Japan sits on the Ring of Fire that encircles the Pacific Ocean. With more than 100 active volcanoes, its geothermal energy potential is estimated to be 23 Gigawatts, or the equivalent of 23, 1-gigawatt nuclear power plants. But despite this potential, only 0.3% of the electricity generated in Japan comes from geothermal sources. This untapped potential seems weird when you consider that Japan has limited fossil fuel resources to burn in thermal power plants, and since Fukushima, has expressed a wariness about future nuclear power plant builds.
But according to Project Drawdown, a site whose mission is to help the world stop climate change by promoting science-based climate solutions and strategies, unlike in Japan, geothermal is starting to heat up.
Geothermal energy takes advantage of the interior heat of our planet by tapping into it. Geothermal power plants come in various flavours including natural and human-enhanced systems such as:
All of the above involves going deep into the ground where temperatures can vary from just above the boiling point of water at 100 Celsius (212 Fahrenheit) to as high as 370 Celsius (700 Fahrenheit).
But other forms of geothermal energy directly tap into much shallower sources to provide direct heating of buildings, greenhouses and other facilities. These include home geothermal heat pump systems that leverage heat from the ground tapped at depths as little as one metre (3.3 feet) to 100 metres (330 feet) or more and employ closed and open loop heat exchange systems.
Geothermal as a renewable energy source is not intermittent like solar and wind. It operates continuously.
Geothermal is clean. Compared to wind and solar, its footprint on the land is small.
Geothermal power plants have long operational lives. Even geothermal heat pumps used in homes and buildings have a longer lifespan than conventional heating and cooling systems.
The energy source that geothermal taps into will last billions of years with a mere 0.1% of the total heat potential generated by the planet needed to meet global energy demand for millions of years into the future.
Risks include the need to drill. These are the same as those faced by the fossil fuel industry when exploring for oil and natural gas. But unlike in the search for oil and gas reservoirs, finding hot water or hot rocks is a lot easier.
And as in the search for fossil fuels, there are environmental impact risks. Finding hot water could also mean bringing contaminants to the surface such as arsenic, boron, fluoride and dissolved toxins. Drilling could also tap into sour gas (hydrogen sulphide) or other gasses that could be released into the atmosphere and contribute to warming.
Not all geothermal sites are the same. Some sources can initially produce high heat values and then over time see temperatures drop. Others can experience corrosion caused by closed-cycle reinjection.
Then there is the regulatory environment and public resistance. Government policy is still behind the times when it comes to understanding what’s involved with geothermal energy. Considering the Japanese public’s concern that this form of energy could impact natural warm springs, the industry needs to become better at communication.
]]>Project Drawdown, a global program designed to arm communities with the tools to mitigate climate change, talks about green and cool roofs. Green roofs involve applying soil and plants to rooftops for living insulation. Cool roofs use white paint to reflect up to 80% of the solar energy received back into space.
If we were to start painting the world’s roofs white now at a rate of 8 to 10% of the total annually and were to install green roofs at a slighter higher rate of 9 to 11% annually, by 2050 between 47 and 75 billion square metres (506 to 807 billion square feet) would be covered states Project Drawdown. The combination would reduce carbon emissions by between 0.6 and 1.1 gigatons. And lifetime operating savings on heating, cooling and maintenance would amount to between $330 and $593 billion US.
These calculations have been done with the current reflective white paints bouncing back 80% of the sunlight. But what if the reflective efficiency of the paint were to be improved? The pursuit of an inexpensive reflective technology in the form of paint has been undertaken by researchers at Purdue University in Indiana. They have created white paint that reflects 98.1% of sunlight. The paint is considerably better than anything on the market today and could become a practical way for homes and buildings to stay cool.
Xiulin Ruan is a Mechanical Engineer from Purdue University and co-author of the new study that describes the paint’s properties. He and his associates call their invention, Ultrawhite BaSO4. They describe their discovery in an April 15th, 2021 issue of the ACS Applied Materials & Interfaces Journal.
As reported by Scientific American, Ruan has stated, “Our model shows if you’re in, say, Reno, Nevada, or Phoenix, Arizona, you can save up to 70 to 80% on air conditioning in the summer” just by painting a home roof of 90 square metres (1,000 square feet) with their paint. If the building were to be clad in its entirety by the paint, it could even bleed heat away from the structure.
The key ingredient in the paint is barium sulphate nanoparticles in various sizes. The variety contributes to the scattering of light wavelengths. The materials are relatively inexpensive to produce and the paint can easily be commercialized. Ruan and his team have patented their formula and hope to bring it to market in the next two years. He noted, “it is a very affordable nanotech.”
In a separate BBC interview, Ruan states, “We estimate we would only need to paint 1% of the Earth’s surface with this paint — perhaps an area where no people live that is covered in rocks, and that could help fight the climate change trend.”
Barium sulphate is a powder derived from the mineral barite. Today it is primarily used as a compound added to fracking mud. Commercial deposits of the mineral are found in the United States, China, India, and Morocco.
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