Full Chain

SaskPower’s Boundary Dam 3 CCS Facility (BD3), is the world’s first coal-fired power station with a carbon capture and storage (CCS) facility located in Saskatchewan, Canada, and remains the only facility that is fully-integrated with a coal-fired power plant - a ground breaking effort for large-scale capture.  BD3 is renowned for its full-chain approach. It has a thermal coal plant, capture facility, transportation infrastructure (pipelines), enhanced oil recovery (EOR), and pure storage capabilities. 

Full-chain operation is an ideal model for CCS because the EOR creates revenue and royalties from the sale of carbon dioxide (CO2).  Any additional capacity the off-taker of CO2 does not require can be permanently stored.

Carbon Capture Facility at BD3 captures CO2 instead of being released into the atmosphere. This reduces carbon emissions from the coal-fired power plant, while producing a reliable, clean source of energy. 

Enhanced Oil Recovery more commonly referred to as EOR, utilizes CO2 to maximize the removal of oil from reservoirs. Captured CO2 from BD3 is transported by pipeline 50 kilometres to nearby oilfields in Weyburn Saskatchewan. The commercial sale of CO2 helps to offset the cost of the capture process.
 

How does EOR work?

EOR involves the injection of compressed CO2 into an oil reservoir. The CO2 acts like a solvent, causing the oil to expand and flow more easily to production wells.  As the oil is pumped to the surface, the pressure and temperature begin to decrease and the contained CO2 begins to get released from the oil.

This freed-up CO2 (about 60% of the original injection) is collected at the surface, compressed, and re-injected.  The remaining 40% of the injected CO2 stays safely and permanently stored in the oil-depleted reservoir and never comes back to the surface.  

The EOR storage in Weyburn has been well demonstrated. Over the decade of research, at IEAGHG Weyburn-Midale Project scientists monitored changes in the composition of reservoir fluids due to CO2 injection, by sampling well production fluids. These changes have not caused any negative effects in the reservoir or surrounding rocks.  EOR operation is still active in this oilfield and the CO2 continues to be safely stored. Scientists and engineers use the collected data to model and verify safe storage in other geological regions around the world.

Aquistore Storage Project provides a ‘buffer’ storage option for the captured CO2 that is not intended for EOR. Located 2 kilometres from BD3, CO2 is delivered to the Aquistore site via pipeline where it is injected 3.4 kilometres deep in a layer of brine-filled sandstone. Using advanced, measurement and monitoring procedures, the project is demonstrating that storing CO2 deep underground is safe and permanent. 
 

Injection zone, 3.4 km deep. (PTRC)

How does Permanent Storage work?

When CO2 is directed to sites for permanent storage, CO2 is injected into deep, underground rock formations, at a depth of at least a kilometre below the ground surface or below ocean bottom, in the cases of off-shore CO2 storage.

These porous rock formations are referred to as deep saline formations or saline reservoirs and they are almost always sedimentary rocks like sandstones or limestones.  The tiny pores have stored vast amounts of liquids and gases safely for many millions of years and offer a secure space to permanently store CO2.  Injecting into geological storage sites has been done in the oil and gas sector for over half a century and thus the technology is completed understood, test and proven to be safe.

The Aquistore Project has an impressive Monitoring Measurement and Verification Program which is led by the Petroleum Research Centre (PTRC). With over 30 technologies installed in the subsurface and above ground, Aquistore consists of heavily instrumented injection and observation wells that continuously monitor the impact and migration of injected CO2.

 

For more information on EOR and storage, see this factsheet.