Reply to Kooistra in Analog January/Feburary 2009
In this post I am writing about the “Alternative View” article in the January/February 2009 issue of Analog Science Fiction/Science Fact Magazine. In that article, the author Mr. Kooistra makes a number of statements, which I think are a bit misleading to the reader. In the first place let me say that I agree with a lot of things he said in the article for example about how economics are important and so on, however, he then makes several assumptions about “green” technologies that are, in my opinion, misleading or more specifically making straw man attacks. Starting on the bottom of page 69 he states that “No one disputes that a solar power station big enough to supply the energy we get from a coal or oil fired plant would have to be huge.”
I would say that is probably not exactly true (I am sure one could find such a person), and more to the point it is misleading. Solar power is diffuse, and so for the most part is consumption of electricity, thus it makes no economic sense at all to concentrate the generation of solar power in one location. We have a distributed source of power, and distributed use of power and an existing network, and lots of roofs and otherwise unused surfaces exposed to sunlight.
What is needed is not vast single use solar power plants of the same power scale as coal, oil or nuclear plants, but rather inexpensive solar power cells, the individual home or business owner can then use his rooftop(s) and perhaps other surfaces to generate solar power, and then not buy as much power from the power company, or possibly sell power to the power company at his peak production times. If this was a legal requirement for power companies, it could result in for example owners of warehouses that use little electric power installing photo voltaic cells at their own expense and getting additional income from the power sold. We have a distributed power net now; why not take advantage of it?
Near the top of page 70 Kooistra then starts to do a back of the envelope calculation with an assumed efficiency of photo voltaic cells of 10%, and in no way justifies that value. I did some web searches and found the following information see the links.
http://www.futurepundit.com/archives/004418.html
Current world record efficiency in a solar cell – 42.8% set in July 2007 (to the best of my knowledge as of this writing.)
http://www.futurepundit.com/archives/003956.html
Previous world record efficiency in a solar cell 40.7% set in late fall 2006
Note that the below referenced wikipedia article indicates that the record has been a moving target for a number of years and that in 1994 the record was 24.7%, and more important than that some experimental film type photo voltaic cells already have achieved 18 % efficiency.
http://en.wikipedia.org/wiki/Solar_cell#High_efficiency_cells
In addition and critical to making judgments on this issue, commercially available mass produced cheap film photo voltaic cells are now capable of getting over 14% efficiency. See the below website reference.
http://www.aist.go.jp/aist_e/latest_research/2008/20080811/20080811.html
Then Mr. Kooistra correctly points out that the sun does not shine at night (how dare it not!), and so solar power is not available at night. That is, as I have said, true, but it is also misleading.
It is possible to store power, see the below website reference to advances in inexpensive electrolysis of water to generate hydrogen. Other methods also exist, and with less expensive electrolysis either a distributed or concentrated storage of hydrogen system can be used, which ever is more economical.
http://www.sciam.com/article.cfm?id=hydrogen-power-on-the-cheap
http://www.sciam.com/article.cfm?id=new-catalyst-produces-hyd
http://www.rsc.org/chemistryworld/News/2008/December/18120801.asp
In addition to hydrogen storage, other methods can be used such as batteries, or even elevation of water or compressed air, those are less efficient however. If I were to bet, I would bet that hydrogen storage will wind up being the energy storage method most commonly used in terms of quantity of energy stored in 20 odd years or so.
Given the rapid rate of advance of the industry it is unreasonable to expect that commercial solar cell efficiencies will be that low for long, I think that his cite of 10% is about half of what I would use as a long term budgetary number.
The main real objection to solar power is not that it will not work, or that it will take up to much land or that it is diffuse or that it is not available during the day, it is that solar cells combined with existing storage technologies are currently at too high of a price to justify the cost of production when set next to other forms of large scale generation of power. However prices of solar cells per watt produced are falling, as are the costs of energy storage, and the prices of most other forms of energy are unstable and have been rising historically even though we just had a crash in oil prices, I do not see that crash as stable.
Then Mr. Kooistra goes on to state that article starting at the bottom of the first column on page 70 what I see as the single most misleading statement of all: “You can do the same back of the envelope calculation for wind power. No matter how you do it, if you use anything like realistic numbers, you rapidly discover that solar and wind power will never be anything other than adjunct sources of energy.”
