Cleaning up cement industry emissions with carbon conversion

Joule Unlimited
Jet fuel made from converting captured CO2 waste and sunlight at a Joule plant in New Mexico. 

Cement manufacturing is one of the most carbon emissions intensive industries on the planet, but a handful of innovative companies are working hard to change that.

Among the most promising innovations, according to HeidelbergCement, the world’s second or third largest cement company, is technology that takes carbon dioxide from cement’s smoke stack flue gas and uses bioengineering to convert it to low carbon fuel for transportation.

 So Heidelberg entered a joint venture last month with Joule Unlimited, the technology developer, to figure out how to scale the process to commercially viable levels — and it’s betting it will do so within five years.

“For the whole industry, it is key to develop initiatives with technology providers to work on transitioning us into a low carbon industry and Joule is clearly one of the companies that has a technology to significantly contribute to our target,” said Jan Theulen, HeidelbergCement’s director of alternative resources. He sees commercialization "within the horizon of 3 to 5 years."

Lots of fingers have pointed to the cement industry as a big contributor to the greenhouse gases that warm the planet. A typical cement making smoke stack effluent is about 30 percent carbon. “We are by definition carbon emitters because we use a carbonate,” or limestone to make a product, Theulen said.

According to the U.S. Environmental Protection Agency, global carbon dioxide emissions from cement production were approximately 829 million metric tons in 2001, or about 3.4 percent of all global emissions from fossil fuel combustion and cement production.  With the rapid growth of economies in China and India since then, that has likely increased.

But the industry knows its culpability in contributing to climate change and 25 major producers formed the Cement Sustainability Initiative under the umbrella of the World Business Council for Sustainable Development to work to reduce it.  The aim is to cut carbon emissions by 30 percent by 2050 .  HeidelbergCement has been a hard charger in the group.

 “We take our responsibility seriously to take an early developer role,” he said. "We will also benefit early.” HeidelbergCement has reduced its own carbon emissions by 23 percent in the last two decades.

The Cement Sustainability Initiative figures the industry can get half way to its 2050 target through energy efficiency, tweaking the ratio of cement raw ingredients to use less limestone and similar operational efficiencies.

 “So the other half of it must come from innovative solutions like the ones from Joule, which is carbon capture and conversion,” Theulen said.

Joule, which has MIT professors on its staff and board and is backed by $200 million including a recent $40 million round led by Flagship Ventures, has dozens of patents connected to its technology of converting CO2 to biofuels. Its technology uses engineered bacteria as a catalyst to convert the CO2 in a continuous process, according to the company.

Tom Jensen, executive vice president of corporate development, said the technology obstacles have been conquered and the process proven. What the company is working on now is proving commercial applicability.

“It is not question of whether this technology works. We know it does. We need to iterate and prove to the outside world its useful applications,” Jensen said.

Joule’s CO2 conversion technology is essentially about reversing the process of a combustion engine.

Whereas a car or jet’s combustion engine derives power from petroleum fuel mixing with a spark to combust, which produces carbon gas as a byproduct, this technology takes carbon dioxide gas in and mixes it with sunlight from solar and its proprietary bio-engineered catalyst to produce a fuel but with a lower carbon content.

Jensen and Theulen said the venture is unique in using the cement smoke stack emissions as the feedstock for carbon that is converted to liquid fuels. 

But what they both said is needed to make it commercially viable is a market for low carbon solutions — in other words, a price on carbon. 

"Any new technology needs some sort of value attributed to the problem it is solving," Jensen said.

“Governments have an important part to play in making sure that technologies like ours will get into the marketplace,” Jensen said. We need policies that value carbon reduction, or a price on carbon. 

 In Joule’s case, the fuels its product will compete against are fossil fuel-based petroleum and refined gasoline “which have massive advantages in being produced at scale, with a 200 year incubation period and millions in government subsidies.”

Solidia, Calera on the carbon reduction task as well 

In other cement industry innovations to reduce carbon emissions, the technology focuses on creating less carbon intensive cement.

Calera takes captured CO2, mostly from utility plants, and combines it with an alkalinity solution and calcium in the form of carbide residue to convert the CO2 to calcium carbonate and water.  Calera then uses that  calcium carbonate to replace limestone in cement, thus making a lower carbon variety of cement.

Solidia Technologies, another innovator, uses a process it calls reactive hydrothermal liquid phase densification, which uses the CO2 as a binding agent. According to a scientific paper in World Cement, Solidia exposes a solution of water and CO2 to a group of calcium silicate minerals to create bridges or binding agents of silica and calcium carbonate. That process too requires less limestone in the making of cement and therefore produces a low carbon cement.



Joule's plant in Hobbs, New Mexico, where it prototypes carbon waste to liquid fuels conversion using several source materials, including cement manufacturing emissions.

Joule is in the midst of commercializing its technology on several fronts .

It has a similar proprietary method based on gasification and what the industry knows as Fischer Tropsch technology which converts a mixture of hydrogen and carbon monoxide into liquid fuels. 

Joule entered into a merger late last year with Red Rock Biofuels, a developer of renewable jet and diesel fuel bio-refineries, and is in process of building the first plant based on this technology through recycling carbon stored in waste biomass remains from the timber industry as its primary feedstock.

Such materials as branches and sawed off ends of trees are often left on forest floors in the lumbering process. While eventually such mass would biodegrade, what happens more often is that it becomes unintended fuel for forest fires.

 Red Rock and Joule already have lined up FedEx and Southwest Airlines as commercial customers for this bio-fuel and said they expect to be making commercial quantities of the fuel from their plant in Oregon by late 2017.