I recently read "Climate Change Evidence & Causes", a short (32 page) pamphlet produced by the National Academy of Sciences (US) and the Royal Society (UK) which I was sent with a suggestion that I review it. I couldn't find a copyright statement or date but it appears to be recent. As might be expected it is a summary of mainstream scientific thinking regarding anthropogenic CO2 (and other greenhouse gas) emissions into the atmosphere and their predicted effects on the earth's climate. I am familiar with the subject and didn't find anything particularly original or compelling about this write up although it comes of course with the imprint of whatever authority you are prepared to grant to the National Academy and the Royal Society.
The report is rather narrowly focused on climate science. The question of what if anything to do about the predicted warming involves many other issues which the report does not address. For example the most alarming projections are based on an emissions scenario called RCP8.5 in which CO2 levels peak at around 2000 ppmv. This scenario (which isn't original to this report) is generally labeled "business-as-usual" however it has been criticized as being alarmist and essentially impossible as it assumes burning fossil fuel resources (especially coal) which are not currently (and may never be) economically feasible to extract. See here and here. I am not sure who is right but the dispute is important and it isn't addressed at all in this summary. Another important issue is to what extent active mitigation measures are feasible which the report just mentions in passing " ... or they can seek as yet unproven 'geoengineering' solutions ...". And of course any attempt to seriously limit emissions will involve a host of complicated political and economic questions.
So I am not sure what this report really contributes to the political debates about climate change. Most people are aware of the conventional wisdom but don't perceive any imminent threat to themselves personally and so aren't willing to make any great sacrifices to avert climate change. So little is likely to get done.
So in summary I doubt this report will have much impact and I don't see any reason to make a special effort to read it.
Showing posts with label environment. Show all posts
Showing posts with label environment. Show all posts
Saturday, August 2, 2014
Monday, July 5, 2010
Oil and Obama
I haven't been too critical of Obama's somewhat floundering response to the Gulf oil spill because in truth it hasn't seemed that there was really that much to be done. However one thing he (or his appointees) could do is make sure the cleanup effort is not being needlessly obstructed by government regulations and red tape. This story suggests this is not being done.
The Americans don’t have spill response vessels with skimmers because their environment regulations do not allow it. With the Dutch method seawater is sucked up with the oil by the skimmer. The oil is stored in the tanker and the superfluous water is pumped overboard. But the water does contain some oil residue, and that is too much according to US environment regulations.
In my opinion this regulation (intended to prevent pollution from ships flushing out their fuel tanks with water and the like) shouldn't apply to skimmers which are discharging cleaner water than they took in. It clearly doesn't make any sense for the current spill where the alternative to removing 99% of the oil is removing 0% of the oil. Apparently the Dutch skimmers have now been approved for use in the Gulf after a long delay. Hopefully this sort of thing is not actually a significant problem. However I have seen a number of claims to the contrary (most admittedly by people with axes to grind).
The Americans don’t have spill response vessels with skimmers because their environment regulations do not allow it. With the Dutch method seawater is sucked up with the oil by the skimmer. The oil is stored in the tanker and the superfluous water is pumped overboard. But the water does contain some oil residue, and that is too much according to US environment regulations.
In my opinion this regulation (intended to prevent pollution from ships flushing out their fuel tanks with water and the like) shouldn't apply to skimmers which are discharging cleaner water than they took in. It clearly doesn't make any sense for the current spill where the alternative to removing 99% of the oil is removing 0% of the oil. Apparently the Dutch skimmers have now been approved for use in the Gulf after a long delay. Hopefully this sort of thing is not actually a significant problem. However I have seen a number of claims to the contrary (most admittedly by people with axes to grind).
Wednesday, December 30, 2009
Superfreakonomics
One of the presents I received for Christmas was the book, "Superfreakonomics", by Levitt and Dubner, a sequel to their book, "Freakonomics", which I reviewed here .
