Is clean coal really clean?
Tuesday, 25 November 2008
Billy Ahmed
There are major environmental groups who have received major grants to convince the public that 'clean coal' is just around the corner and that we should be investing many billions of dollars each year in 'clean coal'.
These groups include the Union of Concerned Scientists, the Clean Air Task Force, and the Natural Resources Defense Council.
There are roughly 500 coal-fired power plants in the U.S., burning about 1.05 billion tonnes of coal each year to produce half the nation's electricity.
These plants emit 1.9 billion tonnes of carbon dioxide (CO2) each year, which is 1/3 of the nation's annual total CO2 emissions.
Most proposals for "clean coal" focus narrowly on this CO2 problem, intending to capture CO2 and bury it in the deep earth, thus converting it from our problem to our children's problem.
Besides 1.9 billion tonnes of CO2 released by coal-burning power plants each year, another 120 million tonnes of toxic wastes are created (so-called coal ash, or coal combustion waste [ccw]).
These 120 million tonnes of waste, produced yearly, will remain toxic forever, and they have to be put somewhere.
'Clean coal' advocates tend to give lip-service to this other 120 million tonnes of toxic waste. Their preferred solution for these toxic wastes is to capture them and bury them in shallow pits in the ground called landfills or 'surface impoundments.'
Unfortunately, all landfills and surface impoundments eventually release their contents into the local environment, so storing coal wastes in landfills and surface impoundments is just another way of passing these problems along to our children.
How toxic is this toxic waste? The 1.05 billion tonnes of coal we burn each year contain 109 tonnes of mercury, 7884 tonnes of arsenic, 1167 tonnes of beryllium, 750 tonnes of cadmium, 8810 tonnes of chromium, 9339 tonnes of nickel, and 2587 tonnes of selenium.
These are tremendous quantities of toxic materials and they are produced each year, year after year. Where do these toxic materials go?
As coal is prepared for burning, it is crushed and washed. The coal wash water is 'disposed' of at the mine site, meaning it is dumped into a large bathtub in the ground.
Of course sooner or later it leaks out the bottom of the bathtub, carrying with it each year an estimated 13 tonnes of mercury, 3236 tonnes of arsenic, 189 tonnes of beryllium, 251 tonnes of cadmium, and 2754 tonnes of nickel, and 1098 tonnes of selenium.
During combustion, coal-fired power plants emit into the air each year 52 tonnes of mercury, 47 tonnes of arsenic, 8 tonnes of beryllium, 3 tonnes of cadmium, 62 tonnes of chromium, 52 tonnes of nickel, and 184 tonnes of selenium.
However, as air pollution control technology improves, more of these airborne toxicants are captured in the form of a finely divided ash. Coal ash (also called coal combustion waste, or CCW for short) contains large quantities of toxic metals: 44 tonnes of mercury, 4601 tonnes of arsenic, 970 tonnes of beryllium, 496 tonnes of cadmium, 6275 tonnes of chromium, 6533 tonnes of nickel, and 1305 tonnes of selenium. Many of these are toxic to humans and other life forms in microgram quantities.
The ash containing these toxic metals is buried in shallow pits near the coal plants that produced it. There, rain filters through the toxic ash year after year, leaching out the toxic metals and moving them downward (pulled relentlessly by gravity) into the soil and eventually into the groundwater below.
If the total weight of coal combustion waste is 120 million tonnes per year in the U.S., then each of our 500 coal-fired power plants is producing, on average, 240,000 tonnes of toxic waste each year.
If a power plant runs for 40 years, it leaves behind just about 10 million tonnes of toxic waste (9.6 million tonnes to be exact). This does not include the 'overburden,' as it is called -- all the dirt that must be removed to get at the coal.
Then there is acid mine drainage that sours streams below mines for centuries after mining stops. The waste produced by coal mining is enormous and enormously destructive.
The 120 million tonnes of toxic waste also does not include the pollution produced by transporting coal from mine to power plant. About 40 per cent of all rail freight in the U.S., by weight, is coal.
Another serious waste problem created by coal mining is methane gas. Methane is a greenhouse gas that, pound for pound, has a warming potential 23 times as great as CO2.
Since 1750, human industrial activities have roughly doubled the natural amount of methane in the atmosphere, and each year for the past 15 years atmospheric methane has been increasing about 1.0 per cent per year. Ten per cent of this methane is contributed by coal mines.
