Boundary Dam Carbon Capture and Storage Project
Capture: SaskPower – The Saskatchewan Government is the sole owner
Transport and Storage: Cenovus Energy has constructed a pipeline to transport the CO2 on behalf of the Weyburn Oil Unit partners. SaskPower owns an onsite disposal well, otherwise known as Aquistore.
LOCATION: Saskatchewan, Canada
CO2 capture source: Production unit 3 at the Boundary Dam coal–fired power station near Estevan
CO2 storage site: Primary site is at the Weyburn Oil Unit, northwest of the Boundary Dam power station
INDUSTRY (FEEDSTOCK): Power generation (lignite / brown coal)
OVERALL PROJECT LIFECYCLE STAGE: Operate
CO2 CAPTURE CAPACITY VOLUME: 1 million tonnes per annum (Mtpa)
CAPTURE TYPE: Post-combustion capture
CAPTURE METHOD: Absorption chemical solvent-based process (Amine), Shell Global Cansolv technology
NEW BUILD OR RETROFIT: Retrofit (to a generating unit recently refurbished)
CO2 CAPTURE START DATE: October 2014
PRIMARY STORAGE OPTION: Enhanced oil recovery
STORAGE FORMATION AND DEPTH: Weyburn Oil Unit – oil-bearing formation at 1.5 kilometres / 1 mile depth
A portion of the captured CO2 is transported to the Aquistore project – Winnipeg and Deadwood formations at 3.4 kilometres / 2.1 mile depth
TRANSPORTATION TYPE: Pipeline (onshore to onshore)
TRANSPORTATION DISTANCE TO STORAGE SITE (LENGTH OF PIPELINE): 66 km / 41 miles to the Weyburn Oil Unit; 2 kilometres / 1.2 miles to the Aquistore project
SaskPower is the principal electric utility in Saskatchewan, Canada. SaskPower has a total available generating capacity of around 4,400 megawatts (MW), including approximately 3,500 MW available from the company's own facilities (three coal–fired base load facilities, five natural gas–fired facilities, seven hydroelectric facilities and two wind power facilities). SaskPower also buys-in generating capacity of around 900 MW available through long-term power purchase agreements with independent power producers.
Boundary Dam is the largest of the coal–fired facilities with a net generating capacity of around 670 MW (coming from production unit Nos. 3-6, with units 1 and 2 being decommissioned in 2013 and 2014 respectively). The coal feedstock for the plant is mined about 13 kilometres / 8 miles from the plant.
Production unit 3, with an original net generating capacity of 139 MW, was built in 1969 and scheduled for closure in 2013, after almost 45 years in service.
A number of coal–fired generation option studies have been undertaken to evaluate how best to meet the province’s future energy needs. Saskatchewan has an estimated economically recoverable 300–year supply of (lignite) coal. Lignite coal is an important part of the province’s energy supply and coal accounts for around 35 per cent of SaskPower's available generating capacity. Different development options, plant locations, generation capacities and technologies have been, and continue to be, evaluated.
In early 2008, the provincial government announced that it would proceed with plans for refurbishment of Production Unit 3 at Boundary Dam in concert with a fully integrated carbon capture system. Final approval for the refurbishment of the power island was given in December 2010 and for the carbon capture and storage facilities in April 2011.
The refurbishment of production unit 3 included, among other things, boiler modifications and replacement of the old steam turbine with a new state-of-the-art turbine that is integrated with the CO2 and sulphur dioxide (SO2) removal mechanism. After allowing for the energy requirements of the capture plant, net generating capacity for production unit 3 is placed at around 115 MW. The refurbishment is expected to extend the life of production unit 3 by at least 30 years, if not more.
Removal of the SO2 and CO2 streams uses regenerative amine technologies and takes place in a two-stage process. Firstly, the flue gas is desulphurised, releasing a pure stream of SO2 that is further processed on site and provides feedstock to a 60 tonnes per day sulphuric acid plant, which is to be sold as a byproduct. The CO2 removal process follows after the flue gas has been desulphurised.
The application of capture facilities will reduce CO2 emissions from production unit 3 by around 90 per cent and, when fully operational, capture approximately 1 Mtpa of CO2.
Mechanical completion of the carbon capture facilities was in December 2013 with commissioning activities beginning thereafter. The completion of the power plant refurbishment occurred in the second quarter of 2014. Operation of the project commenced in October 2014.
In July 2016, SaskPower announced that the CO2 capture unit at Boundary Dam had surpassed the capture of one million tonnes of CO2 since operations began in October 2014. By March 2017, total CO2 captured was almost 1.5 million tonnes.
From an annual perspective, SaskPower has indicated that production unit 3 captured almost 800,000 tonnes of CO2 in calendar year 2016, with the carbon capture process being operational almost 85 per cent of the time on average (the facility was online 100 per cent of the time during six of the twelve months in 2016).
The CO2 captured from production unit 3 is used primarily for EOR at the Weyburn Oil Unit and supplements the existing CO2 supply to the Weyburn–Midale fields delivered by the 330 kilometre / 205 mile Souris Valley pipeline from a gasification facility in North Dakota (see Great Plains Synfuels Plant and Weyburn-Midale Project).
In December 2012, SaskPower announced it had reached an agreement with Cenovus, on behalf of its partners in the Weyburn Oil Unit, to purchase approximately 1 Mtpa of CO2 for 10 years. The CO2 is transported 66 kilometres / 41 miles to Weyburn by the new purpose-built Rafferty CO2 pipeline. Cenovus, on behalf of its partners, has built and operates the pipeline.
A portion of the CO2 captured from the Boundary Dam plant will be injected into a deep saline formation through SaskPower’s Carbon Storage and Research Centre (CSRC). The CSRC hosts the Aquistore project, which is currently administered by the Petroleum Technology Research Centre (PTRC). The Aquistore project is located in the Williston Basin and is a short distance (around 3 km / 2 miles) from the Boundary Dam facility. The targeted injection zones for the project are the Winnipeg and Deadwood formations. Two wells – one injector and one monitoring – have been drilled into the formation at intervals of about 150 metres / 495 feet and to a depth of 3.4 kilometres / 2.1 miles. The injection zone is 'capped' by numerous layers of impermeable rock.
In April 2015 it was announced that CO2 injection had begun at the Aquistore Project, which by late 2016 had reached the milestone of over 100,000 tonnes injected and stored (and which included an extensive seismic monitoring program).
Key project milestones
February 2008: Province of Saskatchewan announces SaskPower will proceed with refurbishment of Production Unit 3 at Boundary Dam, including application of a carbon capture system.
February 2008: The Canadian Government allocates CAN$240 million to the project.
December 2010: SaskPower formally approves the refurbishment of Production Unit 3 at Boundary Dam.
April 2011: SaskPower formally approves construction of the carbon capture system at Production Unit 3.
December 2012: SaskPower and Cenovus announce Cenovus will purchase approximately 1 Mtpa of CO2 captured at Production Unit 3 for 10 years.
December 2013: Mechanical completion of carbon capture system.
June 2014: Power plant refurbishment complete and on line.
August 2014: Unit 2 of Boundary Dam Power Station reaches the end of its useful life and is decommissioned.
October 2014: The Boundary Dam Carbon Capture and Storage Project commences operation.
April 2015: CO2 injection begins at the Aquistore project.
July 2016: Saskpower announces that the Boundary Dam CO2 capture unit has surpassed the capture of one million tonnes of CO2 since operations began in October 2014.
November 2016: Aquistore Project announces over 100,000 tonnes of CO2 stored.