By Emily Davis, Secretary/Treasurer, Southeastern Pennsylvania Group
World Geothermal Energy Day is October 17th, and the Geodelphia team of SPG is holding a rally at Philadelphia City Hall from 4:30 to 5:30 to celebrate, educate people about geothermal energy and advocate for the inclusion of more geothermal energy as the city moves to 100% sustainable, carbon-free energy.
Often, when we think of sustainable energy sources, we often think only of wind and solar, but we need to include geothermal in the mix.
So, what is geothermal energy? One kind is from the heat deep in the earth (around 10 kilometers down). I usually think of New Zealand, or places with volcanoes and geysers when I think of this type of geothermal, but it just needs to be a place where we can drill down to the hot rocks. The US generates more electricity from geothermal than any other country. Most of these generation plants are in the western part of our country, for example Coso in California, Cove Fort in Utah or Desert Peak in Nevada. There is a spot in northwestern Pennsylvania where the earth is 390°F (200°C) at a depth of 10 kilometers, and we might generate electricity from geothermal energy there.
There is another geothermal type that does not require this deep drilling; it draws on the heat stored in the earth just 12 feet under the surface where the earth remains at a constant temperature of about 55° (about 13° C) year-round and can be accessed in all of Pennsylvania. With a ground source heat pump, we can draw this source of energy to heat and cool our homes and buildings.
Unlike solar energy and wind energy, ground source heat pumps are not intermittent, but draw on a constant source of energy. Heat pumps became an option for heating and cooling in the residential market in the 1950s. The cooperative apartment building in which I live adopted air source heat pumps about 40 years ago because residents found they could save about 40% on their electric bill. Geothermal is underground, so it is unseen and leaves the surface of the land fully available for other uses, including nice views.
There are several places in Philadelphia that already use ground source heat pumps for heating and cooling including Kensington CAPA High School and the German Society of Pennsylvania. Bartram’s Garden not only saves on its energy bill, but found that without the noise of the air conditioners, wandering in the garden is more enjoyable for visitors.
Ground source heat pumps for heating and cooling use 75% less energy than traditional heating and cooling systems. Heat pumps are more efficient for heating and cooling our homes than electric heaters and air conditioners. A ground source heat pump uses about 30% less electricity than an air source heat pump. As we move to electrify everything, this savings will be very important to reduce the stress on our electric grid.
Finally, a geothermal heat pump system is cost effective over the life of the system and provides a healthier indoor environment.
This blog was included as part of the October 2023 Sylvanian newsletter. Please click here to check out more articles from this edition!