(The writer is a tea planter, columnist and researcher)
There are major environmental groups who have received major grants to convince the public that 'clean coal' is just around the corner and that we should be investing many billions of dollars each year in 'clean coal'.
These groups include the Union of Concerned Scientists, the Clean Air Task Force, and the Natural Resources Defense Council.
There are roughly 500 coal-fired power plants in the U.S., burning about 1.05 billion tonnes of coal each year to produce half the nation's electricity.
These plants emit 1.9 billion tonnes of carbon dioxide (CO2) each year, which is 1/3 of the nation's annual total CO2 emissions.
Most proposals for "clean coal" focus narrowly on this CO2 problem, intending to capture CO2 and bury it in the deep earth, thus converting it from our problem to our children's problem.
Besides 1.9 billion tonnes of CO2 released by coal-burning power plants each year, another 120 million tonnes of toxic wastes are created (so-called coal ash, or coal combustion waste [ccw]).
These 120 million tonnes of waste, produced yearly, will remain toxic forever, and they have to be put somewhere.
'Clean coal' advocates tend to give lip-service to this other 120 million tonnes of toxic waste. Their preferred solution for these toxic wastes is to capture them and bury them in shallow pits in the ground called landfills or 'surface impoundments.'
Unfortunately, all landfills and surface impoundments eventually release their contents into the local environment, so storing coal wastes in landfills and surface impoundments is just another way of passing these problems along to our children.
How toxic is this toxic waste? The 1.05 billion tonnes of coal we burn each year contain 109 tonnes of mercury, 7884 tonnes of arsenic, 1167 tonnes of beryllium, 750 tonnes of cadmium, 8810 tonnes of chromium, 9339 tonnes of nickel, and 2587 tonnes of selenium.
These are tremendous quantities of toxic materials and they are produced each year, year after year. Where do these toxic materials go?
As coal is prepared for burning, it is crushed and washed. The coal wash water is 'disposed' of at the mine site, meaning it is dumped into a large bathtub in the ground.
Of course sooner or later it leaks out the bottom of the bathtub, carrying with it each year an estimated 13 tonnes of mercury, 3236 tonnes of arsenic, 189 tonnes of beryllium, 251 tonnes of cadmium, and 2754 tonnes of nickel, and 1098 tonnes of selenium.
During combustion, coal-fired power plants emit into the air each year 52 tonnes of mercury, 47 tonnes of arsenic, 8 tonnes of beryllium, 3 tonnes of cadmium, 62 tonnes of chromium, 52 tonnes of nickel, and 184 tonnes of selenium.
However, as air pollution control technology improves, more of these airborne toxicants are captured in the form of a finely divided ash. Coal ash (also called coal combustion waste, or CCW for short) contains large quantities of toxic metals: 44 tonnes of mercury, 4601 tonnes of arsenic, 970 tonnes of beryllium, 496 tonnes of cadmium, 6275 tonnes of chromium, 6533 tonnes of nickel, and 1305 tonnes of selenium. Many of these are toxic to humans and other life forms in microgram quantities.
The ash containing these toxic metals is buried in shallow pits near the coal plants that produced it. There, rain filters through the toxic ash year after year, leaching out the toxic metals and moving them downward (pulled relentlessly by gravity) into the soil and eventually into the groundwater below.
If the total weight of coal combustion waste is 120 million tonnes per year in the U.S., then each of our 500 coal-fired power plants is producing, on average, 240,000 tonnes of toxic waste each year.
If a power plant runs for 40 years, it leaves behind just about 10 million tonnes of toxic waste (9.6 million tonnes to be exact). This does not include the 'overburden,' as it is called -- all the dirt that must be removed to get at the coal.
Then there is acid mine drainage that sours streams below mines for centuries after mining stops. The waste produced by coal mining is enormous and enormously destructive.
The 120 million tonnes of toxic waste also does not include the pollution produced by transporting coal from mine to power plant. About 40 per cent of all rail freight in the U.S., by weight, is coal.
Another serious waste problem created by coal mining is methane gas. Methane is a greenhouse gas that, pound for pound, has a warming potential 23 times as great as CO2.
Since 1750, human industrial activities have roughly doubled the natural amount of methane in the atmosphere, and each year for the past 15 years atmospheric methane has been increasing about 1.0 per cent per year. Ten per cent of this methane is contributed by coal mines.
(The writer is a tea planter, columnist and researcher)