Submitted by brad on Tue, 2009-05-05 16:45.
The earlier post on whether solar gives the best bang per buck in greening our electricity ran into some opposition, as I expected. Let me consider some of the objections and issues.
As a recap, I put forward that if we are going to use our money and time to attain greener electricity, what matters is how many MWH we take off the “dirty” grid (particularly coal plant output.) I measured various ways to do that, both green generation and conservation (which do the exact same thing in terms of grid offset) and worked out their cost, the MWH they take off the grid and thus the cost per MWH. Solar PV fares poorly. Converting incandescent bulbs to fluorescent in your own home or even other people’s homes fares best.
A big part of the blame lies on the fact that crystalline silicon is an expensive way to make solar cells.
It is, however, quite common since many PV plants started with technology from semiconductor fabrication.
One frequent objection is that purchasing expensive solar panels today encourages the market for solar panels, and
in particular better solar panels. Indeed, panel makers are generally selling all they can make. Many hope that this demand will encourage financing for the companies who will deliver panels at prices that make sense and compete with other green energy.
I call this being “evangelical green.” Leading by example, and through encouraging markets. While I understand the logic, I am not sure I accept the argument. read more »
Submitted by brad on Mon, 2009-03-16 15:39.
Last week I wrote about what I consider the main goal of green electricity
efforts, namely to stop burning coal. You can do that, to
some extent, by removing demand from the grid in places where the grid is
coal-heavy. Even in other places, removing demand from the grid will be
fairly effective at reducing the production of greenhouse gases.
Update: Since this article a flood of cheap solar panels from China has been changing some of the economics discussed here. I have not altered the article but some of its conclusions deserve adjustment.
No matter what you do — conserve, or put up solar or wind — your goal is
to take power off the grid. Many people however, consciously or unconsciously
take a different goal — they want to feel that they are doing the green
thing. They want their electricity to be clean. This is actually a
dangerous idea, I believe. Electrons are electrons. In terms of reducing
emissions, you get the exact same result if you put a solar panel on your
house than if you put it on your neighbour’s house. You even get a better
result if you put it on a house that’s powered by a coal plant, so long as
you also reap the benefit (in dollars) of the electricity it makes.
People don’t like to accept this, but it’s much better to put a wind
turbine somewhere windy than on your own house. Much better to put a solar
panel somewhere sunny than on your own house. And much better in all cases
if the power you offset is generated by more by coal than at your house.
However, the real consequences are much deeper. The following numbers
reveal it is generally a bad idea to put up solar panels at all, at least right
now. That’s because, as you will see below, solar panels are a terrible
way to spend money and time to make greener electricity. Absolutely
dreadful. Their only attribute is making you feel good because they
are on your roof. But you should not feel good, because you could (in theory, and I believe with not much work in practice) have
made the planet much greener by using the money you spent on the panels
in other ways.
The true goal is to find the method that provides the most bang per buck in removing load from the dirty grid.
Keep reading to see the math and a spreadsheet with some very surprising numbers about what techniques do that the best. read more »
Submitted by brad on Wed, 2009-02-25 15:47.
There are many ways to go green, though as I have identified, the vast bulk of the problem is in just a few areas — personal transportation, electrical generation, building design/heating/cooling and agriculture.
While those who focus on CO2 work from the fact that both Natural Gas and Coal, which produce 70% of the USA’s electricity, emit CO2, coal is a much bigger villain.
- Coal is 50% of the US electricity supply, gas is only 20%.
- Coal produces all sorts of nasty pollution in addition to CO2, including sulfur products for acid rain, radioactive elements and worst of all, fine particulates, which are major killers of the elderly.
- Coal mining is highly destructive, and lives are regularly lost.
- Coal power plants are not as efficient as gas ones. This is both due to the simplicity of gas plants, and the fact that many coal plants are older. The worst coal plants are almost twice as inefficient, and emit more than twice the greenhouse gasses, as gas plants. Some modern coal plants are a bit better, but the gap is still large.
- Coal plants are slower to turn off and on than gas plants. They are better than nuclear plants.
- There are lists of more at other web sites.
The problem is that coal is cheaper. Particularly once you have the coal plant. I’ve seen estimates all over the map but many suggest that the fuel cost of coal electricity is in the range of just 2-3 cents per kwh, and 1-2 cents more for gas fired. Hydro doesn’t really have a fuel cost, and while nuclear does, it’s a much harder cost to measure.
That cheaper price has given us a 50% coal electric infrastructure. With hydro, the amount of water that is going to flow through your plant is fixed by the weather. You want to use all of it (ideally at peak times) and keep your reservoirs at the same level each year. Nuclear is hard to start and stop, so you use it for base load. It’s expensive to build, but you want to use the plants you have to their capacity.
So my understanding is that if demand on the grid goes down (say, because somebody puts solar panels on their roof or conserves energy) the first reaction of the power companies is to burn less natural gas, because it’s a bit more expensive, and the easiest thing to cut back on. However, the power grids (there are 3 main ones in the USA and various sub-grids) are not superconductors, so due to line losses, it is cheaper to reduce output on the plants closest to the reduced demand. So the situation varies a lot.
All the power sources have their downsides. Nuclear’s are well known and controversial. Hyrdo is clean but destroys river systems and habitats. Gas emits CO2 but is clean as far as fossil fuels go. (Leaks of it also emit methane.) Oil is barely used. Coal’s only upside is its price, and the existing base of coal plants and mines.
So while it is good to look at reducing all energy production that has problems, right now if you want to do something green, it’s a fair, if broad statement to say that the best way to do it is to stop the burning of coal.
What that means for people who don’t run power companies is that reducing electrical demand in a sub-grid that is heavy with coal (such as Chicago or West Virginia) is a fair bit better than doing it in a coal-light sub-grid like California. And doing it in a place like China would be even better.
