Guest Essay by Kip Hansen – 4 November 2020
The image used here is of the charcoal-burning kilns in the Adirondacks, much of which were clear-cut in the late-1700s and early 1800s to provide timber and charcoal for the big cities of the Northeastern U.S. – particularly for New York City.
Quoting from Joel T. Headley’s “The Adirondack: or Life in the Woods” written in 1849:
“The first harvesting of the Adirondack forests began shortly after the English replaced the Dutch as the landlords of New Netherlands and changed its name to New York [September 8th, 1664] . Logging operations generated wealth, opened up land for farming, and removed the cover that provided a haven for Indians.”
“After the Revolutionary War, the Crown lands passed to the people of New York State. Needing money to discharge war debts, the new government sold nearly all the original public acreage – some 7 million acres – for pennies an acre. Lumbermen were welcomed to the interior, with few restraints: “You have no conception of the quantity of lumber that is taken every winter… A great deal of land is bought of government solely for the pine on it, and after that is cut down, it is allowed to revert back to the State to pay its taxes.”
Why “16th Century”?
In England, there was an Energy Crisis caused by widespread deforestation through the cutting of wood for building materials and for fuel for heating and cooking. This led to a gradual shift from wood burning to coal burning in the century following 1550 or so. Coal burning also supplied the fuel, the energy, for Britain’s early Industrial Revolution.
We all know that humans have been “burning stuff” for the heat energy available from the rapid oxidation of wood and other plant material (grasses, straw, dung, etc.) since early man “discovered” and harnessed fire – “perhaps as early as 1.5 million years ago in Africa” – and subsequently learned how to keep a fire going through saving hot coal in ashes and how to start fires through friction and later using flints and, eventually, chemical matches
And we have been doing so ever since. We burn firewood, we burn peat blocks, we burn wood pellets and wood chips, we burn petroleum products and natural gas, we burn trash and municipal waste. All for the heat produced. We heat our homes and our factories, we use the heat to make electricity in huge power plants. Our transportation systems depend on internal combustion and jet engines that burn gasolines and diesel fuel.
After all these years, despite all of our scientific advances, all but a small fraction of the world’s energy supply comes from “burning stuff”:
There is hope — we can and should do better than this.
In this essay, I will look at Geothermal Energy. [ Lots of illustrations, not too much text. ]
A recent headline declares:
Geothermal energy is poised for a big breakout
David Roberts at VOX writes an excellent informative, well-worth-reading, article [link just above] on the advances made in the geothermal energy arena:
“After many years of failure to launch, new companies and technologies have brought geothermal out of its doldrums, to the point that it may finally be ready to scale up and become a major player in clean energy. In fact, if its more enthusiastic backers are correct, geothermal may hold the key to making 100 percent clean electricity available to everyone in the world.“
“Iceland is a pioneer in the use of geothermal energy for space heating. Generating electricity with geothermal energy has increased significantly in recent years. Geothermal power facilities currently generate 25% of the country’s total electricity production.”
“During the course of the 20th century, Iceland went from what was one of Europe’s poorest countries, dependent upon peat and imported coal for its energy, to a country with a high standard of living where practically all stationary energy is derived from renewable resources. In 2014, roughly 85% of primary energy use in Iceland came from indigenous renewable resources. Geothermal sources accounts for 66% of Iceland’s primary energy use.”
In the United States, the federal Department of Energy [DOE] issued a major report on geothermal energy in May of 2019. [Various versions and chapters of the report are available at the link.] One of the featured images is this:
[GHP = Geothermal Heat Pump EGS = Enhanced Geothermal Systems]
Why is the core of the Earth hot?
“There are three main sources of heat in the deep earth: (1) heat from when the planet formed and accreted, which has not yet been lost; (2) frictional heating, caused by denser core material sinking to the center of the planet; and (3) heat from the decay of radioactive elements.
You or your neighbor may already be using geothermal energy to heat (and cool) your home. Residential heat pump systems are already very popular in many areas of the United States. These systems use the relative warmth of ground water (well water) and a heat pump. A Heat Pump is just like an air conditioner, but, in this case, instead of pumping heat out of a residence, it “concentrates” the heat from the well water and pumps that heat into the house. It can also work in the `opposite direction, and pump heat out of your house into the well water.
