James McKenzie believes the UK government’s ambitious 10-point-plan for a “green industrial revolution” can deliver – if we put our collective minds to the problem
World’s Aging Big Dams Pose ‘Emerging Risk’: UN
By 2050, more than half the global population will live downstream from tens of thousands of large dams near or past their intended lifespan, according to a U.N. report released Friday.
PARIS (AFP) — By 2050, more than half the global population will live downstream from tens of thousands of large dams near or past their intended lifespan, according to a U.N. report released Friday.
Most of the world's nearly 59,000 big dams — constructed between 1930 and 1970 — were designed to last 50 to 100 years, according to research from the U.N. University's Institute for Water, Environment and Health.
"This is an emerging global risk that we are not yet paying attention to," co-author and Institute director Vladimir Smakhtin told AFP.
"In terms of dams at risk, the number is growing year by year, decade by decade."
A well-designed, constructed and maintained dam can easily remain functional for a century.
But many of the world's major dams fail on one or more of these criteria.
Dozens have suffered major damage or outright collapse over the last two decades in the United States, India, Brazil, Afghanistan and other countries, and the number of such failures could increase, the report warned.
Compounding the risk in ways that have yet to be fully measured is global warming.
"Because of climate change, extreme rainfall and flooding events are becoming more frequent," lead author Duminda Perera, a researcher at the University of Ottawa and McMaster University, said in an interview.
This not only increases the risk of reservoirs overflowing but also accelerates the build-up of sediment, which affects dam safety, reduces water storage capacity, and lowers energy production in hydroelectric dams.
'Catastrophic consequences'
In February 2017, the spillways of California's Oroville Dam — the tallest in the U.S. — were damaged during heavy rainfall, prompting the emergency evacuation of more than 180,000 people downstream.
In 2019, record flooding sparked concern that Mosul Dam, Iraq's largest, could fail.
Aging dams not only pose a greater risk to downstream populations, but also become less efficient at generating electricity, and far more expensive to maintain.
Because the number of large dams under construction or planned has dropped sharply since the 1960s and 1970s, these problems will multiply in coming years, the report showed.
"There won't be another dam-building revolution, so the average age of dams is getting older," said Perera.
"Due to new energy sources coming online — solar, wind — a lot of planned hydroelectric dams will probably not ever be built."
A global fleet of nearly 60,000 aging dams also highlights the challenge of dismantling — or "decommissioning" — those that are no longer safe or functional.
More than 150 years old
Several dozen have been torn down in the United States, but all of them small, Smakhtin said.
More than 90% of large dams — at least 15 meters from foundation to crest, or holding back no less than 3 million cubic meters of water — are located in only two dozen countries.
China alone is home to 40% of them, with another 15% in India, Japan and Korea combined. More than half will be older than 50 within a few years.
Another 16% of the world's dams are in the United States, more than 85% of them already operating at or past their life expectancy.
It would cost some $64 billion to refurbish them, according to one estimate.
In India, 64 big dams will be at least 150 years old by 2050. In North America and Asia, there are some 2,300 operational dams at least 100 years old.
Worldwide, there is about 7,500 cubic kilometers of water — enough to submerge most of Canada by a meter — stored behind large dams.
vtsnowedin wrote: Concrete does not get lighter as it gets older so there is no expiration date for the concrete portion of the dam
mousepad wrote:vtsnowedin wrote: Concrete does not get lighter as it gets older so there is no expiration date for the concrete portion of the dam
Isn't the problem of reinforced concrete that the steel rusts away leaving the concrete cracked and much weaker over time?
https://www.cement.org/learn/concrete-t ... 20reaction.
vtsnowedin wrote:mousepad wrote:vtsnowedin wrote: Concrete does not get lighter as it gets older so there is no expiration date for the concrete portion of the dam
Isn't the problem of reinforced concrete that the steel rusts away leaving the concrete cracked and much weaker over time?
https://www.cement.org/learn/concrete-t ... 20reaction.
Unlike a road bridge that gets exposed to deicing salt and impact loads from trucks the rebars in a dam if it even has any are pretty much protected by the concrete cover and rust very slowly if at all.
Clear Creek Dam in Washington, which was breached, suffered from a variety of deterioration mechanisms and the concrete properties diminished
mousepad wrote:vtsnowedin wrote:mousepad wrote:vtsnowedin wrote: Concrete does not get lighter as it gets older so there is no expiration date for the concrete portion of the dam
Isn't the problem of reinforced concrete that the steel rusts away leaving the concrete cracked and much weaker over time?
https://www.cement.org/learn/concrete-t ... 20reaction.
Unlike a road bridge that gets exposed to deicing salt and impact loads from trucks the rebars in a dam if it even has any are pretty much protected by the concrete cover and rust very slowly if at all.
Look, there's a whole study about dam safety and concrete.
https://www.usbr.gov/ssle/damsafety/Tec ... -03-05.pdfClear Creek Dam in Washington, which was breached, suffered from a variety of deterioration mechanisms and the concrete properties diminished
As always, things are probably more complicated than the layman would suspects.
mousepad wrote:As always, things are probably more complicated than the layman would suspects.
Newfie wrote:Duestche Welle Us reporting the German Energy Minister says the 3 remaining nukes are too far along in decommissioning to put back online. He wants to increase wind and solar so they are completely off fossil fuels by 2030 (or 2035?).
