Volcanos in Gakkel Ridge NOT responsible melting the Arctic ice

I am not only a global warming skeptic, but a skeptic in general.  I call ‘em as I see ‘em.

There have been some attempts to link the arctic sea ice loss of the last several years to reports of volcanoes under thousands of feet of water in the Gakkel Ridge,

The truth is that all the energy from a volcano the size of Mount St. Helens could only melt 100 square kilometers of three meter thick ice.  This is a trivial amount of ice for the arctic region, which typically oscillates between about 4 million and 14 million square kilometers every year.  100 square kilometers is only one hundred thousandth of the yearly change in Arctic sea ice extent

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Arctic region showing the location of the Gekkal ridge.  This Google Earthimage, with annotation by Moriarty, obviously does not show the arctic sea ice.

Let’s do some simple math to work this out:

First, how much energy is released by a volcano?  Of course, if varies greatly, but we just need an order of magnitude approximation for now.  A common estimate  for the energy released by the Mount St. Helens explosion is 24 megatons, where a megaton is supposed to be equivalent to the energy released by a million tons of TNT.  A joule is the basic SI unit for energy, and one megaton is equal to 4.2 million billion joules (4.2e+15 joules).  Therefore the 24 megatons released by Mount St. Helens translates into about 100 million billion joules (1.0E+17 joules).  That is:

(4.2E+15 joules/megaton  X  24 megatons  = 1.0E+17 joules).

So now the question is: how much ice could be melted by 100 million billion joules of energy?  It takes about 4 joules to heat one gram of water by 1 degree C.  But it takes many more joules to melt a gram of ice.  The amount of energy needed to melt a gram of a solid to a liquid is called the “heat of fusion.”  The heat of fusion for water is 334 joules per gram.   If we divide the total energy of the volcano by the heat off fusion of water, we will get the number of grams of ice that could be melted.  Doing the math:

1.0E+17 joules   /   334 joules per gram   =   3.0E+14 grams

OK, the energy released by Mount St. Helens would melt about 3.0E+14 (three hundred million million) grams of ice.  A gram of ice is about 1.1 cubic centimeters (1.1 cc), so we can round it to 1 cc just to make things simple.  That means that Mount St Helens released enough energy to melt 3.0E+14 cubic centimeters of ice. 

Let’s get a handle on what “3.0E+14 cubic centimeters of ice” means.  A cubic meter of ice is the same as 1,000,000 cubic centimeters of ice.   So, 3.0E+14 cubic centimeters of ice are the same as 3.0E+8 cubic meters of ice.  Still a pretty big number to grasp.  A sheet of ice that is one meter thick and one square kilometer would have a volume of 1 million cubic meters (1.0E+6 m3).  In this case, 3.0E+8 cubic meters of ice would be the same as 300 square kilometers of ice that is 1 meter thick.

Now we have a number that is easier to deal with.  That is, the energy of Mount St. Helens would be enough to melt 300 square kilometers or ice that is 1 meter thick.  Finally, we’ll make the estimate that the ice is about 3 meters thick in the arctic.  (Of course, it is much thicker some places and much thinner in others.)  Then the energy of Mount St. Helens would melt about 100 square kilometers of ice in the Arctic.

The bottom line

The Arctic goes through some serious changes in sea ice extent every year as the season change.  The sea ice extent changes by about 10 million square kilometers every year.  100 square kilometers is about one hundred thousandth of that.  It would take a thousand volcanos the size of Mount St. Helens every year to account for just 1% of the yearly Arctic ice loss.

I am not only a global warming sceptic, but a skeptic in general.  I call ‘em as I see ‘em.

Mount St Helens explosion, May 18th, 1980.

Energy cost for shipping food is minor

Criticism of our great system of food delivery because of a slavish adherence to a “green” lifestyle is simply unfair.

Ellen Goodman’s syndicated column for July 3rd introduced us to Roger Doiron.  Doiron belongs to a group called “Kitchen Gardeners.”  According to their web site:

“Kitchen Gardeners are a special breed. They are self-reliant seekers of “the Good Life” who have understood the central role that home-grown and home-cooked food plays in one’s well-being. By seeking an active role in their own sustenance, they are modern-day participants in humankind’s oldest and most basic activity, offering a critical link to our past and positive vision for our future.”

