Hello, back to Energy 101. We are talking about electric power
technologies, and today we're going to, going to talk about fossil fuel
technologies which of course is primarily comprised of the coal and natural gas, but
we'll also throw in, hydro, you know, since it doesn't really fit topic wise but
this is a good place to put it compared to other options.
So fossil fuel electric power technologies plus hydro I should add.
Cold power plants, which are the most dominant and here's a picture of one and
let me just comment that this all looks like with all those Plumes coming out of
the stacks, it looks like that there's a lot of pollution, most in fact, over 90%
of these plumes are, is just water vapor. As a matter of fact the plumes right here,
that is all water vapor, because those are cooling towers, and hot, warm water that
the coal power plant has rejected heat to has heated up and is put in and sprayed
into these, into these cooling towers. And air is blown in the opposite direction
and evaporates the water, and the evaporation of some of the water cools the
remainder of the water. So all of, all of these plumes right here
are. Basically water vapor.
Now this is a plume from the combustion process.
Those tall stacks right there. And those do have some pollution.
They got a lot of clean up down here. The clean up the ash, the soot, the soot,
to keep the particulate matter out. They clean up the sulfur dioxide and the
nitric oxides get cleaned up there also. So that's, that's what the overall plant
looks like. I can't tell much about what goes on
inside, but here's a. Quick, quick diagram of what goes on
inside the power plant. You have a coal storage that the coal is
put into a conveyer and is brought to the combustion chamber that's a boiler, or
furnace, if burned. And water is pumped into the pipes the
tubes, the boiler tubes we call them inside the boiler, Boiler and the water is
boiled to high pressure steam. And the steam is then carried over to a
steam turbine These are turbine wheels that when the steam expands from a high
pressure to a lower pressure Which they do is they flow and this is shown as a two
way turbine here. And comes down and it spins the shaft and
the shaft turns an electric generator. And the electric generator, of course, the
wire's carried out to a transformer substation to adjust the voltage, and then
is distributed over transmission lines or distribution lines.
So that's the basic components of the power plant, and of course as we
mentioned, we have to throw away about two thirds of the energy that is released in
the combustion process because of the second law of thermodynamics, or the
quality of energy in converting heat to electricity, the heat generated by the
combustion. So that, this steam, in order to complete
the cycle, has to be cooled back down and condences, and that's done with a
condenser, and river water power plants are built on rivers, is brought in And,
pick up the, it's warmed up as they pick up the heat from the heat from the steam
and is carried back to the river, that's one situation but, in the case of the
picture where I just showed you these are cooling towers so in that case the In that
case, the water is carried to a cooling tower and part, probably two or three or
4% of it is evaporated, and that cooled it and is brought back.
So it uses water and puts, by putting it in evaporating, and putting it in that
atmosphere where This closed system takes the water and just, warm water, and just
puts it back to the river, and of course that's the thermal pollution issue that
has, has restrictions on it regarding how much thermal energy and how hot the water
can be returning it to the river. So that's the coal fired power plant.
A gas turbine is a different situation. There's no steam involved in just a simple
gas turbine. Although we combine it with a steam cycle
that, does involve steam. But this is, is the picture of the
hardware of a 400 megawatt gas turbine. These, these gas turbines are derivatives
of aircraft jet engines. And the technology of developing the.
High temperature that take the, take the high temperature gases and spin it at a
high speed is, was, developed by the Department of Energy.
Excuse me, Department of Defense, for the military and jet air craft.
So this is a technology, fundamental basic technology that was developed by the
military for fighter aircraft and other aircraft to make jet engines more
efficient. And that technology has been, has been
brought down to gas turbine power plants. And, in the combined cycle, what we call a
combined cycle. The, hot exhaust gases that are coming out
of the of, of the engine, these are hot, these are hot gases you, you put it
through a boiler. So these gases are put through the boiler.
That you see back here, right here. So rather than putting coal and burning
coal to create hot gases to boil the water, you do it with the hot gases coming
out of the gas turbine. That's called a combined cycle, because
you're combining a steam cycle with a gas turbine cycle.
So, there's two kinds of gas turbine power plants; one is a simple gas turbine that
just has the gas turbine by itself and, and it the shaft turns a generator to
generate electricity and then the caught gases are just exhausted and the combined
cycle then whereas I just mentioned the hot gasses go through and boil water to
steam and drive a steam power plant so you have two generators.
One generator being turned by the gas turbine the other generator being, being
turned by the steam turbine in the po-, in the steam power cycle.
Hydro I mentioned, of course this is not fossil, but I threw it in here, is where
you have a dam and the dam, it builds up water behind it and it creates a lake.
And most of these dams that we are currently operating to get
hydroelectricity from were created with the primary motivation or recreation of
the lakes. People like water.
They build houses around the lake and boat on the lakes and etcetera.
So but this water that is at high pressure behind the dam, at the bottom of the dam
can be used to generate electricity, as we see in the next slide with this diagram.
So here you have the reservoir, the lake back here, and you have the, the water
pressure increases toward the bottom of the lake.
So you have the high pressure water then come through a grate.
So that fish and things can't get in it, and trash, and it comes through a pipe or
penstock, and it goes through a water turbine.
So we've seen three kinds of turbines so far.
We've seen a steam turbine that's cur-, that's rotated with high pressure steam
and high temperature steam. We had a, gas, turbine that is rotated
with high temperature gases. That is gases that is just the air
combusting with natural gas and the exhaust products from that natural gas
combustion process with mostly air, and then we have the water turbine.
So it turns a generator, and generates electricity like the other turbines do,
and then it goes down into a river. This, this is a good way you can peak
shave, so to speak. Increase, saves the, the water and the
reservoir back here in the lake for the times when they need a high, to meet, they
have to meet a high power demand like in the air conditioning season and the late
afternoon and then they release the water and generate a lot of electricity to, to
generate power during the high power. The man periods which is the best way to
utilize that water reserve because there's, there's not enough water in the
lake to, to generate all of the time 365 days of the year 24 hours a day.
So those are the three power technologies, electric power technologies with a general
operating characteristics, the coal plant, the natural gas plant, and the hydro
plant. One of them, of course, hydro is
renewable. Thank you.