SciTech Forefront
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SciTech Forefront

Meeting the Goals of the Virginia Clean Economy Act Using Carbon Capture

To reduce emissions of carbon dioxide (CO2) to the atmosphere, the Virginia Clean Economy Act (VCEA), directs the State Air Pollution Control Board to adopt regulations to reduce carbon dioxide emissions from electric generating units for the period of 2031 to 2050, with a goal of 100 percent carbon-free electric generation by 2045. In recent years, alternative CO2 reduction methods known as carbon capture have emerged that can accelerate achieving the VCEA carbon-reduction goals. Carbon capture technologies work by capturing CO2 emitted during industrial processes rather than releasing the CO2 into the atmosphere. This captured CO2 can then be reused for power generation as a renewable resource or sold as a usable commodity to other industries.

Diagram of various uses of carbon captured from industrial facilities, by CC BY-SA 4.0

This issue brief was submitted to the Virginia legislature’s Joint Commission on Technology and Science (JCOTS) to (1) define and identify established and emerging carbon capture technologies through the first three sections, as well as provide a (2) summary of the broad uses and applications of carbon capture. The final sections will provide a (3) summary of carbon capture technology developments in other states and globally, as well as a (4) brief summary of Virginia’s carbon capture history, followed by a (5) cost comparison of the three main carbon capture technologies that are currently available for use.

Definitions

For the purposes of this issue brief, the following definitions are provided; these terms prioritize utility rather than scientific accuracy.

“Carbon dioxide,” “carbon,” or “CO2” is the predominant greenhouse gas that is emitted into the air from the burning of carbon-rich substances, such as wood, coal, oil, gasoline, or natural gas, causing a greenhouse effect that warms the Earth.

“Greenhouse effect” means the accumulation of greenhouse gases such as carbon dioxide and methane in the atmosphere, trapping heat from the sun in the same way that glass traps heat in a greenhouse, or as a windshield traps heat in a car on a sunny day.

“Renewable energy” in the VCEA is referred to as energy derived from wind and solar. However, the Oxford Languages defines “renewable energy” as a source that can be renewed: “a source that is not depleted when used”. This issue brief uses the Oxford definition of “renewable energy.”

“Carbon capture” means the process of capturing carbon dioxide emissions to prevent additional carbon dioxide accumulation in the atmosphere. This issue brief focuses on “carbon capture” processes using technological and man-made carbon capture methods such as retrofitting a facility to filter out carbon dioxide from smokestack emissions, rather than natural methods such as a tree taking in carbon dioxide (photosynthetic uptake).

Background

Climate change is caused by the emission of carbon dioxide (CO2) and other greenhouse gases, which that primarily come from fossil fuel burning during power generation, transportation, as well as emissions from animal agriculture, and concrete. Fossil fuels continue to occupy 80% of U.S. energy needs. The resulting greenhouse gases form a heat-trapping layer in the atmosphere, somewhat like a car’s windshield on a hot day.

Windshield traps the sun’s heat inside a car. Photo from https://pxhere.com/en/photo/1245301
Photo by Pxhere

But this CO2 windshield is heating the entire planet.

Photo by Tara Illgner

To help reduce carbon dioxide emissions to the atmosphere, there has been increased emphasis on:

  1. Energy efficiency, for reduced CO2 emissions, including:
  • LED light-bulbs
  • Energy Star certified appliances

2. Renewable energy, for zero CO2 emissions, including:

  • Wind
  • Solar

3. Carbon capture, for reduced or zero CO2 emissions

Chart displays two distinct categories of CO2 reduction solutions: renewables and carbon capture. Each category is further broken down into various methods and technologies.

There are two main categories of CO2 reduction solutions, (1) Renewables, and (2) Carbon Capture. Each of these categories represent various methods and technologies. Renewables generally refer to methods of generating energy that produce zero emissions, using replenishing resources.

The existing carbon capture options are (1) natural, and (2) technological.

