# Bicycles

The DOT says that bicycling is awesome, and has a happy dude in a suit to prove it. see site.

Make sure you make it all the way to the bottom for the funny comic!

What's the big deal about bicycles? Everything! You get exercise and you get around. MrMoneyMustache has a great post on bicycles that you should check out if you have time.

So what's this doing on a climate change website? This one is easy. Unless you eat only beef all the time, a bike produces less CO2 per mile than a car.

Maths!

Good news! The maths this time are super easy! Also, great news! You can eat bacon and then bicycle and it is better for the environment than driving a car!

Burning a gallon of gas gets you about 20 miles and produces 8kg of CO2. Let's assume you weigh 175 lbs and bicycle 20 miles. Most calculators show you burning about 1000 calories to do this. Let's further assume you eat potatoes to get that energy. Potatoes are about .2kg CO2 per kg potato, and a kilogram of potato has about 500 calories that we can use (it has many more, but we can't consume them all perfectly). So you need to eat 2kg of potatoes in order to gain 1000 calories and then bicycle a mile. This equates to .4kg of CO2, or literally only 5% the emissions of a car.

Let's go to worst-case scenario. You eat only beef (note that you will likely die young) which makes way more CO2 in its production than potato (just picture how much cows fart, and that they produce a very strong greenhouse gas). Luckily cow is very energy dense, and you only need to eat .6kg to get 1000 calories. Unfortunately, a cow makes 29kg of CO2 equivalent per kg of meat, and 1000 calories produces 20kg of CO2 equivalent. So you are pumping the equivalent 20kg of cow farts into the air to get those 20 miles (more seriously, it is probably like .5kg of cow farts, plus some CO2, cause them cow farts really are strong greenhouse gases).

So good, but not worth it for the environment

Okay, so I have good news! before you go all vegan on me, Pigs are much more efficient! You only need to eat .3kg of these bad boys to get 1000 calories, and they only produce 8kg of CO2 per pound (pigs don't fart as much methane, I guess? Actually they require less feed and less water to make meat). So you produce about 3kg of CO2 if you eat bacon and bike 20 miles, which is still better than a car. Moral of the story: eat bacon and buy a bicycle. Or you could eat potatoes and veggies and be really good for the environment, but let's be realistic, Americans aren't gonna eat much less meat, so at least they can substitute pig in there.

Eating bacon and then bicycling is still better for the environment than driving.

Other important stuffs (like getting fit and sexy)

I bike in Boston and Cambridge. I bike to work every single day. I never have to worry about finding parking. Better yet, I get to go straight from my door to the door of work. I go shopping with my bike, and that's even better. Nearly all stores have a place to park my bike right at the door, and I can usually fit all the foot I need into a large backpack.

I bike to bars at night, I bike home from the same bars. When I go to a friend's party, I always bike. I pretty much never drive anywhere, and usually don't take the subway. It turns out that biking takes less time than nearly any form of transportation. One great example: my friend Erik and I were walking home from a party (I was walking my bike). He hailed a cab, I jumped on my bike as soon as he was in the cab. Erik lives next door to me. Going at my usual after-party biking pace I beat him home. And then I waited for the cab to arrive, arrogantly leaning my bike against his apartment complex like it wasn't an effort. I had just saved a $10 cab ride and a few minutes. This is not rare. If traffic is heavy, I beat friends in a cross-town trip by about 20 minutes. I live a mere mile from work, but I can get there faster than any other form of transportation. It's faster than driving cause I don't need to go pick up my motorcycle from the garage and then find parking at work. Biking is faster than the subway in nearly all cases, and more convenient in Boston cause my bike doesn't shut down at midnight (nor has it been stolen). Also, every time I take my bike instead of the subway, I save at least$4 round trip. Usually it is more like $20, cause I don't have to take an expensive Boston cab back home after a night out. So let's say I go out twice per week and save an average of$10 every time. That is $20 per week, for 50 weeks, or$1000 per year. Just paid for several of my bikes, yo. Or like 3 beers a week.

What's the best part about bicycling everywhere? Being fit. Your clothes will fit better, you will have more energy, and people find you sexier. Including your spouse or significant other. Yes, yes, they do say that they love you as you are. They are lying. Get on a bike.