My first inclination on reading that was to make a rude noise, however most of Mr. Kooistra’s readers may well not know any better so I will provide evidence. First off I found the below graph in a Wikipedia article on wind power. However the root source is the world wind energy association which you can see by looking at the below website.
http://en.wikipedia.org/wiki/Wind_power
The graph shown in the below website indicates wind energy production growth over the past decade, and projected future growth, both look exponential to me.
http://en.wikipedia.org/wiki/File:WorldWindPower2008.png
Further let me add that in my professional experience as an engineer working in the offshore industry, the wind energy people are and have been loudly cursed as the people who are buying up nearly all the available production of large planetary gearboxes and large roller bearings (also used in the offshore industry), and so driving prices and production delays through the roof.
To most fundamentally refute Mr. Kooistra on the matter of wind energy, according to a study published in the Journal of Geophysical Research volume 110 (2005) titled “ Evaluation of Global Wind Power” by Archer and Jacobson of Stanford University. According to that study, potential wind energy available is actually five times greater than the total worldwide consumption of energy of all types. I provide a link to the paper below:
http://www.stanford.edu/group/efmh/winds/2004jd005462.pdf
If you actually read the paper you will see that the value calculates is very conservative and only considers wind energy generated in high wind areas on land (~ 12% of total land area world wide), and totally ignores the much larger potential energy offshore, and lower velocity wind areas on land and restricts the evaluation to three 77 meter diameter wind turbines per square kilometer at a centerline elevation of 80 meters off the ground, which is also rather conservative. Note that at this density of use, the land can still be used for agriculture or grazing. Offshore wind energy actually has more potential, than onshore, and the problem of getting energy back to shore from has been solved. See references provided below:
http://tdworld.com/underground_transmission_distribution/prysmian-uk-wind-1008/
http://www.nrel.gov/wind/pdfs/41135.pdf
The “problems” with wind energy are that it takes a lot of infrastructure and capital investment, which is being done now, it just takes time to build and install, and it’s intermittent nature which can be dealt with by a combination of storage and averaging of a large numbers of wind turbines spread over wide areas. However the intermittent nature of wind power is less of a problem than with solar as the wind is not a daylight only energy source.
If you look at the Stanford paper by Archer & Jacobson you can see that there is an enormous potential to generate power within say two hundred miles of all coasts, probably much greater than the total potential on land.
That is with zero use of solar energy. A more reasonable “back of the envelope” calculation for solar energy would look at per capita consumption of electricity first, then look at what it takes to fill that consumption. Per the below site US per capita electric power consumption is 1460 watts, or 46.0 E+9 Joules per year per person.
http://en.wikipedia.org/wiki/List_of_countries_by_electricity_consumption
Per the below reference site,image, average solar power falling on the earth depends a lot on location on earth. Note this is the average solar incidence on that location including allowance for hours of darkness and cloud cover.
http://en.wikipedia.org/wiki/File:Solar_land_area.png
I live in Houston TX so I will look at the value for that location which seems to be about 200 Watts per square meter, while in New York City it looks more like 170 or 180. Then we figure the 14% efficiency of the above reference for cheaply available film type solar cells, and to get that 1460 watts I will need 52.14 square meters (561.3 square feet) of solar cells per person. If in NYC you would need 61.3 square meters, more, but not an immense difference.
The first area is equivalent to a roof area of about 7.2 meters square (23.7 foot square). That is less than the typical area of the roof of a suburban home. If the roof of your home measured 20 ft x 30 ft the square area would be 600 square feet and just over the total per capita requirements of all Americans which includes your share of commercial and industrial uses. My suspicion is that most American homeowners could run their household needs off of solar panels on the roof if the power could be economically stored, or stored and redistributed via our existing power net and some sort of large scale storage system, probably using hydrogen, and even sell a surplus to be used by industry and people who do not own homes, or choose not to install solar power systems.
The question then becomes how much do such solar cells cost per square meter, and how much will the consumer have to pay for storage. At the present time, the cost of solar cells is prohibitive. The references I find indicate a cost of $4.84/ watt currently.
http://www.solarbuzz.com/Moduleprices.htm
The below reference indicates costs of batteries in terms of $/watt-hour, which is currently about $2.04/watt-hour. The cost will depend on how much power you will need overnight.
http://www.solarbuzz.com/Batteryprices.htm
Also the issue is the life cycle, as neither solar cells nor batteries last forever. When you look at these costs and compare them to the cost of electricity bought from the power company, you will see that although it is possible to power your home this way, it is more costly to use solar energy, but not by an immense margin. My latest power bill indicates a price per kW-hr of 0.161 $/kW-hr. At 1460 watts per person average that works out to an average per person cost of electricity of $2059/year. We shall then assume that the energy usage is constant, and so we need a wattage capacity of well over double the average use as the sun only shines during the day, and we have cloud cover. I shall assume I need a factor of 3, then we need 3*1460*4.84= $21,200 worth of solar cells, and 1460*12*2.04= $35,740 worth of batteries to make it totally independent. For a total of $56,940, at that rate we need over 27 years to break even at 0.00 percent interest. So the issue with solar power is money, nothing else.