There is an irony here. Californians tend, on average, to be more eco-conscious than others. This is the birthplace of the Sierra Club after all. And because it is natural for people to focus on where they live, you see lots of effort to conserve energy or use alternative energy in California. But the same efforts would get 65% more bang for the buck if they took place in the midwest or southwest. This calculator claims to report the CO2 cost of electrical production in each zip code. It uses numbers from the North American Electric Reliability Council (NERC) for different sub-grids:
NERC region acronym
NERC region name
Alaska Systems Coordinating Council
Electric Reliability Council of Texas
Florida Reliability Coordinating Council
Hawaiian Islands Coordinating Council
Midwest Reliability Organization
Northeast Power Coordinating Council
Reliability First Corporation
SERC Reliability Corporation
Southwest Power Pool
Western Electricity Coordinating Council
Combined National Average
This conclusion will be disturbing for some. If you’re considering putting a solar panel on your roof in California, you would do 65% better at reducing pollution if you put the panel up on a roof in Arizona. (Actually a little better as Arizona has better sun.) If you are considering putting a solar panel up in Vermont, you would do almost 3 times better to put it in the southwest, since not only is their power twice as dirty, but they get a lot more sun.
What you would not get is the personal satisfaction of seeing panels on your roof and feeling that you personally are green. But there really is no such thing as solar electrons. Electricity is just electricity. There’s a big grid (and not being grid tied is really non-green) and the most you can do is improve how green the grid is. It doesn’t make a difference if you put the solar panels up on your house or a house across town. And it makes a positive difference if you put it up where it will have the best effect. It just doesn’t feel as good.
Now, can you go put panels on another roof? Not at present. But it certainly could be made to happen. In fact, oddly, the tax breaks are better for corporations who put up panels then they are for individuals, though this may change with new laws. Leaving out rebates and credits, a business could be set up to offer people in high-sun, high-coal areas subsidized solar power on their houses. The money they would have paid their power company could go instead to pay your power company as you continue to buy energy from your cleaner grid, having reduced demand in their dirtier grid. This works best when the power prices are similar — with PG&E’s “tiered” pricing in California this may not pan out.
It would also be possible to set up green power companies that put up green power plants in coal-heavy areas. They sell their power there, and the income would flow to investors on greener grids to pay for their grid power.
However, in a future blog post you’re going to learn something even more surprising, if you’ve been a booster of solar. It’s that it is a poor idea to put up solar panels at all, even in the coal-heavy, sunny southwest. In fact, it’s one of the worst ways you could use your money to green the planet. Stay tuned.
Submitted by brad on Tue, 2008-10-21 19:25.
We need renewable energy, such as solar power. Because of that, companies are working hard on making it cheaper. They can do this either by developing new, cheaper to manufacture technologies, cheaper ways of installing or by simply getting economies of scale as demand and production increase. They haven’t managed to follow Moore’s law, though some new-technology developers predict they someday will.
However, there is a disturbing paradox in these activities. Unlike computers, it does not make financial sense to buy solar (or any other low or zero operating cost energy technology) if you have reasonable confidence the price is going to improve at even modest rates.
Imagine you have an energy technology with effectively zero operating cost, like PV panels. Let’s say that it’s reached the point that it can match the price of grid power over a 20 year lifetime. That means that, if it costs $10,000, it costs $72 per month or $872 per year at a 6% cost of funds. (Since $872 buys 9688 kwh at the national average grid price of 9 cents, that means you need a 4800 watt PV system to match the grid which is hard to do for $10,000 but someday it won’t be.)
But here’s the problem? Let’s say that it’s very reasonable to predict that the cost of solar will drop by more than 9% over the coming year. That’s a modest decrease, entirely doable just with increased production, and much less than people hope from new technology. That means that your $10,000 system will cost you $9,100 to buy a year down the road. Since we are talking about a grid-equivalent price system, the cost of grid power in this example is $872. So you can buy the power from the grid, wait a year, and save money. The more you expect the price of solar to drop, the more it makes financial sense to delay. (Note that at this lower price the system is now beating the grid. What matters really is whether the dollar cost reduction of the solar system exceeds the dollar cost of the grid electricity purchased.)
Indeed, if you predict the cost-drops will continue for many years, it sadly does not make sense to buy for a long time. Effectively until your predictions show that the cost decrease of the system no longer exceeds the cost of the power generated by it. That has to eventually come some time, since as it gets very cheap it can’t really drop in price by more than the cost of grid power, especially while there are physical install costs to include in the mix. But it can certainly drop by 6% per year for a decade, which would take it down to half its original cost. Possibly longer.)
Now, you will note I speak of the financial cost. This ignores any motivations based on trying to be greener. This is the analysis that would be done by somebody who is simply looking for the best price on power. This is frankly how most people think. This can be altered by both government incentives to buy solar and by externality taxes on polluting grid power.
This also applies not simply to solar, but any technology where you invest a lot of money up front, and have close to zero operating cost. Thus wind, geothermal and certain other technologies face the same math. Even nuclear to some extent.
All of this also depends in your confidence in your predictions. The more uncertain your predictions of price drops, the more you might be pushed in other directions to obtain certainty.
The paradox is this. We may be in a situation where solar is competing with grid power, and many are poised to buy it. If many do buy it, economies of scale will drive the price down. Thus, nobody should buy it, as they should wait for that price decrease! But if nobody buys it, it won’t decrease in price as much, creating a chaotic system. Some will buy it (to be green, for example) so it’s not a total loss, but it becomes harder to understand.
We’re used to dealing with computers, which reduce in price not just 6% a year but 40 to 50%. We’ve all felt the dilemma over whether to buy a computer or other electronic device that will lose its value so quickly, or whether to wait. However in that case, if we wait, we don’t get our nice new computer or camera, and thus lose out. You can wait forever which makes no sense. This is not the same logic with power. With power, we’re talking about a commodity that you can buy elsewhere, and get all the benefit — for less than the depreciation on what you considered buying.
What can keep the market for solar going if it looks like it will drop in price? Well, first of all, many people want to buy solar other than to save money. (Indeed, only a few people today with high local electricity prices and fat government rebates can save money with it.) Secondly, it seems that few people, even if their goal is to save money, think this way. And if they do, they are uncertain of their predictions, and would rather get the solar now than risk grid power going up or solar going down. But curiously, it remains the case that if people make predictions of cheap solar in the near term, and they are believed, it should kill most sales of solar in the present term.
Submitted by brad on Thu, 2008-07-17 17:36.
Last weekend I attended a small gathering in the Grand Tetons where Boone Pickens came to promote his new energy plan. The billionaire oilman is spending $56M of his own money per year on ads for this plan, and you will see them if you watch ads. Otherwise they are at his Pickens Plan web site.
Pickens’ thesis is that the most ruinous thing in energy is the 700 billion dollars per year the USA spends importing oil, a number destined to go up to a trillion. He thinks the price will continue to rise, simply because demand now exceeds supply, and that supply can’t be radically increased — ie. he believes in the Peak Oil thesis. He doesn’t seem to mind burning the fuel so much as importing it, which is giving trillions to other nations at U.S. expense. He is happy to support any domestic oil production, such as offshore, as good because it reduces the import numbers, but doesn’t think these are long term solutions.
His main goal is to get cars off of oil and onto domestic energy. He thinks the best way to do that is with LNG (liquid natural gas) or compressed natural gass cars. He says they have been far cheaper than gasoline for some time — half the cost — but that this was not enough to make people care enough to switch. Any new fuel has a chicken and egg problem when it comes to fueling infrastructure, something that Robocars solve, by the way.
To do that, he needs to take natural gas from the power grid. NG produces 20% of U.S. electricity. So he is promoting wind and solar. The wind in a high-wind corridor that runs up the center of the country, the solar in the sun-belt (the southwest and California.)
It’s an interesting plan, and he points out that whatever flaws you may find in it, at least it is a plan, something that’s been lacking for some time.
That said, some notes:
- Getting power from the wind belt is not easy. In spite of what you may think, there is no national power grid, and certainly no infrastructure to power the coasts from the middle. This would have to be built, and would be very expensive. Pickens admits this. New technology of high voltage DC transmission could help.
- I’m not sure that adding wind power would free up NG for cars. I think we would just use more electricity if you increase the supply. That’s what we do.
- Indeed, from a pollution standpoint, we would be far better to shut down coal plants when the wind/solar comes online, but we won’t, because it’s cheap. Only moving cars to NG (or electric or other domestic energy source) reduces oil imports.
- Pickens is buying a pretty old-school marketing campaign with his spare millions. We all thought he could have done it for far less with clever use of the internet and a more modest TV budget.
- The 700 million isn’t all bad, of course. The largest source of imported oil is Canada. Saudis are #2 and Mexico is #3. Venezuela is #4, though it recently switched from from a friendly ally to an unfriendly.
Still, it’s good that Pickens will get people talking about this. NG for cars is already a reasonably popular fleet fuel. New extraction technologies have opened up a lot of new sources of NG of late. Of course, burning NG still emits CO2, though not much else, once refined to more pure methane, it’s the cleanest fossil fuel.
Submitted by brad on Fri, 2008-06-20 17:01.
In light of my recent studies into transportation energy efficiency I’ve learned a lot more about the energy budget of the USA and the world.
One conclusion from those investigations is that if you are serious about greening the world, there are really only a few areas worthy of serious effort. Yes, you can make a difference anywhere, and if all you’re going to make is a personal difference there are scores of things you can change in your life to reduce your own footprint. But if you want to make a real difference, by affecting groups of people and whole sectors, the choices are few and clear.
The footprint of cars and light trucks is so large — 63% of transportation energy — that I am tempted to say that if you’re not working on cars, you’re not working on being green. Freight trucks are another 17% of transportation energy. Transit is in the noise — it only has bearing in that it can, in the rare cases it is done well, take people out of cars to make their travel greener. These numbers are huge, so of course differences can be made in the other transportation areas, but if the question of cars and trucks is not fixed, the rest of transportation barely matters in comparison. The one exception is jet airliners, which at 9% take the next largest shot of the energy budget.
However, transportation is “only” 28.5% of the total U.S. energy budget, so it’s not quite the only place to go. However, adding the energy cost of manufacturing cars bumps them up to around a third.
The rest of the energy budget is split 32% industrial (including making cars,) 18% commercial and 21% residential. But 70% of residential energy, 78% of commercial energy and 34% of industrial energy comes from electricity. (Just .3% of transportation energy does, but that will change if we move to electric cars.)
All these energy uses are quite diverse. There are many targets to attack, all worthy within their own scope but there’s only one truly big target, and that’s electricity generation. In the USA that’s currently 50% coal and 20% natural gas. So if you’re working to fix this — with renewable energy or nuclear — then you’re working on one of the big problems. Right now hydro and nuclear are the largest non-fossil power generators. All the other renewables are currently in the noise.
One of the biggest commercial users of energy is agriculture. It’s estimated that the equivalent of 400 gallons of gasoline per person in the USA is used to grow our food. Part of that is that 5% of all natural gas goes into making fertilizer. This makes this a particularly large non-electrical target. In addition, most of the methane we emit comes from livestock. I need to do more research but currently agriculture looks like another big target.
So it’s not quite true that if you’re not working on cars, you’re not working on being green, but it does suggest that projects like the Automotive X-Prize and DARPA Grand Challenge are among the most important projects in the world for going green.
Submitted by brad on Mon, 2008-06-09 20:11.
As part of my research into robotic cars, I’ve been studying the energy efficiency of transit. What I found shocked me, because it turns out that in the USA, our transit systems aren’t green at all. Several of the modes, such as buses, as well as the light rail and subway systems of most towns, consume more energy per passenger-mile than cars do, when averaged out. The better cities and the better modes do beat the cars, but only by a little bit. And new generation efficient cars beat the transit almost every time, and electric scooters beat everything hands down.
I encourage you to read the more detailed essay I have prepared on whether green U.S. transit is a myth. I’ve been very surprised by what I’ve found. It includes links to the sources. To tease you, here’s the chart I have calculated on the energy efficiency of the various modes. Read on, and show me how these numbers are wrong if you can!
I have added a follow-up post on the comparison between lots of small personal ultralight vehicles and larger shared transit vehicles.
Note: If you want to comment on the cyclist figure, there is different thread on the fossil fuel consumption in human food which details these numbers and invites comments.
Submitted by brad on Wed, 2008-06-04 16:58.
A subject of debate in environmental circles revolves around whether the successful 70s opposition to nuclear power was a wise idea. At the time, it was never thought of as a choice between nuclear and coal, it was thought of simply as fear of the dangers of nuclear. Unexpectedly, it ended up being a push for coal, which of course kills far more people and emits more radiation than U.S. nuclear plants ever have.
But today, the big question remains of what to do with the waste. As I wrote earlier, if you accept the most dire global warming predictions, the worst waste predictions are quite tame by comparison.
But here’s another way to examine the question, in terms of moral duty. Nuclear power has a serious waste concern, and it is as yet uncertain how best to deal with it. But now, fossil fuels also have a serious waste concern from both particulates and CO2, and it is also uncertain how to deal with it. However, in many circles, there is very high confidence that there are extreme dangers from CO2.
Here’s the difference: What is done by the CO2 we emit is done to the whole world. The problems caused by it will be borne by the whole world. In fact, there are good arguments that while the USA and developed world produce most of the CO2 emissions, they will suffer a minority of the damage. The problems of nuclear power, however, largely remain within the country. If there is a nuclear waste problem, it’s our problem. If there is a meltdown, it’s our land that is ruined, our people killed.
(At least in places like the USA where there are not foreigners living near/downwind from most nuclear reactors.)
Both choices, nuclear and fossil have predicted risks. But very different sets of people who pay the price. This makes it hard to say that the moral choice is fossil fuel over nukes.
Well, of course, the even more moral choice is to cut back on energy use and develop cleaner power. And both of those tasks are being worked hard upon. But it would be foolish to just assume we will reach quick success on this, and not still have to make the nuclear vs. coal/fossil choice for a few decades. Perhaps we won’t, but can we bet on it?
As always, there are some complicating issues. Nuclear power sometimes begets nuclear weapons, so it can’t be used everywhere. And it can certainly be argued that the problems of nuclear waste are visited not upon foreigners, but upon our descendants. But again, they are our descendants, and will still have more right to foist problems on them than we do on remote peoples. This argument could also apply to environmentally destructive hydro power, which again destroys our river valleys and animals, not somebody else’s.
It is, of course, for this very reason that fossil fuels have had some advantages. Almost all pollution has been driven by the fact that you can foist your waste problems off on somebody else. If they lived in the same legal jurisdiction, they eventually got power to stop you, but it always took a while.
Submitted by brad on Sat, 2008-03-29 14:20.
It was good to see a major newsmagazine like Time do its cover story on the corn ethanol scam this week. I’ve been worried about corn as a source of biofuel for some time. So far, it makes no sense, and is only used because of the power of the corn lobby and senators from agricultural states. I’ve read various arguments (all with political agendas) about just how much petrofuel is burned in order to make corn based ethanol. Some figures calculate it takes more petrofuel than you get ethanol out — in other words, by putting ethanol in your car, as we all do 10% during the summer in California, you’re actually burning more fossil fuel than you would otherwise. E85 (85% ethanol) is even worse. Other figures, supported by the corn ethanol lobby, say it is not nearly that bad, but even with their best numbers they can only make it a modestly positive gain.
It’s hard to work out who to believe, but the most telling fact I learned was this: None of the corn-ethanol producers run their whole system — tractors, trucks and ethanol conversion plants — on their own product. Since they should be able to get their own product at a discount, this makes no sense.
Adding to the confusion is that a gallon is not a gallon. In particular, a gallon of ethanol has only 70% of the energy of gasoline, so you’ll only get 70% of the mileage. (Diesel has 12% more energy per gallon than gasoline, which is the real reason why diesel cars get better mileage. They aren’t really much better per kg of carbon burnt.)
The only ethanol source that’s provably positive is sugar cane. More on that later. There are a lot of worthwhile efforts to develop ethanol from cellulose (like switchgrass) or algae, and they could make a real difference. The corn lobby is not that excited about those.
In spite of this, we watch ads describing E85 cars as green, when they are anti-green. People see E85 priced 19% cheaper than gasoline (national average) and think it’s some bargain. It isn’t.
Corn for ethanol is driving up the price of corn. That make more land get converted to corn. In turn, Time found, that was making shifts in land use in Brazil, and the result was that more land in the rainforest is being cleared (often by burning) than ever before. But now there’s a horrible irony — all this is happening because people imagine they are doing something green by using corn based ethanol. (Brazil uses sugarcane for its own ethanol production.)
Now on to sugar. In the USA, sugar costs more than twice as much as the rest of the world. That’s why Coke from Mexico has real sugar, because sugar is cheap there. In the USA it has — surprise, surprise — high fructose corn syrup.
Sugar is expensive in the USA because there are import taxes and quotas that benefit a fairly small number of families who are really sugar agribusinesses. Those families love their little monopoly on sugar production of course, and fight to defend the laws that provide it. But the corn lobby joins in to help of course, to sell more high fructose corn syrup. (Though now HFCS has dropped in price to be closer to the world sugar price so we would not entirely get rid of it.)
We need to:
- Immediately remove laws that require the addition of ethanol to gasoline. Find something besides MTBE or ethanol if need be.
- Clearly label corn based ethanol and E85 as lower mileage and non-green, punishing those who advertise it as green. Or make them run their machines on their own ethanol and publish the numbers.
- Put more into research of truly net-positive biofuels that don’t use existing crop-lands or involve clearing of forested land, and use them only if we can show they are net-green.
- Abandon sugar quota and sugar tarrifs
- Consider growing more sugar cane if we want biofuels, but again, factor in the cost of the crops displaced or land cleared.
Biofuels are a hard problem. Using recycled veggie oil is great, and we’ve run our Burning Man camp on that, but there is only so much of that out there. Even if we converted all our croplands to biofuels, we would only modestly dent our fuel consumption. This suggests that only solutions like algae or wild grasslands could work.
Submitted by brad on Tue, 2008-03-25 18:47.
Note to new readers: This article explores the consequences of using so much fuel to produce our food. If you come out of it thinking it’s telling you to drive rather than get some exercise, you didn’t read it! But if you like surprising numbers like this, check out the rest of my Going Green section and other sections.
In my growing research on transportation energy economics, I’ve come upon some rather astonishing research. I always enjoy debates on total cost analysis — trying to figure out the true energy cost of things, by adding in the energy spent elsewhere to make things happen. (For example, the energy to smelt the metals in your car adds quite a bit to its energy cost.)
Humans are modestly efficient. Walking, an average person burns about 100 Calories per mile at 3mph, or 300 per hour, while sitting for the same hour burns around 80 Calories just keeping you warm. In other words, the walking 3 miles uses about 220 extra Calories. Calories are kilocalories, and one Calorie/kcal is about 4 BTUs, 4200 joules or 1.63 watt-hours.
While walking 1 mile burns an extra 74 Calories, on a bicycle we’re much better. Biking one mile at 10mph takes about 38 extra calories over sitting. Again, this is the extra calories.
A gallon of gas has about 31,500 Calories in it, so you might imagine that you get 815 “mpg” biking and 400 “mpg” walking. Pretty good. (Unless you compare it to an electric scooter, which turns out to get the equivalent of 1200 mpg from pure electricity if you allow the same perfect conversion.)
But there’s a problem. We eat, on average about 2700 Calories/day in the USA, almost all of it produced by agribusiness. Which runs on fossil fuels. Fossil fuels provide the fertilizer. They run the machines. The process and transport and refrigerate the food. In many cases our food — cows — eats even more food produced with very high energy costs.
I’ve been digging around estimates, and have found that U.S. agriculture uses about 400 gasoline-gallon equivalents per American. Or 1.1 gallons per day, or about 10 Calories (40 BTU) from oil/gas for every Calorie of food. For beef, it’s far worse, as close to 40 Calories of oil/gas (160 BTU) are used to produce one Calorie of beefy goodness.
You can see where this is going. I’m not the first to figure it out, but it’s worth repeating. Your 3 mile walk burned 220 extra Calories over sitting, but drove the use of 2,200 Calories of fossil fuel. That’s 1/14th of a gallon of gasoline (9oz.) So you’re getting about 42 miles per gas-gallon of fossil fuel.
If you eat a lot of beef or other livestock, and want to consider your incremental food as having come from beef, it’s around 10 miles per gallon. A Hummer does better!
So yes, if you drive your Prius instead of walking it’s going to burn less fossil fuel. If 2 people drive in a more ordinary car it’s going to burn less fossil fuel than both of them walking.
Biking’s better. The average-diet cyclist is getting 85 miles per gallon of fossil fuel. Still better for 2 to share a Prius. The beefeater is, as before only 1/4 as good. At 21mpg he’s better than a Hummer, but not that much better.
This is a fuel to fuel comparison. The fuel burned in the cars is the same sort of fuel burned in the tractors. It has extra energy costs in its extraction and transport, but this applies equally to both cases. And yes, of course, the exercise has other benefits than getting from A to B. And we have not considered a number of the other external costs of the vehicle travel — but they still don’t make this revelation less remarkable. (And neither does this result suggest one should not still walk or bike, rather it suggests we should make our food more efficiently.)
And no, picking transit isn’t going to help. Transit systems, on average, are only mildly greener than cars. City buses, in fact, use the same energy per passenger mile as typical cars. Light rail is sometimes 2 and rarely even 3 times better than cars, but in some cities like San Jose, it uses almost twice as much energy per actual passenger than passenger cars do.
Taking existing transit vehicles that are already running is green, of course, but building inefficient lines isn’t.
Many people take this idea as a condemnation of cycling or exercise. It isn’t. Cycling is my favourite exercise. It is a condemnation of how much fossil fuel is used in agriculture. And, to a much lesser extent, a wakeup call to people who eat the average diet that they can’t claim their human-powered travel as good for the planet — just good for them. What would be good for the planet would be to eat a non-agribusiness diet and also walk or bike. How your food is farmed is more important though, than where it comes from. It’s the farming, not the shipping, that’s the big energy eater.
Obviously if you were going to need the exercise anyway, doing it while getting from A to B is not going to burn extra oil. Human powered travel well above the need to exercise is the only thing that would hurt, if fueled by U.S. agriculture. And eating a high calorie diet and not exercising would be just as bad.
What’s not wrong with these numbers
As I note, since most of us need to exercise anyway, this is not at all a condemnation of walking and cycling, but rather of the amount of fossil fuel that agriculture uses. However, a lot of people still find faults with this analysis that I don’t think are there.
