2019 Applied Science Showcase: Carbon Capture & Storage

Thornton Tomasetti has been helping manage the risk associated with carbon capture and storage (CCS) since 2006, when we began working with BP on decarbonisation projects intended to safely capture and transport CO₂ waste from the point of origin to secure storage. Since then, through our involvement with the Carbon Capture and Storage Association, we’ve been engaged in industry dialogue to improve and expand CCS technologies.

Tony Byrne, a vice president in our Applied Science practice, spoke to us about how Thornton Tomasetti is supporting the development of CCS technologies for projects in the United States and United Kingdom.

Carbon capture and storage is a new concept for many, although you’ve been in this game for some time. How does it help mitigate climate change?

TONY  A lot of industry processes emit CO₂ and contribute to global climate change. Power stations are big contributors, because to produce power requires combustion of fossil fuels and release of CO₂. Coal-fired power plants are the biggest culprits. Also, a number of industrial processes that involve manufacturing steel, cement, glass and fertilizers release CO₂ through chemical reactions. CCS can reduce the emission of CO₂ by 95 percent in these industries.

CCS can serve as a “bridging technology,” meaning that it’s not the only solution, but can aid in the transition between traditional processes and a green energy future. Right now, the infrastructure in place creates CO₂. If we can capture these emissions, we can use this infrastructure for longer but be less polluting.

Climate change reduction targets are set high, and meeting them solely through the use of renewables like wind and hydropower is challenging. But if the United States turned 100 percent to renewables, some industries would have to shut down and we’d end up offshoring industries to other countries, where CO₂ would still be emitted. This bridging technology enables energy independence (allowing the use of existing fossil-fuel reserves) while maintaining our industries and keeping people in their jobs.

Carbon capture and storage must be tricky. What are some of the challenges?

TONY  There are several ways to achieve CCS, including post-combustion capture and precombustion capture. In post-combustion capture, CO₂ is extracted from flue gases using a chemical process, and then compressed. It is then transported and stored underground – for example, in a depleted hydrocarbon reservoir from which oil or gas has been removed, or saline aquifers. Precombustion capture involves breaking down hydrocarbons in natural gas or coal into hydrogen and CO₂, and then using the hydrogen as fuel for power plants to fire gas turbines.

In these scenarios, the process plant and pipelines transmitting high volumes of CO₂ could fail and cause major accidents. If you’ve ever seen the film Apollo 13, you have some idea of what happens when too much CO₂ is in the air we breathe. At relatively low levels, it has toxic effects, which, in the movie, impaired the astronauts’ mental functions, such as memory recall. Understanding the behavior of CO₂ is the key to knowing the risks and how to control them.

CCS is planned in a number of areas for the production of hydrogen. Hydrogen is a useful gas, but it’s also flammable. Using it requires foresight and knowledge of how to avoid or contain fire and explosions within a power-station area.

How has Thornton Tomasetti's modeling expertise helped meet the challenges of transporting and storing hazardous materials?

TONY  We worked on a project involving a 450-megawatt power station that produced 1.5 million tons of CO₂ each year. No one at that time understood how to model the dispersion of CO₂ if a pipeline failed. We participated in experimental-release trials with BP, in which dense-phase CO₂ was released at high pressure at a test facility in the United Kingdom. These trials helped validate models for the release rate and dispersion of dense-phase CO₂ under a variety of source and atmospheric conditions (a dense-phase fluid's viscosity is similar to that of a gas, but its density is closer to that of a liquid). The tests were carried out with U.K. regulator involvement and a panel of independent observers from BP and academia.

This was a challenging project. BP gave us certain parameters for the releases, and we used computational fluid dynamics (CFD) to model the releases and dispersion. CFD is a branch of fluid mechanics that uses algorithms and numerical analysis to evaluate and solve problems involving the flows of fluids (liquids and gasses).

Regulators in the United Kingdom had concerns about the safety of transporting CO₂ in such large volumes and at such high pressures, particularly in dense phase . Our modeling and analysis allowed the development of mitigation strategies to ensure safety.

This initial work for BP was followed up by a similar development project in California. We also provided E.ON UK with technical safety support for a 1,600-megawatt Kingsnorth post-combustion CCS project.

You once worked for an energy company, so you can relate to our clients’ interest in CCS. What excites you most about this work?

TONY  I’m seeing a lot more interest in CCS recently. The U.K. Committee on Climate Change recently included carbon capture as a valuable strategy for mitigation, and incentives now exist for CCS from the U.S. and U.K. governments. Investors like BlackRock are pulling their investments out of fossil fuels unless the firms have sustainability strategies. We’re talking to a company right now that will lose its operating license if it can’t demonstrate CCS capabilities.

CCS is just one area of our decarbonization work. To achieve net-zero targets for greenhouse-gas emissions, several strategies need to be applied – there’s no silver bullet. So we’re working on hydrogen, energy storage, on- and offshore wind energy, and other renewables.

This kind of work makes a real difference in people’s lives. We must mitigate climate change. But the solution that many propose – renewable power generation – is variable and is unlikely to provide sufficient mitigation of greenhouse emissions within the required time frames (e.g., the United Kingdom has set a target of net-zero emissions by 2050). CCS as a bridging technology helps balance out that variability for the power industry, and allows for the decarbonization of various industry sectors.

Supporting Information

• Carbon Capture and Storage
• Global CCS Institute
• U.S. Department of Energy - Carbon Storage FAQs