I think the difference here is real-world implementation vs. what’s technically possible.

If money is no object, you can certainly create an all-star performing geothermal system, but in addition to the cost, the technical competence is still rare and highly specialized (not terribly unlike solar).

As a result, what we find in the field are installations that don’t meet the homeowners expectations or live up to what was promised by the installer. These range from systems that are poorly designed and so use up a lot of electricity, or systems that are just undersized for the heating load.

Another engineering challenge that was pointed out to me by an engineer here at ReVision is that in Maine there’s a very low A/C load (for residential buildings). This is key because not only does geothermal provide A/C very cost effectively, but running some A/C actually helps the system performance come heating season – i.e. when you run heat you are cooling the soil, but when you run A/C you are warming the soil back up.

So when you have a situation like in Maine, where the heating load exceeds the AC load, the ground temperature around the well is slowly falling not only throughout the heating season but also year after year, resulting in a performance loss for the system. And this becomes more and more of an issue if the well has not been sized properly.

We’ve seen and heard of systems where by the end of the heating season the incoming water temp is down in the 25-30 degree range – hardly more compelling than an air-source heat pump!

So anyways, we’re not trying to bash geothermal, simply to help people understand their options and make the best decision based on engineering rather than hype. In our experience it’s really a more compelling story to focus on overall building efficiency, so that the heating needs of a home are more modest, and consequently, so are the heating systems.

- Fred

Sounds great on the solar side. Not to be argumentative, but I’m a little confused about the geothermal perspective. The only information I’ve ever found is that geothermal heatpumps are the MOST efficient heating and cooling system to operate available on the market bar non. Particularly in Maine where there is a lot of space so horizontal space for a ground loop (cheaper then drilling) and many times people are already drilling wells (due to rural area), thus eliminating the cost of a boring because a standing column well system can be utilized.

HOWEVER, to your point of small (>1500 sq ft) homes, if they were super insulated, I can see geothermal being too big of a hastle and just throwing in a wood stove.

Have I just been fed all the wrong information?

You got it! I love how I can roll my own media experience with related RSS feeds, twitter search feeds, friend feeds, etc. and keep apprised of the latest happenings in the industry with an economy of effort.

We’re doing very well up in Maine and New Hampshire with grid tied-PV and solar domestic hot water. We actually aren’t the biggest fans of geothermal, as often times we find that other heating methods are more economical, and in super-insulated homes an air-source heat pump and large grid-tied PV array can cost-competitive, performance-competitive, and less hassle than ground-source heat pumps.

We touch on this a little bit on our site: http://www.revisionenergy.com/solar-space-heating-maine-new-hampshire.php

Agreed. I think the greatest benefit of ease of communication is that like minded people can find each other easily.

To me, the hard part of taking the awareness and actually make action out of it. Information doesn’t always lead to a change of action. I always think that McDonalds is the best example of this.

Aside from that, I like the work revision is doing. I’m from Maine so am familiar with your work. How is the geothermal business developing in Maine?

Chris

Email me the details on Erics gathering for Friday.

Chris

I was only pointing it out so that people who may follow you wouldn’t become really excited to start getting tweets, only for them not to come. But I completely agree, it many businesses its hard to see the benefit of it.

See you on Thursday my man!

Chris

Great post. I will certainly be watching these companies.

Also, the last hyperlink for @reworld goes to @evcast.

Mona
Brightstar Solar
http://www.brightstarsolar.net