Molten Carbonate Fuel Cells
Exploring the use of Molten Carbonate Fuel Cells to capture carbon dioxide from natural gas-fired processing units while generating electricity
Reducing the greenhouse gas intensity of in situ steam generation and providing clean energy to the Alberta power grid
There are two methods to extract bitumen from the oil sands. The 20 per cent of deposits located less than 70 metres below the surface are mined using large shovels and trucks. The remaining 80 per cent of deposits are too deep to be mined, and so the bitumen is extracted in place, or in situ, by drilling wells.
The most common method of in situ production is called steam assisted gravity drainage (SAGD). Using this method, two parallel horizontal wells are drilled into the oil sands reservoir. Steam is injected into the reservoir through the top well to heat the bitumen. The softened bitumen then falls to near the bottom of the reservoir, where it is pumped to the surface through the second well.
Both mining and in situ production require energy to produce steam and heat, resulting in greenhouse gas (GHG) emissions and higher GHG intensity compared to conventional oil production. The members of COSIA’s GHG Environmental Priority Area (EPA) are looking at ways to reduce the GHG intensity of in situ oil production by exploring a number of different technologies including improved energy efficiency, alternative sources of less carbon-intensive energy, and carbon capture and storage (CCS).
Alberta Innovates, along with its partners, are exploring a Molten Carbonate Fuel Cell (MCFC) technology that would combine capturing carbon dioxide (CO2) with generating low GHG-intensity electricity.
Technology and Innovation
A fuel cell converts chemical energy from a fuel into heat and electricity through an electrochemical process. MCFCs are one type of fuel cell that operate at high temperatures to produce electricity, heat and water. They contain an anode, a cathode and a molten electrolyte salt layer. The flow of electrons from anode to cathode through an external circuit produces electricity (see picture below).
MCFCs have been used in commercial power generation since the 1990s. In 2014, POSCO Energy started up a 59-megawatt MCFC power plant in Hwasung City, South Korea.
“The fact that MCFCs are already being used for commercial power generation represents a significant step forward for the technology,” says Craig Stenhouse, Manager, COSIA at Cenovus. “MCFCs can also be adapted to capture carbon dioxide.”
Cenovus led a joint industry project (JIP) to estimate the cost of a pilot to capture CO2 from a natural gas-fired combined heat and power generation plant and to produce electricity by using MCFC technology.
The purpose of the 1.4MW Molten Carbonate Fuel Cell Preliminary Front End Engineering Design (Pre-FEED) JIP is to estimate the cost of a demonstration scale pilot to capture CO2 from a natural gas-fired plant’s flue gas supply and to produce electricity by using MCFC technology.
Learn more about incorporating carbon capture into MCFCs
To capture CO2, part of the internal CO2 circulation in a traditional MCFC could be replaced by CO2 from a natural gas-fired unit’s flue gas without affecting the fuel cell’s operation (see picture below).
In a SAGD application, the MCFC may be directly connected to the flue gas of a once through steam generator (OSTG) or process heaters used in upgrading and refining. The CO2 can be separated from the flue gas, and power is produced simultaneously. The separated CO2 may be further purified, compressed and shipped to storage sites or used for enhanced oil recovery. With this technology, the normally costly process of separating CO2 from the exhaust stream is offset by the value of the electricity generated by the fuel cell.
Learn more about incorporating carbon capture into MCFCs
The JIP builds on a feasibility study funded by Cenovus, BP, Devon, Shell, Suncor, Alberta Innovates and MEG Energy, which concluded that using MCFCs would potentially be far less energy-intensive and more cost effective than conventional post-combustion carbon capture methods. Cenovus, Devon, Shell, Alberta Innovates and the University of Calgary also carried out a preliminary front end engineering design (pre-FEED) JIP associated with installing and operating a 200-kilowatt pilot project. The pre-FEED included a cost estimate for equipment installation and operation.
Following this, with increased interest from other partners and government, the JIP membership conducted a larger scale pre-FEED to evaluate the preliminary cost of piloting a 1.4 megawatt power generation capacity MCFC at an oil sands facility. A decision on advancing the pilot is expected during Q4 2017.
Depending on the outcome of the pre-FEED, a decision will be made on whether or not to advance the pilot.
Combining MCFCs and Once Through Steam Generators (OTSGs) to cogenerate steam and electricity at in situ production facilities will produce significantly lower GHG intensive steam and electricity at the same time as CO2 is captured. Excess electricity may be sold into the Alberta power grid. The electricity export will provide clean energy to Albertans and a revenue stream to offset the costs associated with carbon capture.
Having a close to zero GHG-intensive electricity output may also earn carbon credits, further offsetting the carbon capture costs.
“One of the main issues with technologies like carbon capture is their cost,” says Jonathan Matthews, Director of COSIA’s GHG EPA. “Combining MCFC technology with carbon capture is transformative because it could bring the cost of carbon capture down, making it a more viable solution – economically and environmentally.”
Alberta Innovates is leading the Molten Carbonate Fuel Cell JIP with COSIA members Cenovus Energy, BP Canada, Canadian Natural, Devon and Suncor. Other non-COSIA participants are MEG Energy, Husky Energy and Shell.
“This is a novel example of pursuing a high impact GHG technology in a highly collaborative manner. We are fortunate to have an ideal number of participants with a wide range of management and technical skills,” says Candice Paton, Acting Executive Director, Advanced Hydrocarbons at Alberta Innovates. “By sharing the costs associated with the project, the risk is also significantly reduced.”