I have now read Superfreakonomics and my take is that it is similar to Freakonomics. That is, it is a provocative and entertaining read but should not be taken as the last word on the subjects it covers.
As with Freakonomics it covers a diverse set of topics somewhat peripheral to the main concerns of economists. It has nothing much to say about macroeconomics and the recent crisis.
The chapter on global warming has been widely criticized but I didn't find it highly objectionable. They do make a much criticized remark about the color of solar panels which, as I explain here , seems rather fundamentally misguided. However it is not central to their main point which is that it may be more sensible and feasible to find ways to mitigate the effects of CO2 emissions than to eliminate them. I see no justification for dismissing mitigation strategies out of hand as many global warming alarmists would prefer. However it is not surprising that many people would find the author's irreverent attitude about global warming offensive as the subject has taken on a quasi-religious aspect in some circles.
The book considers numerous other topics. Some conclusions I find rather plausible. For example that child safety seats for children older than 3 provide little benefit over using adult seat belts. Others less so. Such as the conclusion that children's exposure to TV caused an increase of 50% increase in property crime and a 25% increase in violent crime in the 1960s.
In general I suspect the author's arguments rely on assumptions which may or may not be true. An egregious example occurs at the start of the book. The authors wish to compare the risks of driving home drunk and walking home drunk. In order to do this they need to know the fraction of drunk pedestrians. With no justification at all they just assume this is the same as the fraction of drunk drivers. Perhaps this is true (or nearly true) but arguments based on these sorts of guesses are obviously not ironclad.
So in conclusion a fun read but should not be taken too seriously.
I have now read Superfreakonomics and my take is that it is similar to Freakonomics. That is, it is a provocative and entertaining read but should not be taken as the last word on the subjects it covers.
As with Freakonomics it covers a diverse set of topics somewhat peripheral to the main concerns of economists. It has nothing much to say about macroeconomics and the recent crisis.
The chapter on global warming has been widely criticized but I didn't find it highly objectionable. They do make a much criticized remark about the color of solar panels which, as I explain here , seems rather fundamentally misguided. However it is not central to their main point which is that it may be more sensible and feasible to find ways to mitigate the effects of CO2 emissions than to eliminate them. I see no justification for dismissing mitigation strategies out of hand as many global warming alarmists would prefer. However it is not surprising that many people would find the author's irreverent attitude about global warming offensive as the subject has taken on a quasi-religious aspect in some circles.
The book considers numerous other topics. Some conclusions I find rather plausible. For example that child safety seats for children older than 3 provide little benefit over using adult seat belts. Others less so. Such as the conclusion that children's exposure to TV caused an increase of 50% increase in property crime and a 25% increase in violent crime in the 1960s.
In general I suspect the author's arguments rely on assumptions which may or may not be true. An egregious example occurs at the start of the book. The authors wish to compare the risks of driving home drunk and walking home drunk. In order to do this they need to know the fraction of drunk pedestrians. With no justification at all they just assume this is the same as the fraction of drunk drivers. Perhaps this is true (or nearly true) but arguments based on these sorts of guesses are obviously not ironclad.
So in conclusion a fun read but should not be taken too seriously.
Monday, December 7, 2009
Climatology vrs Economics
The exchange between Hansen and Krugman regarding the relative merits of a carbon tax vrs cap and trade as a means of reducing CO2 emissions reminded me of one of the more annoying things about climate change alarmists. Which is many of the same people who will argue that laymen should defer to the expert opinion of climatologists are themselves completely unwilling to defer to the expert opinion of economists. People who happily expound silly and ignorant economic arguments have little grounds for objection when other people come up with silly and ignorant climatology arguments. I have never seen a convincing explanation for why climatologists should be granted more deference than economists.
Tuesday, November 10, 2009
Convenient falsehoods
I have been reading Obama's other book "The Audacity of Hope". It is pretty heavy going and I haven't finished yet. However I have completed chapter 5 "Opportunity" which contains some policy discussion. I disagree with much of it which doesn't mean too much as Obama and I have different priorities. What is more disturbing is that Obama seems to have difficulty critically evaluating proposals which appeal to liberal prejudices but won't actually work.