The good news is that solar cell prices may be falling soon, to perhaps as low as $1.00 per watt, see the below reference.
http://www.technologyreview.com/Energy/20476/?nlid=967
In addition the recent above referenced advances in electrolysis of hydrogen may make the battery problem go away as well.
Then Mr. Kooistra admits his agenda is to push nuclear power. He writes as if it has no problems of it’s own other than the huge numbers of activists who protest it, and lobby legislative bodies to restrict or eliminate it. As a rule, people do not become adamant activists against something for a lark. Nuclear power has it’s own issues.
First off it is finite, one can get into a long technical argument about how much nuclear fuel is available, but frankly the wind will still be blowing and sun still shining long after the last dregs of Uranium and Thorium ore practical to mine have been mined out.
Second off regardless of the fact that many anti-nuclear activists are guilty of scare mongering and gross exaggeration, nuclear power has significant risks associated with its use. The most dangerous of which in my opinion is terrorists stealing nuclear material to make dirty bombs.
Third nuclear power is concentrated and has very, very high minimum capital costs, that and the fact that it can be used to make nuclear weapons, means massive government involvement, and that makes it even more expensive.
One cannot honestly rely on economic figures from the nuclear industry as for the most part they have heavy government subsidy, often hidden in the form of eminent domain, risk, security, decommissioning, and waste disposal costs often being sloughed off on the public through taxation and government requirements. I am not “anti-nuclear”, nuclear energy has many uses and especially in specialized niches where it is the best practical solution, but I do think that the term “adjunct energy source” is honestly more applicable in the long run to nuclear power than to wind power.
In this post I am writing about the “Alternative View” article in the January/February 2009 issue of Analog Science Fiction/Science Fact Magazine. In that article, the author Mr. Kooistra makes a number of statements, which I think are a bit misleading to the reader. In the first place let me say that I agree with a lot of things he said in the article for example about how economics are important and so on, however, he then makes several assumptions about “green” technologies that are, in my opinion, misleading or more specifically making straw man attacks. Starting on the bottom of page 69 he states that “No one disputes that a solar power station big enough to supply the energy we get from a coal or oil fired plant would have to be huge.”
I would say that is probably not exactly true (I am sure one could find such a person), and more to the point it is misleading. Solar power is diffuse, and so for the most part is consumption of electricity, thus it makes no economic sense at all to concentrate the generation of solar power in one location. We have a distributed source of power, and distributed use of power and an existing network, and lots of roofs and otherwise unused surfaces exposed to sunlight.
What is needed is not vast single use solar power plants of the same power scale as coal, oil or nuclear plants, but rather inexpensive solar power cells, the individual home or business owner can then use his rooftop(s) and perhaps other surfaces to generate solar power, and then not buy as much power from the power company, or possibly sell power to the power company at his peak production times. If this was a legal requirement for power companies, it could result in for example owners of warehouses that use little electric power installing photo voltaic cells at their own expense and getting additional income from the power sold. We have a distributed power net now; why not take advantage of it?
Near the top of page 70 Kooistra then starts to do a back of the envelope calculation with an assumed efficiency of photo voltaic cells of 10%, and in no way justifies that value. I did some web searches and found the following information see the links.
http://www.futurepundit.com/archives/004418.html
Current world record efficiency in a solar cell – 42.8% set in July 2007 (to the best of my knowledge as of this writing.)
http://www.futurepundit.com/archives/003956.html
Previous world record efficiency in a solar cell 40.7% set in late fall 2006
Note that the below referenced wikipedia article indicates that the record has been a moving target for a number of years and that in 1994 the record was 24.7%, and more important than that some experimental film type photo voltaic cells already have achieved 18 % efficiency.
http://en.wikipedia.org/wiki/Solar_cell#High_efficiency_cells
In addition and critical to making judgments on this issue, commercially available mass produced cheap film photo voltaic cells are now capable of getting over 14% efficiency. See the below website reference.
http://www.aist.go.jp/aist_e/latest_research/2008/20080811/20080811.html
Then Mr. Kooistra correctly points out that the sun does not shine at night (how dare it not!), and so solar power is not available at night. That is, as I have said, true, but it is also misleading.