- No, it doesn’t matter that making the fuel costs energy. It’s (roughly) the same fuel going into the tractors as going into the gas tanks. We’re comparing fuel in tank to fuel in tank. But if you really want to factor that in, about 82% of well energy makes it to the gas tank of the car or tractor.
- Yes, I do account for the fact that just eating or sitting consumes calories. This calculation is based on the extra calories that biking or walking take, compared to sitting in a car. The base “keep you alive” calories are not counted, but they do require more fossil fuel to create.
- I don’t include the energy required to make a car, which ranges from 25% (Prius) to 7% (Hummer) of its lifetime energy usage. However, most cyclists and pedestrians still own cars, so this is still spent if it sits in the garage while you walk. And while a 2000lb car may take 60-100 times as much energy to make as a 30lb bike, this is not so large a difference if expressed per lifetime vehicle-mile.
- This is based on the USA averages. Of course different food means different results, but doesn’t change this story, which is about the average eater.
- I don’t include the energy needed to build roads for bikes, cars and food delivery trucks. The reality is, we’re not going to build fewer roads because people take some trips walking for exercise. Nor are people going to not buy a car because they do that.
Submitted by brad on Tue, 2007-09-18 23:50.
Burning gasoline is ruining the world. It accounts for 40% of greenhouse emissions, and a large percentage of other nasty emissions including the particulate matter that kills millions each year. Getting it has driven the world to wars. When you burn it, you pollute my air, hurting me, and you owe me something for it, which is a reason that gasoline taxes make sense even in a libertarian context.
So while gas should be taxed to $5 or $6/gallon, the public won’t stand for it. So here’s an alternate idea. Tax gasoline up to $6/gallon in a revenue neutral way. That is to say, figure out how much tax revenue that raises per adult. Americans consume 140 billion gallons/year, so a $3 tax raises 420 billion (before consumption drops.) There are about 200 million adults, so this works out to just over $2,000 per adult. As such, each person (regardless of how much oil they burned) would receive a $2,000 tax credit — a refundable credit payable even if they owe no taxes.
Update: The core idea here came from an earlier comment on this blog, which I forgot about (See comments below for references.)
For people who ride transit or walk or otherwise don’t use cars, this turns into a $2,000 windfall, offset by an increase in the cost of taxis and transit. In theory, for the average gasoline user, it works out to a wash — pay about $2,000 more per year for your gasoline, but get a $2,000 tax refund. At most it’s an enforced savings program.
For heavy gasoline burners — those taking very long commutes, those electing to buy Hummers and Suburbans — it means paying lots more, and subsidizing those who don’t. Those who buy a Prius would be well rewarded, as would those who switch to transit or anything more fuel efficient.
The consequences of this would be:
- A giant and popular win for non-drivers, and for transit systems, which would get many more passengers to offset their increased costs.
- Everybody would file a tax return now, even those making little or no money. This would cost the IRS more, but they would probably love it for making everybody file. Not filing would become remarkably suspicious. This is both good and bad, of course.
- There would probably be some identity theft to try to steal the refunds, this would need to be watched for.
- It creates a major issue for illegal immigrants. Those who want to cause them trouble would like it for this, as these immigrants would now pay large fees for gas but have no means to get the refund, unless they file tax returns, which of course they are scared to do — and they have no SSNs.
- Fuel efficient technologies would become very popular and competitive, and the market would immediately start sorting out winners.
- Fuel consumption would drop, reducing the amount of the credit — or requiring an increase in the tax.
- Poor people with very long commutes could face serious problems, possibly forcing them to change jobs or homes, or try to carpool.
- People would drive into Canada and Mexico to get tanks of gas. There would also be a black market in gas smuggled from those countries.
This could be applied to all fuel use, including power plants and factories. In that case many products would increase in price, all offset by the credit.
Aside from the immigrant problem, it is also important to note how bad governments are at restraint, and there would be much temptation to not make the tax revenue neutral, and just make it a tax increase.
Would voters vote for this? Well, designed properly, if we assume that 50% of the gas is used by fewer than 50% of the people, then this is a win for more than 50% of the people, probably more than 70%. And of the top 30% of gasoline users, many of them would intellectually agree with it though it costs them more money. If people realized they would pay less, not more, under the tax, this could win voter support.
This could also be done on a state by state basis in some states. However, it would create problems on the state borders. Border gas stations would die, and need compensation. There would be a lot of smuggling from the other states. More people would risk using purple gas, as well. Enforcing is tough without some draconian system we wouldn’t like so much. It thus would be possible only in states that have few people living on their borders, mostly western rural states. California is not out of the question. It has no large cities on state borders, but does have some decent sized towns.
The positives of this idea are many, as are the negatives. But those positives are pretty valuable. In particular, this system would drive the market to work hard at producing technologies that really reduce fuel consumption, resulting in perhaps the biggest benefits of all.
Submitted by brad on Tue, 2007-05-01 14:05.
I’ve been writing a lot about self-driving cars which have automatic accident avoidance and how they will change our cities. I was recently talking again with Robin Chase, whose new company, goloco attempts to set people up for ad-hoc carpools and got into the issues again. She believes we should use more transit in cities and there’s a lot of merit to that case.
However, in the wealthy USA, we don’t, outside of New York City. We love our cars, and we can afford their much higher cost, so they still dominate, and even in New York many people of means rely strictly on taxis and car services.
Transit is, at first glance, more energy efficient. When it shares right of way with cars it reduces congestion. Private right of way transit also reduces congestion but only when you don’t consider the cost of the private right-of-way, where the balance is harder to decide. (The land only has a many-person vehicle on it a small fraction of the time compared to 1-3 passenger vehicles almost all the time on ordinary roads.)
