Calculating the gasoline equivalent price of your electricity.

[NNadir]

Here in New Jersey, I pay about $0.11/kw-hr for my electricity. This is my delivered price, which consists entirely of internal costs: The cost of generation of the electricity, including fuel, operations, and maintenance of power plants, electrical lines, and of course, a healthy dollop of profit for the company that sells my power to me.

I don't pay directly the external costs, loss of life from air pollution, destruction of my property through extreme weather events brought on by destabilization of the climate, food costs from acid rain, the costs of wars to maintain oil supplies, etc. These are the external costs, and I am encouraged to think of these as free, although clearly they are not so.

I don't know how other people think about it, but I tend to think of my electric bill in purely abstract terms. I seldom think about the rate. I know I conserve, use fluorescent bulbs, try to buy energy efficient appliances, etc, but I don't actually calculate the costs a particular refrigerator or television might save or consume. I simply pay the bill and forget about it.

Recently in another thread, http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=115x56208 I found it useful to convert the cost of electrical power to a unit that most of us seem to understand better, the price of a gallon of gasoline.

This is relatively simple to do. Most people pay some sum, usually a few cents, per kilowatt-hour. A "kilowatt-hour" is a unit of energy, since a watt is a joule per second. That a kilowatt is 1000 joules per second, and as there are 3600 seconds in an hour, a kilowatt-hour is 3.6 million joules. Thus if I pay $0.11/kw-hr = 0.11/3600000J = $3.06 X 10^-8/J. Since a gallon of gasoline contains 132 MJ/gal, http://bioenergy.ornl.gov/papers/misc/energy_conv.html, I find that my electricity costs$ 3.06 X 10^-8/J X 132 X 10⁶J/gallon = $4.03/gallon, gasoline equivalent.

Here directly from a spreadsheet is the calculation.

$/kw-hr $/J $/gallon equivalent
0.07 1.94444E-08 $2.57
0.08 2.22222E-08 $2.93
0.09 0.000000025 $3.30
0.1 2.77778E-08 $3.67
0.11 3.05556E-08 $4.03
0.12 3.33333E-08 $4.40
0.13 3.61111E-08 $4.77
0.14 3.88889E-08 $5.13
0.15 4.16667E-08 $5.50
0.16 4.44444E-08 $5.87
0.17 4.72222E-08 $6.23

Again, these are internal costs. Later on, if I feel like it, I'll try to attach the costs here in New Jersey to the external costs to see what I can learn about energy in my state.


Thus we see that electricity is not cheap, internal costs only, when compared to electricity.

[Ready4Change]

1. So...

Around 9 cents of electricity has about the same amount of energy as a gallon of gas?

No wonder Prius owners are so interested in a plug-in option.

[NNadir]

2. No, that's not what it's saying. It's saying that charging a Prius

so that it could drive as far as it could on a gallon of gasoline, would cost me $4.00.

[banana republican]

3. YOU FORGOT TO ASSESS THE EFFICIENCY

of the difference between an electric car & a gas car. how much of the energy consumed is actually used as opposed to the amount lost.

For example a heat pump has an efficiency rating of approx 200% while an oil furnace has an efficiency of approx. 90% (or less).

These factors will significantly influence one's choices...

[NNadir]

4. I didn't forget, but it indeed a consideration. By the way, I'm not

focusing here on cars. My real point, which I will be making later, is to explore energy as currency, so we can begin calculate external costs.

[skids]

11. I think it's fairly important in this case...

...given that gasoline is only worth 40% of its energy value when used in the way that it dominantly is, and electricity is generally converted to useful effect 85% or better (granted in both cases many of our activities I loath to call "useful effect",) your price ends up off by a factor of 2.

So I'd advocate that the ability to capture a form of the energy "currency" be embedded in it's price. Otherwise we'd have to say the sun beams 1000W per square meter to us for free, when in reality we can only harness a portion of that.

Not on a bigger level, but just for the sake of what you're trying to do, it's too bad more people don't heat with oil, because then you could more directly relate the two.

[NNadir]

12. Well, one has to consider how one is using the electricity.

If one is storing the electricity, it is very likely that the efficiency is not as high as 85%. One has to tack the efficiency of the battery on top of the efficiency of the device. One loses heat in charging, in discharging, and in the device itself. If one is attempting to store the energy for a long time, this will also make a difference. If one is using electricity directly, maybe, especially if one is using it for devices like fluorescent bulbs.

Of course, one could argue that a co-generation system, a diesel generator which uses the waste heat for home heating or water heating, is a highly efficient device as well. Then, of course, the efficiency of the captured energy is very, very high. Just such a consideration is of significant industrial and environmental importance. The substitution of combined cycle power plants has been a success, inasmuch, as it gets more use of the otherwise abysmally unacceptable fossil fuels.

One also needs to account for abstruse factors - factors on which I am certainly less qualified to comment than you are - such as the weight of the battery, and how the energy/mass density effects the efficiency moving device. If you have to lug a lot of weight for the fuel system, it's going to cost you. This is most obvious on spacecraft, but it applies everywhere. According to this Wikipedia article, the energy density of a lithium ion battery is incredibly low compared to gasoline, which probably accounts for the wide use of gasoline.

http://en.wikipedia.org/wiki/Energy_density

For the sake of reference, the energy density of dimethyl ether, the fuel with which I advocate replacing all fossil fuels, has an energy density of 31.7 MJ/kg. If used in fuel cells, having higher efficiency than internal combustion engines, there is no reason to expect that it could not be roughly as useful as gasoline, while being a hell of a lot cleaner and safer, if generated from nuclear or a form of solar power. In fact, DME isn't too bad in internal combustion engines either. One could probably drive several hundred kilometers without refuelling in a DME/diesel car. Of course, DME is not a source of energy, but a means of storing energy, just like the more famous or infamous hydrogen (from which DME would be made).

http://hypertextbook.com/facts/2005/JennyHua.shtml

But, the point of the "dollars per gallon" idea is not to offer high precision work by any means, or to account for all situations. It's just a useful rule of thumb. Again, the point is that the price of energy with which people are most familiar (in the U.S.) is dollars per gallon. Of course the number of dollars per mile (or as I would prefer, dollars per km) varies with whether one drives a Hummer or a Honda Insight, and though most people are aware of this, their frame of reference is still dollars per gallon.

[skids]

13. WRT energy density...

All very true points. Mine was just that one should compare the efficiency of the most commonly prevalent mode of use in order to obtain the "price equivalency."

Though it can impact performance, the energy density of a power source is a somewhat overrated benchmark, in that the mass of the fuel is usually dwarfed by the mass of the rest of the vehicle. Weight seems to be a big deal among auto-enthusiasts due to it's effect on handling, and they carry this prejudice over into their dialogues on energy. Also industry regulations tend to put more of an emphasis on vehicle weight than perhaps they should. This is not to say that "rolling loss" is not signifigant, nor to ignore that the majority of vehicles do not recapture energy on braking or the effect of vehicle weight on roads, but it's by no means the end-all and be-all of an energy storage system's merit.

WRT energy storage lead acid is horrible, NiMH is pretty bad at around mid-eighties, and Li-ion is actually excellent, sometimes up into the high nineties in round-trip efficiency. Been a while since I read up on it but I think it may be the case that even lead acid can be pretty efficient if it is just being used as a float reserve to cache power for several-second intervals. FWIW. Of course ultracaps blow them all away, barring those pesky trivial considerations of energy size and cost.

[Ready4Change]

8. Confused

So, charging a Prius, with electricity costing $.09kw-hr, with enough electricity to go as far as a gallon of gas (lets say 40 miles for a light, efficient car?) would cost $4?

