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The National Academy of Engineering calls it the greatest engineering achievement of the 20th century. Others call it the largest machine ever made. It snakes through and between cities and lives in the walls of our homes.
Containing the bottled lightening that is electricity, the electrical grid is the foundation for much of our quality of life. While oil mainly powers transportation, electricity powers everything else.
If the grid is so pervasive in our lives, how come it’s seems so brittle when it comes to renewable energy? Before we answer that question, we start with basics of the grid. Think those wires you see everywhere are like the Internet? Think again. They’re more like…well…listen to find out.
2 Comments
Joel,
I love what you are doing with the podcasts. Please keep ‘em coming. I just finished Grid 101.
I must respectfully challenge your grid-as-radio metaphor, because it does not represent the inherit coupling, enforced through laws of nature, of supply and demand on the grid. In radio, if everyone in the country turns on their radio at the same time, the transmitter doesn’t experience it.
For most people, I find the metaphor of a special bathtub more illustrative because everyone has seen a bathtub in action. What makes this bathtub special is that everyone can attach their individual drain on the side, with everyone’s drain all around the tub. And it is very shallow, say 1 inch for discussion. Producers pour water into the tub and must keep the level at 1 inch or the system fails. Consumers take water out, depending on what they turn on in their homes, offices and factories. As consumers take more out, the producers must put more water in to keep up with the flow AND keep the level at 1 inch.
By forcing the special tub to be shallow, we illustrate that the tub (grid) does not have any storage. And the 1 inch level? Think of that is the 120V as you receive at your house. If it falls because not enough water is being poured in to match what is going out — that’s your brown-out condition.
I could go on adding texture to the metaphor to cover spinning capacity, black-outs, etc., but you get the idea.
Don B., P.E. (electrical)
Hi Don,
Thanks for the challenge. No metaphor is perfect. I like yours as well, especially thinking about a million drains hooked up to the bathtub.
The main point of using radio as the metaphor is really one of a broadcast model as opposed to a distributed network model like the Internet. Hi tech geeks need to understand the grid is not an earlier version of the Internet (maybe the telegraph was). It’s a completely different animal.
From an historical perspective, I think it’d be interesting to understand a 1920 engineer’s mind better. Radio was the big idea of the day, so I think if I had the time to dig, I’d find how radio influenced the thinking of other networks. From the engineers perspective, I think radio was the big paradigm shift, as opposed to TV which is, after all, radio with pictures.
But your point about utilization is a good one. With radio, it doesn’t matter how many dumb endpoints there are: adding them doesn’t affect the network. Adding drains to the bathtub does affect the system, as does adding more electrical devices to the grid affect the grid.
I find an interesting property of devices that provide electricity to be that they will supply as much electricity as is needed, even if the load destroys them. If everyone empties the bath tub, the system still exists, there’s just nothing in it. With an electrical device, unless there is some means of regulating it (circuit breakers, electronics, fuses, etc.) it will try to pump out whatever’s needed, even to its own detriment.
I came to understand this unique property when building and designing battery-powered R/C sailplanes. The size and pitch of the propeller determined the load the motor drew from the battery. Size it wrong and the prop would destroy the battery as the battery tried in vain to provide whatever load it demanded.