Overhead electric power lines history present future

tahanson43206 · 2023-06-20 09:01:36

In another topic, Terraformer has reminded us that there was a time on Earth when delivery of electric power using overhead lines was truly state-of-the-art! Cities built networks of overhead powered systems, and in the United States there were even interurban lines that provided reliable, silent, environmentally friendly transportation for many years.

The arrival of the personal vehicle put an end to that in the United States.

However, there may be factors in play that would make such systems attractive once again.

Since this is the Mars forum, it is quite reasonable to consider distribution of electric power using overhead lines for travel there.

There are posts in the forum archive that touch on this idea, or variations. This topic is available for those who would like to add to a collection of posts about the history of the technology on Earth, how it may still be in use in remote or isolated locations, and what potential it might have to be brought back into use.

(th)

kbd512 · 2023-06-20 11:09:01

tahanson43206,

This is a very attractive solution for ground transportation efficiency and it absolutely does work, even in a very hilly place like San Francisco. The issues with using it at a global scale have very little to do with how efficient it is, and much more to do with electrification logistics and maintenance costs, plus the ever-present NIMBY issue. I would say that it's more practical to use it inside of a densely populated city where it also costs the most money to operate, but grossly impractical to wire up a great enough percentage of roadways to make it more practical than self-propelled vehicles with onboard energy storage, which is probably why it's not done outside of cities. There are 2.6 million miles of paved roads in America. We'd need giant electrical cables that reach to the moon and back to wire-up 25% of it, or move huge swaths of the population into cities with a population density equal to New York or Tokyo. Yet again, even less practical. Asphalt is cheap compared to train tracks and overhead power cables, so you get more miles of roadway and it requires very little in the way of maintenance cost as compared to the electrification solution. It's another great idea that doesn't economically scale, which is why it's mostly not used.

Very generally, rail infrastructure construction costs can range from $2 million per mile in flat rural areas to $300 million per mile or more in urban areas.

Nonetheless, here are the daunting numbers: constructing a two-lane, undivided road in a rural locale will set you back somewhere between $2 and $3 million per mile — in urban areas, that number jumps to between $3 and $5 million.

Rail costs in Europe:

Most newer routes cost at least $10 million per mile to construct. Clearly, the more expensive the line is to build, the more difficult it will be to break even. While operating costs vary, the cheapest European rail line costs more than $50,000 per seat to operate annually.

So, $50M per year for 1,000 seats on a train in Europe, on top of $10M per mile in construction costs.

Austin's light rail boondoggle will cost $978M per mile in initial construction costs. I'm guessing that that project will never pay for itself, regardless of ridership. If Houston's light rail system provides any metrics to go off of, the city will limit the length of rail line to a few short and rather useless miles near the downtown area, which has quite a bit of foot traffic to begin with. It's a black hole that tax money is being thrown into for vanity's sake, rather than broader utility to the community. "Look at us! We have light rail here in Texas. We're so progressive." Yeah, sure you are, so long as you have a limitless supply of someone else's money to spend.

This seems to indicate that railways make a lot more economical sense in sparsely populated rural areas than urban areas, where there is also very little demand for transportation services.

Why is rail so costly in the areas that would benefit the most from using them?

Land cost, politics, plain old fraud, and NIMBY.

tahanson43206 · 2023-06-20 11:51:42

For kbd512 re #2

Thanks for giving this new topic a running start!

For Terriformer ... this topic was created to give you some running room ...

I'd like to see some history of the technology, with difficulties encountered and solved at the time, and suggestions for how this (relatively old) technology might be updated for the present age.

One option that is available now that was not available in the early 20th Century is electromagnetic refueling of passing vehicles.

The idea of embedding electromagnet induction service in existing roadways is feasible but likely to be considered too expensive in return for benefits that might be achieved. An overhead power line would (presumably) cost less to install, but then the challenge is to figure out how to deliver power to passing vehicles.

In any case, this topic is your's to develop as far as it can go, in the present or near future.

(th)

kbd512 · 2023-06-20 12:27:00

tahanson43206,

I don't think the technology requires any significant changes. It works astonishingly well, as-is, and we'd be hard-pressed to significantly improve upon what we already have. How well it works in operation is not a point of contention, at least not to me. Either public land use gets cheaper in built-up areas, the trains get smaller (and potentially less useful), or we accept that the cost of these systems is primarily why they tend not to be chosen over roadways more often than not. I think familiarity with any technology ultimately breeds contempt, but most of that contempt is misguided. Novelty seems to be a recurring theme with people who want "something new". The novelty quickly wears off, though, and then you're left with how well something works in routine operation and at what cost. I've had no complaints with the trains or trolleys or city buses themselves in the US or Japan. They all ran on time, more or less, were comfortable to ride in, and basically did their job as well as anyone can reasonably expect them to- no frills low-cost transport.

Whatever a more practical overhead electrification solution looks like, it needs to address cost-per-mile and operating cost per seat per year. The only way you can get more of something you want is by reducing the manufacturing and operating costs. I don't know how to do that in a city, because the train itself is not a major expense. It's almost trivial compared to construction and operating costs of all the supporting equipment.

tahanson43206 · 2023-06-20 13:42:59

https://willbrownsberger.com/saying-goo … -trolleys/

For Terraformer ... here is a short essay about why overhead wires will be replaced with electric buses in one jurisdiction.

