Wednesday, March 14, 2018

Hydro, Water

[–]JustSomeBadAdvice 7 points 3 days ago*

Alright, I hope this answer lives up to /u/mhmthatsmyshh's expectations...

So /u/ajak1121's answer covers a significant part of it - Generators don't do a very good job of adjusting to the load you are applying to them and also can't provide the power on-demand the instant you need it. But there's more detail that I think is noteworthy to explain. To do this, I'll compare and contrast a generator versus The Grid. Fair warning: Long, but those reading my posts on this probably already know what they're in for. :)

Generators

To run basic appliances in your house such as the lights, water heater, and oven you need at least 10 kilowatts of power available, more likely 20 if more than one thing could be turned on at the same time. A 10-20 kilowatt standalone generator costs about $5-8k with today's economies of scale, just for the generator. After installation you're looking at more like $9-$15k in costs. So you're already perilously close to the $15k per home cost I calculated in my previous post.

But that isn't the half of it. Generators need to be powered, which means you need to transport the fuel to it. If you are on a rural farm that doesn't want to transport electricity, which is comparatively cheap, transporting fuel constantly isn't going to be very appealing. Among other things it simply costs more. The two most efficient power sources on the planet are wind power and hydroelectric power(and, similarly, tidal) - Wind power costs about 1.3 cents per kWH to generate and hydroelectric costs about 2.1 cents per kWH to generate(Solar follows soon after and is dropping). Fuel-based electricity starts at more like 5 cents per kWH. These costs are all for large scale production, but transporting the fuel is even more difficult for a farmer. Should they burn gas (and time) to transport gas? Paying for a natural gas pipeline to be buried is right out due to cost. Of course they can always use the electricity less, but what's the point of that when the cost of the generator was flat and large to begin with?

To make matters worse, you can only expect to get at most 10 years of heavy use out of a generator - practically the entire thing is a moving part, and moving parts fail. Contrast that with the 20-30 years you can get out of a utility distribution system and the relative value of the utility system shoots up. Next up is who fronts the money? How many individuals and families have $15k sitting around to front to have electricity production today? Utilities are able to do this easily because they can expect to amoritize the costs of the infrastructure they buy over a very long period of time, and they also have a captive paying customer base - which makes it very easy for them to secure investment bonds at low rates. To a farmer, coming up with the $15k up front is a pretty scary proposition, but once the generator is installed, there's no captive customer base, no way for them to get a low-rate loan on the basis of their reliable longevity.

The Grid

So comparing that to The Grid. The Grid is an astonishingly amazing invention. Generators struggle with problems related to their rotational kinetic energy. If your generator is on and you turn on the oven, the generator is suddenly under extremely heavy load. Where before it was spinning at a certain rate with almost no resistance, the next instant tons of force is holding it's spin back and it must ramp up the fuel combustion to get back up to the correct speed. That entire process causes a voltage drop. The lights flicker. Sensitive electronics may fail or worse - be damaged - by the sudden voltage fluctuations. When the oven is switched off, the reverse happens, and the voltage may spike up as a sudden force is removed from the generator. The Grid is powered by multiple two-hundred-megawatt rotors located hundreds of miles away, with multiple layers of transformers in between whose magnetic flux can provide a sudden surge of power no problem. Do you think a two-hundred-megawatt rotor could even have any idea that you turned on your 0.005 megawatt oven?

The next thing to consider is reliability. Assuming you live in the U.S., how often do you have power outages? Or a better question... How often do you have power outages that aren't localized to an area immediately near you? The answer is... almost never. The Grid is astonishingly reliable. There's a dedicated team of hundreds of individuals who track and adjust grid and power provider parameters to keep this operating - a quick visit to /r/Grid_Ops can show some fascinating things for those inclined.

Remember the moving parts? Guess what... The Grid has almost no moving parts. That's why our electrical infrastructure can last so long when so many other things fail over time. Between the power source and your home, generally the only moving parts are the generator's rotors, an occasional cooling fan in heavy power distribution equipment, and whatever device you're powering on your end. Transformers work by induced magnetic flux from wrapped wire coils. The cooling oil filling them moves slowly around distributing heat, but that oil neither leaves, enters, nor reacts with anything else in the system - It is completely passive.

An astute observer of the above might point out that portable generators are much much cheaper than standalone, so why not use something like that? Except portable generators are even less designed to operate under heavy/frequent loads or for long time periods, and they generally speaking are not large enough to power an oven safely.

Water

/u/MrDowntown helpfully reminded us that water utilities are generally quite different from power utilities. Why would that be? The answer comes back around to a similar comparison to generators. But this time, the tables are completely flipped in favor of our rural farmers.

Water distribution is completely different than electrical distribution. In electrical distribution, there are two things whose costs get much much better per unit as they scale up - Generators and Transformers - while wires actually cost slightly more per unit as they scale up and circuit breakers get significantly more expensive as they scale up. I wrote up another thread a few months ago explaining exactly why this is - I can dig that up if someone is curious. But for electricity, it is better to have fewer large sources and fewer primary electricity routes - Because the large sources get better economies of scale, and the primary routes become expensive to safely control but can traverse great distances with relative ease.

