The Layman’s Guide to Electricity Part 1

From plant to plug and back

The Layman’s Guide series is a series of short articles going over particular aspects and principles of fields normally considered complicated or too academic for the average person. Emphasizing the principles and ideas that an average person may encounter in their daily life, while tying them together to the discipline as a whole, The Layman’s Guides are intended to be both a reference and an introduction. It is in essence what I wish I had when I was younger, a series of articles explaining key principles of a profession that allow one to begin exploring the field more holistically. This is the first part of the Layman’s Guide to electricity, meant to be a quick primer on why there’s an energy industry but not an electricity industry and an overview of how it gets from plant to meter.

The sequels to this Guide are available at the bottom of this post.

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Energy vs. Electricity

First things first – in policy and finance debates, we often hear about the energy sector and the electricity industry. The energy sector deals with all the methods we have to harness energy at scale, from the traditional coal mining, oil drilling, natural gas tapping and distribution, hydropower dams, and biomass growing and burning companies to the newer technologies of modern solar panels and wind turbines. These are all types of primary energy – energy that serves as an input to the system. Crude oil and natural gas, for example, can be burned for energy as is, or refined and burned to convert to electricity or heat. These are forms of secondary energy, best thought of as the most convenient method of moving the work done by primary energy from where it is generated to where it is needed. Secondary energy includes fuel oils (the refined products that go into motors), electricity, heat (enthalpy) and mechanical work. For a clear view of the difference between primary and secondary energy, see the Wikipedia article here.

I make this distinction because it’s very important to remember that electricity only covers 20% of the world’s energy needs[1] – and that only counts final consumption, meaning that that 20% falls to 10% when production is considered[2]. The energy sector is incredibly complicated and will need its own Layman’s Guide if this one does well. With electricity being the form of energy the average person is most likely familiar with, I thought it would make the best place to start getting into this tangled morass.

That being said, let’s get started.

Structure of the Layman’s Guide to Electricity

Despite being a subset of the much larger energy sector, electricity is no less complicated. To make it easier for us to probe its depths, I’ll be structuring this guide in a back-and-forth fashion. We’ll tackle the physical half of the process first, describing the three different parts of the process of providing electricity. We’ll begin with a brief explanation of what electricity is, and why it’s such a useful form of energy for our purposes,

Do not try this at home.

Then move on to generation in power plants and renewable farms,

If the flues are doing their job, that’s mostly water vapor.

electricity moves along the transmission system, crossing the country through substations and over high-tension cable,

Country roads, take me home….

to your local distributor, which takes the high-voltage electricity and distributes it through your local area via roadside poles and cables or tunnels, depending on the needs of the area.

Probably on a street near you.

Once we’ve done that, we’ll go from the meter all the way back to the plant, this time following your monthly electrical bill payment back through the entire system to see where that money ends up.

Every month, they cometh.

We’ll be using this sample bill as a method of tracking where we are, and how what we’re talking about fits into how your power is priced. This varies between distributors, regions, and countries, but I hope to keep this Layman’s Guide general enough that we won’t run into that problem.

Why Electricity?

Electricity is the most prevalent form of energy in our day-to-day lives. From the device I’m typing it on to the device you’re reading this on, every step in bringing this essay to you was probably performed on an electrically-powered device. This personal experience makes it easier for the layman to understand just how well the system works – or rather, just how much incredible effort and artifice goes into making it work so seamlessly.

Basics of the Grid

Before anything else, I need to talk about the “grid”. A grid[3] is a single network of synchronized power providers and consumers, connected by transmission and distribution lines, and operated by one or more control centers. As a general rule, each grid must be self-sufficient and handle its own generation and load. It’s like running your house off a generator when the power’s out; if you plug in too many things or the generator stops, that’s it. The only way to move power between grids is with grid interconnections[4] - synchronized interconnections that tie together smaller grids that allow power to be transferred from grid to grid.

Electrical grids often span wide areas – even the North American continent only has two major grids (Eastern and Western Interconnection), three regional grids (Texas, Alaska, and Quebec)[5]. Europe has five; one large one for continental Europe (basically everything from Spain to Ukraine and Turkey), one for the Nordic countries (Finland, Norway, Sweden, Iceland), one for the three Baltics (Latvia, Lithuania, Estonia), one for Great Britain and one for Ireland[6]. Grids are made as large as possible to maximize the number of different generators and consumers that are connected to a single grid, for two purposes – first, to ensure that there is both the generation and demand on hand to balance the load, and second, to have a greater number of plants and lines as backup in case of outages.