Here is a good description:
“Open Loop Low Temperature Systems
Since open loop geothermal projects involve the direct use of low temperature groundwater from wells, this category will be the primary topic. In a typical open loop system, geothermal water is brought up from a well and circulated through a heat exchanger (heat pump). After heat is extracted from or added to the water, the water is then either returned to the underground aquifer or original well by injection or discharged onto the ground or into or under a surface water source.”
Closed Loop Low Temperature Systems
The closed loop method uses a contained fluid (often an environmentally friendly antifreeze/water solution) that circulates through a series of pipes (called a loop) under the ground or beneath the water of a pond or lake and into a building. In the winter, an electric compressor and heat exchanger pulls the heat from the pipes and sends the warmed air via a duct system throughout the building. In the summer, the process is reversed as the pipes draw heat away from the building and carry it back to the ground or water outside where it is absorbed. – Water Well Journal
Geothermal for Utility Scale Electrical Production
For the electrical production sector, the current high-end systems, labelled Binary Power Plants in the DOE Geothermal Diversity diagram above, are currently in use around the world:
Here’s a description from Ormat Technologies, Inc. (NYSE: ORA) which has operating geothermal plants in 25 countries:
Binary plants are ideal for geothermal reservoirs to maximize sustainability and return on investment. Binary plants maximize sustainability by reinjecting 100% of the geothermal fluid, maintaining reservoir pressures. Return on Investment (ROI) is maximized due to much lower operating costs and higher resilience to changing reservoir conditions thereby maintaining higher efficiency over the long term. Binary technology can be utilized on a wide range of resources from low enthalpy to high. Multiple high enthalpy binary facilities are in service around the world.
How It Works
The fluid is extracted from an underground reservoir and flows from the wellhead through pipelines to heat exchangers in the Ormat Energy Converter (OEC).
Inside the heat exchangers, the geothermal fluid heats and vaporizes a secondary working fluid which is organic, with a low boiling point. The organic vapors drive the turbine [much like the steam in a steam turbine – kh] and then are condensed in a condenser, which is cooled by either air or water. The turbine rotates the generator. Condensed fluid is recycled back into the heat exchangers by a pump, completing the cycle in a closed system. The cooled geothermal fluid is re-injected into the reservoir.” — Ormat, Binary Technology.”
An example of an operating plant is Ormat’s McGinness Hills Complex in Nevada, which produces 143 MW or 3,400 MWh a day. The larger Geysers complex in California produces about 21,600 MWh . This is comparable to the average coal-fired power plant, which at about 600 MW, produces 14,400 MWh. A very large coal-fired complex, like the Gibson Generating Station in Indiana, produces approximately 74,000 MWh.
The United States has lots and lots of geothermal potential.
Global Geothermal Production
“The installed capacity of geothermal energy has gradually increased worldwide over the last decade, reaching 13.93 gigawatts in 2019. Geothermal technologies are among the growing renewable energy trend occurring across the world, as environmentally friendly technologies are sought after due to lower emissions and the use of a renewable source.”
“After the United States, Indonesia and the Philippines lead the world in terms of cumulative installed nameplate geothermal power capacity installed. These three countries still have plenty of geothermal projects under development and are also home to some of the largest geothermal plants in the world. However, in 2018, Turkey installed the most geothermal capacity additions at 219 megawatts, after completing several new projects.”
While geothermal still represents a small fraction of the world’s energy infrastructure, geothermal is on the rise and hopefully will continue to take a larger and larger share of electrical production in the United States and around the world. The source of the energy, the heat of the core of the Earth, will not diminish in any time frame relevant to Mankind.
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I awoke one morning a couple of years ago, went down and threw a few logs in the woodstove that we use to supply most of the heat for our home. I realized that my grandfather and his grandfather had done the same in their day. Looking back down the timeline, I realized that mankind had been doing this – or something similar – for thousands of years: Burning Stuff for Energy.
The only other truly modern electrical power source is solar. Photovoltaic cells are wonderful for supplying electrical power when and where the Sun shines and there are no other alternatives – such as on an expedition to the Sahara where there are no power lines. But for homes and cities and factories, these all require 24/7 dependable full electrical service. Solar always requires base-load backup for the majority of the day when the sunshine is not sufficient or non-existent. And solar farms, as they are sometimes called, take up a lot of real estate. So, Solar is not a end-all solution for supplying the electrical energy needs of the modern world.
Starting each comment with the name of the person to whom you are speaking is always good manners. Address your comments to “Kip…” if speaking to me in particular. Thanks.
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