Nissan Leaf - 367 MPGe! Truth or Fiction?

The calculation for the Leaf does this... and then ... and then... multiplies the result by 6.67! You may think I am making this up, but I am not. This fudge factor is also written into the law:

Ah marketing and mathematical smoke and mirrors. I know how you feel and this has been covered before on CR4 on this and similar topics including solar power systems, audio power PMPO statements and even pseudoscience free energy and over unity devices (especially water electrolysis for cars).

* Why would you want to come up with some MPG equivalent? To confuse people. To make them think, for example, that Nissan has discovered a magic way to power a car: tens times as efficient as even an economy car!

The whole point of the MPG figure is so that an apples-for-apples comparison can be performed between standard gasoline and electric vehicles (whose cost per mile calcs are more involved, especially for hybrid vehicles). Unfortunately the only real outcome of this comparison is a nice marketing ploy that hides the expensive hidden costs of electric vehicles and a MPG figure for electric and hybrid cars that is not only inaccurate (bordering on marketing scam proportions in some cases) but who's value will be highly dependant on the marketing team's professional integrity.

marketing team's professional integrity

I am trying to parse these words to make sense of them... but then I have trouble with "jumbo shrimp" too.

The government figures for well-to-wheels square pretty well with yours -- in the first part of the CAFE calculation, they would get 55 mpg for the Leaf. (Their efficiency figures are lower than yours.)

Then in the weird political part, they multiply this by 6.66 to get 376. Magic.

In the other thread I talked about comparing the energy in a gallon of gas from the pump to the energy used (say coal) to create 1 kWh at the outlet in your house. It appears that I was forgetting a lot of stuff.

For gasoline I would have to add the energy needed to get it out of the ground, transport it to the refinery, refine it, transport it to the gas station, and finally pump it out of the tank in the ground at the gas station into my car.

For coal I would have do the same for getting it from in the ground to ready to burn at the power plant.

My head hurts.

I thought about that, but I was trying to get an reasonably accurate comparison of electricity with the gasoline we buy at the pump without getting too complicated. Fuel at the pump to fuel at the boiler.

DrMoose and msm98lw: The hard work of figuring out well-to-wheels efficiencies has already been done by Argonne National Lab, and is available in spreadsheet form. They call the model GREET : Greenhouse gases, Regulated Emissions and Energy usage in Transportation.

Often the term "well-to-wheels" is used fairly loosely, and I'm not sure that the energy used in (for example) exploration is taken into account. For most established fuels, the difference between the fuel at the pump vs boiler is fairly small -- because most established fuels are quite efficiently brought to the pump (or boiler). As a result, the term WTW is often used even when talking about fuels at the pump vs the boiler (rather than in the ground). (Then, as in the analysis you did, DrMoose, at least the huge losses in converting the fuel into electricity via a heat engine are fairly accounted for.)

For less established fuels, ethanol and hydrogen being the most publicized (with hydrogen being more correctly considered an energy carrier rather than a fuel) the differences in processes and feed stocks make it hard to pin down a number, and also the losses are much higher, because these fuels are created, rather than just dug out of the ground. (Petroleum products are, of course, refined, but the energy consumed there is surprisingly small: the well-to-pump efficiency is about 82%.)

Thankfully, the "H2 economy" is fading into history, because a WTW analysis reveals that the losses in creating H2 (which does not and can not exist alone on earth or in the atmosphere in meaningful quantities) are too high to be feasible. In electrolysis (used for about 4% of the H2 sold -- because it is too costly) you take perfectly good electricity (itself created with losses) and then incur further losses in the process. In reforming methane, you take a good fuel and pull out CO2 (of which we already have too much) to leave H2. Then you have the losses of compressing, refrigerating (for liquid), etc. The GREET spreadsheets are useful for showing these relative efficiencies.

The simple and most basic way to deal with our energy woes immediately is to use less. Unfortunately, the schemes often used to hype one car over another (or one technology over another) make it appear that you are using less when you are really using more. The most egregious example is the H2 Hummer promoted by California's governor. Another is the LincVolt promoted by Neal Young: it's a heavy 1959 Lincoln, which can be made to appear efficient if you ignore the fact that it is powered by electricity, and focus only on the smaller amount of liquid fuel used.

This is something I've thought about quite a bit over the last few years, and have written about it several times here in CR4. But it's worth saying again.

Every bit of energy we us is converted sunlight, in one form or another. Now, sunlight is streaming by at a rate of 1.4kW/m2, but by the time it gets down here, it's attenuated by an order of magnitude and constantly interrupted by weather and the planetary rotation. Thus, solar energy is not all that efficient.

However, what if we were to build out solar power stations in orbit? Granted it might be a little bit expensive to get it off the ground (pun intended), but assuming space-based raw materials and manufacturing, once it got up and running these power stations would be little if any more expensive to build than here on earth. In some ways it would be easier, since we wouldn't be constantly fighting gravity. And the spin-offs? WOW

The nice thing is that the "fuel at the boiler" is absolutely free. The sun is going to keep on shining, and in high orbit it's 24/7. So, it doesn't really matter what our thermal efficiency is, as long as we can get something delivered to the ground, and the numbers I've seen are actually pretty good.

