With all the air conditioning needed in the summertime, why would a winter time freeze cause the electrical grid to “spike” out of control as we saw in Texas? Most people know that air conditioning loads in the middle of August usually drive the greatest demand on the grid. However, electric heaters, often used to handle peak heating loads, can double or triple the peak in the wintertime.
- 1 watt of electricity = 3.412 BTUs
- I kW of heat consumed by an electric heater = 3,412 BTUs of heat
- I kW of heat consumed by an electric Heat Pump = 17,060 BTUs of heat*
- It takes 20% the kW to do the same heating with a heat pump *(@5.0COP)
As it gets colder outside, Air Source Heat Pumps lose efficiency. Geothermal Heat Pumps continue high efficiency operation regardless of outdoor temperature.
Cold temperatures can reduce efficiency of heat pumps, simply because it's hard to extract heat from outside air as it gets colder. The efficiency of air source heat pumps drops as it gets colder outside, just as the gas mileage efficiency of a car drops when it’s climbing a mountain road. Geothermal heat pumps are not subject to drastic temperature fluctuations, because they're coupled to the temperature in the shallow earth, which ranges between about 45 and 75 degrees in the US.
As you look at the efficiencies of heat pumps at the ASHRAE building in Atlanta, you can see that air source heat pumps are closer to geothermal heat pumps efficiency in the summertime, but in the winter time, when heating is needed most, the air source heat pumps are using much more electricity that geothermal by comparison. Geothermal clearly reduces peak electrical demand on the grid, eliminating problems like Texas experienced this winter.
Wintertime electrical peak load management is a well-known challenge as Northeastern states make the transition to total building-stock electrification. New York is eliminating combustion heating of all types in buildings (as is stipulated in the New York State’s Climate Leadership and Community Protection Act (CLCPA). As they make that transition, competent studies have proven that Geothermal Heat Pumps must play an integral role in Beneficial Electrification in order to manage peak electrical load in the coming decades.
Ontario completed a study at the end of 2020 that gives a 30 year roadmap to managing electrical grid spikes through the implementation of geothermal heat pumps. In the image, we can see the savings in reduction of fossil fuels, the cost for implementation of air source heat pumps, the cost for implementation of geothermal heat pumps, and at the far right is that Ontario will save half-a-trillion dollars on electrical grid modifications by choosing the geothermal solution. The reason is simple. Winter time peak loads are leveled through the implementation of geothermal heat pumps.
When I started in the GHP industry in 1990, I was asked by a reporter what the future held for the industry. I said that while excavation and drilling are required now for the systems, the day would come when geothermal pipelines would be worked into the infrastructure of communities. This is the place at which we find ourselves today.
Read more about geothermal grids in “New Contractor Opportunities with Geothermal Districts”
Read more Beneficial Electrification in “The Integral Role of Geothermal Heat Pumps in Beneficial Electrification”
Jay Egg is a geothermal consultant, speaker, writer, and the owner of EggGeothermal. He has co-authored two textbooks on geothermal HVAC systems published by McGraw-Hill Professional. He can be reached at email@example.com.
©Egg Geo, LLC 2021