Ensuring that both generation and demand are on hand for the grid might seem like a strange idea. Generation, sure, but why would we need to make sure that there is demand on the grid? As it turns out, one of the most important aspects of electricity is its frequency[7], measured in Hertz. This frequency is the number of times per second the electricity moves from the positive to negative pole. Changes in this frequency can make appliances run too fast (higher than design frequency) or too slow (lower than design frequency), or not work at all to avoid damage (outside tolerable frequencies). If there is too much of an imbalance between generation and demand, that imbalance changes the frequency. While this doesn’t have much of an effect on the individual, frequency can play havoc on utilities and industry, as the motors running their large generation facilities or factory machines suffer from the changing frequency. We’ll get into this later, but the equipment used by utilities and industry far exceeds our appliances in complexity and scale, making any bit of disruption very dangerous.

There is another reason that we like to make sure generation and demand are in sync – at a grid scale, electricity resembles a service more than a good, because it must be used as it is being generated. This is for two reasons; first, electricity travels near-instantly across power lines and second, storage of large amounts of electricity for future use is something we have only recently attempted at grid scale. The Tesla Megapack, a large grid-scale lithium-ion battery module with 10 gigawatt-hours deployed and 3.9 megawatt-hours per pack, is a great example. It holds great promise in allowing us to store electricity as is, and not potential electricity in the form of water behind hydro dams or piles of coal or natural gas, but it has also been involved in multiple fires – we’ll get into why later in the Guide, but simply storing and moving that much energy plays a big part in it. For the most part, every time you turn on the lights, the power plant has to work a little bit harder, and every time you turn them off, the power plant relaxes a bit. To make sure we don’t suffer any outages and deal with unplanned increases in demand, the grid needs to run at a small surplus, and with sinks on standby, like pumped hydro.

Size T battery.

As to the second reason, we like big grids because more plants and lines on the grid means more backups in case something goes wrong. Since the generation, transmission, and distribution of electricity requires large capital investments in generating plants, substations, transmission lines, and so on, redundancy is expensive. A larger grid both helps offset this cost and allows for different facilities to pick up each other’s slack by using a larger network, rather than having to cross grid lines. This is most evident in the terrifying prospect of a black start[8] – starting up a grid that has gone completely dark.

Electrical generators are themselves consumers of electricity – air compressors, water pumps, air fans, and so on are run with electricity, and in a total blackout, these cannot draw from the grid or the main generator. They have to keep on hand small diesel generators, in turn used to start larger generators, to power the auxiliary services for the main generator, bringing the whole plant online. This restarts an individual power plant, but to turn the whole grid back on requires coordination. The different plants on the grid must now synchronize their output and turn on one at a time to avoid overloads at any point at the grid. Most often, individual plants supply their local area and reach the correct frequency before connecting to other plants, and reviving the grid one area at a time. Any mistakes in this process could damage the sensitive equipment that brings you electricity every day, perhaps plunging the grid right back into the darkness it just escaped.

As you can see, electricity is complicated, with a lot of moving parts and coordination required to make things happen. All this effort goes into the system behind the scenes, but all we see are poles, wires, and light switches and outlets at home, which I find incredible. The electrical system is a utility –one of the highly complex, underappreciated backbones that allow us to live our lives in the historically unprecedented comfort that we experience today. While they normally fade into the background noise of our daily lives and are taken for granted, I’ll be shining the spotlight clear on them during the Layman’s Guide, as much as my unqualified self can manage.

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By the way, if you have some experience or knowledge in this field, I’d like to ask for your help. As an amateur in this field, reading on my own, it can be a little overwhelming to start, and with no formal education, I sometimes feel a little lost. If you want to help, please e-mail me at argomeditations@proton.me. If you want to support the Guide, buy me a Ko-Fi with the button below.

I’m also providing links to the rest of this Guide, available here:

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[1] https://yearbook.enerdata.net/electricity/share-electricity-final-consumption.html

[2] https://yearbook.enerdata.net/total-energy/world-consumption-statistics.html

[3] https://www.techtarget.com/whatis/definition/electric-grid

[4] https://www.cleanenergyfinanceforum.com/2022/03/09/explainer-what-are-grid-interconnections-and-what-complicates-them

[5] https://en.wikipedia.org/wiki/North_American_power_transmission_grid

[6] https://en.wikipedia.org/wiki/Wide_area_synchronous_grid

[7] https://en.wikipedia.org/wiki/Utility_frequency

[8] https://en.wikipedia.org/wiki/Black_start