Renewable Energy: A Closer Look

by Catherine Haug

The July 2010 issue of Rural Montana, the Magazine of the Montana Electric Cooperative Association, included two interesting articles, described below. You can download a pdf copy of this magazine issue: Rural Montana, July 2010 Issue.

The point of these articles is that renewable energy options are more costly than that produced by coal or natural gas, but they have a higher “green factor” (eco-friendliness). One of the renewables stands out on all counts: reliability, cost and eco-friendliness. Can you guess which it is?

“Cost of Renewables By the Numbers”

Article by Scott Gates and John Lowrey (see page 6 of Rural Montana July 2010), synopsis by Catherine Haug.

This article indicates the Co-op stake in five renewables (hydro, wind, biomass, geotherm and solar) as compared with non-renewables (oil, coal, natural gas and nuclear).

Renewables currently provide 11% of Montana Co-Op’s energy supply, of which the largest portion (of that 11%) by far is Hydro at 81.7%.

“Dollars and Green, the True Color of Power “

Article by James V. Smith, Jr. (see page 7 of Rural Montana July 2010); synopsis by Catherine Haug

This one delves a bit deeper into eight power sources used by Montana co-ops: hydro, coal, geothermal, nuclear, natural gas, biomass, wind and solar. Each is rated by Continuity/Reliability, Price per KW-Hour, Green Factor, and Percent in use by Co-ops, presenting these ratings in a colorful bar-graph copied below.

The Green Factor is a subjective/intuitive representation on a a relative scale, and is not based on hard statistics like the other stats from NRECA (National Rural Electric Cooperative Association). It mainly reflects greenhouse gas emissions (CO2, methane, etc.) or lack thereof.

  • The renewables: hydro, geothermal, wind, and solar are all ranked the same (90%).
  • Nuclear is give the same high 90% ranking as renewables, because it is “safe and reliable,” with little or no greenhouse gas emissions. I find this absurd because of its potential to leak destructive and harmful radiation, and heats neighboring bodies of water to a point that is destructive to aquatic life.
  • Biomass is ranked at 65% because of its CO2 emissions.
  • Natural gas ranks at 50% because because it is relatively low in greenhouse gas emission (compared with coal), and often accompanies more green but less continuous alternatives such as wind and solar.
  • Coal is ranked low at about 3% (because such plants, tho high in greenhouse gas emission, meet existing standards).

The Price comparison has solar PV cells ranked the highest at 100%. Hydro is ranked lowest at about 13%; coal, geothermal, nuclear and natural gas all rank about the same at 18%; biomass ranks at 25%; and wind at 30%.

All but wind and solar rank high in Continuity/Reliability at 95%. Wind is the least continuous/reliable at 35% and solar is in the middle at 50%.

From this somewhat arbitrary analysis it is clear that geothermal power is the best of the options, ranking high in Green Factor and Continuity/Reliability, and among the lowest in Price/KW-Hour. Unfortunately, it is the least in use by our Co-ops at 0.001%. The explanation given is that “too few sources can be tapped in large scale, and most are in remote areas.”

A Closer Look at Geothermal

As discussed in the Gathering Summary for our Alternative Energy event (June, 2010), geothermal power can be used to produce electricity; geothermal heat exchange can be used to heat/cool buildings and/or produce hot water.

Rural Montana’s analysis evaluated only large-scale geothermal power production from hot springs and geyser basins that are currently being used by co-ops. But you don’t need a hot spring source of heated water; and you don’t need a large-scale power generation plant. Consider  the following ideas; it is my belief that such installations should be pursued with vigor.

Geothermal Asphalt

A clever combination of solar-termal and geothermal, involving asphalt streets, is currently being used in parts of Europe, both to generate power and to heat/cool buildings. Check out Huffington Post: Asphalt Power: Power From Below Our Feet (That Doesn’t Involve Drilling). The premise is that the sun warms the asphalt, which in turn heats water circulating in pipes buried beneath the asphalt.

Geothermal Heat Exchange

Geothermal heat exchange to provide heat and hot water can be deployed on a smaller scale than geothermal power generation. It is fairly expensive for one home, but when an installation serves clusters of homes/buildings, the cost for each is lowered dramatically.

And while it does not provide electric power, it does dramatically reduce electricity consumption (as a replacement for electric heat and hot water), because the systems are 300% (or more) efficient.

A Cluster Example

Last year I looked into adding an open-loop geothermal heat exchange system to provide heat and hot water for my home (see diagram, left, from US Department of Energy). This involved:

  • retrofitting an old unused well,
  • drilling a new, second well to complete the open loop system; and
  • installing a heat pump.

The cost estimate was about $15,000 and was more than I could afford for myself. However, the system could have been shared by the eight homes on our short private road. That is, each of us would have been responsible for:

  • the full cost of our individual heat pumps, and
  • a share of the cost of the two wells and piping for the open loop system (or piping for a closed loop system).

The total cost of this shared project (including 8 heat pumps) would have been $55,000, or $6100 per home. Much much more reasonable than the cost for just my home.


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