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A NEW system that adds concentrated solar power to existing gas-fired power plants promises to cut natural gas use by 20% while still generating the same amount of electricity.

Researchers at the Pacific Northwest National laboratory (PNNL) in the US have developed a system that uses solar heat to convert natural gas into syngas – a mixture of hydrogen and carbon monoxide that produces more energy when its combusted.

The system uses a mirrored parabolic dish to direct sunlight on to a device measuring around 1 m long and 50 cm wide, containing a chemical reactor and several heat exchangers. The concentrated sunlight heats up the natural gas flowing through the reactor’s channels, which contain a catalyst to convert it into syngas, while the heat exchangers recycle heat left over from the reaction.

Tests on an earlier prototype of the device showed that more than 60% of the solar energy that hit the system’s mirrored dish was converted into chemical energy contained in the syngas.

Researchers say that the devices could be installed alongside existing natural gas power plants to create what they are calling hybrid solar-gas plants. They are now working to develop cheaper manufacturing techniques for the system in a bid to drive the cost of electricity production to no more than US$0.06/kWh by 2020, which they believe will make the system competitive with conventional gas-powered plants.

“Our system will enable power plants to use less natural gas to produce the same amount of electricity they already make,” said PNNL engineer Bob Wegeng, who is leading the project. “At the same time, the system lowers a power plant’s greenhouse gas emissions at a cost that’s competitive with traditional fossil fuel power.”

Meanwhile, the team says the system overcomes a key problem with existing solar setups in which plants cease operating when it’s cloudy or nighttime. With PNNL’s system, the gas plant would simply bypass the solar unit and burn natural gas directly.