Obama uncritically supports ethanol on pages 169-170. Corn based ethanol is a good example of something which is superficially appealing but doesn't actually advance environmental priorities.
On page 161 Obama claims "... Recent studies show that the single most important factor in determining a student's achievement isn't the color of his skin or where he comes from, but who the child's teacher is. ...". Obama doesn't cite these studies so I can't specifically address them but this statement is contrary to numerous other studies that show the most important factor achievement in student achievement is the characteristics of the student and the next most important is the characteristics of his classmates. The quality of his teacher (within the range commonly found in American schools) hardly matters.
Finally on page 177 in discussing health insurance Obama claims "... The bigger the pool of insured, the more the risk is spread, the more coverage provided, and the lower the cost. ...". This misunderstands how insurance works. Pooling costs spreads them more equally but it doesn't reduce them. Pooling a bunch of high risks doesn't make them low risk or low cost.
This inability to recognize well intentioned nonsense won't matter too much if Obama appoints good advisers to handle the details. And Obama would hardly be the first President to be a big picture guy. Still Obama is the President we have at the moment and I would prefer a President with a better BS detector.
Obama uncritically supports ethanol on pages 169-170. Corn based ethanol is a good example of something which is superficially appealing but doesn't actually advance environmental priorities.
On page 161 Obama claims "... Recent studies show that the single most important factor in determining a student's achievement isn't the color of his skin or where he comes from, but who the child's teacher is. ...". Obama doesn't cite these studies so I can't specifically address them but this statement is contrary to numerous other studies that show the most important factor achievement in student achievement is the characteristics of the student and the next most important is the characteristics of his classmates. The quality of his teacher (within the range commonly found in American schools) hardly matters.
Finally on page 177 in discussing health insurance Obama claims "... The bigger the pool of insured, the more the risk is spread, the more coverage provided, and the lower the cost. ...". This misunderstands how insurance works. Pooling costs spreads them more equally but it doesn't reduce them. Pooling a bunch of high risks doesn't make them low risk or low cost.
This inability to recognize well intentioned nonsense won't matter too much if Obama appoints good advisers to handle the details. And Obama would hardly be the first President to be a big picture guy. Still Obama is the President we have at the moment and I would prefer a President with a better BS detector.
Thursday, October 22, 2009
Photovoltaic cell color
A silly controversy has arisen concerning the color of photovoltaic solar panels. Apparently a new book "SuperFreakonomics" contains the following (quoted here):
As an example he points to solar power. “The problem with solar cells is that they’re black, because they are designed to absorb light from the sun. But only about 12 percent gets turned into electricity, and the rest is reradiated as heat — which contributes to global warming.
Yglesias (among others) jumps on this statement (here and here) posting a photo of solar panels that appear to be dark blue and claiming:
... Still, it is worth dwelling a moment on the fact that their critique of photovoltaic literally rests on the idea that PV cells are black whereas in reality they’re usually blue:
First their critique depends on solar cells being dark (low albedo) not black. Perhaps they should have said "dark" instead of "black" but this is not a serious error. Especially since, Yglesias to the contrary, many cells are black. It is hard to judge color from photos because the cells are often reflecting the blue sky. See for instance this photo where the cells appear to be blue except at the upper right where they appear to be brown because they are reflecting brown branches instead of blue sky.
Anyway the critique is because solar cells are dark they may absorb more sunlight than whatever background they are replacing thus heating the earth. This can occur whether the cells are black or dark blue in appearance. However this effect is not important. Coal power plants also generate considerable waste heat as their thermal efficiency is only about 33%. It is doubtful that solar cells produce more excess heating per unit of electricity generated than the waste heat from coal power plants. And in any case the global warming concern with coal power plants is not their waste heat (which is not significant globally compared to solar heating) but the much greater long term heating effect from the CO2 emitted when coal is burned.
Does this mean photovoltaic solar cells make sense? Not really, they are inferior to wind turbines which also don't emit CO2 and are much cheaper .
As an example he points to solar power. “The problem with solar cells is that they’re black, because they are designed to absorb light from the sun. But only about 12 percent gets turned into electricity, and the rest is reradiated as heat — which contributes to global warming.
Yglesias (among others) jumps on this statement (here and here) posting a photo of solar panels that appear to be dark blue and claiming:
... Still, it is worth dwelling a moment on the fact that their critique of photovoltaic literally rests on the idea that PV cells are black whereas in reality they’re usually blue:
First their critique depends on solar cells being dark (low albedo) not black. Perhaps they should have said "dark" instead of "black" but this is not a serious error. Especially since, Yglesias to the contrary, many cells are black. It is hard to judge color from photos because the cells are often reflecting the blue sky. See for instance this photo where the cells appear to be blue except at the upper right where they appear to be brown because they are reflecting brown branches instead of blue sky.
Anyway the critique is because solar cells are dark they may absorb more sunlight than whatever background they are replacing thus heating the earth. This can occur whether the cells are black or dark blue in appearance. However this effect is not important. Coal power plants also generate considerable waste heat as their thermal efficiency is only about 33%. It is doubtful that solar cells produce more excess heating per unit of electricity generated than the waste heat from coal power plants. And in any case the global warming concern with coal power plants is not their waste heat (which is not significant globally compared to solar heating) but the much greater long term heating effect from the CO2 emitted when coal is burned.
Does this mean photovoltaic solar cells make sense? Not really, they are inferior to wind turbines which also don't emit CO2 and are much cheaper .
Friday, October 16, 2009
Westchester recycles
Westchester occasionally has recycling days at Croton Point Park. Two were scheduled for today and tomorrow so I took the opportunity to get rid of some plastic bags . They took #4 plastic bags (used for newspapers) as well as the usual #2 plastic shopping bags and gave me in return (for 20 or more plastic bags while supplies last) the free reusable bag pictured. It looks like cloth but is really plastic itself which seems a little ironic.
Tuesday, September 29, 2009
Solar vrs Wind
My last tirade about rooftop photovoltaic installations prompted a request for alternative suggestions.
The problem with rooftop solar photovoltaic electricity generation is that it costs too much. According to this a 4 KW rooftop photovoltaic installation costs $32000 or $8000 per KW. By comparison a 1.5 MW GE wind turbine like those in the Walnut Wind Farm appears to cost about $3000000 or $2000 per KW. So the wind turbine is 1/4 the cost per KW. It can be expected to have a better capacity factor as well. Note rooftop solar in particular will often have a lower capacity factor because of unfavorable location or orientation. So wind is much cheaper.
The above figures are rough estimates. For a sanity check see this account of a HSBC investment report which says in part:
What’s really interesting about HSBC’s new report is how solar power stacks up today against other ways of generating electricity—it doesn’t. That is, all the other power-generation technologies are in roughly the same neighborhood, even wind power—but not solar.
For instance, HSBC estimates costs per megawatt for different options: Combined-cycle gas, 43 euros; regular coal, 62 euros; onshore wind, 58 euros; nuclear power, 48 euros; geothermal, 43 euros. Photovoltaic solar power costs 290 euros per megawatt; concentrated solar power 181 euros.
Again wind power is much cheaper than photovoltaic solar power. In fact if we ignore the fact that wind is intermittent it is competitive with fossil fuels.
So wind is real, rooftop photovoltaic is just symbolic.
