tel jetson

steward
+ Follow
since May 17, 2007
Forum Moderator
tel jetson currently moderates these forums:

zone 7? 8?: woodland, washington and portland, oregon. grower, builder, beekeeper, engineer.
woodland, washington
Apples and Likes
Apples
Total received
95
In last 30 days
2
Total given
134
Likes
Total received
588
Received in last 30 days
23
Total given
247
Given in last 30 days
10
Forums and Threads
Scavenger Hunt
expand Pollinator Scavenger Hunt
expand First Scavenger Hunt

Recent posts by tel jetson

I've never had chestnut honey. I've seen it for sale at fairly exorbitant prices, though, so maybe it's real good.
1 day ago
I see bees on chestnut flowers every year. where I'm at, there are a lot of blackberries flowering at the same time, so it isn't lack of forage that leads the bees to the chestnuts. my guess is they're after the pollen, which chestnuts produce prodigiously.
1 day ago
I've got a line on some free IBC totes that I want to use for rainwater and greywater projects. only trouble is that they held water-based drywall primer and there's some residue left in them.

so my question is how to clean them. it should be relatively easy to rinse the primer out, but I don't know what to do with all that wash water. typical advice is to let paint dry then put it in the garbage, but I don't think that will work in this case. I could open the totes up and let the primer dry, but I don't know how I would get it out after that.

so, any ideas?
2 days ago
I don't know, Stuart. in a city, especially one that's dense and human-scaled like NYC, I don't think there's any reason the able-bodied shouldn't just walk or ride a bike. I don't think personal automobiles belong in cities no matter how they're powered.
3 weeks ago

Eric Hanson wrote:Actually I have heard of that as well but in the context of reviving the Aral Sea.  In my personal opinion, the destruction of the Aral Sea is the single greatest environmental crime ever.



as an engineering problem, it wouldn't be terribly difficult to reverse that destruction, at least the hydrologic part of it: tear out all the water diversions on the Amu Darya and Syr Darya. that would still leave a whole lot of pollution to deal with. of course, the actual issue isn't engineering. it's politics.
3 weeks ago
the Soviet Union considered a similar idea for rivers that drain into the arctic from that continent. talked to an oceanographer about it who figured it could have drastically disrupted global thermo-haline circulation and therefore weather patterns worldwide.
3 weeks ago
you mean Teton Dam in the Snake River Basin?

I mean, you're right that there aren't really any Hoover Dams left to build. but there are still a few undammed reaches of river left in the US. and dams are being considered for many of them. I'm working on a project right now modeling the water quality impacts of a proposed flood control dam in Washington State. there are dams in the river basin in question, but none on the entire main stem. so while there might not be any more dams with the immense destruction of the Colorado River or Columbia River Basin dams, there's plenty of damage left to do (and plenty of work to do tearing existing dams down).
3 weeks ago

Eric Hanson wrote:I totally agree with your thoughts on habitat loss from hydro.  At least in the US, that last hydro ship sailed back in the 70s, but elsewhere these plants are still going up.  Further, hydro power is sort of but not really emissions free.  A real conundrum now that we actually have them.



dams are still being built and augmented in the US. for electricity, flood control, irrigation, drinking water, and--in a few cases--providing better spawning conditions for anadromous fish (releasing cool water into streams at critical times). dams are also being removed, which I find very encouraging. it is impressive how quickly river ecosystems recover after dam removal, from upstream spawning habitat and nutrient cycles to sediment transport and estuary function.

regarding reservoir emissions: sediment diagenesis creates the most methane where there is a lot of organic matter in sediments and warm conditions. this is most common in tropical reservoirs. unfortunately, dam-building is becoming fashionable in several tropical regions. if a dam is built for some reason other than electricity generation, I guess it might as well have generation capacity, too, since turbines don't add a whole lot of additional problems.


anyway, I appreciate your initial question. it's worth exploring the reality of these things that are sold to us as unmitigated good, especially as huge amounts of public resources are used to promote and develop them. to me, electrification of our transportation system is a bit of a red herring. is it an improvement? probably. but I think it's an improvement in the same way that using a tablespoon is an improvement over using a teaspoon for emptying the ocean. it's three times as effective, but still...
3 weeks ago
I sure haven't done that, but it sounds like a fun project.

