“Be kind, for everyone you meet is fighting a hard battle” - Often attributed to Plato but likely from Ian McLaren (pseudonym of Reverend John Watson)

Sunday, February 21, 2010

34 Max?

Through a series of links, I wound up at a blog advocating mechanically (or electronically, I presume) limiting the maximum speed of passenger vehicles to 55 kilometers/hour (34 m.p.h.). Scott (the blog's publisher) lists the benefits, among others as: elimination of oil imports; reduction of CO2 emissions to below 1970's levels;
reduced loss of life and reduced injuries in motor vehicle accidents; reduced air pollution from exhaust; reduced particulates from tire wear; reduced energy in automobile manufacturing due to smaller and lighter components; reduced expenditure for infrastructure maintenance; increased motivation to use (now comparatively much faster) public transportation; and others.

He addresses many of the objections he anticipates as well, though I doubt that many who contemplate his suggestion will agree that he has adequately done so. He moderates his comments and states that a huge portion of the comments he's received consist only of name calling and doesn't publish them. In fact, there are very few comments published. I left several; time will tell if he publishes them.

And though a few of the comments I posted related to his erroneous use of "exponentially" and his stating that aerodynamic drag (as opposed to power required to overcome it) varies with the cube of speed (rather than the square), my main point of contention was that he makes broad claims (elimination of oil imports, reduction of CO2 emissions to pre-1970's levels) with no data or calculations to support them. This is something I try never to do, as claims without backup are plentiful on the 'tubes. I'm willing to be convinced, but he'll have to convince me.

Further, I am instinctively opposed to mandates and top down controls, so I suggested that the externalities of fast driving be paid for by those doing the driving, probably by a tax. With OBD-II on all modern cars, this could easily be accomplished at registration renewal time without big brother-like GPS tracking. The idea would be that people would be taxed on the extent to which they exceeded, on average, some speed and probably multiplied by the number of miles driven. I can already hear the howling!

But let me do his job and suppose such a thing was done. Would we eliminate oil imports? This needs to be a two part question because we'd use less energy to travel and use less energy to manufacture automobiles. For the first part, I'm going to assume that the adjustment has been made and that enough of the new variety of cars optimized for such a maximum speed are on the road to use them as the de facto standard. In the real world, that will take a while but let's see where it leads us.

We used (in 2005) 320,500,000 gallons of gasoline per day at  17.2 m.p.g.  I made liberal (but not completely unrealistic) assumptions on vehicle characteristics of weight, drag coefficient, rolling resistance, and area and calculated in the usual way - details can be provided if requested- and determined that we'd be able to get vehicles achieving about 134 m.p.g. after this rule is implemented and the situation stabilizes as described. At that rate, we'd save about 87.2% of the gasoline we now use, or 279,000,000 gallons per day. Now, we get about 19.5 gallons out of a barrel of oil, so we'd save about 14.3 million barrels per day. This is, in fact, more than we import so Scott is correct. This doesn't even include savings from reduced energy use in manufacturing lighter vehicles. I'll attack that, and CO2, in a subsequent post.

Who's in?

Saturday, February 20, 2010

The Nissan Leaf

I've posted a couple of times on supplying the necessary electrical energy to replace our passenger automobile fleet with electric vehicles, and I also discussed the Chevy Volt. An all-electric vehicle appears ready to enter the fray in late 2010 - the Nissan Leaf. While Nissan seems to be playing it close to the vest (the vehicle's weight and price as well as many other specifications are not given), between Nissan's site and Autoblog's site some conclusions can be reached.

Let's look at the combined aerodynamic and rolling resistance efficiency of the vehicle. The Leaf is claimed to deliver about 100 miles on a full charge, the lithium ion battery pack capacity is stated to be 24 kilowatt-hours or about 86.4 megajoules. The electric motor is less than 100% efficient in its use of the energy in its source. Based on this page and the 80 kilowatt (or 107 horsepower) motor in the Leaf I'll use 92% (the table shows the minimum as 91.7%). Also, the Leaf site discusses "0% to 100% charge" so I'm going to assume that the vehicle uses all 24 kilowatt-hours of energy in the battery pack to go 100 miles. Thus, the Leaf uses .92*24=22.1 kilowatt hours or 79.6 megajoules to go 100 miles.

How does this compare to "miles per gallon?" The 79.6 megajoules is the energy in about .66 gallons of gasoline, but the internal combustion engine is quite inefficient so I'll use 22%. Then we'd be considering a car that goes 100 miles on (0.66/0.22) or about 3 gallons. Thus, we're looking at a car whose efficiency in terms of aerodynamics and rolling resistance is about that of a gasoline burning car getting 33 m.p.g. Seems quite reasonable, though certainly not awe inspiring.