The problem with rooftop solar photovoltaic electricity generation is that it costs too much. According to this a 4 KW rooftop photovoltaic installation costs $32000 or $8000 per KW. By comparison a 1.5 MW GE wind turbine like those in the Walnut Wind Farm appears to cost about $3000000 or $2000 per KW. So the wind turbine is 1/4 the cost per KW. It can be expected to have a better capacity factor as well. Note rooftop solar in particular will often have a lower capacity factor because of unfavorable location or orientation. So wind is much cheaper.
The above figures are rough estimates. For a sanity check see this account of a HSBC investment report which says in part:
What’s really interesting about HSBC’s new report is how solar power stacks up today against other ways of generating electricity—it doesn’t. That is, all the other power-generation technologies are in roughly the same neighborhood, even wind power—but not solar.
For instance, HSBC estimates costs per megawatt for different options: Combined-cycle gas, 43 euros; regular coal, 62 euros; onshore wind, 58 euros; nuclear power, 48 euros; geothermal, 43 euros. Photovoltaic solar power costs 290 euros per megawatt; concentrated solar power 181 euros.
Again wind power is much cheaper than photovoltaic solar power. In fact if we ignore the fact that wind is intermittent it is competitive with fossil fuels.
So wind is real, rooftop photovoltaic is just symbolic.
Monday, September 21, 2009
Solar madness
I have complained before about the foolishness of encouraging residential photovoltaic installations. Recent posts by Yglesias and Drum about feed-in tariffs which obligate utilities to buy (at exorbitant rates) power produced by small scale photovoltaic generation have provoked me into revisiting the subject. According to Drum:
... And yes, it's a very good idea that makes small-scale solar installations economically worthwhile.
Actually it's a very bad idea as the highly subsidized small scale photovoltaic installations are only economically worthwhile for the owners. They are economically wasteful for society as a whole because they are highly uncompetitive in cost with other means of generating electricity.
It is ironic that Yglesias and Drum who once claimed to be members of the reality based community (in contrast to the delusional Bush administration) now give uncritical backing to liberal programs that are equally detached from reality. It appears Republicans and Democrats just live in different fantasy worlds.
... And yes, it's a very good idea that makes small-scale solar installations economically worthwhile.
Actually it's a very bad idea as the highly subsidized small scale photovoltaic installations are only economically worthwhile for the owners. They are economically wasteful for society as a whole because they are highly uncompetitive in cost with other means of generating electricity.
It is ironic that Yglesias and Drum who once claimed to be members of the reality based community (in contrast to the delusional Bush administration) now give uncritical backing to liberal programs that are equally detached from reality. It appears Republicans and Democrats just live in different fantasy worlds.
Friday, August 28, 2009
Cash for Clunkers
A few days ago Kevin Drum linked to this defense of the cash for clunkers program.
I have a copy of comments. First this:
I don't think the CEA factored in the economic benefit of lowering people's gasoline bill, which puts more money in their pocket to save or spend in their community.
makes no sense. Suppose you drive 12000 miles a year and turn in a clunker getting 15 mpg for a new car getting 25 mpg. This will reduce your yearly gasoline consumption from 800 gallons to 480 gallons. So you are saving 320 gallons a year. At 3$/gallon this is $960 per year. But you have had to pay for the new car. Even after a $5000 rebate this is probably $15000+ out of your pocket. So you will not have more money in your pocket anytime soon.
Second the goal of reducing oil consumption and CO2 emissions and the goal of stimulating the economy are fundamentally in conflict. To the extent this program revives economic activity it will increase oil consumption and CO2 emissions. This is not acknowledged.
I have a copy of comments. First this:
I don't think the CEA factored in the economic benefit of lowering people's gasoline bill, which puts more money in their pocket to save or spend in their community.
makes no sense. Suppose you drive 12000 miles a year and turn in a clunker getting 15 mpg for a new car getting 25 mpg. This will reduce your yearly gasoline consumption from 800 gallons to 480 gallons. So you are saving 320 gallons a year. At 3$/gallon this is $960 per year. But you have had to pay for the new car. Even after a $5000 rebate this is probably $15000+ out of your pocket. So you will not have more money in your pocket anytime soon.
