What Is Geothermal?
Geothermal energy also known as GSHP (ground source heat pump) is a device that extracts heat from the earth beneath the frost
line or from a body of waterby pumping a heat transfer fluid through this "geothermal heat source"
(as the temperature below the frost line is a fairly constant 50
degrees Fahrenheit in much of Alberta) then
transferring the available heat with a heat pump to the building by either a forced air or radiant heating system.
This process is similar to reverse air conditioning, drawing heat from the ground and transferring it to the building.
Essentially to heat a building to 50 degrees Fahrenheit, the only energy required is that used by the pumps.
Additional energy is now required to heat the building to a comfortable temperature.
So as an example - the difference in energy required to create a comfortable building temperature of 70 degrees Fahrenheit with a
geothermal system is only 20 degrees (difference in temperature from 50 degrees Fahrenheit).
Compare that to a conventional electric heat source (electric baseboard, boiler, furnace, etc.) which essentially has to
generate the total difference in temperature between the current outside temperature which we will say is -30 degrees to 70
degrees Fahrenheit which would be a 100 degree difference in temperature generation required.
This is what makes a geothermal system approximately three times more efficient then
other electric sources
In summer the process can be reversed, with excess building heat pumped back into the ground, so the system is now working as
an air conditioner cooling the building and potentially warming the geothermal heat source.
Contrary to what you might think geothermal is not a "green" and renewable form of energy!
Even though the heat from the "geothermal heat source" is a renewable resource, but the electricity required by the geothermal
system to heat the building to a comfortable living temperature is not
typically a renewable resource.
(unless it's tied to a renewable source like wind, solar PV or hydro power).
A typical geothermal heating system for an average residence will use 11,000 kilowatt hours of electricity per year
(according to the Canadian GeoExchange
). As the majority of our electricity in Alberta is generated by burning
non-renewable coal, which produces twice as much carbon dioxide as does an equivalent amount of natural gas, to generate that
much electricity would produce approximately some 10 tonnes of carbon dioxide per year.