It occurs to me that energy from oil & gas subsidizes the development & utilization of alternatives.
Imagine all the various activities necessary to build and maintain a nuclear power plant, or build and deploy a wind farm, or create & use PV panels. All the engineers and designers, technicians & operators performing all the related tasks involved in these technologies.
From the foundries which cast the parts, to the machinery used to build the facilities, to the trucks that deliver the materials, and many, many other activities which are utterly oil & gas dependent, & critical to exploiting alternatives; how will the net energy return of these new technologies fair as the hidden subsidy of oil diminishes?
In other words, as oil & gas become more expensive, this cost comes directly out of the bottom line of alternative energy solutions, making them even less attractive than is currently understood.
Does oil's secret subsidy destroy the potential value of alternative energy? _________________ "When you understand why you dismiss all the other possible gods, you will understand why I dismiss yours." - Stephen F Roberts.
I agree completely. I think a better example is shale oil. They calculated that shale oil would be profitable at an oil price of $40. But this was calculated for a gas price of $4.
Since the gas price has risen to $7 shale oil is still not profitable. As long as these energy prices keep rising in sync, these types of alternatives might stay out of reach.
Joined: Apr 03, 2004 Posts: 6497 Location: My Grandkids' Farm
Posted: Thu Jul 15, 2004 3:45 pm Post subject:
The quote, "Nothing was ever mass-produced without cheap energy" seems to apply.
Too bad I can’t remember who said it.
-----
Japan and the End of Cheap Oil
Published in ni Japan (New Internationalist Japan) No.24, July 2001
Tony Boys:
“The problem here is that nuclear power probably could not exist without cheap energy inputs from oil or natural gas. Uranium mining and refining, nuclear fuel manufacture, nuclear power plant construction, treatment and/or storage of nuclear waste all require energy, and most of these things are more easily carried out using oil than any other energy source. I would estimate that nuclear power could not operate in Japan for much more than a year following termination of oil supplies to this country.”
Then there is this I found but have no idea what it says. Well, I think it says that life cycle energy for PV is positive pretty fast but maybe someone could help me out. _________________ Make a plan and work it:
It is true you need to look at energy requirements of alternative energy, or any energy.
If you insist that inputs have to be in oil and there are no substitutes for oil, then with no oil, there is no energy of any kind.
Fortunately, energy can be substituted somewhat.
You still need to look at energy needed to create something vs. energy outputs. IE how much energy in the form of oil, electricity, whatever went into creating a nuclear plants, vs. how much energy comes out.
If a 1000MW nuclear plant is built with 1 million barrels of oil equivalent, for everything including cement making, generators, roads, fences, etc, Then that is 1 million barrels * 6.1 GJ/ barrel or 6.1e15 joules or about 2 billion kwh. This is the heat value of all that oil. The actual "work" value is lower due to efficiency.
The average nuclear plant uses 150 tons of fuel at $40/kg say. Suppose all of that is "oil", then that is about 150,000 barrels of oil per year at $40/barrel. The 150,000 barrels is .3 billion kwh.
The nuclear plant would generate about 8 billion kwh of electricity.
So using this simple example it would be 2 billion kwh energy upfront, .3 billion per year in fuel, and the payoff is 8 billion per year.
You already seem to mention it in your post, but I think you have to be extremely careful with the comparison between electricity and oil. It suggests that oil and electricity are interchangeable.
Oil is a mixture of unique chemical compounds. You can convert oil to electricity, but you can’t convert electricity into oil. Nor can you expect electricity to perform the same functions as oil.
So I think with these calculations you need to look at the amount of oil you use only. The amount of electricity you gain is irrelevant because you will never be able to convert that electricity back to oil.
A nuclear plant can generate hydrogen more efficiently than electricity. IE instead of 1000MW electric it can generate directly 1000+MW hydrogen. This is by thermochemical splitting and not electrolysis.
This hydrogen can be combined with carbon to make a "hydrocarbon". Coal could be one feedstock. Coal is 3-6% hydrogen by weight, and oil is about 16%. Really you can think of it as "hydrogenating" coal. The resultant molecule would be C13H28.
You could take electricity from wind and put it through an electrolyzer and make hydrogen also. But you'd lose a good chunk of the electricity.
In general electricity is a much higher grade energy than oil. That's why this isn't done. Electricity carried to your house can do 100% of the work you ask. If you were to use oil, you'd have to generate electricity with it first in order to get it to do work.
Even in a car, oil is put through a heat engine and only 15-20% of the energy hits the wheels. If you could use a big enough battery a much higher percentage of electricity would hit the wheels. It doesn't have to go through a heat engine first. (in a sense it's already been through one).
Anyway, if it were truly the case that oil is not replaceable in any way, then we'd be in a lot of trouble.
Even in a car, oil is put through a heat engine and only 15-20% of the energy hits the wheels. If you could use a big enough battery a much higher percentage of electricity would hit the wheels. It doesn't have to go through a heat engine first. (in a sense it's already been through one).
That is exactly why I believe the next logical step for automakers is to make a hybrid capable of pluging in, recharging at night, and getting 20 to 60 miles directly from the grid each day.
The pure savings in oil is the largest conservation measure possible within the next 10 years.
This hydrogen can be combined with carbon to make a "hydrocarbon". Coal could be one feedstock.
Converting coal to gas is simple, energy efficient, and has been used for the past 200 years or so. It is just a matter of heating coal in the vicinity of oxygen and water.
Before WWII this was the only type of gas that was available to us.
The heat content of this gas will be somewhat lower than gas derived from your method but you have to realise that thermochemical splitting is a very complex 4 or 5 step process with an efficiency of only 40-50%. Subsequent hydrogenation of the coal will even lower the efficiency.
Hardly worth the effort of building a nuclear plant for.
Quote:
In general electricity is a much higher grade energy than oil.
Depends on your perspective. For heating purposes a combusting material is always preferable above electricity. A burner flame has a much larger radiating volume than an electrical heating element and can thus better distribute the heat. If you're talking about a medium to large size industrial furnace (500-1000m3), electric heating is hopelessly inefficient.
Quote:
Even in a car, oil is put through a heat engine and only 15-20% of the energy hits the wheels. If you could use a big enough battery a much higher percentage of electricity would hit the wheels.
However the bigger the battery the heavier the car. This is the problem of the Prius, which weighs in at nearly 1500kg, much more than a conventional car of that size. Much of the increased efficiency is lost in increased weight.
Each and every day we use 80 million barrels of oil. There is only one reason for that: oil is superior to any other energy source we know. Believe me, if we would know anything better we would use it by now.
Of course the people who work at alternative energy sources have to promote their work in the best way possible. They have to overstate the feasibility and to omit the drawbacks.
But the basic picture is. Yes, we can replace oil by alternative energy sources for some purposes, but it will always be a step back, not forward. A step back in costs, safety and efficiency.
There are no 'better' alternatives to oil, we just have to choose the least bad one.
You undoubtedly know more about coal gasification than me.
Anyway, the point about coal gasification is alot of the carbon, I would think would be wasted...emitted as CO2. Maybe on a cost basis, since coal is cheap it would make sense.
Using an outside source of hydrogen (that was created with a high EROEI) would allow hydrogen to bond to the carbon atoms and you'd need less coal overall. It would probably be cheaper to just go straight from coal to oil, but it would use more coal. YOu could even use waste heat from nuclear to add to the process. If you used waste heat it would thus be "free".
As for electricity being a higher grade than oil, you're right, for heating purposes oil is much more efficient. It doesn't have to go through a heat engine, because the goal IS heat. But most uses of oil in this country are heat engine related. Gas is less so...about 1/4 is used directly as heat I think.
About the Prius, how much do the batteries weigh? I think it's 45wh/kg and it's about 2kwh, so that's 50kg or about 110 pounds. Not really that much more weight. The engine is smaller too so that evens it out.
Overall it's about 3000 lbs (US) which is about what a Camry is, I think.
For a plug in hybrid, you'd need 10kwh which is 5x what the Prius is. NiMH batteries in the prius can be up to 65wh/kg (less energy dense in the Prius b/c they are optimized for power (w/kg) not energy (wh/kg)). They are working on Lithium batteries (similar to notebook computers) which are 100+wh/kg and some are as high as 400+wh/kg. Don't know when they'll be out.
10kwh of electricity would take you 40-50 miles. A gallon of gas is 36kwh heating value, but it only take you 25 miles, due to efficiency. So this is one way around EROIE, in that nuclear electricity (or coal) is much more efficient at doing the work (if it's auto related) than oil.
With 100wh/kg you'd need 100kg of batteries, which is about 220 lbs. Not really a dealbreaker, especially if the engine could be made smaller and optimized.
The reason why current engines are so big is for acceleration. With the batteries being so good at acceleration...you can use a much smaller engine...it can be optimized and made lighter.
I believe the main problem with these types of systems is weight. Since you have two engines (electrical and combustion) plus a generator, plus a battery and fuel tank, the combined weight will always be more than a single engine car. The Prius is basically a 1.4l car with a lot of electrical goodies mounted on it.
A better option would in my view be to forget about the combustion engine and go to a totally electric car. That way you can save a lot of weight. Since the motors can be mounted directly on the wheels you can completely forget about the drive train, axels, gearbox, exhaust etc (not to mention the combustion engine itself).
These are very heavy components a much lighter chassis will suffice. I wouldn’t be surprised if you can design a car with the same specifications as the Prius but with half the weight.
The Prius is just a marketing trick. Those who are really concerned about the fuel usage can better buy an Opel Corsa ECO. It has just a plain 1.0l combustion engine, it has no electrical gimmicks, no hybrid stuff, but is more fuel efficient than the Prius (60 Mpg).
And it costs a lot less energy and resources to make the ECO than the Prius.
Electric vehicles would be great. The only problem is range. I could see people having 2 or 3 cars one of which would be an EV. But range limitations and the idea of being stranded would limit their usage.
Prius isn't really just a trick. One thing it does is use the Atkinson cycle instead of the Otto cycle. The power stroke is much longer than the compression stroke. This enables you to get a much higher % of the gas's energy out in terms of mechanical energy. That alone probably improves the engine's efficiency by 30%.
So why don't more car engines use the Atkinson? Because it's very low torque at low RPM. Prius uses an electric motor to get around this.
I think it's 1.5 liter and 70 hp. Most 1.5 liter cars would be 100 hp.
Electric cars will be hard to sell if the downside is long charge ups and the prospect of being stranded after 100-200 miles and unable to move. Fine for city use then. You can walk to a gas station if you run out of gas.
ken - please clarify that that last paragraph. I understood it as refering to an electric would be fine for city use because you could always walk and get some gas. Surely you meant go and get some, uh, batteries ?[/i]
Actually I meant that ~now~ you can walk and get gas (with a gas car)...as opposed to an pure electric woul leave you dead in the water.
I don't know how feasible it would be to get batteries....I'm not sure if you can just plop one in. You'd probably need a tow or need a tow truck to charge you with a generator (gas powered)...either way, it is one reason why people are not so psyched about pure electric vehicles.
If you used one for errands and such or lived say 10-20 miles from work in a city...then it's feasible. But a family would want at least one car that could make a long trip...or just be able to run errands all day (maybe 100 miles). So that would necessitate a gas engine of some kind. The energy density and ease of refueling of a liquid is just much greater than a battery.
Gas is 13000 wh/kg approx. A good battery is 100wh/kg. So gas is 140x. Now if it's only 15-20% efficient then that it is effectively less but it's still much greater than a battery.
Joined: Jun 26, 2004 Posts: 1189 Location: Madison,Wisconsin
Posted: Fri Jul 16, 2004 10:11 am Post subject:
Hybreds where the first thing we could bring about because there is no infrastructure currently in place, except in some parts of california, that would allow a person to use an electrical car long range.
But seriously, why do you NEED to use an electric car for longer than 100 miles? If people where conserving, job placement would become important. A few transit lines into a major city, and all you would need do is instead of parking your car at a park and ride, park your electric car at a charging station and take the train into the city for your job. People would stop thinking in terms of but I can't travel like i used to and realize that guess what, no, you can't. Does that mean that an electric car would not be a very viable option? And all of this is based on the assumption that we won't be able to develop more effective batteries that can handle the load of a longer trip between charges. Or, (gasp) solar panels on the roof would make a huge difference as well. Gotta go drive my gas guzzler to work. Note that almost all of my trips are less than 15 miles before i stop the car for more than 30 minutes. Sounds like a good way to have an electric car to me :D
Joined: May 26, 2004 Posts: 309 Location: Ontario, Canada
Posted: Fri Jul 16, 2004 10:37 am Post subject:
Is there any fair hope of electricity powered construction vechiles? In our out of the city? I'd assume at least within a city it could be done, but I've seen no real analysis of industrial electric vehicles. _________________ "Our forces are now closer to the center of Baghdad than most American commuters are to their downtown office."
--Defense Secretary Donald Rumsfeld, April 2003
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