Hello, we're at Energy 101 and today were going to talk about the characteristics of
electric power. We reviewed the, these different
technologies that we used to generate electricity and now we're going to look at
the characteristics of those technologies once they're in the field or new ones that
are being installed. So the care, the technologies that we
mentioned already, and we'll look at quickly today to look at the appropriate
efficiency coal fired, steam, ranking cycles, we call that, natural gas
turbines. They're simple cycles where the It's a
simple gas turbine. And the exhaust heat is, is exhausted to
the atmosphere and is lost. The natural gas turbines combine cycle
where the exhaust is still hot of course. From the turbine is used in a boiler to
boil steam and is put through the same cycle that a coal-fired power plant but
this time, rather than using coal to boil the steam in the ranking cycle, you use
the hot exhaust gases from the gas turbine.
It costs more, but that's essentially almost every thing in the gas turbine area
that's being installed today are the combined cycle gas turbines.
Nuclear, the nuclear plants are steam cycles and they boil steam by the nuclear
fusion process. The hydro that we mentioned, wind turbines
that take kinetic energy out of the air and convert it to a spinning shaft that
can turn a generator and solar photovoltaics that's magic what we call
direct energy conversion. It takes solar energy, the photons in the
radiation from the sun. Is, strike a semiconductor service.
And that gets, it produces electricity directly from the chip, with no moving
parts. And then solar thermal, where we
concentrate the sun's. Rays onto a, a central spot and heat or
boil water in order to again run, run the steam cycle.
Just as a cold fired power plant and as the nuclear plant does.
It's just a different source of thermal energy.
This time being the sun that heats the boiler as it concentrates the sun down to
a very small surface. So let's look at the efficiencies first.
The efficiencies are, are particularly important for the for the fossil fuel
plants. And if we look at coal and biomass,
because biomass is just used in the same way as coal the fire, the boiler, then the
new plants are up a little above 35% and. Peak efficiency.
If you look at the installed base of all of the steams, coal-fired plants out
there, it's around 34%. So that's about, throws away about two out
of every three ener-, BTUs that the coal gives off when you It burning.
So it's a big source of heat that's thrown away in general to the rivers or to the
atmosphere. Natural gas.
A simple cycle gas turbine. I've already mentioned, that just is a gas
turbine without Recovery of the exhaust heat in a stream cycle.
New plants you can get around 35% and these are approximate numbers.
But the install number are actual data, field data, from the energy information.
Agency, there is about 29%, 29% for the simple gas turbine cycle.
And then we have the combine cycle. The, they will go to 55 or even.
Up towards 60 operating and a steady state at their peak efficiency operation.
Which once you get in the field, you don't operate it always at that steady state
peak efficiency condition, and they throttle up and down and you have to get
'em warmed up And plus, some of the technology of course, the plants in the
field are older technologies that have been installed 10 years or 15 years ago.
And those are around 45%. So you can see.
At the combined cycle gas turbine utilizes natural gas at a much higher efficiency
then the coal does, which is only 35%. Versus 45% for the natural gas combined
cycle. That's one of the reasons that you have
lower carbon emissions. Nuclear, nuclear power, as I mentioned, is
just another heat source for the coal-fired steam rankine cycle.
That boils the steam rather than coal, and that is around 35% new plants and around
30% installed plants, it's hard to get data on those numbers becuase nobody
worries too much about The fuel efficiency for nuclear plants because the fuel is
very cheap, it's, it's not even close to the fuel costs to run a coal plant or a
natural gas plant. But of course, the plant's more expensive
to build and you have to amortize that capitol cost and interest on the money
that, over the life of the plant for the kilowatt hours that is produced.
And, the going on for the renewable power plant technologies, hydro.
Hydro actually produce, ca, converts about 90% of the Of the energy in the water,
that is behind the dam due to the depth of the, height of the dam that water the
lower part of the dam is under high pressure, and that moves through a water
turbine and spins the shaft. Produces electricity.
That's not a heat cycle that's limited by the, the second law of thumb on an annex
in that case. It is limited by the first energy that you
can't get more. No more than 100%, because you can't get
more energy out of it then you put in, then the water has when it goes in.
Wind turbines of course extracts kenetic energy out of the, wind, and that extracts
about 45 to 50% Of the kinetic energy that's in the wind, that's passing through
the turbine blades is converted into electricity.
There's a bet, there's a theoretical limit to that.
You can't go to 100%. Even though that's not a heat cycle,
that's limited by the ah[UNKNOWN] efficiency we call it or the heat equation
on the, for the second law, but the best limit no matter what you do, you get rid
of friction and do everything in an ideal manner is 58% so you can't Extract more
than 58% of the kinetic energy in the wind.