Will Brownsberger STATE SENATOR
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transportation » mbta » 71 watertown bus »
Saying good-bye to the trolleys
Posted byWill Brownsberger January 27, 2022 64 Commentson Saying good-bye to the trolleys
I’ve ridden the 71 and 73 routes for my whole life and I love the old trolley buses. But soon, they will be gone and it’s a change for the better.
The current fleet of trolley buses is nearing the end of its life. By 2024, they will be replaced by battery electric buses.
Trolley buses have to run close to their power lines. If they catch up with each other — the chronic problem of bus bunching — they can’t pass each other. The lack of ability to pass also makes it hard to design express service. Nor can they deviate around a traffic accident. If there is a construction project in the roadway, they have to be replaced with diesel buses. And, of course, they cannot be shared with any other route that doesn’t have the necessary wires, reducing operational flexibility.
With battery electric buses, we will have the best of both worlds — a low pollution vehicle that has the flexibility necessary to provide more reliable service. And the catenary polls and wires will no longer add to the clutter of our streetscape.
That’s the positive end state that we can look forward to. Getting there, while accommodating planned road projects, is going to force the MBTA to use diesel-hybrid buses on the 71 and 73 during a two-year interim period starting this spring.
For many months, the MBTA has been working with the City of Cambridge and the Town of Watertown to develop a plan to accommodate the following major road reconstruction projects: Mount Auburn Street in Watertown, Belmont Street in Cambridge between Mount Auburn Street and the Belmont line, and Huron Avenue in Cambridge between Fresh Pond Parkway and Cushing Street. Additionally, there are two major utility installations that need to occur on Mount Auburn Street before it is paved — gas lines for the whole length and 1000 feet of 20-inch water main.
These projects would together force the de-energization of the catenary wires for over five years, forcing five years of diesel operation on the 71 and 73. However, the MBTA is going to accelerate its planned replacement of the trolleys with electric buses so that the diesel interim will only be two years.
During the two year interim, the MBTA will install the charging infrastructure needed to support a battery electric fleet out of the North Cambridge garage that currently houses the trolleys.
Replacing the trolley fleet working out of the small North Cambridge garage is a good way to test out the new battery technology at a modest scale. The diesel fleet operates out of much larger garages which are harder to convert. It will take some experimentation to work out charging and operational protocols for the battery buses. The main challenges relate to the performance of batteries in our cold weather climate.
To protect against cold weather failures, the battery buses that the MBTA plans to purchase will have a backup heater that uses diesel fuel to reduce battery drain on the coldest days. With this very limited use of diesel, the new battery fleet will be cleaner than the current mixed trolley and diesel fleet — diesel buses are routinely used as replacements for the trolleys for operational reasons.
Ultimately, the MBTA is committed to the full electrification of its fleet. As larger electrification plans have firmed up, advocates have become more comfortable with North Cambridge as an early step.
The MBTA engineers have developed a complex plan to deal with a complex set of challenges. I appreciate their efforts and I fully support their plan, even though it will mean two years of diesel operation on the 71 and the 73.
RESOURCES
Joint press release on the plan for the trolley buses
Recording of February 15 public meeting about the plan
MBTA electrification plans
MBTA funding presentation including the North Cambridge Garage and other electrification projects
Discussion of electrification funding on January 26 (view video at 1:13:00).
MBTA lifecycle cost comparison for BEBs and ETBs
MBTA carbon impact comparison of BEBs with auxiliary diesel heaters and ETBs with substitutions

For kbd512

While noting your (sensible) observation about the state-of-the-art of overhead trolley service, I am inclined to suppose that if nothing changes, all those systems will disappear in a few years.

(th)

Terraformer · 2023-06-21 13:06:15

Calliban wrote:

HV transmission lines are already made from aluminium alloys. Compared to aluminium alloys, copper has a poor strength-weight ratio. This makes it unsuitable for long spans. There are problems with substituting aluminium for copper in other electrical applications. It is relatively strong, but quite soft, making it unsuitable for sliding contacts. It is also vulnerable to fatigue, making it unsuitable for constant flexing. Aluminium was trialled as a domestic wiring material in the US. It caused a number of fires and fell out of favour. Iron and steel are potential conductors. Because of their ferromagnetic properties, skin effect makes them useless for AC power transmission. But both conduct DC without any problems. Steel is less vulnerable to flexing fatigue and wear, but more vulnerable to corrosion. A layer of graphite grease will suppress corrosion in conductor cables and rails.

If iron conducts DC with little issue, presumably it is suitable for delivering power on overhead wires? Not for one long continuous electrified iron wire for sure, but aluminum could be used to carry power along the length of the line to each short section of iron?

Calliban · 2023-06-21 14:36:47

Terraformer wrote:

If iron conducts DC with little issue, presumably it is suitable for delivering power on overhead wires? Not for one long continuous electrified iron wire for sure, but aluminum could be used to carry power along the length of the line to each short section of iron?

That is how third rails work on UK southern railways. There are transformer-rectifier stations every 1-4 miles along the track. They convert AC at 11kV into DC at 750v. Thick rubber insulated cables, either copper or aluminium alloy, carry the direct current to the third rail, which is an electrically conductive steel. The cables are about 1" thick. At full power, a train can draw up to 4000 amps at 750v. Those are scary currents. Steel only works with DC.

Last edited by Calliban (2023-06-21 14:38:23)

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#1 2023-06-20 09:01:36

Overhead electric power lines history present future

#2 2023-06-20 11:09:01

Re: Overhead electric power lines history present future

#3 2023-06-20 11:51:42

Re: Overhead electric power lines history present future

#4 2023-06-20 12:27:00

Re: Overhead electric power lines history present future

#5 2023-06-20 13:42:59

Re: Overhead electric power lines history present future

#6 2023-06-21 13:06:15

Re: Overhead electric power lines history present future

#7 2023-06-21 14:36:47

Re: Overhead electric power lines history present future

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