Speaker 1: Get in touch with technology with tech Stuff from how
Speaker 1: stuff Works dot Com. Hey there, and welcome to tech Stuff.
Speaker 1: I'm your host, Jonathan Strickland. I'm an executive producer with
Speaker 1: how Stuff Works in my Heart radio, and I love
Speaker 1: all things tech. So today I want to take a
Speaker 1: look at proposals for clean coal power plants and what
Speaker 1: that actually means. And before I jump into that topic,
Speaker 1: I do want to get this out of the way
Speaker 1: because I want to be as honest and forthright as
Speaker 1: I possibly can be. I'm in favor of renewable energy sources.
Speaker 1: I'm also in favor of pursuing research into nuclear fusion
Speaker 1: as a power source, if in fact that is possible
Speaker 1: to make a sustainable, effective power source. I'm very much
Speaker 1: in favor of getting off of all fossil fuels, particularly coal. However,
Speaker 1: I will do my best to discuss this topic without bias,
Speaker 1: in other words, without just constantly spitting on coal. And
Speaker 1: even an advocate for clean energy like me has to
Speaker 1: admit there are enormous challenges in the way of weaning
Speaker 1: ourselves off of coal and other fossil fuels as an
Speaker 1: energy source. There are big things we have to be
Speaker 1: able to make work for that to happen. So we're
Speaker 1: gonna talk about those two because it's important to look
Speaker 1: at these problems from a big picture perspective and to
Speaker 1: not just ignore the very real hurdles that are in
Speaker 1: our way, because if we do, if we ignore those hurdles,
Speaker 1: then we set ourselves up for failure when we try
Speaker 1: to change things. If we acknowledge the challenges, then maybe
Speaker 1: we can figure out a way of getting around them,
Speaker 1: over them, or through them. So what is coal. I've
Speaker 1: already mentioned that it's a fossil fuel, but what that
Speaker 1: really means is that originally comes from or gain nic material,
Speaker 1: most notably pete. Pete is a large source of a
Speaker 1: lot of the coal that we use today. So this
Speaker 1: organic material accumulates, it gets buried over times of animals die,
Speaker 1: plants die, they decompose, they get buried by sand and
Speaker 1: other stuff, and centuries go by and more and more
Speaker 1: layers build up around this material, and the material then
Speaker 1: starts to compact under all that pressure, and the temperature
Speaker 1: grows because it's under pressure like the Wonderful Queen and
Speaker 1: uh David Boisong. And then as it has all of
Speaker 1: this pressure and heat, the material hardens into a rock
Speaker 1: like substance and it turns into coal. So to call
Speaker 1: it coal, it has to contain a significant amount of
Speaker 1: carbonaceous material by weight or volume. Carbonaceous just means that
Speaker 1: it has to contain carbon or carbon compounds. The amount
Speaker 1: and type of carbon and coal determines how much energy
Speaker 1: the coal contains, and really, to us, what that mostly
Speaker 1: means is how much heat the coal is capable of
Speaker 1: producing when it is burned when it's combusted in a furnace. This,
Speaker 1: in turn is dependent upon a few things, including how
Speaker 1: much heat and pressure went into creating the coal in
Speaker 1: the first place. There are a lot of different ways
Speaker 1: of classifying coal, but there are four main ranks of coal.
Speaker 1: There's anthracite coal, and that has at least eight ton
Speaker 1: carbon in it. This coal has the highest heating value
Speaker 1: of coal, and there ain't a lot of it. It's
Speaker 1: not plentiful in the United States. Less than one percent
Speaker 1: of all the coal mind in the country ranks as anthracite.
Speaker 1: The one place in the United States where it is
Speaker 1: mined right now is Pennsylvania. This coal is used nearly
Speaker 1: exclusively by the metals industry. Coal blaze an important part
Speaker 1: in producing various types of metal and metallurgy. Then you
Speaker 1: have by tuminous coal. Bituminous coal contains between forty five
Speaker 1: to eighty six carbon, and this makes up nearly half
Speaker 1: of all the coal mind in the United States. Specifically,
Speaker 1: it's around for of all the coal we mine here
Speaker 1: in the US. This is the coal that's used primarily
Speaker 1: for coal burning power plants for generating electricity. It's also
Speaker 1: used in iron and steel industries. Five states in the
Speaker 1: United States produced nearly all of the coal for the
Speaker 1: entire country. Those five states are West Virginia, Pennsylvania, Kentucky, Illinois,
Speaker 1: and Indiana. Then you have sub bituminous coal that contains
Speaker 1: between thirty five carbon, so as less carbon. You'll notice
Speaker 1: in these ranks were going down by the amount of
Speaker 1: percentage of carbon the material. It also has a lower
Speaker 1: heating value. It doesn't burn as hot as bituminous coal.
Speaker 1: It makes up about for of all coal production in
Speaker 1: the US. So sub by tuminous and bituminous coal make
Speaker 1: up when you add it up. And remember the anthracite
Speaker 1: makes up less than one percent, so the rest of
Speaker 1: it is made up of lignite. As the last rank,
Speaker 1: it contains only twenty carbon. This stuff can convert into
Speaker 1: synthetic natural gas with some processing. We also call it
Speaker 1: sin gas s y n G A S, and i'll
Speaker 1: talk about that again a little bit later in this episode. Now,
Speaker 1: human beings have been using coal for at least three
Speaker 1: thousand years, though many early references to coal actually are
Speaker 1: referring to charcoal, not to the stuff we mine out
Speaker 1: of the ground. Charcoal is not the same thing as coal.
Speaker 1: Charcoal is what you get when you remove water and
Speaker 1: several compounds from wood, and typically you do this in
Speaker 1: a low oxygen environment, and you would apply a lot
Speaker 1: of heat to the wood. So if it were a
Speaker 1: high oxygen environment, the wood would catch fire and burn,
Speaker 1: but because it's low oxygen, that reaction can't happen. We
Speaker 1: remember the triangle that you need in order to make fire.
Speaker 1: You have to have heat, and you have to have fuel,
Speaker 1: and you have to have an oxidizer, typically oxygen. So
Speaker 1: you're not you're you're you're heating up in a low
Speaker 1: oxygen environment, you're essentially cooking the wood. The technical term
Speaker 1: for this would be pyrolysis. So again you're not burning it,
Speaker 1: you're just removing moisture and heating up the wood in
Speaker 1: this low oxygen environment, and you end up with about
Speaker 1: a quarter of the mass that you started with, or
Speaker 1: a quarter by weight, So all those compounds in the
Speaker 1: water make up a lot of the weight, the majority
Speaker 1: of the weight of the wood, so you end up
Speaker 1: with something that's about the weight of whatever you started with.
Speaker 1: Now we've used coal, the mineral, the stuff we mine
Speaker 1: for a really long time, uh, But the widespread, large
Speaker 1: scale use of coal, the industrial use of coal, really
Speaker 1: didn't get going until the eighteenth century. That's when you
Speaker 1: had inventors like Abraham Darby who developed methods for using
Speaker 1: coal in blast furnaces. And the Industrial Revolution, which really
Speaker 1: began in England and then spread throughout the rest of
Speaker 1: the world, saw an enormous need for coal, and that
Speaker 1: pushed the mining industry from being sort of a modest effort.
Speaker 1: And there were mines that existed before the Industrial Revolution,
Speaker 1: but the need for coal was much more modest then,
Speaker 1: so they were very much surface minds. At this point,
Speaker 1: the need for coal was voracious, so mine started getting
Speaker 1: deeper and going further and requiring way more manpower to operate.
Speaker 1: It became an enormous enterprise, employing thousands of people, tens
Speaker 1: of thousands of people. Coal mining became a lucrative but
Speaker 1: dangerous business. Miners encountered deadly gases, some of them explosive,
Speaker 1: so if you were to create a spark while mining,
Speaker 1: you could ignite that explosive gas and have have a
Speaker 1: true catastrophe. Some gases are poisonous. Uh, there was always
Speaker 1: an issue with flooding. That was always a danger with
Speaker 1: mine chefts. There was also the possibility of mine chefts collapsing,
Speaker 1: but the demand for coal created enough of a reward
Speaker 1: to merit the risk, at least in the minds of
Speaker 1: the coal mine owners, if not the actual miners who
Speaker 1: were doing the work. Britain led the way in coal
Speaker 1: mining in this early time in the eighteenth century, and
Speaker 1: because it was plentiful, lower rank coal in England, not
Speaker 1: the stuff that we would use today to generate electricity,
Speaker 1: would frequently be used as a fuel to warm homes
Speaker 1: in coal furnaces. So you have a furnace, throw some
Speaker 1: coal in there and that was what would generate heat.
Speaker 1: That created a lot of air pollution in England. London,
Speaker 1: which had a reputation for heavy fogs, was frequently blanketed
Speaker 1: in smog, and smog, of course, is made up of
Speaker 1: particulate matter that comes out of burning fossil fuels, particularly coal.
Speaker 1: This peaked in nineteen fifty two with the Great Smog
Speaker 1: of London, which produced a smog so thick and so
Speaker 1: persistent it reduced visibility drastically to just a few meters,
Speaker 1: and it had an enormously negative impact on citizen health.
Speaker 1: People started developing really terrible respiratory illnesses as a result.
Speaker 1: So what does burning coal produce, apart from heat that
Speaker 1: we can use in applications like boiling water into steam
Speaker 1: to turn a turbine and generate electricity. Well, the burning
Speaker 1: process breaks the chemical bonds between the atoms and coal.
Speaker 1: Those molecular bonds get broken and that's what releases energy
Speaker 1: and also several potential pollutants, including contaminants that could be
Speaker 1: part of the coal. That can include stuff like mercury,
Speaker 1: which is a toxic heavy metal. Mercury is dangerous stuff.
Speaker 1: It can damage health in numerous ways. It can cause
Speaker 1: damage to the nervous system, the digestive system, the immune system.
Speaker 1: In fourteen, US coal plants emitted more than forty five
Speaker 1: thousand pounds of mercury coal plants are responsible for of
Speaker 1: all mercury emissions in the United States, so that's a
Speaker 1: big one. Sulfur dioxide is another one that's an emission
Speaker 1: that's very dangerous. Coal frequently has sulfur in it, and
Speaker 1: when sulfur reacts with oxygen during the coal burning process,
Speaker 1: because again you need to have that oxygen to have
Speaker 1: combustion happen, you end up getting sulfur oxide, and that
Speaker 1: sulfur oxide can combine with other molecules. These emissions are
Speaker 1: harmful to us. Also, sulfur dioxide, once it has reacted fully,
Speaker 1: it's got a strong link to acid rain, so that's
Speaker 1: terrible also to smog and can be linked to problems
Speaker 1: like bronchitis and asthma. Then you also have nitrogen oxides.
Speaker 1: It's another byproduct that it can also contribute to smog,
Speaker 1: and it also can end up leading to the development
Speaker 1: of respiratory ailments or make existing respiratory ailments much much worse.
Speaker 1: These are just a sample of some of the pollutants
Speaker 1: that can come out of burning coal. You also get
Speaker 1: coal ash. Uh. These are also called coal combustion residuals
Speaker 1: or CCRs, and this is actually again a collection of stuff.
Speaker 1: It's not just one thing. Um. There's fly ash, which
Speaker 1: is mostly made of silica, which is powdery and very
Speaker 1: very fine. There's bottom ash, which is made up of large,
Speaker 1: coarse ash particles. These particles are too large for heat
Speaker 1: to carry them up the smoke stack of power plants,
Speaker 1: so they tend to gather at the bottom of furnaces.
Speaker 1: There are some types of furnaces that create molten ash,
Speaker 1: also called boiler slag, which has to be drained or
Speaker 1: drawn out of furnaces regularly using a tap, and typically
Speaker 1: you would cool this mixture with water and at that
Speaker 1: point the ash turns into glassy pellets. And then there's
Speaker 1: the flu gas desulfurization material, which is a byproduct produced
Speaker 1: by a sulfur dioxide emission reduction process. It's typically either
Speaker 1: a dry, powdered material or a wet sludge, depending upon
Speaker 1: the reduction method employed. I'll talk more about that in
Speaker 1: our next section. Now, coal ash also contains dangerous stuff
Speaker 1: in it, like lead, cadmium, arsenic, and mercury, and for
Speaker 1: that reason, regulatory agencies like the e p A, the
Speaker 1: environment Environmental Protection Agency, maintain pretty strict rules about how
Speaker 1: power plants may dispose of coal ash to prevent contaminants
Speaker 1: from polluting the environment. These regulations under more recent years
Speaker 1: have been scrutinized and somewhat cut back due to political
Speaker 1: maneuvers by people who are in the e p A
Speaker 1: who previously came from the coal and power utility industries.
Speaker 1: I'll talk more about that because one of the big
Speaker 1: challenges we have to look at isn't a technological challenge.
Speaker 1: It's not a scientific challenge, it's a political challenge. So
Speaker 1: burning coal releases a lot of energy that's useful, but
Speaker 1: it also produces stuff that's harmful to us and to
Speaker 1: the environment. And coal is plentiful and cheap, so it
Speaker 1: makes it a very attractive energy source. It definitely has
Speaker 1: its downsides. The pollutants are undeniably bad, but the fuel
Speaker 1: source is easy to get, and that's one of the
Speaker 1: big reasons why it's hard to wean ourselves off of
Speaker 1: coal that's cheap and other options are less cheap. So
Speaker 1: how do experts propose to mitigate the pollution problems? In
Speaker 1: the next section, we're going to take a look at
Speaker 1: what clean coal is and how it works and try
Speaker 1: to answer the question how clean is it really? But first,
Speaker 1: let's take a quick break to thank our sponsor. All right,
Speaker 1: let's get this out of the way first. Clean coal
Speaker 1: refers to processes and technology, not to coal itself. The
Speaker 1: coal used in clean coal applications is just as dirty
Speaker 1: as coal thrown into an otherwise unremarkable blast furnace, and
Speaker 1: coal is the dirtiest of fossil fuels, meaning that it
Speaker 1: produces more pollution and a wider variety of pollutants per
Speaker 1: unit burn than any other fossil fuel. However, the fact
Speaker 1: that coal is plentiful and inexpensive means it's likely to
Speaker 1: remain important in major industries like generating electricity for quite
Speaker 1: some time unless something major changes. So engineers have dedicated
Speaker 1: a lot of time, research, and effort into creating systems
Speaker 1: that can limit the amount of pollution emitted into the environment.
Speaker 1: There are procedures that can reduce some of the stuff
Speaker 1: that would otherwise be released when you burn coal. And
Speaker 1: this is another important point. There's no single process that
Speaker 1: is good for reducing all pollutants. There's no one system
Speaker 1: that we can put coal through and get clean air
Speaker 1: coming out of the smoke stack. On the other side,
Speaker 1: there are lots of individual systems that are really effective
Speaker 1: or pretty effective at reducing one or more of the pollutants,
Speaker 1: but there's no single approach that gets everything. So if
Speaker 1: you wanted to burn coal with a bare minimum environmental impact,
Speaker 1: you would have to employ multiple methods and thus have
Speaker 1: a more complicated system. And we'll talk a little bit
Speaker 1: more and a bit about why that's a big challenge. Now.
Speaker 1: One of the methods you could use to have a
Speaker 1: clean coal application is called coal washing, and it's pretty
Speaker 1: much what it sounds like. There are two main approaches
Speaker 1: you can take. One involves a physical process in which
Speaker 1: you rely upon the different densities of the various contaminants
Speaker 1: found in coal to be able to separate them out
Speaker 1: and remove them and leave the coal behind. The other
Speaker 1: relies upon chemical processes to remove those same contaminants. The
Speaker 1: most common of the two is the physical approach, not
Speaker 1: the chemical approach. Chemical approach is still one of those
Speaker 1: things that's constantly being studied, but so far, as far
Speaker 1: as I can tell, has not been scaled up to
Speaker 1: a degree where it could actually be used practically in
Speaker 1: widespread applications. So with coal washing, with the physical approach,
Speaker 1: you take the raw coal that you've mined out of
Speaker 1: the ground, and then you use some heavy machinery to
Speaker 1: crush it up into much smaller pieces. You sift the
Speaker 1: crushed coal and you separate it into different sized particles
Speaker 1: um and you can use a series of sieves this
Speaker 1: way right. You can use one that's very fine, and
Speaker 1: that way only the smallest particles come through. And once
Speaker 1: you've got all those out, you transfer the material to
Speaker 1: a sieve that has slightly larger grids in it, so
Speaker 1: that way slightly larger particles can come through. You do
Speaker 1: this several times until you've divided up the coal particles
Speaker 1: into different piles, and then you put them through their
Speaker 1: respective cleaning processes. The process is pretty much the same
Speaker 1: for each one. It just it makes it easier to
Speaker 1: divide them up, so they all tend to work essentially
Speaker 1: the same way. You put the coal particles into a
Speaker 1: container like a vat, and it has jets water jets
Speaker 1: in it that can push water up through the coal,
Speaker 1: and it creates this upward current. The coal is lighter
Speaker 1: than the contaminants, so the coal gets pushed towards the
Speaker 1: top the contaminants to sink towards the bottom and you
Speaker 1: can then separate out the coal from the contaminants. This way,
Speaker 1: then you have to dry the coal before you can
Speaker 1: use as a fuel. That's a process takes quite a
Speaker 1: bit of time and energy in itself. Uh. It reduces
Speaker 1: but does not eliminate all pollutants. So you could reduce, however,
Speaker 1: you know the amount of pollutants you're releasing into the atmosphere,
Speaker 1: but you don't eliminate them entirely, and it requires energy
Speaker 1: to do this system. That's something that we also have
Speaker 1: to keep in mind in each of these steps is
Speaker 1: that the whole purpose of using coal in the first
Speaker 1: place is to generate electricity, at least in the applications
Speaker 1: I'm talking about here. But if you have to dedicate
Speaker 1: energy towards the process, that means you're you're eating into
Speaker 1: your own returns. Right. If your goal is to create
Speaker 1: electricity and you're having to use some energy in your process,
Speaker 1: more and more of the energy and your process to
Speaker 1: get acceptable to generate electricity in this way, then you're
Speaker 1: eating into your own ability to generate the thing you're selling.
Speaker 1: You're you're eating into your own revenue, if you like. So.
Speaker 1: Another process focuses on the gas generated from burning coal.
Speaker 1: Using what are called wet scrubbers, you can treat that
Speaker 1: gas so that a chemical reaction renders otherwise harmful emissions
Speaker 1: inert This is what I was talking about a little
Speaker 1: bit earlier in the last section. So sulfur dioxide, which
Speaker 1: can react with other gases in the atmosphere and create
Speaker 1: fine particles that are harmful to the environment and to
Speaker 1: the health of humans, is a great example. Sulfur dioxide
Speaker 1: scrubber is a flu gas desulfurization technology. As the gases
Speaker 1: from burning coal moves from the furnace into a special chamber,
Speaker 1: nozzles spray a slurry made up of limestone and water.
Speaker 1: Limestone has calcium in it, and the calcium in the
Speaker 1: limestone reacts chemically with the sulfur dioxide. The main byproduct
Speaker 1: is a substance called calcium sulfate. You have this chemical
Speaker 1: reaction and you get calcium sulfate as a result, also
Speaker 1: known as synthetic gypsum. This stuff can be used in
Speaker 1: other materials, including cement, so you can actually put it
Speaker 1: to use elsewhere, which helps bring down the cost. Right
Speaker 1: if you can, if you can put a byproduct to
Speaker 1: use it brings down the overall cost of the process
Speaker 1: because you recapture some of that by repurposing the material.
Speaker 1: Discrubbers can move a lot, but not all, of the
Speaker 1: sulfur dioxide emissions from coal firing plants if they are
Speaker 1: properly used. Nitrogen Oxides are another problem, and they require
Speaker 1: a different approach. Nitrogen Oxides are a group of highly
Speaker 1: reactive gases that are poisonous. Coal combustion produces fuel nitrogen
Speaker 1: oxide and thermal nitrogen oxide. Nitrogen can't be removed ahead
Speaker 1: of time from coal, so the only options you have
Speaker 1: to come up with are away to remove it during
Speaker 1: or following combustion. You can't do a pre combustion cleaning
Speaker 1: to remove nitrogen. You can only do it as you're
Speaker 1: burning it or after you've burned it during combustion. You
Speaker 1: could use what is called a low nitrogen oxide burner.
Speaker 1: This actually requires careful management of the ratio of fuel
Speaker 1: to air to reduce the amount of nitrogen oxide emissions
Speaker 1: during several stages of combustion, so it slows down this process.
Speaker 1: It's possible to retrofit existing boilers with these types of burners,
Speaker 1: but they're limited in their effectiveness. They can reduce emissions
Speaker 1: between thirty to which is not bad, but it still
Speaker 1: means that you have almost you can have up to
Speaker 1: more than half of all emissions still going out into
Speaker 1: the environment, which is not great. After combustion, you can
Speaker 1: use something like selective catalytic reduction, in which you inject
Speaker 1: ammonia into a catalytic reactor and you can use something
Speaker 1: like titanium oxide as a catalyst as flu gas flows
Speaker 1: through it. This is the gas given off by combusting.
Speaker 1: The Colt's very hot and it's got all these chemicals
Speaker 1: in it. All. The reaction with the catalyst and with
Speaker 1: the ammonia creates some byproducts like water, vapor, and nitrogen,
Speaker 1: not nitrogen oxide, but just nitrogen. This process reduces nitrogen
Speaker 1: oxide emissions by eight to nine though unreacted ammonia ammonia
Speaker 1: that did not actually go through this chemical reaction can
Speaker 1: also become an emission that's not great. There's a similar
Speaker 1: approach called the selective non catalytic reduction that requires a
Speaker 1: higher operating temperature because you're not using a catalyst, which
Speaker 1: you know, catalysts make chemical reactions easier if you like.
Speaker 1: They facilitate chemical reactions well in the absence of a catalyst,
Speaker 1: you have to compensate by increasing the temperature um But
Speaker 1: then you don't have of a catalyst, and instead of
Speaker 1: using ammonia, use a different chemical. The reaction with the
Speaker 1: fluid gas results in nitrogen, water, vapor, and carbon dioxide.
Speaker 1: The overall reduction of nitrogen oxide emissions tends to be
Speaker 1: between seventy four. But then you also have CEO two,
Speaker 1: which we'll get to a little bit later. Then there's
Speaker 1: the particulate matter that gets carried up in smoke stacks,
Speaker 1: the the coal ash, if you will, and can contribute
Speaker 1: to stuff like asthma and other respiratory problems. One way
Speaker 1: to reduce those emissions is to use an electrical field
Speaker 1: or a series of high voltage electrical fields. The purpose
Speaker 1: of this is to impart an electrical charge onto the
Speaker 1: particulate matter as it moves through the system. Now, once
Speaker 1: those particles are charged, they will move near collection plates
Speaker 1: that carry the opposite charge, and opposite charges attract, so
Speaker 1: the particular dust will cling to the collection plates. They
Speaker 1: can be really effective in removing that particulate matter, like
Speaker 1: percent effective in some cases. However, this also means using
Speaker 1: some of the electricity you're generating to power the system,
Speaker 1: so again you're getting a reduced return on your investment
Speaker 1: because you have to use some of that electricity just
Speaker 1: to keep the process from being too dirty. Another method
Speaker 1: involves a different approach to using coal called gasification, which
Speaker 1: gives you a hint at what's involved. Use steam and
Speaker 1: pressurized air or pressurized oxygen, and you have that air
Speaker 1: oxygen heated too very high temperatures, and you combine all
Speaker 1: this with the coal. This forces a chemical reaction in
Speaker 1: which carbon molecules break apart and produce sin gas. That's
Speaker 1: synthetic natural gas I talked about earlier. Sin gas is
Speaker 1: a mixture of hydrogen and carbon monoxide. You also get water, vapor,
Speaker 1: and carbon dioxide from this process. The sin gas, once
Speaker 1: chemically scrubbed, can be used in a gas turbine to
Speaker 1: generate electricity. So instead of generating heat to boil water
Speaker 1: and turn a steam turb line, you can have a
Speaker 1: a sin gas powered turbine that just takes the fuel
Speaker 1: and uses that to generate electricity directly. Not only that,
Speaker 1: but then you can also capture waste heat from this
Speaker 1: process to boil water and turn a second turbine a
Speaker 1: steam turbine, so it can increase the the efficiency of
Speaker 1: a power system this way, and um, you essentially turn
Speaker 1: waste heat into productive heat. You still produce carbon dioxide
Speaker 1: this way, and that's a greenhouse gas, and that's still
Speaker 1: a big problem. Uh. And carbon dioxide emissions continue to
Speaker 1: contribute to climate change, so reducing them is critically important
Speaker 1: to limit the damage we face in the years to come.
Speaker 1: Not to avoid the damage that's going to happen one
Speaker 1: way or the other, but to mitigate it. We need
Speaker 1: to cut back on carbon dioxide emissions in order to
Speaker 1: have that happen. So in the next section, I'm going
Speaker 1: to talk about carbon capture and storage, and then we'll
Speaker 1: wrap up the whole clean coal conversation. But first let's
Speaker 1: take another quick break to thank our sponsor. Carbon dioxide
Speaker 1: makes up the vast majority, percentage wise, of all greenhouse
Speaker 1: gas emissions. Back in it was of all greenhouse gases
Speaker 1: emitted by man. Now, there's a natural process on our
Speaker 1: planet in which carbon gets removed from the atmosphere. Plants
Speaker 1: do it as part of their normal life cycle. They
Speaker 1: take in carbon dioxide, but we're dumping way more c
Speaker 1: O two into the air than plants can absorb, and
Speaker 1: on top of that, we tend to wipe out large
Speaker 1: areas of plant life in order to do stuff like
Speaker 1: build cities or have farmland. The carbon we're introducing into
Speaker 1: the atmosphere has been locked away in coal for millions
Speaker 1: of years until suddenly unleashed and dumped in there. So
Speaker 1: is there some way we could reverse that right and
Speaker 1: take carbon out of the air and lock it back up.
Speaker 1: The answer is not only yes, but also that there
Speaker 1: are lots of different ways we can do this. There
Speaker 1: are three general approaches when it. We're talking about coal
Speaker 1: power plants in particular, because there's no simple way of
Speaker 1: just grabbing carbon dioxide from the atmosphere in general. So
Speaker 1: if we look at the places where we're dumping a
Speaker 1: lot of c O two and say, can we find
Speaker 1: a way to capture it right there at that source,
Speaker 1: that would be very helpful. So first, you can use
Speaker 1: sorbents or solvents to capture c O two. Adds orbins
Speaker 1: such as activated carbon or zeolites can separate c O
Speaker 1: two from other gas mixtures, and it's used in the
Speaker 1: process of hydrogen production. It's also used to remove c
Speaker 1: O two from natural gas, but when it comes to
Speaker 1: coal power plants, that's a different story. Absorbent materials have
Speaker 1: a limited capacity to take out CEO two, and they
Speaker 1: aren't quite up to the task of doing the job
Speaker 1: on so large a scale as on flu gas. So
Speaker 1: while it does work in smaller applications for things like
Speaker 1: a cold power plant, this approach would not work. Solvents
Speaker 1: are more promising, and in fact are actually being used
Speaker 1: in some carbon capture facilities already right now as the
Speaker 1: primary way of capturing carbon dioxide. UH there's a process
Speaker 1: called amine scrubbing in which derivatives of ammonia called amines,
Speaker 1: react with flu gas. They can potentially remove an enormous
Speaker 1: amount of carbon dioxide, practically all of it at least
Speaker 1: on paper. But there are some questions about how quickly
Speaker 1: certain amines may degrade in flu gas, or how much
Speaker 1: energy is needed to regenerate the system. You know, how
Speaker 1: much do you how much energy do you need to
Speaker 1: put in to put in enough of the solvent the
Speaker 1: solvents to take out the CEO too, And without answering
Speaker 1: those questions, we can't really know if this is an
Speaker 1: effective approach on a large scale. But there are a
Speaker 1: lot of pilot programs out there that are using this method.
Speaker 1: The next big way, because that was one, right, the
Speaker 1: sword bids and the solvents, The second big way to
Speaker 1: remove CEO two from gases is to use gas separation membranes,
Speaker 1: which is pretty much what sounds like. You can think
Speaker 1: of it again kind of like a sieve um. They
Speaker 1: allow certain materials to pass through and they keep other
Speaker 1: materials back. And there are lots of different types of
Speaker 1: membranes out there, so I'm not going to go through
Speaker 1: them all because they get real technical and there are
Speaker 1: tons of them, but you would typically need several membranes
Speaker 1: along an entire stream because they don't individually achieve a
Speaker 1: high degree of separation. In other words, stuff can get
Speaker 1: through one membrane, so you want to have extra layers
Speaker 1: kind of extra layers of protection to capture all of
Speaker 1: the CEO two. However, adding membranes adds complexity to the system,
Speaker 1: and complexity tends to translate into cost. It means, the
Speaker 1: more complex system, the more expensive it tends to be.
Speaker 1: You would likely need different types of membranes, not all
Speaker 1: just the same one. Because of the various byproducts that
Speaker 1: come from coal, combustion, and in any case, the membrane
Speaker 1: approach isn't currently scalable to be an effective, efficient and
Speaker 1: affordable process for something like a coal power plant. So
Speaker 1: maybe one day it will be, but right now it isn't.
Speaker 1: It's still in the sort of research and development phase.
Speaker 1: The third big process is another one that's not going
Speaker 1: to work too well for major coal power plants, but
Speaker 1: it's cryogenic approaches. That means using the processes of cooling
Speaker 1: and condensation to separate carbon dioxide from other flu gases. Again,
Speaker 1: it wouldn't be an effective process for post combustion treatment
Speaker 1: because you have to do a lot of other stuff
Speaker 1: to the gases first, like you would have to separate
Speaker 1: out the water vapor before you could use a cryogenic approach.
Speaker 1: You could use it in a pre combustion process, so
Speaker 1: before you've actually um started to combust the coal. Capturing
Speaker 1: the CEO two, however, is just the first step after
Speaker 1: preventing the carbon dioxide from going into the atmosphere at large.
Speaker 1: Now you gotta do something with it, right, You captured
Speaker 1: it all, you put it into canisters. Now what Well,
Speaker 1: there are two main long term storage options. One involves
Speaker 1: burying the CEO two deep in the earth. I mean
Speaker 1: literally pumping it there. That's where we got the carbon
Speaker 1: from from the first place. After all, right, we went down,
Speaker 1: we dug out coal, We burned the coal that released
Speaker 1: the CEO two. So in a way, we're just putting
Speaker 1: it back where it blocks, if you think of it
Speaker 1: that way. The other option is putting it into the ocean.
Speaker 1: We call these two approaches the geologic and the oceanic
Speaker 1: carbon capture strategies. So with the geologic approach, you inject
Speaker 1: carbon dioxide deep into the earth itself, typically into underground
Speaker 1: oil or gas fields, where it can get absorbed in
Speaker 1: the into the ground, or you can actually pump it
Speaker 1: into any part of the earth that happens to have
Speaker 1: some salty water and poorous rock in the mix, and
Speaker 1: the carbon dioxide will soak in. The idea is that
Speaker 1: it will lock into the ground and stay there and
Speaker 1: slowly bind with the materials in the surrounding rocks over
Speaker 1: the course of millions of years. The oceanic approach requires
Speaker 1: another step. First, you take the c O two you've captured,
Speaker 1: and then you have to pressurize it to get it
Speaker 1: down to the super critical liquid states. So now you've
Speaker 1: got liquid CEO two. This, by the way, is another
Speaker 1: energy hungry process and one that becomes less efficient as
Speaker 1: you scale up the system. You have to pour energy
Speaker 1: into it in order for it to happen, which again
Speaker 1: eats into your bottom line. Anyway, now you've got liquid
Speaker 1: carbon dioxide. You inject the liquid c O two into
Speaker 1: deep water, and by deep, I'm talking about between five
Speaker 1: hundred and three thousand meters, which is around feet to
Speaker 1: just under ten thousand feet deep. At that depth, the
Speaker 1: waters pressure, the amount of water pressure is enough to
Speaker 1: dissolve the CEO two into the water. However, this process
Speaker 1: would in turn lower the pH of the water at
Speaker 1: that region, turning it slightly acidic, which could end up
Speaker 1: being harmful to aquatic life. So this is something that
Speaker 1: we're not entirely sure would have a net positive environmental impact.
Speaker 1: Now keep in mind, to truly be clean coal, you
Speaker 1: would have to use multiple strategies I've talked about on
Speaker 1: this episode in order to get all the pollutants. Carbon
Speaker 1: capture is not going to do you any good for
Speaker 1: things like stopping mercury from getting out into the environment.
Speaker 1: And even then, you're talking about reducing some of those
Speaker 1: pollutants significantly, but not eliminating them, so some of it's
Speaker 1: still getting out into the environment. And as you add
Speaker 1: in these various systems, as I mentioned earlier, it creates
Speaker 1: more and more complex facilities, and the more complex a
Speaker 1: facility is, the more expensive it gets. Maintenance is also
Speaker 1: an added expense, so you end up with a system
Speaker 1: where the will is still cheap, the fuel is cheap
Speaker 1: and plentiful, but using it gets more and more expensive,
Speaker 1: especially if you want to use it in a way
Speaker 1: where you're capturing as many of these pollutings as possible.
Speaker 1: Some of that expense also, like I said, it means
Speaker 1: dedicating some of the energy or some of the electricity
Speaker 1: in the in the system just to keep the whole
Speaker 1: thing running, So you lose out on some of the
Speaker 1: stuff you would otherwise sell to the public. And in
Speaker 1: order to stay profitable that might mean that you have
Speaker 1: to raise the cost of electricity of the service. So
Speaker 1: as a general rule, and again this is this goes
Speaker 1: without saying that I'm gonna say it, companies aren't terribly
Speaker 1: keen on increasing costs and eating into the bottom line.
Speaker 1: That's generally thought of as a bad thing in business.
Speaker 1: You want to cut costs and maximize profits. So the
Speaker 1: coal industry and power utilities in in the United States
Speaker 1: have lobbied historically to great extents and vigorously to limit
Speaker 1: regulations and in more recent years to reverse previously established regulations.
Speaker 1: And that's because clean coal, if implemented properly at scale,
Speaker 1: is gonna be expensive. It is more environmentally conscious, It
Speaker 1: is the better choice to make from a health perspective,
Speaker 1: from an environment perspective, and I would argue from a
Speaker 1: long term economic perspective, but from a short term economic perspective,
Speaker 1: it may not be the most attractive option if you're
Speaker 1: just looking at literally a return on investment. Shareholders want
Speaker 1: to see money come back to them when they pour
Speaker 1: it into an industry or a company, So it's hard
Speaker 1: to make that case to say in the short term,
Speaker 1: we are not going to see big returns, but further
Speaker 1: down the road, we're going to see much better returns,
Speaker 1: and we're also going to avoid doing further critical damage
Speaker 1: to the environment. Now, when I say that a coal
Speaker 1: power plant that's running on a clean coal strategy is
Speaker 1: more expensive, what does that mean. It means that it
Speaker 1: costs about more to operate a clean coal coal plant
Speaker 1: than a normal coal plant. That's a tall order. Now,
Speaker 1: the cost of clean coal might make it less attractive
Speaker 1: than say, greener renewable energy sources, and you might say, oh, well,
Speaker 1: instead of doing this clean coal approach, maybe we should
Speaker 1: invest more in wind power or hydro power or solar power.
Speaker 1: A carbon tax, which is a tax in which companies
Speaker 1: would have to pay a fee in return for being
Speaker 1: allowed to emit carbon dioxide. Sometimes there's like a credit program.
Speaker 1: You purchase credits, and for each credit, you're allowed a
Speaker 1: certain amount of CEO two emissions, but you have to
Speaker 1: pay for it. The idea is that this creates the
Speaker 1: incentive for companies to not emit carbon, to cut back
Speaker 1: on carbon emissions so as to avoid having to pay
Speaker 1: those fees. It's the idea of creating an economic system
Speaker 1: of pressure to force companies, or at least to encourage
Speaker 1: companies to cut carbon emissions. That that could also help.
Speaker 1: And it would be really nice to see a move
Speaker 1: toward more renewable methods. If companies said, well, coal itself
Speaker 1: is still cheap, it's still easy to get, but using
Speaker 1: it as too expensive. I would love to see that
Speaker 1: because I would love to see more money going into
Speaker 1: renewable energy sources, which have a much lower environmental impact
Speaker 1: than coal or even natural gas, because again coal is
Speaker 1: the dirtiest fossil fuel. It's not hard to have a
Speaker 1: lower environmental impact than burning coal. Uh And and also
Speaker 1: I shouldn't mention renewable energy sources still have an environmental impact.
Speaker 1: You know, we can't just say that they're magical and
Speaker 1: they don't harm the environment at all. That's not entirely true.
Speaker 1: You have to if you look at the big picture
Speaker 1: at how these things are made, there's still an environmental
Speaker 1: cost to be paid. It's just not nearly as dear
Speaker 1: a cost as using coal. So one of the really
Speaker 1: big challenges facing renewable energy is that it's up against
Speaker 1: a super cheap fossil fuel. If we decide the only
Speaker 1: way we can allow coal combustion is if we require
Speaker 1: coal plants to reduce emissions as much as possible, then
Speaker 1: it might become financially viable for more companies to invest
Speaker 1: in alternatives, because getting a coal plant up to speed
Speaker 1: incorporating all these systems might be more expensive than just
Speaker 1: scrapping it and saying all right, we're gonna get into
Speaker 1: solar now. Um, so that's that's actually something that is
Speaker 1: possible if the regulations are put in place, But that
Speaker 1: has not been the trend, at least in the United
Speaker 1: States over the last couple of years. The trend has
Speaker 1: actually been in the reverse, getting rid of regulations as
Speaker 1: opposed to strengthening them. Now, some people could argue that
Speaker 1: advocating for clean coal at all is really a smoke
Speaker 1: screen pun intended to keep the status quo for as
Speaker 1: long as possible. In other words, someone who says no, no, no,
Speaker 1: we need to keep investing in clean coal might really
Speaker 1: be saying I want to be able to keep using
Speaker 1: coal as a fuel source, and if I can argue
Speaker 1: that the research and development into clean coal is going
Speaker 1: to pay off and dividends, I can keep using coal.
Speaker 1: In the meantime, it becomes like a shell game. Uh.
Speaker 1: Some clean coal technologies are mature technologies. They are proven
Speaker 1: and they can be used right now, and they are
Speaker 1: used and widely some of them, but others are still young,
Speaker 1: they're still in development. There's still questions about whether or
Speaker 1: not they can actually work on large scale applications. So
Speaker 1: the meantime, there are a lot of coal power plants
Speaker 1: out there with few of those systems in place, and
Speaker 1: they're dumping more CEO two and other pollutants into the atmosphere.
Speaker 1: There are a lot of environmental advocates who say we
Speaker 1: can't continue with this, that we can't argue for clean
Speaker 1: coal and simultaneously not use the techniques that we already
Speaker 1: have created to mitigate coal's pollution. So it's a pretty
Speaker 1: dirty argument. Ultimately, clean coal the combustion of coal in
Speaker 1: a way that has the minimal environmental impact. I believe
Speaker 1: that is going to be possible with the right investments.
Speaker 1: Whether those right investments are ever fully made and implemented
Speaker 1: is another question, because it may turn out that companies
Speaker 1: make this decision that it makes more sense to switch
Speaker 1: to a different energy source than it does to update
Speaker 1: all of these old power plants and have them run
Speaker 1: under this new system. I worry right now that some
Speaker 1: of those advocates are absolutely right that clean coal is
Speaker 1: really just allowing an excuse to stick with an old,
Speaker 1: dirty fossil fuel that is doing more harm than good
Speaker 1: rather than and and pulling our focus away from alternatives
Speaker 1: that could be much more beneficial. The nice thing I
Speaker 1: can say is that over the last few years, natural
Speaker 1: gas production has been on the rise, and natural gas,
Speaker 1: while still a fossil fuel, produces fewer pollutants than cold does,
Speaker 1: so the d emphasis on coal is a good thing.
Speaker 1: The problem is we need to make much more drastic
Speaker 1: cuts in greenhouse gas emissions than just switching from coal
Speaker 1: to natural gas will allow. We have to go further
Speaker 1: than that, and the question is do we have the
Speaker 1: willpower and the ingenuity and the innovation necessary to do it.
Speaker 1: I think we do have the ingenuity and innovation. It's
Speaker 1: the willpower part that I question. Um. I certainly hope
Speaker 1: we do, because I would love to see a world
Speaker 1: where we are able to move off of fossil fuels entirely.
Speaker 1: I think it would improve not just the environment, but
Speaker 1: it could improve the economy. It could certainly improve things
Speaker 1: like national security. If you are able to be self
Speaker 1: sufficient for your power needs entirely and you're not having
Speaker 1: to import fossil fuels, that's fantastic. It's a great way
Speaker 1: to improve national security. There are a lot of good
Speaker 1: arguments for it, but economically it maybe a harder sell,
Speaker 1: And sometimes that's the toughest battle to fight, is the
Speaker 1: battle of the price tag. What do you guys think.
Speaker 1: I'm curious to hear your thoughts about energy and what
Speaker 1: we should be turning to? UM, what should we really
Speaker 1: focus on? I'm curious you guys are all tech savvy
Speaker 1: folks right to me let me know I want to hear.
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