So wait. I just said you could do something that saves time, saves money, saves the environment, makes you more attractive, and will get you the ladies/men and/or make your relationship spicier? Why isn't everyone biking right now?!?

More seriously, people might have three reasons: you work too far away (this is a bad idea to start with, both environmentally and from a money perspective), up front cost, and safety concerns.

The first: future post. Too big to include in this one. Suffice it to say, if you don't live close enough to work to bicycle there, you live too far from work. If your job is in an area where you don't want to raise your family, you are probably either in a rough place financially or maybe you are financially well-off financially and are still making poor life decisions (more on this later, too).

The second: A bike costs a lot less than a car. Buy a cheaper car and then buy a bike. More legitimate: you have enough money to afford monthly subway fare, but not a bike. And/or you live in an area where your bike gets stolen. I got nothin' for you here. Try to take public transportation or walk, cause driving is still bad for the environment. If you can afford a car, you can afford a bike and a lock.

The third: Safety! Wear a helmet. Everyone on a bike should wear a helmet. I know helmets make you sweat and mess up your hair. You know what is worse than having bad hair from a helmet? Becoming a vegetable from getting smeared on the road.

Back to accidents. Bicycles do have a slightly higher accident rate per mile. But if you live near work and bicycle, you drive few miles. If you then consider that you cover 6x as many miles on your average car commute as your average bike commute, your death rate per minute is actually equal to that of a car. Mr Money Mustache does a great job of describing this, so I won't go farther. Moreover, If you factor in the health benefits of bicycling, you gain health and actually increases your chances of living longer (same link describes this).

Okay, this is getting long. Time to Summarize!

Bicycling will save the environment, save you time, prolong your life, make you sexier, and save you money. It's a damn miracle drug, and if you aren't on it, you are doing something wrong with your life.

-Jason Munster

# Other Alternatives

Here we will cover a few more electricity producing alternatives, specifically geothermal in its different flavors, and the waste of money that is tidal power. Before that, let's make a quick roadmap of what we have covered, where that is going, and what we haven't yet covered.

Pretty much, we have talked about electricity producing resources. We have only briefly touched on energy as a whole. In the US, for example, 35% of all energy use is petroleum for transportation. None of the stuff we have discussed is useful to replace that without better battery technology. Nonetheless, it is likely that at some point in the next century, much of our domestic energy needs, including transport, will be covered by electricity. And we will require a lot more of it. An upcoming post will assess all the different tech for producing energy we have discussed, and which ones can be potential solutions.

# Geothermal

Geothermal energy exists because it gets hot underground. In general, the temperature of the Earth rises by 30 degrees C for every km you go underground. This temperature increase in depth is called the geothermal gradient. If you go 7km underground, you are pretty much guaranteed temperatures of higher than 200 degrees C. Which, as we all know, is hot enough to boil water. 7km underground is pretty deep, however. In some places, the underground is much hotter. The temperature rises much more rapidly. It could be due to volcanic activity in the area, or radioactive decay underground. Either way, when hot temperatures are closer to the surface, that heat can be harnessed to drive a turbine.

Map of the geothermal resources available in the US. In general, this represents areas of higher temperature gradients.

Geothermal comes in two main flavors. One directly harnesses the steam from the ground to produce electricity (called flash steam, cause the pressurized hot water comes out, flashes to steam at atmospheric pressure, and drives a turbine), the other uses a heat-transfer mechanism where pressurized hot water from the subsurface (it needs to be pressurized, because it is above the boiling point of water at atmospheric pressure) is run through a set of heat-exchanging pipes before being put back underground. There is a third type discussed later in the article called hot dry rock.

Surprisingly, the first mechanism of directly using steam, in practice, is unsustainable and produces pollution. This is because the used steam is often vented to the atmosphere. The steam produced underground has pollutants. Like CO2 and sulfur, amongst other things. If the steam is used directly in a turbine and then expelled to the atmosphere, these pollutants come with it. If the used steam is instead re-injected into the formation, this problem is avoided.

