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My hope is that this series will brighten your spirits a bit about the challenge of climate change, and increase your curiosity about some lesser-known ways to make electricity that are close to home.

SACKA recent report by the Intergovernmental Panel on Climate Change found that the impacts and costs of global warming will be far greater than expected and are already evident in record-breaking storms, wildfires, droughts, coral bleaching, heat waves and floods around the world.

I am a retired OHSU psychiatrist/sleep disorders doctor, and I would understand if this report caused you to lose some sleep.

I have tried coping with my personal climate anxiety by surfing the web, looking for some more optimistic news. I was fascinated to find that, in addition to solar and wind, there are some lesser-known sources of clean energy that could someday power our electric cars and heat/cool our homes.

I have summarized my findings in a series of short articles about underappreciated, carbon-free sources of energy that are under development right here in Oregon. The first "snapshot" is about geothermal energy; it will be followed by articles over the next few months in The Review about other alternative energy topics, such as offshore wind and new sources of hydropower.

I am not an engineer and do not claim expertise on these topics — only curiosity and, being retired, some time on my hands to write about them.

For these articles, I have restricted myself to energy production in Oregon, and was surprised to learn how close we are to generating a homegrown, plentiful supply. These alternative resources are within striking range of feeding the grid, but they have obstacles to overcome if they are to connect to our power lines, including cost.

With the advent of fracking, cheap natural gas has become the economic benchmark for any competing energy resource. So either these alternative sources have to meet that price point, or there has to be a cap on carbon and we have to be willing to pay more for electricity (which could save money in the long run by preventing environmental degradation).

Even alternative resources have their drawbacks; wind turbines kill birds and hydroelectric dams restrict salmon migration. Thus, there are bound to be a few tradeoffs when we consider energy to be "clean."

My hope is that this series will brighten your spirits a bit about the challenge of climate change, and increase your curiosity about some lesser-known ways to make electricity that are close to home.

Snapshot #1: Really Hot Geothermal

There is a potentially inexhaustible supply of energy stored in the molten rocks deep below our feet.

When these very hot rocks are mixed with an underground source of water, they generate steam. If there is an opening to the surface, the steam shoots into the air as a geyser. And if the steam can be captured, it will turn a turbine to make electricity.

That is how the 22 geothermal power plants located in the Geysers Geothermal Field in Northern California meet 60 percent of the electricity demand for the coastal region between the Golden Gate Bridge and the Oregon state line. This is carbon-free energy, available 24/7.

SUBMITTED PHOTO: CORINNA CAMPBELL-SACK - If the steam from geysers like Old Faithful can be captured, it could turn turbines to make electricity.Oregon does not have a natural geothermal field like Geysers, but perhaps we could make one. Just pick a favorable site, drill a hole deep enough to reach the hot rocks, inject some water down the hole, let the water seep into the rocks, drill a few more holes around the original water injection site and harvest the generated steam.

The is a simplified picture of an engineered geothermal system (EGS), the kind being considered for a site near the Newberry Crater, southeast of Bend. The area has been studied extensively for 40 years and contains one of the largest geothermal heat reservoirs in the western U.S., and the hot rocks are relatively close to the surface.

Although the concept of EGS is straightforward, the economics are not quite there; the fuel is free, but the overall price for electricity, using currently available drilling and construction technology, would be more expensive than natural gas or wind (although perhaps less than solar PV plus storage).

But there may be a way to bring the cost down — maybe even lower than any of the other sources of green energy. You just have to drill deeper, down to where the rocks are really, really hot.

With current technology, it is relatively easy to drill down 1.5 miles, where the temperatures are about 200 degrees Celsius (292 degrees Fahrenheit). That's not hot enough for cost-effective electricity production. However, if you drill down three miles, you can reach the rocks that could heat water to a "super-critical" 400 degrees Celsius (750 degrees Fahrenheit). With that intensity of heat, you could produce 10 times the energy compared to a 200-degree-Celsius well, greatly enhancing the economics of electricity production.

In September 2017, a consortium of scientists and engineers held a workshop in Bend to tackle the challenges of ultra-deep drilling. There is already a 2.4-mile drill hole at Newberry, reaching temperatures of 320 degrees Celsius (600 degrees Fahrenheit); the consortium would like to extend that hole down another mile. If successful, this would be one of the hottest geothermal wells in the world.

Among the challenges are developing drill bits that can withstand the extreme temperatures that will be encountered at that depth. The engineers admit it is something of a "moon shot," but the payoff could be enormous.

For more information, see: altarockenergy.com/super-hot-egs.

Next time: Offshore wind.

Bob Sack is a member of the Lake Oswego Sustainability Advisory Board (appointed by the City Council) and is on the board of the Lake Oswego Sustainability Network, a citizens' group. The views expressed in these articles are his own, and do not necessarily represent the views of the organizations with whom he is associated.


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