It is possible to store power, see the below website reference to advances in inexpensive electrolysis of water to generate hydrogen. Other methods also exist, and with less expensive electrolysis either a distributed or concentrated storage of hydrogen system can be used, which ever is more economical.
http://www.sciam.com/article.cfm?id=hydrogen-power-on-the-cheap
http://www.sciam.com/article.cfm?id=new-catalyst-produces-hyd
http://www.rsc.org/chemistryworld/News/2008/December/18120801.asp
In addition to hydrogen storage, other methods can be used such as batteries, or even elevation of water or compressed air, those are less efficient however. If I were to bet, I would bet that hydrogen storage will wind up being the energy storage method most commonly used in terms of quantity of energy stored in 20 odd years or so.
Given the rapid rate of advance of the industry it is unreasonable to expect that commercial solar cell efficiencies will be that low for long, I think that his cite of 10% is about half of what I would use as a long term budgetary number.
The main real objection to solar power is not that it will not work, or that it will take up to much land or that it is diffuse or that it is not available during the day, it is that solar cells combined with existing storage technologies are currently at too high of a price to justify the cost of production when set next to other forms of large scale generation of power. However prices of solar cells per watt produced are falling, as are the costs of energy storage, and the prices of most other forms of energy are unstable and have been rising historically even though we just had a crash in oil prices, I do not see that crash as stable.
Then Mr. Kooistra goes on to state that article starting at the bottom of the first column on page 70 what I see as the single most misleading statement of all: “You can do the same back of the envelope calculation for wind power. No matter how you do it, if you use anything like realistic numbers, you rapidly discover that solar and wind power will never be anything other than adjunct sources of energy.”
My first inclination on reading that was to make a rude noise, however most of Mr. Kooistra’s readers may well not know any better so I will provide evidence. First off I found the below graph in a Wikipedia article on wind power. However the root source is the world wind energy association which you can see by looking at the below website.
http://en.wikipedia.org/wiki/Wind_power
The graph shown in the below website indicates wind energy production growth over the past decade, and projected future growth, both look exponential to me.
http://en.wikipedia.org/wiki/File:WorldWindPower2008.png
Further let me add that in my professional experience as an engineer working in the offshore industry, the wind energy people are and have been loudly cursed as the people who are buying up nearly all the available production of large planetary gearboxes and large roller bearings (also used in the offshore industry), and so driving prices and production delays through the roof.
To most fundamentally refute Mr. Kooistra on the matter of wind energy, according to a study published in the Journal of Geophysical Research volume 110 (2005) titled “ Evaluation of Global Wind Power” by Archer and Jacobson of Stanford University. According to that study, potential wind energy available is actually five times greater than the total worldwide consumption of energy of all types. I provide a link to the paper below:
http://www.stanford.edu/group/efmh/winds/2004jd005462.pdf
If you actually read the paper you will see that the value calculates is very conservative and only considers wind energy generated in high wind areas on land (~ 12% of total land area world wide), and totally ignores the much larger potential energy offshore, and lower velocity wind areas on land and restricts the evaluation to three 77 meter diameter wind turbines per square kilometer at a centerline elevation of 80 meters off the ground, which is also rather conservative. Note that at this density of use, the land can still be used for agriculture or grazing. Offshore wind energy actually has more potential, than onshore, and the problem of getting energy back to shore from has been solved. See references provided below:
http://tdworld.com/underground_transmission_distribution/prysmian-uk-wind-1008/
http://www.nrel.gov/wind/pdfs/41135.pdf
The “problems” with wind energy are that it takes a lot of infrastructure and capital investment, which is being done now, it just takes time to build and install, and it’s intermittent nature which can be dealt with by a combination of storage and averaging of a large numbers of wind turbines spread over wide areas. However the intermittent nature of wind power is less of a problem than with solar as the wind is not a daylight only energy source.
If you look at the Stanford paper by Archer & Jacobson you can see that there is an enormous potential to generate power within say two hundred miles of all coasts, probably much greater than the total potential on land.