Reinjecting the steam is easier and more common in the heat-exchange mechanism. The super heated stream of steam from underground is already isolated, and re-injection is pretty simple.

And here comes the fun part. If the steam is used and then vented rather than reinjected, the formation will run out of water. Instead of being a renewable resource, the geothermal will be a depletable resource that will only last for 10 or 20 years. This is because the pressure of the formation will drop, and the steam will no longer be able to rise. Does this sound familiar? Oil and gas production need to do this all the time to get maximum recovery rates. Reinjection of fluids is rather easy, and has been pretty well developed by the oil and gas industry.

Hot Dry Rock

The next major innovation takes a cue from the oil and gas industry. Hot dry rock is exactly what it sounds like. The rock starts off hot and dry. It has plenty of heat in it, but there is no steam or water to produce and then make energy from. How is this dealt with? Hydrofracking and injection. A well is drilled, the drill hole goes horizontal, it is fracked to drastically increase the surface area that the well hole can be exposed to, and water is injected into the rock. The water heats up a lot, then it is produced via a separate well to make steam. It is fairly complicated, and costs a lot more.

EGS

EGS stands for enhanced geothermal systems. You will run across this term a lot these days. It more or less means that the heat in the field is managed by either fracking beforehand, injecting water afterwards to maintain pressure in the field and extend the life of the geothermal power plant, or a combination of both. It drastically increases the lifetime and viability of a geothermal site.

Cost

The capital costs of geothermal pretty much will dictate the average cost of electricity produced. It looks like flashed steam will cost the least. In reality, unless the steam is reinjected afterwards, the field won't last as long, and the capital investment costs will have to be paid out over a shorter period of time, resulting in higher costs. Hot dry rock will undoubtedly always remain more expensive because of the costs associated with fracking and reinjection.

Footprint and other

Most of our power plants produce heat above ground, and need storage for either spent nuclear fuel or a coal pile (except for gas plants. They just need pipelines). So geothermal power plants don't take up a ton of space

fun uses of geothermal: geothermal heat is produced and used in Iceland to melt snow on the roads and such.

Tidal

I tend to think that tidal power sucks. In part because it is very expensive, and in part because at best it could provide all of 1% of world electricity.

Tidal power has two main problems: it uses salt water and it has only a few areas that it will work. There needs to be tides of sufficient strength that it can produce electricity, and even then, salt water is corrosive, limiting the lifetime of these power plants and making the levelized capital cost very high.

Tidal power also comes in two main flavors. One is tidal impoundment. Think of it as creating a hydroelectric dam every time the tide goes out. The tide comes in, fills up the area behind the impoundment dam, and then as the tide goes out, the area behind the impoundment dam is filled, and as it flows out, it generates electricity. As you recall from the hydropower article, the energy produced from a hydro dam directly relates to its height. The height of a tidal impoundment dam is limited by the height of the tide. In most parts of the world, this is not very high, so it is not very efficient. Moreover, it kinda messes with natural habitats.

The other type of tidal power is more or less an underwater wind turbine. The problem is that all the moving parts are underwater in the ocean. Where decay and breakdown happens quickly. Moreover, looking at the equation of energy produced via such a turbine:



where A is area, and v is velocity,

we quickly realize that the area of the rotor for a tidal turbine is small (wind turbines have 40m blades, and we aren't gonna have 80m of water depth in most places to replicate that scale in tidal areas), and the speed is slower (water doesn't flow at 6-8m/s very often). Tidal power can't scale and produce as much energy as wind. And the environment is unfavorable. In short, this is not a viable resource for large-scale energy production. And it costs a lot.

Hokay, that is all for today! Thanks for reading!

-Jason Munster

# Solar 2

Photovoltaic solar cells. Solar PV.

This is not an easy thing to describe. For some, you may want to just skip past the technical section, cause it is pretty technical.

Solar PV: they used to take as much electricity to make as they produced in their lifetime. Now they they produce about 5x as much energy as they take to make, and the time to break-even on emissions compared to our cleanest fossil fuel stations is about 6 years (see Kannan, 2005, Lifecycle Assessment Study of Solar PV). Of all the clean technologies (nuclear power excluded), this is the only one with the potential to supply world energy needs (that is the subject of a later post).

In other words, when you hear some fool saying that solar panels take as much energy to manufacture as they ever produce, they are referring to a specific type of solar cells called thin film. A type that was made in the 70s and 80s and only goes into things like calculators. Feel free to ask them to stop being foolish.

Some Math

The light we see is not a homogenous single color. In fact, the light we see is not even all the light that is coming from the sun. Infrared and UV rays are also light, but we cannot see them at all. All this light is just an electromagnetic wave. The waves have different wavelengths, but the same speed, and so all the different wavelengths travel together. What we see is a blend of a tiny part of the electromagnetic spectrum.

This is the electromagnetic spectrum. Visible light, what we can see, is only a small part of it.

The amount of energy contained in a photon is equal to

 where  is the wavelength. h and c are Planck's constant and the speed of light, respectively.

Smaller (shorter) wavelengths give more energy. This is easily shown just by plugging a smaller number into the denominator. Stuff in the infrared is long wavelength, and stuff in UV, X-ray, Gamma ray, etc, are really short wavelength.

Technical Stuff

There is no easy way to do this. I am going to use some terminology that most of you all are unfamiliar with.

A Photo Voltaic (PV) solar panel is a sandwich of two materials. The materials are largely the same, with a few key differences. Both are likely made of silicon (processed sand). But each one has very specific impurities put into them, in a process called doping (not the same type that Lance Armstrong does). This doping is incredibly technical, and very skilled chemists are paid a ton of money to figure out how to do it.

Doping

I won't get into specific materials. Some elements cause there to be a shortage of electrons, or a electron hole, in the whole material (p-type semiconductor). Other elements cause an excess of electrons (n-type semiconductor). So you have one material that can accept electrons, and another material that can give electrons. Putting them together (literally stacking them together) makes magic happen. And by magic, I mean quantum mechanics. Which to most people, including many who study it, is no different than magic.

Just because one has more electrons doesn't mean it wants to be nice and share them. The electron in the n-type literally needs to be excited to be shared. And in PVs, what turns the n-type material on is sunlight. More specifically, photons. Photons are particles of light. ("But Jason!" you say, "Isn't light, like, a wave?" to which I say, "It is both a wave and a particle! Please don't ask me why, just accept it.") Photons contain energy based on their wavelength. Shorter wavelength, more energy (see above).

Here's the fun part. It takes energy to make the n-type semiconductor want to party with the p-type semiconductor. There is a threshold level of energy that needs to be met to kick that electron up from the n-type to the p-type. Too little energy, and the photon doesn't get excited enough to go to the electricity-production party. If there is enough energy from the particular wavelength of light to make that electron jump, then is does jump.

But what if there is more than enough? This threshold level is pretty much determined. Any extra energy will be wasted. This is why PV cells are not particularly efficient. There is a huge amount of light that is too low-energy (all of infrared) for the cell to gather any energy from. There is a lot of light that has much higher energy than required to meet the threshold energy as well. The excess energy is wasted as heat. This can be solved by having a multiple junction cell (multiple junctions just means it has a bunch of different width absorption gaps, so it can harness tons of different energy levels in light). It is capable of absorbing more wavelengths of light, increasing efficiency. And since it has multiple junctions, it is also more expensive and complicated to produce.

Hokay, so, what happens next? You have an electron that has jumped the gap. Then you close the circuit by connecting them with a wire. The electron will go home, back to the n-type, and create an electric charge on its way down. That's about it.

New Methods

Transistors are expensive. Normal glass optics are relatively cheap. The transistors absorb about 20% of the light that hits them. So it would make sense to use cheap optics to focus more light on the transistors and make the transistors small, yes?

One problem with these cells is how warm they get. If they warm up too much, they begin to lose efficiency. Here we see that we have a tradeoff. We want more optics and fewer cells, but if we do this, they get too warm. They stop being efficient. Some scientists and engineers are working on increasing the efficiency of the cells instead, to get more electricity from light. Otherwise, there are clever ways that some mechanical engineers are trying to get around these issues. One new design uses focusing mirrors and liquid cooling to get around this issue.