  1. Natural methods of carbon capture, which are being evaluated by the Carbon Sequestration Task Force established in SB 1374 (Lewis, 2021 Special Session I), include regenerative agriculture, improved forestry, wetland management, and protecting coastal marshes. The Task Force is due to issue its report by the first day of the 2022 Session.
  2. Technological methods of carbon capture, the focus of this issue brief, include three established types (1) pre-combustion carbon capture, (2) post-combustion carbon capture, and (3) direct air capture (DAC). Recently, a fourth type of higher efficiency carbon capture, called the Allam-Fetvedt Cycle has emerged that can be categorized as a zero-emission technology, and potentially a negative-emission technology.

Types of Carbon Capture Technologies

  1. Low Carbon Emission Options

· Pre-combustion carbon capture reduces the amount of CO2 emissions that reach the atmosphere by separating CO2 from fuel gases before the fuel gas is burned to generate electricity. During pre-combustion carbon capture, the gas is passed through substances that selectively “pull out” the CO2 before it is finally burned. This way the final burned gases that are emitted to the atmosphere contain less CO2 than they otherwise would have. Pre-combustion carbon capture is cheaper and more efficient than post-combustion carbon capture.

· Post-combustion carbon capture also reduces the amount of CO2 emissions that reach the atmosphere, but does so by separating the CO2 from the exhaust after fossil fuels are burned. When a fossil fuel, such as coal or natural gas, is burned to generate electricity, exhaust is produced. This exhaust contains CO2. Post-combustion carbon capture is a process that “pulls out” CO2 from the exhaust after fossil fuels have been burned so that less CO2 reaches the atmosphere. However, post-combustion carbon capture is less efficient, more energy intensive, and more costly than pre-combustion carbon capture.

2. Zero Carbon Emission Options

· The Allam-Fetvedt Cycle produces zero carbon emissions by functioning both as a renewable, and as a carbon capture technology. The purpose of carbon capture technologies is to reduce the amount of carbon dioxide (CO2) emissions to the atmosphere. Most carbon capture technologies do this by either absorbing CO2 from the atmosphere (like direct air capture) or filtering out some of the CO2 before it reaches the atmosphere (like pre-, and post-combustion carbon capture). However, the Allam-Fetvedt Cycle does both.

While pre- and post-combustion carbon capture generate electricity by burning fossil fuels and emitting some CO2, the Allam-Fetvedt Cycle traps all of the CO2 that is created from burning minimal amounts of natural gas. This trapped CO2 is then used as a renewable resource by circulating through closed pipes to generate electricity, similar to the way the flow of water through turbines generates electricity. Therefore, rather than emitting CO2 as an environmentally harmful waste product, the Allam-Fetvedt Cycle makes use of the CO2 in a closed loop to cycle within its pipes.[1] This trapped CO2 can then be used, reused, stored underground, or sold as a marketable commodity to offset the costs of the electricity production. Thus this process provides a valuable use of CO2 before, during, and after the electricity has been generated,which creates the potential for a circular carbon economy for energy independence.

3. Negative Carbon Emission Options

· Direct air capture (DAC) facilities are designed exclusively to pull CO2 from the air, resulting in negative carbon emissions. The resulting captured CO2 can be sold for industrial purposes or stored in geologic storage sites underground.

Status of Carbon Capture Use

The purpose of carbon capture technologies is to reduce CO2 emissions to the atmosphere from the burning of fossil fuels. Fossil fuels continue to be used primarily during power generation, transportation, while animal agriculture, and concrete also produce substantial CO2 emissions. Carbon capture technologies may offer transitional reduced-carbon energy options to reduce the emissions of these industries while traditional renewable energies, such as wind, solar, and battery storage, continue to improve in reliability, affordability, and accessibility.

Operational carbon capture facilities across the globe have resulted in 340 million tons of CO2 captured to date. The United States, that captures the most carbon in the world, currently averages nearly 30 million tons of captured CO2 annually. However, global carbon emission rates average over 30 billion tons per year. Therefore, in order to close the gap with current carbon emission rates, the rates of carbon capture (using natural and technological methods) would need to increase by nearly 1000-fold.[2]

Comparing global annual rates of carbon capture to global annual rates of carbon emissions

Among current carbon capture options, the Allam-Fetvedt Cycle stands out for being capable of serving both as a renewable energy and carbon capture method, by first capturing carbon and then using it as renewable resource. While the Allam-Fetvedt Cycle is currently a zero carbon emission technology by burning natural gas and capturing all of the resulting CO2, it is also capable of being modified to be a negative carbon emission technology by using CO2 from a DAC facility (that absorbs CO2 directly from the atmosphere). Therefore, if future natural gas sources were to be limited, the Allam-Fetvedt Cycle could continue to produce electricity as a negative carbon emission method.

