ABSTRACT: 

Rocks of intermediate-depth (100-1000 m) and those in the deep (>1 km) subsurface represent an environmental resource to aid the energy transition and to achieve improved environmental outcomes.

Porous and permeable sediments can be used to store fluid and solid wastes through processes of injection.  Suitable porosity and permeability are needed for fluids disposal (CO₂, wastewater, acid gas), and slurried solids may be disposed in sediments through fracture injection, a process that has been taking place in the oil industry for over 40 years.  Particular emphasis is placed on the potential for sedimentary rocks to accommodate injection and to dissipate pressures, but caution is warranted: the huge volumes of CO₂ proposed for injection will exceed the sediments’ capacities in many areas, leading to regional pressurization and increased escape risks.

Biosolids injection leads to Carbon sequestration in solid form (a process of coalification), and in many jurisdictions, this can be done as economically as current high-quality treatment approaches.  Using the example of South Tehran, a framework will be presented for more environmentally secure carbon sequestration combined with safer and economical urban biosolids treatment.

Energy storage in the subsurface may comprise HC storage, but also H₂ storage, compressed air storage, heat storage, and pumped hydro.  In Ontario, Canada, the first adiabatic compressed air storage facility in the world is operating, albeit at a pilot scale of 1.75 MW The compressed air is stored in a repurposed salt cavern 420 m deep.    

The usefulness of the subsurface to store low-grade heat for seasonal use in northern climates is being studied, and methods to cool subsurface repositories for sources of cooler air in warm months is technically feasible.

Intelligent use of the subsurface can, in many ways, help reduce the C-intensity of our energy sources while improving other environmental outcomes such as waste disposal and water clean-up.  

 Zoom meeting:

• Meeting ID: 977 1624 7289
• Password: 997983

BIO:

Maurice obtained a BSc (Engineering) and a PhD (Civil Engineering Geomechanics) from the University of Alberta (Edmonton) in the 1970’s.  He taught and carried out research there for five years before moving to the University of Waterloo in 1982, where he continues to be active in teaching and research on various energy issues.  Maurice is a well-known Professional Engineer (AB and ON) consultant to companies and political entities on issues such as energy storage, hydraulic fracturing, geothermal energy, and many related subsurface engineering areas.  His consulting output has involved well over a hundred reports, plus teaching over 80 professional education courses commercially in over 28 countries in the period 1995-2020.   Over a 45-year career, his output includes over 180 fully refereed Journal papers, 450 full-text Conference papers, over 80 MSc and PhD graduates, and hundreds of undergraduate Project Report students and trainees.  He has a number of patents related to subsurface use and energy domains including CO₂ sequestration, stimulation, deep biosolids injection, compressed air storage, geothermal energy, and monitoring.