my only (possibly) helpful input is that I've heard of folks using surplus electric forklift motors for conversions like this.
3 weeks ago
your chemistry and physics aren't quite right. neither are your numbers for coal's share of electricity in the US (it's roughly 30% and declining). but you are absolutely correct that electric cars are far from a panacea and that electrification generally isn't all that great.

let's start with gasoline. chemists often call it BTEX. that's benzene, toluene, ethylbenzene, and xylenes. none of those really resemble methane except for the basic building blocks (hydrogen and carbon). they're all aromatic hydrocarbons, which have a ratio of carbon to hydrogen that's closer to 1:1 (1:1, 7:8, 4:5, 4:5, respectively) than the 1:4 of methane. I don't know much about the chemistry of coal, but it does have higher ratios of carbon to other elements. coal's energy density is also greater than BTEX, which complicates comparisons.

internal combustion engines are very inefficient. they're heat engines: the heat produced by oxidizing fuel does pressure volume work as it pushes a piston to turn a crankshaft (unless it's a rotary engine, which are pretty rare, or a turbine engine, which are even rarer). a large majority of the heat produced, however, is wasted. some of it through the tailpipe, some of it through the radiator, some of it through the walls of the motor.

electrical power plants are much more efficient. a far greater portion of the heat energy is used to pressurize the working fluid and turn turbines. friction losses in modern turbines are minuscule compared to the inefficiencies of an ICE, as are the inevitable inefficiency of transforming chemical energy to kinetic then electrical energy. transmission losses are also certainly an issue. again, all of these losses are dwarfed by the inefficiencies of an ICE.

instead of fossil fuel, let's say the electricity came from hydro-electric generation. there are a few notable exceptions, but dams generally involve what amounts to the wholesale destruction of otherwise hugely complex and productive ecosystems, not to mention that they cause substantial releases of methane gas from sediment in reservoirs. methane is shorter-lived in the atmosphere than carbon dioxide, but very much more potent as a greenhouse gas.

there are other sources of electricity, but honestly, I think the bigger issue is the ubiquity of automobiles generally, our habit of arranging our entire built environment around them for the last hundred years or so, and the un-examined assumptions that we can't do without them and that there must be some way to keep using them everywhere but without the negative consequences (I'm speaking primarily about the US. other countries aren't necessarily blameless here, either, but the US is the worst I've experienced). once the need for and consequences of so many automobiles are honestly considered, it becomes obvious that their overuse is incredibly damaging in so many ways. that isn't to say they aren't a very useful tool. they most certainly are. but they are overused to an absurd degree. if we collectively decided to only use automobiles when they were actually the best tool for the job (and designed them better for how they're actually used), I don't think it would matter so much how they were fueled, so long as care was taken to avoid toxic pollutants.

which brings me to diesel. compression-ignition engines are, as you suggest, more energy efficient than spark-ignition engines. they also last a hell of a lot longer. a huge drawback, however, is that increasing efficiency comes with increasing air pollution in the form of nitrogen oxides. it's obviously more complicated than this, but increasing efficiency in a diesel engine involves increasing temperatures. that, in turn, leads to more creation of nitrogen oxides which have very negative impacts on air quality. there are urea injection systems in many modern diesels that address this, but it's still a problem. and it's why many European cities are enacting laws that will phase out and eventually ban diesel engines.

there again, though, if diesel motors were used far more sparingly, impacts to air quality wouldn't disappear, but the impacts to environmental quality and public health would be far more acceptable.

in the end, using a 1000-lb contraption to move a couple of 200-lb humans around is more than a little ridiculous, regardless of how that contraption is powered. using a similar 1000-lb contraption to move 5000 lbs of cargo is rather less ridiculous. and I'm being generous here. in reality, many (if not most) private automobiles are much larger than 1000-lbs and are only moving one human.

I've gotten fairly far afield from your question, so I apologize. the answer to that question is that, yes, powering cars with electricity is better in many ways than powering them with internal combustion engines, especially if you're primarily concerned with carbon emissions. but in many other ways, they're essentially the same. in a few ways, they're worse (mining of lithium and other elements for batteries).
3 weeks ago