General Electric wants to be a big renewable energy player but doesn’t want to give up its bread-and-butter business of building fossil fuel power plants. So what does the company do? They are now offering hybrid power plants that make use of natural gas and solar — and they may add wind to really mix things up.

That’s the idea behind the first hybrid project announced by GE and its customer, MetCap Energy Investments, on Tuesday to build a 530 MW power plant in Turkey. The project will include 50 MW of concentrating solar thermal energy production and 22 MW of wind.

The solar thermal energy portion will use technology from eSolar, which is getting an undisclosed equity investment from GE. The investment is a boost for eSolar, which shifted from developing power plants to licensing its technology in the past few years. The company received an investment from NRG Energy and was supposed to see its technology deployed in at least two 92-MW projects in the United States. But NRG decided to ditch that idea and use solar panels instead. It even cut one project to 20 MW (which is being built by First Solar in New Mexico).

eSolar CEO, John Van Scoter, called the GE deal “transformational for eSolar and the whole energy industry.”

“It’s such a right match for GE’s roadmap because of the modular nature of our technology. We really have something unique that we architect.”

eSolar’s technology uses flat mirrors to concentrate sunlight that heats up water in a tank atop a tower for steam production. The steam then runs a turbine and generator to produce electricity. The company designs the configuration iso that each tower has a production capacity of 4 megawatts, Van Scoter said. The sunlight-to-electricity conversion efficiency of eSolar’s technology is 11-12 percent, he added.

GE is licensing eSolar’s technology in order to add it to its offering of combined cycle natural gas power plant equipment. GE said it also wants to build stand-alone power plants. The company has the worldwide exclusive license to use it alongside its combined cycled power plants in perpetuity; it also gets an exclusive license to build stand-alone solar thermal power plants for a period of time, said Van Scoter, who declined to provide more details. The licensing agreement applies to anywhere in the world except India and China, where eSolar has previously licensed its technology to other developers.

It’s no secret that concentrating solar thermal (CSP) technology can compliment a combined cycle natural gas power plant, which uses a steam turbine in addition to a gas turbine. The waste heat from a gas turbine is used to generate steam to produce more electricity. A stand-alone CSP plant needs a steam turbine for electricity production, but a CSP plant can’t produce a steady stream of power day and night like a natural gas power plant. Adding solar thermal to a natural gas power plant cuts the use of natural gas, particularly when natural gas price is high.

FPL built a 75-MW solar thermal energy field next to an existing natural gas power plant in Florida last year. French power plant equipment company, Areva, which bought CPS company Ausra in 2010, has been offering hybrid solar thermal-natural gas or solar thermal-coal fire plant designs and equipment.

GE’s entry will promote the hybrid designs, which are attractive not just for their fuel savings feature but also for their promise to lower greenhouse gas emissions from a fossil fuel power plant. This is also good news for CSP companies that are facing tough competition from developers of solar panel technologies. Solar panel pricing has dropped more than 50 percent in the past few years, and solar panels don’t need strong, direct sunlight does to work, unlike CSP equipment.

For the MetCap project, GE will pair solar with a new natural gas plant design it unveiled two weeks ago. GE designed the plant to address the challenge of integrating solar and wind energy into the grid. A grid needs to have a steady supply of power to run smoothly. But solar and wind energy production only happens when the sun shines and the wind blows. One way to manage power supply is to store energy and release it when needed.

The natural gas plant design, called FlexEfficiency 50, makes use of jet engine technology so that the power plant produces electricity efficiently and is able to ramp up production quickly, at 50 MW per minute. In the past, combined cycle power plants typically couldn’t provide this type of ramp up rate, which can be achieved with simple-cycle combustion turbines (without using the steam turbine). FlexEfficiency 50 can convert 61 percent of the natural gas energy into electricity.

“It’s critical for natural gas to pair well with renewable sources,” said Paul Browning, CEO of thermal products at GE Energy.

By adding solar and wind, GE expects the hybrid plant to achieve 69 percent efficiency. The efficiency is a bit lower than what the plant could achieve if it were located at sea level and under other ideal conditions. The MetCap plant will be located at 1,100-meter elevation, and that reduces the gas turbine efficiency, Browning said. The minimum efficiency provided by the site is 45 percent, said Celal Metin, chairman of MetCap.

Under ideal conditions, the hybrid plant can get over 70 percent efficiency — 61 percent percent efficiency from the natural gas plant, 7 percent from solar and 3 percent from wind, Browning said.

MetCap expects to start construction later this year and complete the project in 2015. The project will cost 400 million euros, Metin said.