The pertinent stuff

Everything pertinent, like insolation and weather, was in the last solar article.

Next post: rounding up some of the stray power sources: tidal, geothermal, wave, and then I am pretty much done.

-Jason Munster

# Solar Power

Solar power. It comes in two primary flavors: photovoltaics (PV) and concentrated solar power (CSP). The latter is easy. I decided to do solar power this week, and go back to the dams next week. Big picture: CSP is a bridge technology at best; an investment in most places is little more than a show that the investor is serious about green tech. Moreover, not all places are created equal to invest in solar power. Many of the places that offer the best incentives to have solar power (NJ, MA, Germany) are far from the best places to have solar power.

So this time: insolation, what it means, where it happens. And CSP. PV comes later. Cause it involves quantum mechanics.

So, first, solar insolation map, AKA "Where is the sun shining all the time" map.

Solar power resources in the US. Darker colors indicate better regions for solar power.

Who is not surprised that Alaska is awful for solar power? But check out MA and NJ. Why are they giving tax breaks to install solar cells? Easy answer. To drive the technology forward. Solar panels are really useful in places without any other power source. Like small villages in Africa and other depopulated places. California also has big incentives to build solar, and at least that makes sense, yes?

What determines how much insolation a place gets? Well, you need sun to have solar power. The sun doesn't come out to party at night, so no solar power. A huge one is how much atmosphere the sunlight has to pass through on the way to the the solar panel. More atmosphere means more absorption and dispersing of sunlight (the atmosphere reflects, absorbs, and spreads out sunlight). So higher elevation, like mountains, helps. Less atmosphere. On a related note, the latitude is also very important. Far northern places don't get as much sun annually (Canada, Alaska). Finally cloud and moisture make a huge difference. If there are clouds or moisture in general, sunlight is blocked. This explains most of the east coast of the US, as well as why Nevada, a giant desert, has great insolation. It has a high elevation, and no moisture to make clouds or block sunlight.

The equivalent amount of sunlight hitting the earth at a high latitude spills out over a larger area. In other words, there amount of energy per area is lower. link

CSP is easy. There are a bunch of mirrors, either flat or parabolic (to focus the light even more intensely), and they reflect light to a single point. It produces heat and and then that heat is used to make steam and drive a turbine, just like the basic thermal power plants we have discussed. The heat is typically stored in molten salt, cause it can store a whole lot of energy before it rises a degree in temperature (kind of like water). The heat from this molten salt is slowly released to make that steam for the thermal part.

CSP in action. Lots of light reflected to a single point that then gets very hot. link.

Given that some places on Earth receive upwards of 500W/m directly to the surface (assuming no clouds, no pollution, and daytime), a CSP plant that is 500m*500m could produce 125MW of power. Sounds great, right? 'Cept we know from basic thermodynamics that a thermal power plant that this thing is likely going to be 30% efficient. So something with a quarter of a square kilometer footprint might produce 40MW of power.

So why don't we use this? First, the depiction above is too rosy a picture. CSP is not all that efficient, because if you look at the picture above, you see that not all the area is used for gathering light. There are plenty of empty spaces. Moreover, the transfer of heat from the salt to water is not very efficient. Cause the high temperature and low temperature of the Carnot cycle are closer together (review the thermal power plant post for a review of Carnot efficiencies for all heat engines). Finally, this stuff is expensive. It is easily 2x as expensive as almost any other power technology (other than PV). It requires water to clean the mirrors and has other maintenance costs, the mirrors themselves are quite expensive, and the entire design is expensive. And, if you want to harness the power of the sun, there are better alternatives. Like PV.

As you can tell, I don't have a very high opinion of CSP. Why is that? Take a look at this guy again:

-Jason Munster

# Oil exports and imports

I am going to be lazy this week and post a very short one.

We discussed the Bakken before. It is producing nearly a million barrels a day of oil. This is $100 million in oil sales a day. It costs up to$45/barrel to lift the oil out of the bakken. The Bakken makes profits of about $50 million a day, or about$18 billion a year.