Dorian, also works with the Eat Local Foods Coalition of Maine, a group of…

“organizations and individuals interested in creating a shift towards a locally-based food system that is economically vibrant, environmentally sustainable, and healthy.  To some, food system reform may not seem like a pressing social need. But food issues play a dominant role in a range of critical social issues, including poverty, hunger, corporate power, misuse of workers, loss of community, and environmental degradation. With each food purchase decision, consumers are — wittingly or not —making powerful choices that will determine the kind of future we live in.”

Kitchen Gardeners and the Eat Local Foods Coalition seem to have several laudable goals, but saving energy by avoiding the burden of shipping foods over long distances to consumers is a dubious one.  Goodman tells us of the lawn sign, shown below, in Doiron’s lawn that expresses their concern.

I have heard frequently from people promoting farmer’s markets, local agriculural, and those opposed to large scale agribusiness, that food shipments are a significant energy drain and a major source of those pesky greenhouse gases.  Therefore, the argument goes, we should all be eating locally grown food.  Let’s put this argument to the test.

First, let’s accept Doiron’s claim that “in Maine the average person’s food travels about 1,500 miles from field to grocery store using up about 400 gallons of gas.”  1,500 miles and 400 gallons of gas would be a lot to have a single pizza or head of lettuce delivered.  I assume what Doiron really means is that produce, meat, canned foods, etc. usually travel by loaded semitrailers, which get about 4 miles to the gallon  when loaded.  So Doiron is correct, 1,500 miles would take somewhat less than 400 gallons (1,500 miles / 4 miles per gallon = 375 gallons).

A typical maximum weight of a semitrailer on a US highway is 80,000 pounds.  Being conservative, we can say that 60,000 pounds represents the net weight of the product being shipped.  60,000 pounds is a lot of pizza or lettuce.  If the typical person eats 2 pounds of shipped food per day, then that 400 gallons of gas has brought food to 30,000 people! Or, each gallon of gas has brought food to 75 people.  (60,000 pounds / 2 pounds per person / 400 gallons  =  75 people per gallon)

I like to think in terms of kilowatt-hours.  The energy content of one gallon of diesel fuel is equivalent to about 40 kilowatt-hours.  So, if a gallon of gas brings food to 75 people, that is about a half of a kilowatt-hour per person.  The total energy consumed per person per day in the US is about 250 kilowatt-hours (see calculation, below*).  Consequently, the half kilowatt-hour used to ship food 1500 miles to one person is about 1/500th of that person’s total daily energy consumption.

Put another way, if a single $5 gallon of gas delivers 2 pounds of food 1500 miles to 75 people, then the shipping cost per person is a puny 7 cents.  That sounds like a bargain to me.

Let’s not forget the huge social benefits to having enough to eat, the variety of fresh foods available to us outside the local growing season, and the ability to smooth out the effects of local weather extremes on agriculture that are all due to the shipping industry.  I am sure gardening has many benefits, but saving the energy and cost of shipping is not one of them.  Criticism of our great system of food delivery because of a slavish adherence to a “green” lifestyle is simply unfair.

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* The total energy consumed per person per day in the US is about 250 kilowatt-hours.  This may surprise many people.  This number is derived by dividing the total yearly energy consumption of the United States by 365 days and dividing again by the population (300,000,000 or 3e+8 people).

According to Lawrance Livermoor National Laboratory, the total energy consumed in the US in 2002 was 97 Quads.  One Quad is 293,000,000,000 kilowatt-hours, or 2.93e+11 kWh

97 Quads  X  (2.93e+11 kWh/Quad) / 365 days / 3e+8 people = 259 kWh/day/person

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Controversy over a proposal build a new electricity generation plant

The Rocky Mountain News reported on a supposed controversy over a proposal by Xcel Energy to build a new electricity generation plant powered by natural gas in Denver.  This plant would cost under $650 million dollars and have a generating capacity of 480 megawatts.  The RMN points out that critics…

“question the need for the plant, whose estimated cost today is more than $600 million, up from initial estimates of $436 million in November, due in part to escalating costs for labor, steel and equipment.

Opponents argue that renewable sources of energy, such as solar and wind, or energy conservation can substitute for an expensive new plant.”

Really? 