Carbon Capture in Virginia

The only identified activity related to carbon capture in Virginia is a case that was brought by Appalachian Power Company to the State Corporation Commission on July 7, 2007.[3] In this case, Appalachian Power Company sought a rate adjustment to its customers’ energy bills to accommodate the added cost of a pre-combustion carbon capture facility. The timing of this case was in response to the Virginia law[4] requiring the State Corporation Commission to review and determine appropriate adjustments to rates of electrical generation and distribution based on changes to circumstances, including the plants’ energy generation efficiency. However, the final order of this case, issued on May 29, 2008, denied Appalachian Power Company’s request for a rate adjustment to fund a new pre-combustion plant.

Carbon Capture in Other States

The information available about carbon capture development in the United States is sparse. With greater focus on renewable sources, such as wind and solar, there exists less tracking and documentation on carbon capture. At this time, one known reliable source, the Global CCS Institute, tracks the development of carbon capture facilities throughout the world, including the United States, in an annual report.

The Global CCS Institute’s 2020 report on carbon capture and storage (CCS) indicates that there has been strong growth in operational commercial carbon capture facilities around the globe over the past three years. As of 2021, there are 65 carbon capture facilities worldwide at various stages of development, of which 26 are operational. The United States claims 38 of the world’s carbon capture facilities.[5]

The largest and longest running post-combustion carbon capture facility in the United States was Petra Nova in Texas. Petra Nova was also the only carbon capture coal plant in the country. However, due to the high cost of the less efficient post-combustion carbon capture process, Petra Nova was shuttered in early 2021, highlighting the need for more efficient technologies.

The Allam-Fetvedt Cycle is showing promise as a cheaper and zero-emission method of energy production. The Allam-Fetvedt Cycle was first validated at large scale in a facility in La Porte, Texas.

Carbon Capture Cost Comparison

The costs of the three different carbon capture technologies are not well publicized. However, the numbers that were found for this issue brief lists the costs of Pre-combustion capture, Post-combustion capture, and the Allam-Fetvedt cycle as 6.1 cents/kWh [6], 6.2 cents/kWh [7], and 1.9 cents/kWh [8], respectively. The lack of published costs of these technologies may be due to the protected or proprietary nature of their operational details. Therefore, there are limited sources for corroborating this pricing data.

Energy cost comparison of carbon capture technologies in cents per kilowatt hour (kWh)

Conclusion

To reduce emissions of carbon dioxide (CO2) to the atmosphere and meet the goal of the General Assembly of Virginia as provided in the Virginia Clean Economy Act (VCEA) of 100 percent carbon-emission-free electric generation by 2045, multiple approaches are needed. In recent years, alternative CO2 reduction methods known as carbon capture have emerged that can accelerate achieving the VCEA carbon-reduction goals.

[1] “Award-Winning Breakthrough Technology.” NET Power. 2021. https://netpower.com/technology/.

[2] “Global Status of CSS Report 2020.” Global CCS Institute. December 4, 2019. https://www.globalccsinstitute.com/resources/global-status-report.

[3] State Corporation Commission, PUE-2007–00068.

[4] Va. Code § 56–585.1 (A)(6).

[5] “Global Status of CSS Report 2020.”

[6] Di Lorenzo, Giuseppina. “Pre‐combustion carbon‐capture technologies for power generation: an engineering‐economic assessment.” International Journal of Energy Research. March 11, 2013. Wiley Online Library, p. 1.

[7]Improvement in Power Generation with Post-Combustion Capture of CO2.” ieaghg.org, p. 4.

[8] Conca, James. “Net Zero Natural Gas Plant — The Game Changer.” July 31, 2019. Forbes.com.

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Tara Illgner

Tara Illgner

Studies atmospheric chemistry, works with legislators on science policy and EJ, published writer, business owner, painter, mom of humans and non-humans.