Geothermal - It Ain’t Sexy But It’s Smart
Wind turbines and solar photovoltaic have become the iconic symbols of clean energy and environmental consciousness. But what about the other less ’sexy’ forms of clean energy? Well, of course using less energy is the cleanest form to use, and it is usually the most cost-effective. But for people who want to increase the uptake of energy from clean sources, it may be more difficult. Unfortunately, not everyone has a strong enough wind or solar resource to make those investments cost-effective. Many folks living in urban settings would find it virtually impossible to implement either of those technologies. However, geothermal can provide or assist with heating and cooling needs for urban and rural alike. Geothermal exchange can be scaled for a single family home on up to entire city blocks, or more.
Especially in the North American west, the geothermal resource is quite accessible. Now there are essentially two kinds of (residential) geothermal and I will not go too far into the details other than to say that one kind only needs to dig down 6-12 feet to tap the earth’s stored temperature. The other kind may take hundreds of feet of drilling but taps into a much hotter source. (There are also utility-scale geothermal facilities that are being developed in places where the source cannot be ignored, because hot waters bubble all the way up to the surface. Iceland, for example, gets 26% of its energy from geothermal and they get their remaining energy from hydro).
I think you need to draw a clearer distinction between ‘geothermal,’ which uses energy from heated sources beneath the Earth’s surface, and ‘geo-exchange,’ which uses the Earth as a steady-temperature heat sink. The distinction is much the same as that between a furnace and a heat pump.
They are two different technologies. Geothermal is location-specific, while ground source geo-exchange can be used anyplace.
But I appreciate the video clip you found about geo-exchange, and I’m going to have a follow up article for Green Building Elements.
Phillip-
You’re absolutely right, I could have made the distinction more clearly. I was really just trying to introduce the video, but I also understand that I muddied the waters a little.
Good resource for geo-exchange: geoexchange.us
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