer would own 40 percent of the project, with 60 percent held by ADWEA.

ADWEA's power plants have sufficient capacity to meet peak summer demand now, but with power needs expected to grow about 15 percent a year to reach some 21,000 MW by 2020, Abu Dhabi needs to build more generation capacity.

Neighbouring emirate Dubai has also been seeking to expand its solar power generation capacity. Sources told Reuters earlier this month that firms including China's Jinko Solar and France's EDF were among bidders for the 800 MW third phase of the Sheikh Mohammed bin Rashid al-Maktoum Solar Park.

(Reporting by David French, editing by David Evans) ((; +971 4 362 5864; Reuters Messaging: