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Leadership Opportunity: Pennsylvania Should Make Mine Water Geothermal A Key Part Of Its Clean Energy Transformation

By: Michael C. Korb, P.E., Senior Mining Engineer, Tetra Tech, Inc.

In a November 7. 2018 paper, Competitive Imperative - Choices for Pennsylvania's Energy Future, Christina Simeone, Kleinman Center for Energy Policy writes “Pennsylvania should develop a strategy to assist individuals and communities impacted by the downturn in coal demand.

“Such a strategy could consider at least two paths. The first should focus on immediate to medium-term transitional needs of individuals most significantly impacted by coal’s downturn. The second would be a community-based approach focused on long-term economic diversification and recovery of communities formerly dependent on coal.”

One of the tactics the Commonwealth could utilize to help this strategy is to boost the use of Mine-Water Geothermal Heating and Cooling and district heating systems utilizing it.

In a 2007 the U.S. Department of Energy presentation U.S. Mining Regions –The Saudi Arabia of Geothermal Energy, the authors Terry E. Ackman and George Watzlaf wrote “Water from a mine is a terrible thing to waste.”

Geothermal heating and cooling with heat pumps (GHPs) are proven, well-established systems that provide extremely efficient levels of indoor heating and cooling at a very economical price, and with a small carbon footprint.

Public buildings such as universities, hospitals, low-income housing and commercial facilities would be ideal settings for GHPs because of their year-round and around-the-clock heating and cooling needs.

GHPs utilize a ground or water source to take advantage of the ground or groundwater’s constant temperature, approximately 55°F, to heat and cool a building. This makes GHPs far more energy efficient than conventional air-source heat pumps, which must compensate for wide seasonal variations in air temperature.

Many public buildings and industrial facilities are looking at retrofitting their HVAC systems with geothermal. Notre Dame University recently announced plans to join more than 100 colleges in the U.S. that use geothermal as a campus energy source.

Marywood University, Scranton, Pennsylvania uses mine pool water pumped to a heat exchanger to cool one of its campus buildings, and water GHPs are especially suited for applications such as data centers which require cooling year-round.

In Pittsburgh, a 2006 project at the John Wesley A.M.E. Zion Church constructed a geothermal circuit to capture the energy from mine drainage to heat and cool the church, and to provide for heating and cooling to a potential development next to it.

Geothermal heating and cooling systems can save 40 to 65 percent in heating costs, 30 percent in cooling costs and 15 percent for hot water costs when compared to conventional air-source heat pumps or natural gas systems.

A geothermal-served facility’s carbon footprint for heating, cooling and hot water would be also reduced by 55 to 70 percent.

Water-source heat pumps are the easiest, fastest and least expensive type of geothermal system to install. Water provides better heat transfer than earth and a large waterbody provides an excellent heat sink.

Water-source geothermal projects do not require the extensive digging and trenching that is needed for burying ground loop pipelines needed for ground-source projects. Water-source heat pumps are not practical without a good aquifer or large body of water nearby.

One of Pennsylvania’s potential sources of water for geothermal systems is mine-water pools. Heating and cooling buildings with mine-water makes use of what was previously thought of as a dirty problem.

Application of this technology is also proven for almost 40 years.

Mine-water geothermal can give many areas of the Commonwealth a rather remarkable source of heating/cooling which is perhaps the most economical, energy-efficient, low carbon footprint scheme.

Marywood University’s system is typical of a mine-water source geothermal system. The Geothermal Energy System design would include supply well(s) and recharge well(s).

The supply wells would each house a submersible pump and the recharge wells would extend back into the mine, serving as a path for the water to be discharged back into the mine pool.

Water from the supply well is pumped to and through plate and frame heat exchangers which heat/cool a separate isolated fluid loop that serves the building's heating and cooling needs.

The mine-water does not have any changes in chemistry and does not see “the light of day” nor does it see oxygen to create precipitates.

Perhaps, in the best scenario for the environment, the water would be treated and discharged to waters of the Commonwealth.

There are currently mine-water geothermal operating systems in Nova Scotia, Scotland, Netherlands, Missouri; and Scranton, Pennsylvania.

The Kingston Community Recreation Center in Luzerne County has been heated and cooled with a mine-pool geothermal heat pump for more than 40 years.

Mines that are flooded with water - mine pools - are essentially almost unlimited aquifers. Mine-water geothermal projects are feasible when there is a mine pool located nearby.

Much of Southeastern and Northeastern Pennsylvania are over water-filled mines. Areas around Washington, Indiana, Johnstown, and Greensburg; and the Eastern, Western and Southern suburbs, and the southern part and selected sites in the City of Pittsburgh; are located over or near abandoned underground mines that may be full of water.

The cities of Scranton, Hazleton, Wilkes-Barre Pittston, Pottsville, and Carbondale in the Anthracite Region are all over mine-water pools.

Pennsylvania should recognize that mine pools are underutilized energy sources, should be considered community assets, and should encourage their use for future sustainable energy projects.

District heating and cooling utilizing mine-water geothermal could be a “community-based approach focused on long-term economic diversification and recovery of communities formerly dependent on coal.”

Water from a mine IS a terrible thing to waste.

Resource Link:

Minepool Geothermal In Pennsylvania, by Michael C. Korb August 2012

Michael C. Korb, P.E has had a 50-year long career working in the mining and mine reclamation field and has been committed to public outreach and education on a wide range of mining and reclamation issues. He can be contact by sending email to: mikekorb@pa.metrocast.net.

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