So, we now have plentiful electricity, cleanly generated in high orbit and beamed down to the planetary surface. No more drilling, no more strip-mining, no more nasty hydrocarbon combustion by-products pouring into the atmosphere. Just clean, cheap electicity. Now what do we do with it?

Obviously, for most things we can just use it straight off the wire. Heat, lights, etc. But we're talking about transportation. Certainly batteries are just fine for short haul commuter stuff, but what about long haul and air transport? Batteries don't have the kind of energy density needed for that. Hydrogen does.

Under these conditions (plentiful, clean, cheap solar power), hydrogen from electrolysis becomes a very viable option. Sure, the efficiency stinks, but it's the only really clean technology with anything like the energy density per unit volume and mass that you just have to have for long haul or air transportation. And besides, where energy is cheap, when have we ever worried about efficiency?

I gave you a good answer on that. Maybe you would answer this: If I had my own natural gas powered micro-turbine generating my electricity, what would the efficiency be? I would be running it with a battery back up, to spread the demand, and use it for the house also. Your answer assumes that the electricity comes from the grid, not from private or local solar panels, wind turbines, natural gas generators, etc.

I have done a bit of research on your question, and the simple answer is between 30-40%. And, if you utilize the waste heat for hot water and home heating, your efficiency goes up significantly, perhaps as high as 80%.

However, there are some pretty major issues. Commercially available micro-turbine generators seem to start at 30kW and go up from there. If you design and build your own, you'd need to find a small turbine engine, about 2hp to run your generator, and that would have to be a pretty highly engineered engine if it was going to run continuously. The only turbines I've found that small were intended to power model aircraft and to run only a matter of minutes at a time.

Then there is the small matter of cost. Turbines are expensive. Even the model airplane engines I found were upwards of $6000US, and something engineered to run 24/7 would likely be a lot more expensive. Plus, you're talking about an absolutely massive bank of storage batteries, and those can be rather pricey as well.

Could it be done? Certainly. Would it be practical? I seriously doubt it.

A far more practical solution would be a combination of wind and solar, geothermal in the form of a heat pump, and possibly even small scale hydroelectric if you happen to have a usable stream on your property. Still kinda costly, but a setup of this kind could render your home almost completely independent of the electrical power grid. And, according to the U.S. DOE, the average American electricity bill is $100/mo so, if it cost $12,000 to install, it would take about ten years to pay for itself. And of course then there are maintenance costs on the system itself. Though I still think it would be worth doing. You might even make a little money on such a thing, since you'd be able to sell your excess power to the utility company. What fun!

A very effective way of doing this is to use something like a Honda cogenerator. You feed it with natural gas, and generate electricity. (The engine is a fairly ordinary commercial engine.) A very large portion of what would otherwise be waste heat is collected and used to heat domestic hot water. Because there is so little waste heat, the overall efficiency is 85%. Whispergen is another company which makes such a unit, with the powerplant being a Sterling engine. They claim 90% overall efficiency, IIRC.

For these to work, there has to be a balance between the need for heat and the need for electricity, but in many cases that balance can work well.

Nifty little device, but it still assumes a connection to the public utility system. The system I mentioned so briefly in my previous comment however, has the capability of rendering one's home completely independent of the grid. And I kinda like the idea of not having to buy power of fuel for my home.

Are you trying to put the utility companies out of business? If a few do it they can live with it, but if too many people generate their own power and sell it back to the power company, they will put an end to it.

I kinda like the idea of putting the public utilities out of business, but it's not going to happen.

First of all, there is no way in which every household in the world could possibly be fitted out with an environmental energy system such as I described, since the concept pre-supposes a fair bit of acreage to work with. Parts of the system could be installed in a city home, but probably not the whole thing.

Second is that our industrial plant runs on electricity, and environmental energy systems do not provide anything like the energy density required.

So the power and gas companies probably have a long future before them, more's the pity.

I am seeing natural gas, shale gas ,landfill gas, propane, and manufactured biogas as the cheap energy solution for the next 100 years. It looks like it can win out over solar, wind, etc. It is well distributed over most of the nation already, and a few more pipelines can serve the rest of the country. The gas can then be converted, locally, to electricity. This will save most of the line loss. In fact various types of electrical generation can produce electricity at any scale desired, from large plants to individual homes. The Leaf can run off of electricity made at home. Heavier vehicles, or fuel cell vehicles can run off of gaseous fuel. Liquid fuels can still be used, and their price can be kept reasonable, by competition with gaseous, and other alternative fuels. I would love to see solar, and wind be competitive, but not be chained to them because of dubious global warming theories. I am more concerned with , what I consider, real pollution.

I am more concerned with , what I consider, real pollution.

Such as methane [natural gas], much better to burn it & turn it into co²

I agree that we should increase efficiency & increase our use of terror free energy!

I would imagine that there are also significant losses involved with pumping natural gas, someone like steve s or petro power I'm sure could definitively quantify...

Still distributed generation of electricity is a good idea. Moving towards a more regional model would bring more stability to the energy markets.

Biobutanol & algae [converted to diesel & biobutanol] are probably also potential solutions, It's hard to beat the energy density liquid fuels.

Electric's & hybred's should have a place in the mix of transportation & logistical options.