Let's compare this to Saudi Arabia. They pull oil out of the ground for $1 per barrel (it is very efficient there). They make profits of roughly$100/barrel. They produce 12 million barrels a day. In other words, they make $1.2 billion per day. The US currently imports 11 million barrels of oil per day, and we use a total of 20 million. We transfer about$1.1 billion out of the US per day to drive cars.

What is the end product of this money? Many countries with oil have what is called the "resource curse." It is also known as Dutch disease. It turns out if your country has a ton of natural resources, it becomes inefficient and actually has less growth than it would have otherwise. This has several reasons. First, if a government makes a ton of oil money (or copper or gems), they tend to provide stuff for free to the populace. They take the money they make and just use it to pay for social things, like schools, hospitals, etc. Citizens pay less or no taxes. Corruption and handouts tend to be rife, but since the citizenry gets stuff for free, they don't even care. It is highly inefficient, and the country does not develop a real economy. They often will not use the money to diversify the economy, and once the resource runs out, the country is literally worse off than it was before they found the resource. Finally, having resources tends to allow despotic regimes to thrive. Iraq, Iran, Venezuela,

Interesting, eh? Maybe is a good reason to drive a fuel efficient car. Except that China and India and other developing countries with increasing numbers of cars will ensure every barrel of oil finds a buyer.

One last thing. The US gets its oil imports almost entirely from North America, from Mexico and Canada. The Middle East oil goes to China and the rest of the east. Why does the US spend so much money to maintain peace in the Middle East? Cause if the oil produced there came off the market, the former buyers will have to go elsewhere to buy their oil. Despite the fact that we don't get oil from the middle east, the global price (and our price) is much lower than it would be if war caused the oil to stop flowing from there. So why doesn't China start also enforcing peace in the Middle East? How come the US is the major country to fund this peace keeping? Frankly put, no other country has the experience of the US with having troops on foreign soil. China doesn't yet have the experience to effectively do this sort of thing. But they are already practicing. Eventually, as China continues to rise, they will likely begin to shoulder responsibility of ensuring the flow of oil.

# Nuclear Reactors Final

I am getting bored of this topic, and I want to get to wind-solar-hydro so I can finish up with the energy technology stuff and write varied stuff. So I am going to compress it a lot. If anyone wants to see it expanded, let me know and I will take care of it later.

This post is about breeder reactors, thorium reactors, preventing nuclear proliferation, how the electricity costs stack up to other power plants, and why nuclear power is so expensive.

Nuclear power is expensive because the up-front costs are massive. The cleanest and most efficient coal fired power plants might cost a billion dollars to build. It might take 5 years to build it. Nuclear power plants seem to cost about $8 billion to build with all the safety features they use to prevent nuclear meltdowns (seriously, the new tech is very safe, and it shows in the cost). And they seem to take 8-15 years to build, depending on how much Greenpeace or pretty much every other group tries to stop construction via litigation. In other words, they take out an$8B loan and accrue interest for 8-15 years before they can start paying it back. Stuff costs a lot. Why do it? Cause nuclear waste can be contained, unlike the NOx and CO2 from natural gas and coal plants. Also, South Korea thinks it can build a nuclear plant a nuclear power plant in a short amount of time for only $5 billion. United Arab Emirates decided this was a good idea, and is buying four South Korean nuclear reactors to desalinate water. Schematic of the South Korean nuclear power plant to be built in the United Arab Emirates, from link above. The US Energy Administration Administration agrees that nuclear power is now less expensive than it used to be. I have ripped a table straight off their web page that shows it (see, I really am getting lazy in this post). Table 1. Estimated levelized cost of new generation resources, 2018 U.S. average levelized costs (2011$/megawatthour) for plants entering service in 2018
Plant type Capacity factor (%) Levelized capital cost Fixed O&M Variable O&M (including fuel) Transmission investment Total system levelized cost
Dispatchable Technologies
Conventional Coal 85 65.7 4.1 29.2 1.2 100.1
Advanced Coal 85 84.4 6.8 30.7 1.2 123.0
Advanced Coal with CCS 85 88.4 8.8 37.2 1.2 135.5
Natural Gas-fired
Conventional Combined Cycle 87 15.8 1.7 48.4 1.2 67.1
Advanced Combined Cycle 87 17.4 2.0 45.0 1.2 65.6
Advanced CC with CCS 87 34.0 4.1 54.1 1.2 93.4
Conventional Combustion Turbine 30 44.2 2.7 80.0 3.4 130.3
Advanced Combustion Turbine 30 30.4 2.6 68.2 3.4 104.6
Advanced Nuclear 90 83.4 11.6 12.3 1.1 108.4
Geothermal 92 76.2 12.0 0.0 1.4 89.6
Biomass 83 53.2 14.3 42.3 1.2 111.0
Non-Dispatchable Technologies
Wind 34 70.3 13.1 0.0 3.2 86.6
Wind-Offshore 37 193.4 22.4 0.0 5.7 221.5
Solar PV1 25 130.4 9.9 0.0 4.0 144.3
Solar Thermal 20 214.2 41.4 0.0 5.9 261.5
Hydro2 52 78.1 4.1 6.1 2.0 90.3

