
The need for steam power was not initially to move people, goods, or services, but to pump water! Much of coal mining in the UK was deep underground mining where flooding is an issue. Thus, to extract more coal, the mines needed to continually pump water. This required a lot of work (work and energy are interchangeable, same units, so this means pumping required lots of energy [in a short amount of time—lots of POWER.) This was one of the first uses of the steam engine. The coal was also the fuel. We will see later that coal is a concentrated energy source that produces a lot of heat (high calorific value) so we can produce lots of steam and do more work with a small mass of coal. This was all happening in my "old" country, England, in the mid-1700s. The presence of coal and the engineers allowed the UK to pioneer the transformation from an agricultural society to that of an industrial society. The steam engine was used to turn looms (used in cloth manufacturing), pump water, turn belts, stir beer, and carry hops up to the upper floors of breweries. This revolution altered the distribution of the populace, enabled mass production, and created the intricate network of communications (road, rail, and canals) so that goods could be moved to different markets.
We will see that most of our electricity is generated from steam. The generator was around in early 1831, but it was not until later in the century (1873) that a practical device was developed. Now, steam engines could turn a generator and produce electric power. By 1936, electric wires had produced a grid that sent electricity throughout Great Britain. We don't even notice the miles of wires that follow the roads and branch off into our houses; it is part of the scenery.
The following (0:41) video gives you the basics of electric power production with steam.
[Dr. Mathews is sitting at a table and we hear a steam engine in the background.] Dr. Mathews: The industrial revolution was powered by coal and steam. I have a little engine here. It's using a solid fuel to produce steam from water. We have it turning a little steam piston and we can use this to make work. I have certainly been to breweries, for example, where they use this type of technology to move the grain up into the beginning of the brewery and everything else would be gravity fed from there. If you were a Ludite (persons opposed to technology), this is what you hated. Because this is what took the jobs away from the people and started the industrial revolution in England in the 17th century - in the 18th century, sorry. Marvelous! [Video ends with Dr. Mathews smiling at the camera.]
Defining Energy
Lesson 2 is really all about the following relationships;
- Energy is the ability to do work.
- Power is the rate (speed) of performing work.
Imagine you have a flooded basement and you go to buy a pump. What you care about is the power of the pump. Either way, the same amount of energy is going to be used moving the water up and out of the basement, but the pump that will do it in a couple of hours has more power than the pump that will take the weekend to do the same amount of work. In essence, you need a pump with more horsepower. A lawnmower may have 5 hp, a garage door opener, 1/2 hp. If I swapped the engines, my garage door would fly open, but my lawn would require a long time to be cut with my now underpowered lawnmower. Much of the rest of the lecture is how we can generate electricity, lots of it and quickly, because, as you now know, we have a huge appetite for electricity (power) and energy in general.
One last thing to keep in mind:
When we generate energy, most of the approaches will also generate some pollution. Our leading contributors in the U.S. to electricity are natural gas, then coal, then nuclear. Even though crude oil is a fossil fuel it is mostly used in transportation. Note that crude oil is an insignificant contribution to electricity generation.