And convert it to shared power. This is the limits of, laws of nature.
Then we get to solar. Solar, there's 2 kinds of solar,
technology. Potovoltaic technologies in addition to
the solar thermal technologies, that's. Get many.
But you have the photovoltaic silicone and photovoltaic thin film.
The thin film, the silicone chips thin, thin wafers Poly-crystalline will get 15
to 20% at the peak radiation efficiency at noon typically.
And converted into electricity so that's 15 to 20% of the sun's energy that's
falling on. The on the moh, module, the suh, suh,
collector module will PV module, will be converted to electricity under the best
conditions. Thin films are much lower.
But these are, can be done out of plastic, can be flexible, and their much cheaper
per unit area to produce than the thin wafer polysilicon and polycrystalline, but
the efficiency of converting the sun's energy that hits is lower, so you have to
have on the order of twice as much area. Of the thin film collectors as you do the
sulakin collectors. So that's a just the nature of the physics
of the thin film technology. And it, its really an infancy, it's really
come, be com, coming on strong through, and Or where it'll end up and how it'll
compete yet to, is yet to be seen. And then the solar thermal, I mentioned
the concentrating collectors, the power towers, or the troughs that we looked at
and explain, talked about the technologies there.
Those will convert about 25 to 35% of the solar energy to electriciyy, and again it
goes through the steam cycle which limits it to about 35% because of some second law
of thermodynamics, limitations, as well as the practical limitations of materials.
And frictions and things. And so those are the fuel energy source to
efficiency ranges of. New technology.
And, for. By the way, I didn't talk about the
difference between install technology, and the new technology with renewables.
Because renewable's so young. Basically, there's not much difference
between. What's already out there and what's being
installed, because it's growing so fast the install base is basically in these,
this range, which is where the new technology is too.
So, that's the reason we don't have install versus, Versus the new technology.
Now what about CO2 emissions? An important characteristic of any power
plant in this day and time, are the carbon emissions or CO2 emissions and that's only
a significant factor where we have fossil fuel plants or look at just coal and
natural gas and, Now, the steam cycle puts out and on the right hand side I've got
CO2 emmisions and units of pounds per kilowatt hour.
And in parenthses, grams, per kilowatt hour.
So, in the steam cycle, coal steam cycle, burning coal.
Produce about 2.2 pounds of CO2 per kilowatt hour that's produced.
That's in the field operation. Again, it comes from energy information
agency, data right off their website. That's about 1,000 grams per kilowatt hour
of carbon emissions per kilowatt hour in. The metric system.
If it's new technology, it's not much difference, 10% or so better.
At 2 pounds per kilowatt hour or 900 grams per kilowatt hour.
Not much difference there between installed and New for the steam cycle.
The stream cycle's been around for over 100 years.
150 years, really. And the original steam engines that used
to, on the, boats to power boats. Was 1 of the first broad application of.
The old steam engine is essentially the same technology.
So we've been working on it and trying to improve it for 150 years.
And it's pretty well asymptote. The efficiency that we can get out of the
coal fired steam cycle. When we go to natural gas, and i've only
looked at combined cycle natural gas here. Because that's the dominant new technology
that's been installed over the last several years.
As well as the new stuff that's installed now.
Very little, I don't know of any simple cycle gas turbines, I'm sure there are.
But there's very, very few. Almost all of the plants installed today
are combined cycle. And almost all of the electricity
generated from natural gas is coming from combined cycle gas turbines.
As you can see, the carbon emmisions from the natural gas cycle.
Gas turbine plants is less than half of what it is for coal.
Both with the install and the new,. It's about 0.96 pounds.
Per kilowatt hour or 440 grams per kilowatt hour.
And the new is about 0.8 pounds per kilowatt hour or 350 grams per kilowatt
hour. So that's the reason that, from a global
warming viewpoint, and if you're worried about carbon emissions, where so many
companies are. Are idling or shutting down totally, the
coal plants, particularly the old ones. Some of these plants that are in operation
today were built in the 40's or 50's even. And are still operating.
So they're shutting down a lot of the old. Very old coal plants and efficiencies are
lower and they're a lot more expensive to maintain because they are so old.
And replacing them with combined cycle gas turbines, particularly today with the
cheap natural gas that we have. How long that, that will remain with us is
the $64,000 question. Anybody's.
Gas in some respects. It'll certainly stay down, we expect it to
stay down for the next year or two anyway. But that's the, the efficiency and the
carbon emission characteristics versus the principle characteristics we're interested
in, in these electric power plant technologies.
Thank you.