How a Combination of Natural Gas and Renewable Power Is Helping Reduce Our Emissions Footprint

By Paul Browning

As energy demand continues to rise around the world, how do we accommodate this increasing global need while reducing carbon emissions? Part of the answer lies with a growing success story: the combination of natural gas and renewables.

One of the biggest changes driving the power generation industry forward is that carbon intensive power plants are being replaced by an increasingly affordable and low-carbon combination of natural gas and renewables. It’s well known that onshore wind and photovoltaic solar power have become increasingly affordable during the past decade in locations that have strong wind and/or solar resources. At the same time, new drilling technologies, combined with revolutionary improvements in the cost and efficiency of natural gas power plants, have dramatically reduced the cost of electricity from natural gas. BP forecasts that the rapid growth of renewables will continue, while natural gas will become the world’s primary energy source by 2040.

Then there’s the environmental benefit. Compared with coal, modern natural gas power generation results in 65% - 70% less carbon dioxide emissions per unit of electricity. And the carbon emissions from a 50/50 combination of natural gas and renewables are about 85% less than the emissions from a coal-fired plant. In addition, natural gas power generation produces dramatically lower emissions of sulfur oxides, nitrous oxides, mercury and other pollutants than coal.

The U.S. has been a leader in deploying a combination of natural gas and renewable power in place of coal, and the results are now clear. U.S. carbon emissions from power generation hit a 25-year low in 2017. Emissions in the U.S. have been falling since 2005 as the power sector uses more low-cost natural gas and much less coal. In fact, in 2016 natural gas overtook coal as the primary fuel for power plants for the first time, ending coal’s nearly century-long reign.

Additionally, cheap and abundant natural gas and renewables appear to have helped keep some 160 new coal-fired power plants from being built over the past several years, which would have emitted hundreds of millions of metric tons of CO2 over their life span.

And the story is not just in the U.S. Natural gas will also be important for the developing world. Abundant natural gas in the U.S., the Middle East and Australia is now being liquefied, allowing for cheap transport around the world. This trend means the combination of natural gas and renewables is becoming cost competitive versus coal even in China, India and other developing economies.

Natural gas is a logical partner for renewables because renewables are intermittent energy sources. They only work when the sun’s shining or the wind is blowing. Today’s natural gas power plants are not just more efficient. They’re also much more flexible and can ramp up and down to address the variabilities of renewables. The combination of the two ensures continual power, with an attractive price point. This marriage will also give us the time we need to develop new energy storage technologies.

Indeed, Mitsubishi Hitachi Power Systems (MHPS) recently demonstrated a new large-scale gas turbine that can lower carbon emissions further from power plants using a fuel mixture of 70% natural gas and 30% hydrogen. This is important not only due to the associated reduction in CO2 emissions, but also because hydrogen for the mix can be produced from water using electrolysis from excess renewable power.

This innovation marks an important first step in a MHPS effort to develop technologies for a “hydrogen society” in which broad use of hydrogen helps create a world with clean, carbon-free energy. Following this successful test, MHPS will accelerate the development of 100% hydrogen-fueled power plants, which will drop carbon emissions to essentially zero.

Ultimately, nobody wins if we can’t control carbon emissions or if we leave too many people in poverty for lack of affordable energy. We need a solution that can meet the world’s energy needs in an economic and low-carbon way. Ultimately, the coupling of natural gas and renewables increasingly appears to be the way of the future.

Browning is the President & CEO of Mitsubishi Hitachi Power Systems Americas