However, my new realization is that transit may not be as energy efficient as we hope. During rush hour, packed transit vehicles are very efficient, especially if they have regenerative braking. But outside those hours it can be quite wasteful to have a large bus or train with minimal ridership. However, in order to give transit users flexibility, good service outside of rush-hour is important. read more »
Submitted by brad on Thu, 2007-03-22 01:34.
This year’s theme for Burning Man is “the Green Man.” It represents a lot of things. For many it just is an inspiration for art centered on nature or the environment. Others are taking it as a signal to try to be better environmentally. That’s going to be a very tough road for a festival centered on building a temporary city far from everything and pyrotechnic art.
So I wrote up some thoughts on the challenges involved. The toughest problem is that transporting an entire city to the desert and then taking it back is a great personal and artistic endeavour, but not one that can be considered green. All efforts to reduce the pollution at the event are dwarfed by the fuel burned to get there. So what can be done?
Read about the problems of having a green man.
Submitted by brad on Tue, 2007-02-20 19:38.
Recently I opened up a surprising can of worms with a blog post about CitizenRe wondering if they had finally solved the problem of making solar power compete with the electrical grid. At that post you will see a substantial comment thread, including contributions by executives of the firm, which I welcome. At first, I had known little about CitizenRe and the reputation it was building. I thought i should summarize some of the issues I have been considering and other elements I have learned.
CitizenRe’s offer is very appealing. They claim they will build a plant that can make vastly cheaper solar. Once they do, they will install it on your roof and “rent” it to you. You buy all the power it produces from them at a rate that beats your current grid power cost. Your risks are few — you put down a deposit of $500 to $1500 depending on system size, you must cover any damage to the panels, and they offer removal and replacement for a very modest fee if you need to reroof or even move. You lock in your rate, which is good if grid rates go up and bad if grid rates go down or other solar becomes cheaper, but on the whole it’s a balanced offer.
In fact, it seems too good to be true. It’s way, way cheaper than any offering available today. Because it sounds so good, many people are saying “show me.” I want to see just how they are going to pull that off. Many in the existing solar industry are saying that much louder. They are worried that if CitizenRe fails to deliver, all their customers will have been diverted to a pipedream while they suffer financial ruin. Of course, they are also worried that if CitizenRe does deliver, they will be competed out of business, so they do have a conflict of interest.
Here are some of the things to make me skeptical. read more »
Submitted by brad on Sun, 2007-01-28 17:33.
In the SF Bay Area, there are carpool lanes. Drivers of fuel efficient vehicles, which mostly means the Prius and the Honda Civic/Insight Hybrids can apply for a special permit allowing them to drive solo in the carpool lanes. This requires both a slightly ugly yellow sticker on the bumper, and a special transponder for bridges, because the cars are allowed to use the carpool lane on the bridge but don’t get the toll exemption that real carpools get.
I think this is good, as long as there is capacity in the carpool lane, because the two goals of the carpool lane are to reduce congestion and also to reduce pollution. The hybrids do the latter. (Though it is argued that hybrids do their real gas saving on city streets, and only save marginally on the highway, comparable to some highly efficient gasoline vehicles.)
However, oddly, the government decided to allocate a fixed number of stickers (which makes sense) and to release them on a first-come, first-served basis, which makes no sense. After the allocation is issued, new buyers of these cars, or future efficient cars can’t get the stickers. (Or so they say — in fact the allocation has been increased once.)
The knowledge that time was running out to get a Prius with carpool privileges was much talked about. And it’s clear that a lot of people who buy a hybrid rush to get one of the scarce carpool permits simply because they can, even if they will almost never drive on the highways at rush hour with them.
Society seem to love first-come-first-served as a good definition of “fair” but it seems wrong here. At the very least there should be a yearly fee, so that people who truly don’t need the stickers will not get them “just in case.” I would go further and suggest the annual fee be decided by dutch auction. For those not familiar, in a dutch auction, all those who wish to bid submit a single, sealed bid. If there are “N” items then the Nth highest bid becomes the price that the top N bidders all pay. There may be a minimum below which the items are not sold.
This can be slightly complex in that you can do this one of two ways. The first is everybody pays their real bid, and losers and overbidders get a refund. This assures all bidders are serious. The other is to set the price, and then bill the winners. The problem here is people might bid high but then balk when they see the final price. You need a way of enforcing the payment. Credit cards can help here. As can, of course, being the government, which can refuse to licence your car until you pay the agreed fees.
Carpool lanes are a hot topic here, of course. The mere mention of the subject of kidpooling (Counting children to determine if a car is a carpool) makes the blood boil in the local newspapers. People feel remarkable senses of entitlements, and lose focus of the real goals — to reduce congestion and pollution. Emotions would run high here, too.
Submitted by brad on Fri, 2007-01-12 15:30.
(Note: I have posted a followup article on CitizenRe as a result of this thread.
Also a solar economics spreadsheet.)
I’ve been writing about the economics of green energy and solar PV, and have been pointed to a very interesting company named CitizenRe. Their offering suggests a major cost reduction to make solar workable.
They’re selling PV solar in a new way. Once they go into operation, they install and own the PV panels on your roof, and you commit to buy their output at a rate below your current utility rate. Few apparent catches, though there are some risks if you need to move (though they try to make that easy and will move the system once for those who do a long term contract.) You are also responsible for damage, so you either take the risk of panel damage or insure against it. Typically they provide an underpowered system and insist you live where you can sell back excess to the utility, which makes sense.
But my main question is, how can they afford to do it? They claim to be making their own panels and electrical equipment. Perhaps they can do this at such a better price they can make this affordable. Of course they take the rebates and tax credits which makes a big difference. Even so, they seem to offer panels even in lower-insolation places like New England, and to beat the prices of cheaper utilities which only charge around 8 cents/kwh.
