The 45Q tax credit for sequestering CO2 has been around for decades. From 2008 to early 2018, it provided a tax credit of $20/ton for geologic storage. A lesser credit of $10/ton applied to carbon capture via enhanced oil recovery (EOR). The credit also applied to carbon capture via enhanced natural gas recovery (EGR).

The Department of Energy notes how Congress increased and expanded the tax credit for CO2 sequestration in 2018. The credit for geologic storage is as high as $50/ton. The credit for CO2 utilization increased to as much as $35/ton. Congress also expanded the applicability of the 45Q tax credit. It now includes EOR, non-EOR and direct air capture projects. Also, various states have implemented tax policies designed to complement the federal tax incentives.

The new Omnibus Spending Bill makes further enhancements. First, it extends the availability of the 45Q tax credit from 2023 to 2025. This means that construction must now begin before January 1, 2026, to qualify. The credit is available for 12 years, beginning with the year a company places the equipment in service.

Bloomberg Green reports that the Omnibus Spending Bill includes other environmentally-friendly provisions. For example, it allocates $2 billion for six demonstration projects in carbon capture. The bill stipulates that one will be in the concrete industry.

Provisions of the Omnibus Spending Bill are part of a broader strategy to simultaneously address both environmental and economic needs. The Department of Energy (DoE) sees tax credits, a successful FE R&D program and high economic growth as a path to millions of jobs.

• Achieving DoE research and development (R&D) goals ONLY yields a 0.5-3.3 million new jobs.

• Using CCUS tax credits ONLY yields 4.3-6.1 million new jobs.

• Achieving DoE R&D program goals AND CCUS tax credits yields 5-10 million jobs.

Carbon capture is a key component of a global effort to reduce global warming. Specifically, to keep temperature increases below two degrees Celsius compared to pre-industrial levels. Carbon capture incentives accelerate progress toward that goal.

The global population generates a lot of carbon emissions. In fact, the International Information Agency estimates the total at about 35 billion metric tons of carbon per year. Current carbon capture is 0.1 percent of global emissions. It is necessary to capture about 10 to 20 percent to mitigate the worst effects of climate change. Although the United States leads all other countries in carbon capture, only about a dozen facilities are operational.

The problem is that carbon capture is still relatively expensive. This is often true of emerging technologies. Cement producers and oil refineries have been slow to start carbon capture projects. Cost is the primary obstacle. In 2018, Congress expanded the 45Q tax credit. The old credit was $20/ton for carbon captured and permanently stored underground. Companies can now deduct up to $50/metric ton.

Still, obstacles remain. Carbon capture projects are complex. Permitting along can take years. The Carbon Capture Coalition (CCC) estimates it takes about five years to begin construction.

Thanks to carbonation, carbon capture in the concrete industry is multidimensional. There's a great deal of exposed concrete in the world. As a result, passive carbonation is already occurring on a large scale.

Weathering carbonation is natural, large-scale carbon capture. It is also known as atmospheric carbonation, a chemical reaction involving:

• calcium compounds in exposed concrete

• water in the concrete’s pores

• atmospheric carbon dioxide (CO2)

Weathering carbonation is a two-step process. First, atmospheric CO2 reacts with the water to form carbonic acid (H2CO3). Second, the carbonic acid reacts with calcium hydroxide (Ca(OH)2) in the concrete. This forms calcium carbonate (CaCO3). Depletion of calcium hydroxide in the concrete pores reduces the pH below 13. The pH is as low as eight in fully carbonated concrete.

There are limitations to this form of carbonation. First, the process requires concrete exposed to air and moisture. Sealed concrete will not work. Climatic conditions impact the amount of carbonation in mature concrete. Usually, relative humidity must be between 40 and 90 percent. Below the 40-percent threshold, atmospheric water vapor is insufficient. There is not enough moisture to dissolve CO2 to form carbonic acid. There's also a problem when humidity is above about 90 percent. Concrete pores contain so much moisture that CO2 cannot enter.

There are numerous carbon sequestration methods in the works. As this video notes, one approach is to inject CO2 directly into concrete mixes. In ready mix applications, CO2 is injected into the hopper. When CO2 reacts with calcium ions in a concrete mix, it is mineralized - permanently captured, that is. Adding CO2 to concrete speeds curing, accelerating the arrival of maximum hardness.

However, industrial-grade carbon capture is still in its infancy. At present, there is but one carbon capture project planned for a cement plant in Norway. There is also a steel plant with carbon capture in Abu Dhabi. Hopefully, demonstration projects will prove the economic viability of the technology. Tax credits should promote such projects. Once innovators refine methods, widespread carbon capture is possible by 2035.