Note that last column is $per megawatt hour. It is the bottom line cost of producing power from that plant. First, what is dispatchable vs non-dispatchable? Dispatchable means you get it whenever you want it. You can ramp it up or down however you please. Non-dispatchable means that you depend on external factors, like the fickle winds of.. well.. winds? Tangent! Winds are really just redistribution of energy from the equator to the poles. The sun shines more at the equator, heating it up, and then energy likes to move from areas of high energy to areas of low energy, so it does it using wind. And sometimes hurricanes. So really, wind power is just really inefficient solar power. You know what else is really inefficient (and slow) solar power? Hydrocarbons and coal. Cause they are really just buried plant and algae matter and such. That is tens to hundreds of millions of years old. So, coal and oil are really just really old, slow, and dirty solar power. Tangent done! Tangent picture? This shows how the equator heats more than the rest of the earth. These extra heat has to redistribute to be more even. Hurricanes start near the equator cause of the heat there, then move away from it. from: http://oceanworld.tamu.edu/resources/oceanography-book/oceansandclimate.htm Nuclear power is almost as cheap as coal power, and cheaper than clean coal (note, clean coal still produces a ton of CO and NO)! What gives? How is nuclear so inexpensive? Well, we haven't built a nuclear power plant in the US in years. We don't know what it will actually cost. Those are just estimates. Also, people are quite scared of nuclear power. The cost of building nuclear power rises when you have environmentalists and NIMBY folks suing the pants off nuclear power developers. But let's make one thing clear: if the new generation of nuclear power plants are as inexpensive as they are supposed to be, the power is less expensive that all other power plants other than natural gas (note: the US does not have capacity to build more hydro power), and less expensive than even that if you account for NO produced by and methane leaks associated with natural gas power (methane production and transport will always have leaks, and it is 23x as powerful a greenhouse agent as CO2). Let's look at a few more things on the chart above. Remember when I said natural gas got cheap? Look at how cheap it is to produce power from natural gas on the chart above. Think anyone is building nuclear, solar, or offshore wind when you can build and deploy reliable natural gas power? Somehow, the answer to this is yes. Yes, people are building all these things, despite being expensive. Which is kind of cool. Before moving away from costs, look at the variable costs. The variable costs are high for everything except renewables and nuclear. Why is this? Cause renewables and nuclear don't really use fuel. Yes, a nuclear plant uses fuel, but it costs almost nothing relative to the labor and the capital costs. All the cost of these is upfront CAPEX (capital expense), and then you get free power. Finally, lets take a really close look at the variable costs. This link is pretty sweet for those of you interested. It contains variable costs for each power source. You can see that fuel is the bulk of cost of fossil steam plants, but less than a quarter of the total cost of nuclear, and nuclear fuel is 1/4 the price per energy unit than even dirt cheap natural gas. Enough about costs! Onto breeder reactors! In the first post I mentioned that one part of nuclear reactions is to give off neutrons. Sometimes instead of a neutron splitting an atom, the atom absorbs it. U-235 is the uranium we use in nuclear reactors. U-238 doesn't produce as much heat, cause it doesn't like to decay as fast, so it isn't viable nuclear fuel. Or is it?! U-238 is like a catcher in baseball. Except it catches neutrons. And then it incorporates them into its nucleus to become U-239. In other words, it really isn't like a catcher in baseball. The breeder reaction series. From: http://nuclearpowertraining.tpub.com/h1019v1/css/h1019v1_76.htm What's special about U-239? It decays rapidly through a special type of decay to become neptunium-239 and eventually plutonium 239! This process can extract up to 100x the energy from nuclear fuel. You know what's magic about that? Less nuclear waste