Neat trick, I am gonna watch how that goes.
vtsnowedin wrote:Newfie wrote:Duestche Welle Us reporting the German Energy Minister says the 3 remaining nukes are too far along in decommissioning to put back online. He wants to increase wind and solar so they are completely off fossil fuels by 2030 (or 2035?).
Neat trick, I am gonna watch how that goes.
You have to wonder what process or activity of decommissioning short of the reactor core being pulled out and scraped can't be halted and reversed?
I suspect it is more a matter of wanting to do it or not that sets that stage.
vtsnowedin wrote:You have to wonder what process or activity of decommissioning short of the reactor core being pulled out and scraped can't be halted and reversed?
I suspect it is more a matter of wanting to do it or not that sets that stage.
AdamB wrote: Once you've pulled them apart you could be in an area of no economic return.
vtsnowedin wrote:AdamB wrote: Once you've pulled them apart you could be in an area of no economic return.
Possibly but would that not be dependent on the cost of alternative fuel produced power?
vtsnowedin wrote: They shut down VT Yankee when it was near an overhaul and hydro Quebec and natural gas produced electricity became cheaper then it's projected future production costs.
If your alternative fuel is gas from a country run by a sadistic mad man you might feel safer in doing even a very costly overhaul.
Quaise is hoping to accomplish those lofty goals by tapping into the energy source below our feet. The company plans to vaporize enough rock to create the world’s deepest holes and harvest geothermal energy at a scale that could satisfy human energy consumption for millions of years. They haven’t yet solved all the related engineering challenges, but Quaise’s founders have set an ambitious timeline to begin harvesting energy from a pilot well by 2026.
...
The plan would be easier to dismiss as unrealistic if it were based on a new and unproven technology. But Quaise’s drilling systems center around a microwave-emitting device called a gyrotron that has been used in research and manufacturing for decades.
theluckycountry wrote:I'm not sure on the current figures, but a year ago US energy consumption by source and sector was 22% wood and 17% bio-fuels. The wood is rarely spoken of because it's Un-tech, everyone down on main street assumes we are increasing our use of solar and wind. In Germany the use of wood is even greater in proportion to other re-buildable sources.
June 16, 2021
Wood and waste energy, including wood, wood pellets, and biomass waste from landfills, accounted for about 22 percent of U.S. renewable energy consumption last year. The EIA noted that industrial, commercial and electric power facilities use wood and waste as a fuel to generate electricity, produce heat and manufacture goods.
https://biomassmagazine.com/articles/18 ... es-in-2020
This in my mind is an example of leap-frogging backward. We're going straight over coal and back to wood lol. What are the emissions from burning wood? Not that different to burning coal I would assume. But ignoring the climate, it's a sad indictment on our 1970's dream of a renewable future. As the oil gets scarcer and more expensive, wind and solar will become more and more expensive as well. But how much wood chip is to be had? And when the fossil fuel based industries that produce it fail, what then? Send the millions of unemployed out to gather sticks as the Israelite's were sent out to gather straw in Ancient Egypt...
Most of the wood energy consumption in the United States is not used in the power sector. It is used in the industrial sector. Ex: waste products from paper mills like black liquor are used to power the mill. So if you are picturing in your mind the US clearcutting it's forests to turn them into wood pellets to throw them into a power plant, you are mistaken. The US power sector only uses 9% of us biomass energy consumption and less than half of that is from wood.theluckycountry wrote:I'm not sure on the current figures, but a year ago US energy consumption by source and sector was 22% wood and 17% bio-fuels. The wood is rarely spoken of because it's Un-tech, everyone down on main street assumes we are increasing our use of solar and wind. In Germany the use of wood is even greater in proportion to other re-buildable sources.
June 16, 2021
Wood and waste energy, including wood, wood pellets, and biomass waste from landfills, accounted for about 22 percent of U.S. renewable energy consumption last year. The EIA noted that industrial, commercial and electric power facilities use wood and waste as a fuel to generate electricity, produce heat and manufacture goods.
https://biomassmagazine.com/articles/18 ... es-in-2020
This in my mind is an example of leap-frogging backward. We're going straight over coal and back to wood lol. What are the emissions from burning wood? Not that different to burning coal I would assume. But ignoring the climate, it's a sad indictment on our 1970's dream of a renewable future. As the oil gets scarcer and more expensive, wind and solar will become more and more expensive as well. But how much wood chip is to be had? And when the fossil fuel based industries that produce it fail, what then? Send the millions of unemployed out to gather sticks as the Israelite's were sent out to gather straw in Ancient Egypt...
Forest Products Industry ProfileENERGY
[The forest products industry is the third-largest industrial consumer of energy and generates more than 2 billion tons of waste each year.]
In 2008, producing a ton of paper required, on average, approximately 24.5 million Btu per ton, a productivity rate that has not changed substantially over the past decade. The industry generates 63% of its own energy using its woody waste products and other renewable sources for fuel (bark, wood, and pulping liquor). As a leader in generation and consumption of renewable energy, the U.S. forest products industry generates 28.5 million megawatt hours annually.
Trends in the U.S. forest products sector, markets, and technologiesThe forest products sector plays a critical role in the economic and social well-being of the United States. The country is the top producer and consumer of forest products, and it has the highest per capita industrial wood consumption. Nevertheless, the country’s forest area has not changed in over a century, owing in part to sound forest management practices and a strong tradition of wood utilization.
What are the emissions from burning wood? Not that different to burning coal I would assume.
But how much wood chip is to be had?
Users browsing this forum: No registered users and 18 guests