How about cost? I drive about 62 miles per day year around, so I'd use about 62/100 of a full charge, or about 14.9 kilowatt-hours from the battery pack. Let's assume the charging system is 85% efficient, so I need (14.9/.85) or 17.5 kilowatt-hours of electricity. This would probably be at a marginal rate of $0.17/kilowatt-hour since I'd invariably be over my baseline rate with the City of Anaheim. So I'd spend 17.5*0.17 or  $3.01 per day on energy to drive. This is, of course, $3.01/62 or $0.049/mile. Right now in my Land Rover LR3 HSE I'm spending about $0.14/mile on gasoline. The Leaf would provide considerable savings, amounting, in the course of a year, to about $2,060. Certainly, that's nothing at which to sneeze (grammatical pedant that I am).

As to performance, the Leaf boasts a torque (from a dead stop) of  280 Newton-meters (208 pound-feet) and a top speed of over 140 km/h (87 mph). It will accept a full charge from a compatible 220 volt system in about 8 hours, about twice that from a 110 volt circuit. At a suitable quick charge station, it will take an 80% charge in under half an hour and a boost good for about 35 miles in about 10 minutes. Such suitable stations are, at the moment, mostly a distant dream however.

What about creature comforts? It appears to be quite comfortable, modern, and light. It will have room for at least four adults, MP3 connections via USB, a proprietary system built into the satellite navigation system to indicate charging facilities within range, systems to allow one to receive emails from the car on their smart phone and to control certain functions (heating, cooling, etc.) remotely via that smart phone. All things considered, I'm going to look very closely at the vehicle when it becomes available.

Addendum: How much might I reduce my costs if I built a solar charging system to charge the vehicle's battery pack during my working hours? I went here to find the insolation available, using average insolation, the month of March, and a horizontal flat plate to see this map:
Conservatively, 4.5 kilowatt-hours/meter^2/day are available on average. If I'm fortunate, maybe I can create a collector of 2 meter^2. If I'm even more fortunate and technology smiles, perhaps I can find cells with 18% efficiency and provide circuitry to charge the vehicle. Thus, I'd get 2*4.5 kilowatt-hours*0.18 or about 1.6 kilowatt-hours. This would be enough to bring the vehicle from, say, 65% charged to 71.7% or to go a little less than an extra seven miles.  To bring it from fully discharged to fully charged would take a little under 15 days. I can do perhaps a little under twice as well in June but still, seemingly not worth the trouble and expense.

Tuesday, February 09, 2010

More reasons to be embarrassed to be called conservative

I am really not interested in having this become a political blog but, as mentioned in earlier posts, I want to be conservative. That is, I want to conserve our natural and cultural heritage, I want to conserve our resources, our civil liberties as enshrined in the Bill of Rights and elsewhere in the Constitution and its amendments, I want to conserve the rule of law, I want to conserve what's left of our nation's wealth.

So what am I to make of the descriptor "conservative" being used to characterize people who hold opinions such as those expressed by the participants in this clip? Here we see, as we saw with Bush, a celebration of intellectual laziness in the guise of condemning the "elite." We wouldn't think of such condemnation of elite athletes, but by God let no one more learned than Homer Simpson dare to govern us.

When one is expected to apologize for holding informed opinion based on study and inquiry and to celebrate a so-called "leader" who can't remember the list "energy, budget tax cuts, lift American spirits" it's about time to pack it in.

Friday, February 05, 2010

The Onion vs. The Science Channel

I've mentioned on several occasions my level of disappointment with the Discovery Network's lineup of channels and shows and the extent to which they have debased the original concept of bringing some level of scientific authenticity to the wasteland that is television. But a big hat tip to Michael at Only In It For The Gold for pointing me to the far superior Onion treatment.

Udate: So I'm watching "G Word " ("G" is for green, I suppose) on Planet Green (a Discovery Channel) and the host, Summer Rayne (think Johnny Rivers - "taps at my window"), is in Abilene, TX interviewing someone from AES Energy Systems at their Buffalo Gap wind energy facility. It's not really bad until Ned Hall, their President, says "this machine is 1.5 megawatts." Summer asks "and what does that mean?" Hall says "it's enough electricity for your home for the whole year." Ummm, an analogous inanity would be me saying "my car goes 125 miles per hour. That's enough to go from here to San Francisco." And this, let me repeat, is the President of an energy company.