There is an old saying that “Nothing succeeds like success.” The comparison of this phrase to geothermal heat pumps (GHPs) is almost parallel, in that this mechanical equipment remains the most efficient on earth for moving thermal energy. And it’s very nimble at that job because it can change the direction of that flow of thermal energy. While that’s true, it could still be argued that the air source heat pump (ASHP) is just as nimble, but that represents only capability and not efficiency.
Efficiency is represented as the work accomplished (thermal energy moved) compared to the energy required for that work. In our world, GHPs move thermal energy (British thermal units—Btu’s) with electrical energy (watts, delivered in a specified voltage range). And again, let us realize that for the Btu’s transferred and the watts consumed to accomplish that—NOTHING beats a GHP! How does this affect sustainability?
Sustainability can be defined as the capacity to endure. In running, it would be marathon exertion without tiring or aging. In botany, it would be photosynthesis perpetuated—yielding food for humans and all animals, with no cessation. This principle also has potential to drive the energy business. It’s measured as renewable or non-renewable energy. The source of energy can be renewable or not by the measure of whether it can be naturally replaced. And replacement speed is predicated on how rapid the consumption is of that energy.
Wood for burning to create interior heating is considered green and renewable. That’s true, up to a point. Next summer, more annual rings will be deposited on all the tree trunks remaining and some will be cut down for next winter’s fuel. Burning wood is carbon-neutral, because if it wasn’t burned, it would be “oxidized” on the ground, slowly, by rotting. But wood is not necessarily renewable, because if everyone burned it for heat (as in the pre-1900s) it would be as gone as it is already in some parts of the world. And it’s combustion by-products are not necessarily clean, even with EPA regulated stoves.
Go to any local valley (particularly around ski areas) and witness the haze of atmospheric inversion in winter. Los Angeles smog has descended on heavenly territory. Wood’s curse in this case is that it is both source and site energy. It is burned and its thermal benefits are utilized in the same place. In the bad old days of electrical resistance heating (red hot toaster coils backed by fans in mountain lodge walls, for example) the site energy was cleaner and the source energy was being provided far away by much dirtier electrons than today’s.
Many states have targets for their renewable portfolio standard (RPS) representing the proportion of their grid electricity source that is by renewable means. In California, the goal for the year 2020 is 33% not including the historical sources by industrial hydroelectricity and nuclear generation. So, in terms of carbon-free electricity to keep making progress toward California’s goals to reduce greenhouse gases—this state is a leader in the struggle for cleaner electrons running the grid. GHPs are more in tune with these policies than might be assumed, since they consume electricity whenever they run.
Geothermal heat pumps use electricity that comes from increasingly green electrons. They are more efficient than all other equipment at mechanical transfer of Btu’s. They don’t push unwanted building heat into the ambient air like standard A/C or ASHPs do, increasing localized temperatures during the cooling season. And they can focus unwanted thermal energy (that isn’t pushed into the air) to heat water or store it underground, boosting what already is replenishing by natural means for the coming heating season. When you can go back to the underground thermal storage resource (perpetually) to either reject or extract thermal energy at will—you have a sustainable system, and it is carbonless on-site.
California plans for more renewables. As the future grid becomes powered by increasingly renewable sources, GHPs will also be marching toward complete sustainability that is. Must we wait for the grid’s progress? Not really. The Zero Net Energy movement has caught the attention of many, and GHPs are an effective technology to unite with solar photovoltaic deployment on any building, to chase the most sustainable design of all. As the future grid becomes powered by increasingly renewable sources, GHPs will also be marching toward complete sustainability that is carbonless. Must we wait for the grid’s progress? Not really. The Zero Net Energy movement has caught the attention of many, and GHPs are an effective technology to unite with solar photovoltaic deployment on any building to chase carbonless, Zero Net Energy, the most sustainable design of all.