- Gas or Compressed Air in Salt Caverns
- Shale Gas Development
These two subjects are highly complementary: both are important elements of the transition to cleaner environments based on more renewables and lower emissions of GHGs and particulates. Compressed air storage makes natural gas power generation more efficient, and allows greater incorporation of wind and solar energy into electrical grids, without destabilization or negative environmental impacts. Natural gas is a superb replacement for coal (or oil), yielding no particulate matter and, along with CAES, giving over two and a half times more power for the same level of CO2 emissions as coal.
Academics, industry and government personnel came together to discuss these new approaches. The Workshop was by invitation only. It included presentations, posters, displays, copies of articles, and other contributions to the Workshop.
Why CAES and Shale Gas?
Replacing coal-sourced electricity is becoming a critical goal in China, Canada and other countries, but factoring in larger amounts of renewable energy to electrical grids is challenging because of the variable and intermittent nature of wind and solar inputs. Renewable energy (wind, solar) needs large-scale storage, and CAES is the best approach, environmentally and economically. A grid-scale CAES facility also provides valuable ancillary services to help manage electrical grids, allowing rapid large changes in power inputs while smoothing them, allowing large increases in the percentages of renewable energy use. CAES in salt caverns allows grid-scale storage (100 – 500 MW per project), easily achieved through dissolving caverns at depth (400-1500 m). Integrating CAES with wind and solar farms is the best option to take advantage of these renewable energy sources that continue to become more and more economical because of technological progress.
Natural gas is a key element in rapidly replacing coal as a large-scale source of electricity. Natural gas can also help replace oil as CNG and electrical vehicles become more and more widespread. State-of-the-art gas turbines provide clean electrical power with 50% of the CO2 emissions of coal, and if the turbines can take compressed air from CAES, the CO2 emissions drop to about 35% of coal. This occurs without particulates, NOx and SOx emissions, without mines, tailings ponds and groundwater impairment, and without deterioration of land quality. Natural gas storage in salt caverns is the most secure and economical method of making sure that it is available to meet the daily and seasonal variations in power demand.
CAES and shale gas clearly fit extremely well together because of similar storage needs, the increased potential to factor in renewable energy, and other possible efficiencies such as integrated storage strategies, hydrogen co-storage, better heat recovery and use. The Geomechanics of Shale Gas and Salt Caverns is therefore an excellent synergetic issue that requires research and engineering developments to allow more rapid and economical applications to improve life quality quickly.
Why Canada and China?
Suitable salt deposits in Canada exist in most provinces, in many cases close to large industrial centers and cities. Similarly, salt deposits in China along the central coastline (Jiangsu, Shanghai…) provide favored sites for CAES. Both countries are committed to reducing GHG emissions and increasing the quality of life in urban centres through gradual shifts toward natural gas and greater electricity use. Both countries have large resources of natural gas trapped in low-permeability shale deposits.
Workshop Subjects
The primary storage cavern focus is salt cavern location, design, construction and operation as CAES or natural gas storage facilities; these are mainly geomechanics issues. The secondary cavern focus is surface facility design and integration with the salt caverns to achieve realistic goals from environmental and economic perspectives; these are mainly mechanical engineering issues. Subjects such as heat storage, cavern monitoring and stability, gas or air cooling, constant pressure or constant volume approaches, cycle time and energy extraction, life cycle analysis, and related technical issues are all of interest.
Shale gas primary focus is on the geoscience and geomechanics of shale gas development. The geomechanical differences for various deposits, ductility, mineralogy and organic content are geoscience factors. Stress conditions at depth, mechanical properties, and the best approaches to hydraulic stimulation of wellbores are geomechanics issues of great importance. Mathematical modeling of stimulation methods, the value and possibility of linking wells, re-stimulation, and CO2 injection as a possible EOR method are topics of interest.