Unmineable Coal Seams

CO₂ can be injected into suitable coal fields where it will be adsorbed onto the coal and locked up permanently in mineral form. According to research from the Massachusetts Institute of Technology, the total worldwide potential for storage in these formations could exceed 7.1 billions tonnes of CO₂.

The Process:

• CO₂ is injected into a suitable seam in an underground coal reserve.
• The CO₂ is absorbed by the coal and methane (CH₄) is typically released and captured.  This can be used as a very clean fuel source.
• By capturing the methane, the coal seam is depressurized allowing an additional 50% more CO₂ to be stored in the coal.

Enhanced coal bed methane, or ECBM as this process is called, is an emerging technology and has potential to be cost-effective. The additional methane that is captured can offset the cost of CO₂ capture.

Currently there are CO₂ enhanced coal bed methane projects in operation. The Allison project in New Mexico has captured more than 100,000 tonnes of CO₂ over a three-year period.

A field test of ECBM production using CO₂ and N₂ mixtures is being carried out by the Alberta Innovates. The combined approach may offer more attractive means of recovering methane for market and storing CO₂.

Canada’s Storage Potential