Solar

I wonder if the opponents have checked the cost of solar energy lately.  According to the June 2008 survey results for the Solar Electricity Global Benchmark Price Indices, the cost per watt for industrial sized solar electricity installations is $4.94 per watt.  At that rate it would cost about $2.4 billion to build a 480 megawatt solar plant, four times the cost of the natural gas plant.  But, of course, the gas powered facility can operate near maximum capacity for 24 hours a day, yielding over 11,000 megawatt-hours of energy per day.  The solar powered plant can realisticly operate at its maximum power for about four or five hours a day on the average (in Colorado), and if lucky would yield maybe 3,000 megawatt-hours of energy per day.  To equal the the daily maximum energy output of the gas powered plant, the solar powered plant would actually need to have about four times the installed wattage, and would cost closer to $10 billion!  With typical silicon solar technology of today, such a solar facility would have a footprint of about 15 square kilometers, or roughly 200 times the size of Coors Field, as illustrated in figure 1, below.

Figure 1.  Click on image to enlarge.  About 15 square kilometers of solar arrays would be needed to yield the same energy as a 480 kilowatt natural gas power plant averaged over a typical day.  That is approximately 200 times the size of Coors Field.  This image shows 15 square kilometers compared to downtown Denver with Coors field near the top.  Image is from Google Earth with annotation added by Tom Moriarty.

Wind

 Wind is a better bet than solar at this time, and in the long run is cheaper than gas per kilowatt-hour generated.  It would still be very expensive to install enough wind turbines to be able to match the continuous output of a gas fired plant.  480 megawatts worth of wind turbines would put out 480 megawatts of power if the wind is blowing fast enough.  But when the wind is not blowing fast enough, the the output will be lower.  A multiplicative number, called the “capacity factor” is used to calculate the amount of energy that is produced over time, versus the amount that would have been produced if the turbine had been running at its maximum output 100% of the time.   Roughly speaking, the capacity factor for wind power in Eastern Colorado is about 35%.  The capacity factor for modern gas fired electricity generation would be better than 85%.  So, in order to get the same energy as a 480 megawatt gas fired plant, you would have to install twice as much wind capacity, or about 1000 megawatts.  The realistic installation cost of wind power (with the required transmission lines, etc.) is about $3 per watt, as seen here.  So it would cost about $3 billion dollars worth of wind generation facilities to replace the $600 million natural gas powered plant.

However, even with the high construction cost, wind energy would still be cheaper per kilowatt-hour than gas in the long run.  Gas is expensive and going up, while wind is still free.  But wind has another problem.  When the wind is slow or zero, the power is low or zero.  It doesn’t make any difference how many watts of wind power have been installed when the wind isn’t blowing.  There is no power.  There must always be enough non-wind (and non-solar) power generation capacity to cover the load when the wind isn’t blowing (and the sun isn’t shining).

The folks at Xcel Energy figured this out a long time ago.  That is why our lights are not going out.  They know that wind turbines are a great asset for reducing the load on the more traditional types of power generation, but only when the wind is blowing.  That is why they are already the leading wind power provider in the United States, with over 2500 megawatts of installed wind capacity and plans for more in the future.  But they still must maintain the non-fickle conventional power sources, like gas, or the lights will start going out when the wind stops blowing.

Conservation.

Who can argue with conservation, if it means not being wasteful.  But be careful when some environmental activists says “conservation.”  The Rocky Mountain News article quotes the environmental activist, Leslie Glustrom expressing her reservations about moving from coal to gas.  In another recent opinion piece in the Boulder Daily Camera Glustom wrote:

“The alternative to building gas turbines to meet the summer peak is to begin using modern internet-based tools to manage the demand by cycling non-essential motors, lights, air conditioning and HVAC systems. There are a growing number of firms that develop these high-tech “demand response” systems, but, despite repeated efforts from citizen interveners, Xcel repeatedly refused to explore this powerful form of demand management.”

In other words, “citizen interveners,” (like Glustrom herself, no doubt) would like to use tools to control your use of pesky wasteful things like motors and lights.  Don’t worry, I’m sure they have your best interest in mind.

Conclusion

I am all for solar and wind energy.  Really.  Just click on the “ClimateSanity by Tom Moriarty” tab at the top of this page if you doubt me.  But I believe the market, rather than demands by “activists”  will ultimately lead to a better mix of renewables and non-renewables, with renewables gaining share as they become more cost effective.  As for Ms. Glustrom’s idea to “manage the demand,” I suggest a better alternative would be to have plenty of generating capacity and a varying rate scale for consumers based on the cost of generation by Xcel or the time of day.  That way, as the cost of generation varies with demand consumers can adjust their own practices and manage their own demand, without any help by Ms. Glustrom.