Cleaner Natural Gas Power Thanks to Fuel Cells

Cleaner Natural Gas Power Thanks to Fuel Cells

Natural gas power is already three times cleaner than coal power. While coal power plant exhaust is 12% to 15% carbon dioxide, natural gas power plant exhaust is only 4% to 5% carbon dioxide. Still, with growing greenhouse gases and global warming being a real concern, we need to ask if we can make natural gas electricity even cleaner.

Thanks to a partnership between ExxonMobil and Fuel Cell Energy, there is a unique solution on the horizon. This solution is the Carbonate Fuel Cell, that will strip out up to 90% of the carbon dioxide from the exhaust, leaving only a half of a percent of CO2 in the exhaust.

Here is ExxonMobil’s explainer video. Beneath the video you will find more …

Why Fuel Cell Carbon Capture Beats Traditional Methods

Cleaning the carbon out of the exhaust of hydrocarbon fueled power plants is not cheap. Still, carbon capture and storage (CCS) is an essential element in meeting tomorrows energy demand while reducing our carbon footprint. Large hydrocarbon companies such as Shell and ExxonMobil recognize the necessity of CCS and are working on more economically feasible solutions. Traditional CCS technology causes the cost of producing electricity to increase by some 70%, unless subsidized by government funding.

According to Technology Review, this new Carbonate Fuel Cell technology will only add 33% to the cost of producing electricity. That’s less than half the added cost when using traditional carbon capture technologies.

So why is fuel cell technology so much cheaper than traditional methods? Let’s take a closer look at how each method accomplishes the carbon dioxide extraction.

How Tradition Carbon Capture Works

According to ExxonMobil, “During the conventional capture process, a chemical reacts with the carbon dioxide, extracting it from power plant exhaust. Steam is then used to release the carbon dioxide from the chemical – steam that would otherwise be used to move a turbine, thus decreasing the amount of power the turbine can generate.”

Natural gas is burned as fuel to produce steam. This steam turns turbines that produce electricity. So using some of the steam for carbon extraction means each megawatt of electricity requires more fuel to be burned, causing more expensive electricity.

It also means each power plant is less efficient and cannot meet the same demand as without carbon capture. For example, a typical 500 MW (megawatt) powerplant that utilized standard CCS technology to scrub 90% of the carbon from the exhaust will only be able to produce 450 MW of electricity. That’s a 10% drop in it’s ability to meet the demand, and 70% added cost to produce the electricity.

How Carbonate Fuel Cell Carbon Capture Works

Unlike traditional carbon capture technologies, carbonate fuel cells do not use chemicals nor steam to extract the carbon. The exhaust from the power plant is pushed through the fuel cell along with some additional natural gas. These fuel cells then cause a chemical reaction that divides out the atoms in the exhaust and natural gas and rebuilds them, producing as an output electricity, CO2, hydrogen and water.

These fuel cells do not reduce but actually increase the amount of electricity produced. For example, in order to scrub 90% of the carbon from the exhaust of a typical 500 MW natural gas fueled power plant, a 120 MW fuel cell system would be required. This adds 120 MW to the capacity of the power plant, increasing it’s capacity by 24%.

Additional Benefits of Carbonate Fuel Cell Carbon Capture

While the fuel cell carbon capture systems will be cheaper than traditional carbon capture technology and increase power plant capacity, there are additional benefits they will provide. One of these benefits is the production of hydrogen. According to ExxonMobil, “Simulations suggest that the new technology can produce up to 150 million cubic feet per day of hydrogen while capturing carbon dioxide from a 500 MW power plant.” This is more hydrogen than is produced in a world-scale steam methane reforming hydrogen plant, according to ExxonMobil.

This hydrogen can be used to make synthetic gas, methanol, olefins, or higher molecular weight hydrocarbons for transportation fuels or lubricants. So while the cost of electricity production may increase from $.06 per MW to $.08 per MW, this does not take into account the additional revenue that the hydrogen production could add to the plant. As this technology develops and improves, and it’s full potential of benefits are realized, it may make carbon capture even cheaper than the projected $.02 per MW.

Current Status of Carbonate Fuel Cell Carbon Capture

In October 2016, the James M. Barry Electric Generation plant was chosen to test this new technology. This is a 2.7 GW (gigawatt) mixed use coal and natural gas power plant. The tests will demonstrate the ability of the carbonate fuel cells to capture the carbon from the exhaust of the natural gas fueled power generation. This is a cooperative of many organizations and all of them deserve our thanks for their efforts to make natural gas power cleaner. Among these organizations are Southern Company, a subsidiary of Alabama Power, whom operates the plant that is testing the technology. The US Department of Energy is also supporting these efforts by funding the research and development.

At the forefront are Fuel Cell Energy and ExxonMobil with their research and development of the technology. Fuel Cell Energy makes fuel cells that generate electricity on more than 50 locations around the globe. ExxonMobil is a leader in hydrocarbon energy, including natural gas. With such a strong team in place we are excited to see this technology come to maturity and help clean up our energy sources.

Hanging H is also proud to work with industry leaders in constructing the pipeline infrastructure that makes natural gas power possible. As this technology advances, we plan on being involved in developing the infrastructure to support it, such as carbon dioxide sequestration, carbon dioxide pipelines, and other fuel pipelines such as hydrogen and syngas.

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