For water, the primary problem comes down to sourcing the water in appropriate volumes, and then having an efficient way to distribute the water. Simply put - a small creek or well can easily provide enough water for a few houses, but will struggle with a neighborhood, and forget about city-scale. City-scale water provisioning requires drawing from large rivers. But the costs of these things are relatively flipped. Generators cost about as much as utility services, but with many more problems coming with them. On the flip side, drawing from a well water source can actually cost less than city water provisioning, and can result in better quality water because deep-enough well water is frequently safe to drink without additives, whereas large-scale city water sources must add trace chemicals to prevent bacterial growth - which also affects taste, costs, and maintenance. But well water sources are often just as reliable as city water sources.

For a farmer, drilling a well tap makes complete sense, it lasts much longer than a generator would, and substantially increases the value of their land. Depending on how far they are from the city, the cost of an underground water pipe of sufficient pressure might be prohibitive. Power poles have the advantage that they can span long distances while only dropping a pole every 300 feet, and the wiring is cheap with almost no maintenance. Underground water pipes requires immense amounts of trench digging, and they must be deep enough to avoid freezing in any conceivable conditions that could happen there, not to mention idiots with shovels or backhoes that don't check where they are digging, tree roots, ground shifts, etc.

And when a problem DOES occur with an underground line, it costs a lot more to deal with. Even finding the problem is difficult - you can't see the lines!

Water systems are intricately tied with sewer systems. Guess what is also cheap and efficient for small homes with sufficient land? Septic systems. City sewer systems suffer from the same / worse maintenance problems that the water supply systems do - When there's a problem, there's miles of pipe to inspect and/or dig up. With a septic system, worst case you're digging up ~50 linear feet of earth, and that'd let you replace almost the entire system.

The only reason cities have water systems instead of wells/sewer systems instead is that the population density and small size of the properties simply cannot sustain that many individual wells & septic systems. They shift to larger-scale systems because they have to, not because it is better.

This explains the massive differences we see in water utilities versus electric utilities. Electric utilities serve a large number of customers over a very wide area, leveraging the amazing nearly limitless Grid as a power source. Many water & sewer systems are reliant on Grid power to operate successfully, but the reverse is almost never true. By contrast, water utilities are localized only to serve the specific area which quite simply cannot be served by the lower-density options.

Whew. Hope that was interesting for other people. :)

[–]MrDowntownUrbanization and Transportation 5 points 2 days ago*

While we’ve now had quite a bit of discussion of the technological aspects of water and power utilities, I feel like we’re not giving sufficient attention to the intertwined political and economic aspects.

Of course, water is a necessity of life, so settlement typically only took place where fresh water was available. As urban growth outran local natural sources, it became necessary for cities to buy watersheds, impound reservoirs, and pipe water long distances. Within the city, water for drinking could be drawn from wells or backyard cisterns, or distributed by wagon—but not water for firefighting. That was largely the impetus for laying networks of pipes all throughout the 19th century city; connections to the interiors of buildings came later, at the building owner’s expense.

But what kind of organization could afford such an undertaking, with a payback that might take many decades or be rather indirect (in the form of fewer disastrous fires)? In the early 19th century, as much as the American political character might have resisted the idea, this was one of those rare jobs that only local government could do.

In contrast, at the end of the 19th century, electric power developed in a period where the large corporation, issuing stocks and bonds and maintaining geographically widespread operations, was a mature and proven concept. The business lessons learned from the growth of railroads in the US were fresh in mind. Once the superiority of alternating current was demonstrated, especially for long-distance transmission, power plants could serve a radius of hundreds of miles rather than only a few miles, and the economies of scale made electricity progressively more affordable to more and more customers. That meant that instead of a front-loaded investment for an indirect payoff (fire protection), electricity could finance itself pretty quickly (at least for urban residents). The concept of the holding company was developed to allow cash flow from established power networks to finance new ones, reducing the risk to bondholders. The consolidation that took place in the industry gives us names such as Consolidated Edison; by 1932, eight holding companies controlled three-quarters of the nation's investor-owned utilities.

In regions where large hydroelectric projects needing government involvement were important to power generation, there were often long bitter fights over public vs. private control. In San Francisco, this resulted in the Solomonic compromise of Hetch Hetchy power being available only for direct municipal use, as in powering streetcars and trolleybuses. In rural areas where it was uneconomic for private companies to extend distribution lines, electrification had to wait for the New Deal-era Rural Electrification Administration to set up co-ops.

Though I think timing is a satisfactory explanation for the different approaches taken with water and power, it is useful to note the outliers. Private water utilities were important for a period, in parts of the country. I believe part of San Jose is still served by one. Much more common are publicly owned electric utilities. In 1972, when electrification had reached virtually every part of the nation, public systems served 10 million customers, investor-owned utilities served 60 million, and REA systems served 8 million.

Sunday, March 11, 2018

Why do Americans feel so entitled to enter a restaurant 10 minutes before...

Boards
Current Events
Why do Americans feel so entitled to enter a restaurant 10 minutes before...

Anisoptera Escort Loser5 hours ago#1

...closing?

Why is it so important that you have a sit down restaurant experience right before a restaurant is going to close?

I want to make music that gives people a warm and fuzzy, happy feeling inside. That's what the music I love does for me.

Search