Seems pricey. If that were trickled into the Prius's battery at a rate of 1kw per hour, that would take (4.00/.09) 44 hours. That seems way too long, so I assume power can come out of a 120v, 30 amp socket faster than that?

Or is my math screwy?

[NNadir]

9. First of all, don't read too much into this.

I'm trying to give a sense of energy costs in a unit with which most people are familiar, the price of a gallon of gasoline.

But yes, charging an electric car would be expensive right now compared to gasoline. On some level this makes sense, since you are adding an extra energy conversion between your drive train and the chemical or nuclear or renewable source of energy. Electricity, not counting for external costs, is more expensive than refined fossil fuel. This may not always be the case. Note that you lose energy through heating both in discharge and charging the battery. This further increases the cost.

The rate at which you charge the car is not limited to 1 kw of power delivered over an hour. Depending on the circuits in your home, the rate could be much faster. The rate is limited by the current your home circuits can support and certain physical parameters in the type of battery you are using. I don't know the specific charging rates for different types of batteries, but there are some people here who know quite about electrical engineering, and some who have direct experience with charging electrified cars.

[IrateCitizen]

5. External costs

External costs are never considered in classical economics. That's why they're referred to as "externalities". If classical economics were to actually start considering them, the whole "dismal science" would rapidly fall apart, because it would become quickly apparent that many of the relationships we would be trying like hell to quantify would actually be qualitative in nature, deserving of informed, reasoned judgment rather than empirical analysis.

In short, this is one of the big issues I have with much of the current debate over energy. Often, we discuss the need to employ centralized, technological fixes in order to maintain the economic and social arrangements we already have. Rarely is the question asked whether these arrangements are things we actually want to continue. My feeling is that our impersonal living arrangments are a major source of collective unhappiness -- post-industrial capitalist society has largely succeeded in taking away much of what makes us "human", and we can't find anything to fill the gaping hole of community and real social relationships that exists in our collective soul.

[NNadir]

6. The imperative to include external costs, however, now exists.

It has become a matter of survival, since the planet as a whole is beyond its carrying capacity. We can no longer slough them off as irrelevant, as the matter of global climate change brings home so graphically.

I agree that we should not be looking at maintaining a dubious status quo. We will have to change our basic assumptions.

Another good post on your part.

[BeFree]

7. Bigger is not better

The centralized processes that form the basis of modern society have to get bigger to carry on. But the diconnection from reality is getting bigger, too.

The loss of connection to the realities leads to a loss of understanding the consequences of our actions, which will lead to a big 'ol slap upside the head someday.

[IrateCitizen]

10. I wholeheartedly agree

I just finished reading Small is Beautiful: Economics as if People Mattered by E. F. Schumacher. I'm going to have to take some time to digest it fully -- and likely read it one or two more times -- but it stated so concretely so many of those things I felt in the back of my head for some time but was unable to put into words.

Modern society has in numerous ways debased man. Sure, we live longer lives and are more comfortable in many ways. At the same time, our quality of life is horrible when compared with before. We sacrificed our sense of community and meaningful social interaction at the altar of modernity. Same for the capacity for people to work with their hands and minds, cooperatively, at a meaningful task. Practically every job that previously fell under the category of artisan has been killed by the insatiable beast of "efficiency".

We really need to find ways to reconnect with the things that make us human. While we certainly should not be dismissive of technology's place in helping us, we must return technology to its proper place -- as a source of ingenuity which cannot be used to irresponsibly harm the cycles of nature. Technology should not be used in ways that seek to control or beat back the environment, but rather to imitate its cycles and work in harmony with it. We need to employ much more of a precautionary principle (placing the onus of proof of non-damage on those who want to implement the technology). Our current practice of placing the onus on detractors in the face of rapidly approaching (or even passing) ecological limits is the height of insanity.

There's plenty more I could riff on right now, but I'll process it for presentation at another time. Peace.