Second the goal of reducing oil consumption and CO2 emissions and the goal of stimulating the economy are fundamentally in conflict. To the extent this program revives economic activity it will increase oil consumption and CO2 emissions. This is not acknowledged.
Wednesday, August 19, 2009
Rooftop windmills
What is it with environmentalists and rooftops? Not content with promoting silly rooftop solar projects I see they are now pushing rooftop windmills which have many of the same drawbacks. The linked article actually points out a lot of the problems with this idea but fails to draw the obvious conclusion.
It appears to me that rooftop windmills are effectively ornamental, like spoilers on ordinary cars. In which case you might as well save money by not actually including any power generation equipment.
It appears to me that rooftop windmills are effectively ornamental, like spoilers on ordinary cars. In which case you might as well save money by not actually including any power generation equipment.
Monday, August 10, 2009
Mother Jones
Last October Kevin Drum announced a contest to predict the results of the November elections. I entered and was fortunate enough to be one of two winners. My prize was a subscription to Mother Jones magazine. When I returned from Denver I enquired as to why I had yet to receive any issues. Apparently whatever the problem was has now been straightened out as I received my first issue (dated September + October 2009) today.
Mother Jones magazine is named for Mary Harris "Mother" Jones an early American radical and labor leader. As might be expected it is on the left. I had not read an issue for many years. It doesn't appear I have missed much, the issue I just received wasn't very interesting. The cover story was about a trendy bottled water, Fiji, which I had never heard of. Apparently it is not as good for the environment as it likes to claim. Not too surprising as importing bottled water from Fiji seems pretty absurd from an environmental standpoint.
Mother Jones magazine is named for Mary Harris "Mother" Jones an early American radical and labor leader. As might be expected it is on the left. I had not read an issue for many years. It doesn't appear I have missed much, the issue I just received wasn't very interesting. The cover story was about a trendy bottled water, Fiji, which I had never heard of. Apparently it is not as good for the environment as it likes to claim. Not too surprising as importing bottled water from Fiji seems pretty absurd from an environmental standpoint.
Wednesday, July 29, 2009
Iowa wind power
I recently drove on I80 through Iowa on my way to Denver and back. West of Des Moines the highway passes through a couple of wind farms with numerous wind turbines visible on both sides of the highway. They were a bit startling to encounter as they had not been there when I drove the same highway in 2007. I also encountered big trucks on the highway carrying wind turbine blades which are very long. Apparently wind power in Iowa is growing rapidly and Iowa has passed California and is now second to Texas in domestic wind power.
The photo was taken in late June and shows wind turbines in the Walnut Wind Farm near Walnut Iowa. The highway is I80.
Thursday, May 21, 2009
High speed rail
As I am afraid of flying I have taken long distance Amtrak passenger trains on several occasions. You might think then I would be sympathetic to the administration's plans for high speed passenger rail . However I am not. Amtrak is already highly subsidized without being particularly competitive for people who aren't afraid of flying. I doubt additional spending will increase volume much which means it would fail any reasonable cost benefit analysis. It is a bit distressing how disconnected these sorts of spending decisions are from any rational evaluation of technical merit.
Wednesday, May 20, 2009
Livermore windmills
Although I was born in Boston I think of Livermore California as my home town as my parents moved there when I was 3 and I lived there until I left for college.
One of the things Livermore is known for is the Altamont Pass Wind Farm which is in the hills just to the east. The windmills are quite visible from I580 as it traverses Altamont pass. They were constructed around 1980 which is after I had left but I would see them when returning home to visit.
This windfarm was a pioneer and encountered a number of problems. The tax credits that subsidized construction were based on capacity rather than actual power generated. Perhaps as a result many of the early wind turbines soon broke down and were not repaired. The resulting derelict windmills were quite noticeable and did not help wind power's image. It was also found that the windfarm was responsible for a large number of bird kills. In part this was because of the location but also because of the older turbine designs with small fast blades passing near the ground. It is believed more recent designs featuring larger slower blades higher off the ground are less dangerous to birds. The newer designs are also more efficient and are gradually replacing the original turbines. Wind power in general has been growing rapidly in recent years.
