For the next few weeks, “Ask Dr. Kaye” is going to focus on renewable energy. I’ll be investigating a select few of the leading sources of non-fossil fuel based power, and taking a look at some of the leading ski areas and resort development companies working to embrace and exploit renewable energy.
The first renewable resource I’m going to examine is geothermal power. Geothermal is one of the most widespread sources of renewable energy, yet most people think that it is relegated to volcanic locations like Iceland or Hawai`i. In fact, geothermal energy is almost everywhere you look.
How does it work?
Geothermal energy comes from heat found within the earth, and is an incredibly simple power-generation system. Groundwater, either naturally occurring or injected via wells, absorbs the earth’s heat and is extracted into above-ground facilities that exchange the heat for usable energy. The water is then re-injected back into the ground, where the earth slowly heats it up again for later use.
On average, temperatures increase about 22.1 degrees Celsius (~68 deg. F) with every 1000 m (about 1 deg. F every 70 feet) down into the earth, and is referred to as the geothermal gradient. The above values are average globally, and they of course vary immensely with local geologic conditions.
Heat within the earth comes from a variety of sources. A large component (more than 70% by some estimates) is derived from radioactive decay of trace elements such as Uranium or Potassium isotopes within rocks deep within the earth. A smaller percentage, around 15-20%, is leftover, or latent heat remaining from the formation of the planet and collisions with meteorites and comets early in our planet’s history.
Areas with higher geothermal gradients are found in locales with active tectonics, since rocks there tend to get pulverized by numerous earthquakes, allowing freer circulation of groundwater (these areas also have higher concentrations of hot springs, so watch out for naked hippies). It should come as no surprise that the geothermal gradient is also much, much higher in places with active volcanoes, like Japan and New Zealand, than it is in areas on older, cooler rocks, like central North America.
Where is it successfully in use?
A wide range of scales of geothermal power are employed, and they are typically tailored to the location where they are being installed. Individual households and office buildings use the technology on smaller scales via ground-source heat pumps to exchange heat for heating and cooling. The geothermal gradient still applies in these areas, and wells on the order of tens to hundreds of feet can help buildings reduce the use of fossil fuels for central heating and air conditioning via underwater heat exchanges.
In areas with much hotter ground water, utility-scale power generating facilities create steam and generate electricity for power grids with massive turbines. More than 8,900 megawatts (MW) of large-scale reliable energy is already being produced in more than 24 countries, equating to the power needs of 12 million typical US households.
Earlier I alluded to the stereotypical assumption that many people make about geothermal energy being available only in the vicinity of areas with active volcanoes. Right here in Tahoe, the Town of Truckee uses geothermal energy via ground-pump heat exchangers to offset the cost of using non-renewable fossil fuels to heat and cool their brand-new, state of the art $12 million-dollar Public Service Center building, which was completed in the fall of 2011.
To the east of Tahoe in Reno, an industrial geothermal plant operated by Ormat produces almost 100 MW of electricity, which, according to the plant’s director, is enough to handle the entire residential capacity of Reno on the NV Energy grid. The RGJ investigated the (to borrow one of my favorite phrases from Steven Colbert) “truthiness” of the claim that “Reno is powered by geothermal energy” and found not surprisingly that while this is possible, it’s not really that simple. In the complex reality of modern electrical grids, power sources wax and wane, and one source rarely accounts for 100% of the electricity. Read more here.
Do Ski Areas Use It?
Ski areas are, by their very nature, terribly environemntally unsound. Large swaths of trees are removed so you can carve groomers through the forest, and lifts typically run on electricity which in many mountainous areas comes from diesel and coal-fueled power plants.
Just last year, Squaw Valley topped the list of the environmental watchdog group Ski Area Citizen’s Coalition “Top-Ten Report Card” list examining practices of habitat and watershed protection, climate change action, and overall environmental policies. Squaw got a 92.1% from the SACC. In the subcategory of renewable energy, Squaw received a score of 6/6 for having geothermal ground-pump heat exchangers in use in the Children’s World and Funitel Buildings. The Gold Coast complex makes use of a solid-waste incinerator to burn all of your $15 hamburger wrappers to produce 1.5 million BTUs per hour for heating the buildings.
Coming in second with a score of 88.1% in the renewable energy category is Aspen Highlands ski area in Colorado. They also employ renewable energy technology to offset fossil-fuel use, but instead of geothermal, they employ solar panels to generate 2.3 kWh at ski patrol HQ, 10.65 kWh at their Thunder River Lodge in Carbondale, and 150 kWh via hydroelectric generation in Snowmass. Last year I would have made the joke that presumably Squaw can’t use solar as much as Aspen because of how much more snow we get, but this year…not so funny.
Back in California, the Mammoth Lakes area is rich in geothermal energy, due to the presence of still-molten magma from the eruption of the Long Valley Caldera 730,000 years ago. Ormat runs the Mammoth Pacific plant just outside of Mammoth lakes, and generates 29 MW of electricity that is used by 20,000 homes in the Mammoth / Bishop region.
A fledgling ski-area restoration endeavor in Alaska, the Manitoba Mountain project, seeks to give fresh life to a long-dead small ski area by resurrecting it with largely sustainable energy sources such as hydro, wind and solar. Organizer Mountain Riders’ Alliance hopes to develop Manitoba with as low a carbon footprint as possible, making it a model for other skis areas around the world.
Geothermal is just one of a suite of renewable energy technologies that is used to reduce our footprint of fossil fuel consumption. Hopefully you will check back in the coming weeks as I examine other renewable sources of energy, and how they are used in ski areas and beyond.
If you can put aside personal politics, you might eventually join me in coming to the conclusion that it would be a great thing for our country and humanity as a whole to move away from petroleum-based energy. If we can figure out how to replacing petroleum industry jobs with renewable energy-generation work, and even create new jobs in geothermal, solar, wind, and hydro, we will be able to reduce our dependence on unstable foreign nations for our energy and make great progress in preserving the natural environment for future generations along the way.