The Lafarge Canada cement plant, located in Exshaw, Alberta, is an unmistakable landmark to travelers as they head for Banff along the TransCanada Highway.

First built in 1906, the location was chosen to take advantage of an outcrop of the Upper Devonian Palliser formation, a finely-crystalline limestone. Output has been used to build high-rise buildings in Calgary and Edmonton and road and infrastructure projects throughout the province. It currently has a capacity of approximately 2 million tonnes per year (tpy) of cement.

It also has a greenhouse gas (GHG) problem. Cement production accounts for about five per cent of CO2 emissions globally and 1.4 per cent nationally; the Exshaw plant is one of the largest in Canada. According to government data, its emissions were estimated to be over 1.1 million tonnes in 2019.

Clinker (the main ingredient in making cement), is produced by heating limestone and other raw materials to 1450C, where it breaks down into calcium oxide (lime), and carbon dioxide. A decade ago, the manufacturing process produced approximately 1 tonne of CO2 for every tonne of cement. Modern technology has reduced that amount to approximately 650 kg, but the goal of Lafarge is to achieve carbon-neutral status by 2050.

To do that, the two major sources of emissions must be tackled. Around 35 per cent of GHGs are released through energy and process inputs, and 65 per cent from the transformation of limestone to lime.

In the former category, a major reduction can be achieved by partially substituting natural gas with low carbon fuels (LCFs) to heat the limestone. LCFs consist of waste materials including old shingles, plastics, and construction demolition waste. The goal of the Exshaw plant over the next decade is to use LCFs to reduce natural gas consumption by 50 per cent, shaving approximately 100 kg of CO2 emissions off every tonne produced.

Carbon capture utilization and storage (CCUS) is the primary method to reduce the CO2 released by the latter category. Lafarge is conducting feasibility studies for full scale carbon capture at the Exshaw plant, with associated transportation and sequestration in the Bow Valley.

Emissions Reduction Alberta (ERA) recently awarded a $5 million grant to Lafarge through their carbon kick-start program to fund pre-FEED and FEED studies. (Lafarge expects to eventually spend approximately $20-30 million on pre-FEED and FEED studies for carbon capture.)

There are several major components to a CCUS network. The first is the carbon capture (CC) module, located at the plant site to capture the CO2 that is emitted from the kilns. “Lafarge estimates that the capture facility will need to accommodate approximately 3500 tpd,” says Stephanie Voysey, senior sustainability manger, Western Canada, for Lafarge Canada. “Capex for the CC is approximately $750 million.”

The second major component is transportation to either utilization or sequestration. Many sectors have potential uses for CO2, including enhanced oil recovery, the manufacture of synthetic fuels, and plastics. “There are no potential users near the Exshaw plant, however, and sequestration is the most likely destination,” says Voysey.

Although capex efficient, vehicle transportation to a disposal site is unlikely. “A CC producing 3500 tpd of CO2 would require over 70 trucks to handle the output,” says Voysey. “Fuel emissions from such a large fleet would largely negate the network’s effectiveness.”

A dedicated pipeline is the most viable alternative. Alberta Energy recently issued a list of 19 potential storage hubs in the province; several are within 100 kilometres of Exshaw. While a pipeline trunk network exists in the Edmonton area, no equivalent has been built in southern Alberta. Lafarge envisions partnering with other nearby de-carbonization projects to share costs of a pipeline to a sequestration hub. In addition, wells and surface infrastructure at the hub would need to be built.

Pre-FEED stage would run through the first nine months of 2023, with a preliminary decision by the end of 2023. If the pre-FEED warrants further action, FEED will proceed through 2024, depending on further financial support from the province and federal agencies. “An FID would likely be made in 2025,” says Voysey. “From there, construction would proceed, with commissioning occurring around 2030.”

By implementing LCF and CCUS, as well as additional new technologies, the amount of carbon emissions per tonne of output would essentially be reduced to zero.

While the total capex and opex have yet to be determined, industry experience shows costs will be in the $70/t range for carbon capture, with additional costs for transportation and sequestration.

The federal government has a carbon price target of $170/t by 2030. Companies that do not mitigate their emissions will pay a carbon tax, and those who do will receive a carbon credit. Lafarge envisions that carbon credits will offset the extra costs so that consumers will not be adversely affected.

Regardless, the company is willing to take the initiative. “Lafarge has a long standing commitment to sustainability and it is at the heart of how we operate our business,” says Voysey. “We will continue to work on developing innovative solutions to help build better cities and communities for future generations.”