The picture was taken in July 2002 looking northeast from Patterson pass (which is on a back road a bit south of I580).
Monday, April 27, 2009
Climate change and fossil fuels
In the 90s I got interested in climate change induced by burning fossil fuels and participated in sci.environment discussions about it. Here is my layman's take.
Simple models predict that increasing the concentration of CO2 in the atmosphere will cause the average temperature at the surface to increase. Burning fossil fuels adds CO2 to the atmosphere and measurements show that in the short term about half of it remains there increasing the concentration of CO2 in the atmosphere. Observations also show that the earth's surface has been warming. The amount of the warming is roughly consistent with the amount predicted by simple models. So it is plausible that burning fossil fuels has warmed the earth and will continue to do so.
There is some room for doubt as the simple models leave out a lot of things and more complicated models are difficult to validate. So detailed predictions are quite untrustworthy. Still there are real reasons for concern even if it is not absolutely certain that major problems will result.
So what can be done? It appears that in the long run the impact will mostly depend on how much of the world's supply of fossil fuels gets burned. Within limits the rate of burning doesn't matter too much. So conservation doesn't help much if it just delays the time it takes to exhaust the earth's supply of fossil fuel. Some fossil fuel has to be left in the ground.
The three main fossil fuels are oil, natural gas and coal. The oil will run out first, followed by the natural gas and finally the coal. I see little chance that all the oil and natural gas won't get burned. There is some chance that we won't burn all the coal. Currently coal is mainly burned to generate electricity and there are alternative ways such as nuclear power to generate electricity. They are more expensive but not impossibly so if limiting climate change becomes imperative.
A key turning point will occur when the oil runs out. It is technically feasible to make oil from coal. Currently oil from coal is not cost competitive but this will change as the oil runs out. If this leads to large scale conversion of coal to oil it seems inevitable that all the coal will be eventually burned. In which case we best hope the climate effects are not too costly or that some sort of active mitigation is feasible.
Simple models predict that increasing the concentration of CO2 in the atmosphere will cause the average temperature at the surface to increase. Burning fossil fuels adds CO2 to the atmosphere and measurements show that in the short term about half of it remains there increasing the concentration of CO2 in the atmosphere. Observations also show that the earth's surface has been warming. The amount of the warming is roughly consistent with the amount predicted by simple models. So it is plausible that burning fossil fuels has warmed the earth and will continue to do so.
There is some room for doubt as the simple models leave out a lot of things and more complicated models are difficult to validate. So detailed predictions are quite untrustworthy. Still there are real reasons for concern even if it is not absolutely certain that major problems will result.
So what can be done? It appears that in the long run the impact will mostly depend on how much of the world's supply of fossil fuels gets burned. Within limits the rate of burning doesn't matter too much. So conservation doesn't help much if it just delays the time it takes to exhaust the earth's supply of fossil fuel. Some fossil fuel has to be left in the ground.
The three main fossil fuels are oil, natural gas and coal. The oil will run out first, followed by the natural gas and finally the coal. I see little chance that all the oil and natural gas won't get burned. There is some chance that we won't burn all the coal. Currently coal is mainly burned to generate electricity and there are alternative ways such as nuclear power to generate electricity. They are more expensive but not impossibly so if limiting climate change becomes imperative.
A key turning point will occur when the oil runs out. It is technically feasible to make oil from coal. Currently oil from coal is not cost competitive but this will change as the oil runs out. If this leads to large scale conversion of coal to oil it seems inevitable that all the coal will be eventually burned. In which case we best hope the climate effects are not too costly or that some sort of active mitigation is feasible.
