by Frits Byron Soepyan

Wyoming Gov. Mark Gordon has signed a piece of legislation that directs public utilities providing electricity to more than 10,000 customers to “generate a specified percentage of electricity that is dispatchable and reliable low‑carbon electricity.” This rule applies to existing coal‑fired plants and equivalent new plants. “Low-carbon” is defined as electricity that is produced with technology that captures at least 18,750 metric tons of CO₂ per year.

How much would this cost? And is it worth it?

Well, as they say, we ran the numbers. Thankfully, researchers from the National Energy Technology Laboratory (NETL) have provided the cost and performance estimates for retrofitting an existing coal-fired plant with Shell’s CANSOLV CO₂ capture system.

Because Gov. Gordon has “set a goal of making Wyoming not just carbon neutral when it comes to CO₂ emissions, but eventually carbon negative,” I will use the NETL estimates for 99% carbon capture. (Here, I am using the term “carbon capture,” rather than “CO₂ capture,” because NETL uses the mass of carbon, rather than the mass of CO₂, in its calculations.)

Before the retrofit, NETL’s baseline power plant had a net output of 650 megawatts (MW). But after retrofitting it with the CO₂ capture system, the power output was reduced by about 26% to 479 MW. In terms of money, the retrofit cost is about $1.06 billion, or about $2.2 million/MW of net power output.

What do these numbers mean for Wyoming?

Based on the U.S. Energy Information Administration, as of March 2024, Wyoming has nine coal-fired power plants in operation in the electric utility sector, with an average capacity of about 5,900 MW. Using the NETL estimates, if we were to retrofit these plants to enable 99% carbon capture, the 26% net power output reduction would bring electricity production down to about 4,400 MW. Applying the retrofit cost of about $2.2 million/MW of net power output to the plants’ reduced power output, we get about $9.6 billion.

Keep in mind, these estimates are only for coal-fired power plants. We haven’t even gotten to retrofitting natural gas power plants, nor have we addressed the cost of replacing the thousands of megawatts lost in the 26% production decrease of converted plants.

And what about constructing brand new coal-fired power plants? How much would that cost?

Again, we turn to NETL for the estimates.

Using NETL’s baseline coal-fired power plant once again, the cost of constructing a new 650 MW plant, without CO₂ capture, is about $1.86 billion. On the other hand, the cost of constructing such a plant with 99% carbon capture is about $3.27 billion, or about 75% more.

So, we clearly are talking about a lot of money to remove carbon dioxide from the big skies of our American West. But is spending the extra money to capture CO₂ worth it?

The Model for the Assessment of Greenhouse Gas Induced Climate Change (MAGICC) was used to estimate the temperature rise prevented if Wyoming had ceased all CO₂ emissions in 2010. The estimated temperature rise averted are 0.0009 °F by 2050 and 0.0022 °F by 2100. Such a difference in temperature is negligible and cannot be felt or measured.

Furthermore, consider this: Plants need CO₂, along with sunlight, water, and nutrients from the soil to produce oxygen and food, both of which are essential for all living beings. In our geological past, CO₂ levels have dropped dangerously close to levels that would have extinguished life on Earth.

Exposing plants to higher CO₂ concentrations also increases their growth, food production and water-use efficiency, which in turn increases their resistance to drought. NASA has confirmed that Earth is greening, with CO₂ “fertilization” being 70% responsible for it.

Finally, the presence of greenhouses gases, including CO₂, in the atmosphere keeps Earth’s temperature warm and stable, which prevents us from freezing to death.

Given the critical role of CO₂ in sustaining Earth as we know it, is spending billions of dollars to remove it from the air sensible? We think not.