My math suggests that with typical numbers of 2 khw/peak watt/year, to deliver 8 cents/kwh for 25 years requires an installed cost of under $2/peak watt — even less in the less sunny places. Nobody is even remotely close to this in cost, so this must require considerable reduction from rebates and tax credits.
A few other gotchas — if you need to re-roof, you must pay about $500 to temporarily remove up to 5kw of panels. And there is the risk that energy will get cheaper, leaving you locked in at a higher rate since you commit to buy all the power from the panels. While many people fear the reverse — grid power going up in price, where this is a win — in fact I think that energy getting cheaper is actually a significant risk as more and more money goes into cleantech and innovation in solar and other forms of generation.
It’s interesting that they are offering a price to compete with your own local utility. That makes sense in a “charge what the market will bear” style, but it would make more sense to market only to customers buying expensive grid power in states with high insolation (ie. the southwest.)
Even with the risks this seems like a deal with real potential — if it’s real — and I’ll be giving it more thought. Of course, for many, the big deal is that not only do they pay a competitive price, they are much greener, and even provide back-up power during the daytime. I would be interested if any readers know more about this company and their economics.
Update: There is a really detailed comment thread on this post. However, I must warn CitizenRe affiliates that while they must disclose their financial connection, they must also not provide affiliate URLs. Posts with affiliate URLs will be deleted.
Some salient details: There is internal dissent. I and many others wonder why an offer this good sounding would want to stain itself by being an MLM-pyramid. Much stuff still undisclosed, some doubt on when installs will take place.
Submitted by brad on Tue, 2006-12-26 23:05.
While I’ve written before about the trouble in making solar competitive with grid power, this is not true when the grid is being blown up by geurilla fighters on a regular basis. Over the past couple of years, Bechtel has been paid over 2 billion dollars, mostly to try to rebuild the Iraq electrical infrastructure. Perhaps it’s not their fault that power is only on in Bagdadh for 2 hours a day after these billions have been spent — but their might have been a better way.
Imagine if that billion had been directed at building a solar power system, with a lower-power grid for night power. A billion would have provided major stimulus to the solar industry, of course, and helped the companies that are working at making PV cost-effective. But it also would have generated a power infrastructure that was much harder to destroy in a civil war. Yes, they might take down sections of the grid, but these would only have been there for night and brownout power. Without them, people would still have had more power. And not just during the day. Mini “neighbourhood grid” systems could allow small areas to have backup diesel generators. Not quite as efficient as the big generators but much more difficult to take down. The “value” targets would still see their local panels and generators under attack, but that’s the way of it.
It seems odd to think of this in a country with so much oil. But doing this would have also had a major effect on greenhouse gas emissions. Putting solar into Iraq would have made the US responsible for major emission cuts. Cutting emissions there so we don’t have to cut them here.
Something to think about next time your country goes and destroys a foreign country’s power grid and then works to rebuild it. (Of course, ideally that’s never.)
Submitted by brad on Tue, 2006-10-17 00:09.
Just on the heels of my prior post on the bad math often found around alternative energy, I see a Google Blog post on Google’s solar installation. It claims Google with save money with their 1.6 megawatt solar installation.
I would be very interested to see Google’s numbers — what are they paying for this PV system, and what do they pay the power company for their grid power? Did they get rebates on the PV install? Rebates can help a single customer save money but they do it at taxpayer expense which makes it a wash, other than as a means to try to increase the market for solar and bring down the price.
Now, I’m not in any way saying that it’s bad for Google to go solar. Large grid-tie solar arrays are quite green, with minimal emissions (only those from their manufacture, shipping and install) and so it’s good to have them, even if they are more expensive than non-green grid energy.
But I want to know, is my math bad, or is Google’s? If companies can really save money with a PV array they should be springing up like weeds.
Today I also read announcements of companies hoping to bring to market new solar panel technologies with thin films that are vastly cheaper than existing tech. When that happens, the panels really should sprout everwhere, and to very positive effect.
Update: The press releases say the system is 1.6MW, and provides 2.6 million khw/year for a saving of $393K per year (about 15 cents/kwh which is about right in California.) The press release also says the system will pay for itself in 7.5 years, which at 7% interest rate means its total cost was $2.2M. (Truth is Google is able to make far better than 7% with its money, I suspect.)
This means an astounding $1.38 per watt for installed solar. I’ve never heard of anything remotely like this.
Even with a bad-math 0% interest rate, 7.5 year payoff is $1.84/watt so it’s not just bad math here. Even with the California rebates of $2.60/watt and 30% federal tax credit, it’s still amzingly cheap — and almost all the savings are coming from the taxpayer.
The release also suggests that 393K per year will result in 15 million saved over a 30 year lifespan. I can’t figure the math in this number. The bad-math 30*393 is under 12 million. The real saving over 30 years at 7% interest has a present value of 4.8 million. The future value, in 30 years time, of $393/year is well over 30M at 7%. You need an interest rate of 1.5% to have a FV near $15M. I suspose the risk-free-rate-above-inflation might correspond to this but it’s not typical in expressing these numbers.
So what are the real numbers?
Submitted by brad on Tue, 2006-10-10 16:26.
I think it’s important that we stop burning petrofuels or indeed any fuels and get energy from better sources.
But there’s a disturbing phenomenon I have seen from people who believe the same thing too much. They want to believe so much, they forget their math. (Or I may be being charitable. Some of them, trying too hard to sell an idea or a product, may be deliberately forgetting their math.)
I see this over and over again in articles about photovoltaic solar, wind and other forms of power. They suggest you could put in a PV panel array for $20,000, have it provide you with $1,000 worth of electicity per year and thus “pay for itself” in 20 years. Again and again I see people take a series of payments that happen over a long time and just divide the total by the monthly or annual amount. read more »