Thursday, April 16, 2009
Plastic shopping bags
Many environmentalists consider plastic shopping bags a flagrant example of environmentally damaging wasteful consumption. I have a bit more sympathy for this view now that I am eating meals at home. Plastic bags do seem to accumulate at a remarkable rate from food shopping and it does seem a bit wasteful to just throw them out. However I suspect that considered objectively they aren't actually that wasteful. A single gallon of gas is probably the equivalent of 100 plastic bags in terms of resource consumption. So there are probably more important things to worry about.
Friday, April 10, 2009
Feed-in tariffs
Bradford Plumer has a post discussing rooftop solar. It mentions Gainseville Florida which has adopted a feed-in tariff which obligates the local utility to buy solar electricity from anyone who produces it. This has produced a flurry of solar power installations which is described as "stunning". However it is considerably less stunning when one learns the tariff has been set (for 20 years for installations through 2010) at the exorbitant rate of .32$/KWh. This means the program is symbolic as it will only be affordable as long as the amount of solar power generated is a small fraction of the power the utility sells.
As I posted earlier I think rooftop solar makes no sense.
As I posted earlier I think rooftop solar makes no sense.
Sunday, March 29, 2009
Compact Fluorescent Light Bulbs
The push to replace incandescent light bulb with more energy efficient compact fluorescent light bulbs has led to some complaints. I have not had any trouble myself, none of the fluorescent bulbs which I have installed have failed. I have been careful to use them as directed. In particular I have not put them in closed ceiling fixtures where they might fail due to excessive heat. It is unfortunate that they have this limitation as replacing the bulbs in my ceiling fixtures is a bit of a job which it would be nice to minimize. Rumor has it there are plans to effectively ban incandescent bulbs, this problem best be fixed first.
The compact fluorescent bulbs do take a second or so to come on which is a little disconcerting at first. And they may take a couple of minutes to achieve full brightness which I didn't initially realize leading me doubt that they were actually as bright as claimed.
The compact fluorescent bulbs do take a second or so to come on which is a little disconcerting at first. And they may take a couple of minutes to achieve full brightness which I didn't initially realize leading me doubt that they were actually as bright as claimed.
Tuesday, March 17, 2009
Electricity
In a previous post I complained that the push to solar panels on rooftops didn't make a lot of economic sense. This is part of a more general problem, you have to be careful when comparing different methods of generating electricity.
Because the demand for electrical power varies over time and because there is no really good way currently known to store electrical power the system has to able to vary generator output to match demand. This means generators that can be throttled to generate power as needed are superior to generators whose power output varies depending on external factors not under the control of the operator. Therefore it can be misleading to compare electrical generation methods just based on cost per kwh as not all kwh are equally valuable.
Unfortunately wind and solar panel power generators fall into the less valuable category whose output varies outside the control of the operator. This means they are not as competitive with fossil fuel generators as they might seem just based on per kwh cost. This effect will become worse as wind and solar panel power account for a greater fraction of total power generated since the remainder of the system will have to accommodate greater swings in demand.
Now these problems are not insurmountable. Power can be stored albeit at considerable cost. However switching away from fossil fuel generators is not going to be easy or cheap.
Because the demand for electrical power varies over time and because there is no really good way currently known to store electrical power the system has to able to vary generator output to match demand. This means generators that can be throttled to generate power as needed are superior to generators whose power output varies depending on external factors not under the control of the operator. Therefore it can be misleading to compare electrical generation methods just based on cost per kwh as not all kwh are equally valuable.
Unfortunately wind and solar panel power generators fall into the less valuable category whose output varies outside the control of the operator. This means they are not as competitive with fossil fuel generators as they might seem just based on per kwh cost. This effect will become worse as wind and solar panel power account for a greater fraction of total power generated since the remainder of the system will have to accommodate greater swings in demand.
Now these problems are not insurmountable. Power can be stored albeit at considerable cost. However switching away from fossil fuel generators is not going to be easy or cheap.
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