That is with zero use of solar energy. A more reasonable “back of the envelope” calculation for solar energy would look at per capita consumption of electricity first, then look at what it takes to fill that consumption. Per the below site US per capita electric power consumption is 1460 watts, or 46.0 E+9 Joules per year per person.
http://en.wikipedia.org/wiki/List_of_countries_by_electricity_consumption
Per the below reference site,image, average solar power falling on the earth depends a lot on location on earth. Note this is the average solar incidence on that location including allowance for hours of darkness and cloud cover.
http://en.wikipedia.org/wiki/File:Solar_land_area.png
I live in Houston TX so I will look at the value for that location which seems to be about 200 Watts per square meter, while in New York City it looks more like 170 or 180. Then we figure the 14% efficiency of the above reference for cheaply available film type solar cells, and to get that 1460 watts I will need 52.14 square meters (561.3 square feet) of solar cells per person. If in NYC you would need 61.3 square meters, more, but not an immense difference.
The first area is equivalent to a roof area of about 7.2 meters square (23.7 foot square). That is less than the typical area of the roof of a suburban home. If the roof of your home measured 20 ft x 30 ft the square area would be 600 square feet and just over the total per capita requirements of all Americans which includes your share of commercial and industrial uses. My suspicion is that most American homeowners could run their household needs off of solar panels on the roof if the power could be economically stored, or stored and redistributed via our existing power net and some sort of large scale storage system, probably using hydrogen, and even sell a surplus to be used by industry and people who do not own homes, or choose not to install solar power systems.
The question then becomes how much do such solar cells cost per square meter, and how much will the consumer have to pay for storage. At the present time, the cost of solar cells is prohibitive. The references I find indicate a cost of $4.84/ watt currently.
http://www.solarbuzz.com/Moduleprices.htm
The below reference indicates costs of batteries in terms of $/watt-hour, which is currently about $2.04/watt-hour. The cost will depend on how much power you will need overnight.
http://www.solarbuzz.com/Batteryprices.htm
Also the issue is the life cycle, as neither solar cells nor batteries last forever. When you look at these costs and compare them to the cost of electricity bought from the power company, you will see that although it is possible to power your home this way, it is more costly to use solar energy, but not by an immense margin. My latest power bill indicates a price per kW-hr of 0.161 $/kW-hr. At 1460 watts per person average that works out to an average per person cost of electricity of $2059/year. We shall then assume that the energy usage is constant, and so we need a wattage capacity of well over double the average use as the sun only shines during the day, and we have cloud cover. I shall assume I need a factor of 3, then we need 3*1460*4.84= $21,200 worth of solar cells, and 1460*12*2.04= $35,740 worth of batteries to make it totally independent. For a total of $56,940, at that rate we need over 27 years to break even at 0.00 percent interest. So the issue with solar power is money, nothing else.
The good news is that solar cell prices may be falling soon, to perhaps as low as $1.00 per watt, see the below reference.
http://www.technologyreview.com/Energy/20476/?nlid=967
In addition the recent above referenced advances in electrolysis of hydrogen may make the battery problem go away as well.
Then Mr. Kooistra admits his agenda is to push nuclear power. He writes as if it has no problems of it’s own other than the huge numbers of activists who protest it, and lobby legislative bodies to restrict or eliminate it. As a rule, people do not become adamant activists against something for a lark. Nuclear power has it’s own issues.
First off it is finite, one can get into a long technical argument about how much nuclear fuel is available, but frankly the wind will still be blowing and sun still shining long after the last dregs of Uranium and Thorium ore practical to mine have been mined out.
Second off regardless of the fact that many anti-nuclear activists are guilty of scare mongering and gross exaggeration, nuclear power has significant risks associated with its use. The most dangerous of which in my opinion is terrorists stealing nuclear material to make dirty bombs.
Third nuclear power is concentrated and has very, very high minimum capital costs, that and the fact that it can be used to make nuclear weapons, means massive government involvement, and that makes it even more expensive.
One cannot honestly rely on economic figures from the nuclear industry as for the most part they have heavy government subsidy, often hidden in the form of eminent domain, risk, security, decommissioning, and waste disposal costs often being sloughed off on the public through taxation and government requirements. I am not “anti-nuclear”, nuclear energy has many uses and especially in specialized niches where it is the best practical solution, but I do think that the term “adjunct energy source” is honestly more applicable in the long run to nuclear power than to wind power.
posted by montestruc at 10:53 AM
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