produced. Also, you produce a ton of nuclear fuel this way. You can also use thorium-232, which then becomes uranium-233 after absorbing a neutron, which can in turn be used for nuclear fuel. Thorium is very cheap and very abundant. So the plutonium and uranium that is magically created through awesomely manipulating nuclear forces is then used in nuclear thermal reactors to produce power. Nuclear proliferation! Having a nuclear power plant does not mean you can make nuclear bombs. Nuclear bombs required U-235 enriched to a very high level. What exactly is enrichment? Natural uranium is less than a few percent U-235, the rest is U-238. The uranium comes as a solid, and is processed by making it dance with a bunch of flourine. UF is produced, which is gasified uranium. The U-238 is slightly heavier than U-235, so it very very slowly settles to the "bottom" if you spin it very fast in centrifuges. Once you have enriched it to somewhere between 5 and 8%, U-235, it is good to go into a reactor and make energy. To make a bomb, you have to enrich it to around 90%. Enriching it further gets exponentionally more difficult. Getting from 50% to 70% is much more difficult than getting it from 10% to 50%. So making bombs is hard. What about plutonium? Seems like any fool can make plutonium. And in fact, they can! All you have to do it get some U-235, wrap it in U-238, and you have make a breeder reactor in your back yard! This seriously happened. Someone made a breeder reactor in their garage at 17. And this wasn't one of those kids that comes from a brilliant family with a ton of money that goes to work in a world famous lab and 'discovers' a new technique under the watchful eye of one of the most brilliant researchers in the world. This was your every day kid who was just really interested in something. Except that building a nuclear weapon from plutonium is even more difficult than from uranium. Cause when you make the plutonium, you always get a large amount of another plutonium isotope. The other isotope loves to go critical much earlier than Pu-239. Remember what happens to a potentially critical nuclear reaction when the fuel gets split up? No? Remember what happened to Chernobyl when a small gas explosion spread the core out everywhere? It completely shuts down the critical reaction. In other words, plutonium loves to accidentally blow up to early and just spread itself around without going critical. Not much of a weapon there. How do we have plutonium bombs then? Really smart people made special triggering mechanisms to make this happen. How do they do this? I dunno. If I did, I wouldn't be out in public writing a blog, I'd be doing super secret awesome research somewhere. Turns out that only the US and a handful of other countries have figured this one out. So while any old fool can make a breeder reactor, the combined science of most nations is not good enough to figure out how to do it. One last thing. If nuclear power is so difficult, how did so many countries get it? Well, US and Russia developed it. The US gave it to China at some point to balance some power issues with the Soviet Union. The US gave it to several other allies as well. The Soviet union gave it out some, too. China then distributed to crazies like North Korea years later, and Pakistan and India were given it through similar pathways. In other words, it is still pretty difficult to develop. Hey, I just covered 4 whole things in one post, and managed to get more terrible jokes in. Awesome. Aww darn, I forgot to include the small amount of original research I did on this topic. Next article Thanks for reading -Jason # Nuclear Disasters Nuclear meltdowns are scary things. Most people don't understand what a nuclear reaction is. They just know it is big. Three major meltdowns have occurred: Three Mile Island, Chernobyl, and Fukushima. Most people know about the last two; Chernobyl was a true disaster, and Fukushima still is leaking radiation into the ocean. Fukushima in particular would have been easy to prevent at two stages: building a higher protective wall around the plant, and flooding the reactor early. Zero people died in Fukushima and Three Mile. Compare that to the disaster that is 11,000 premature deaths and 24,000 heart attacks per year caused in the US alone by burning coal. Moreover, modern nuclear power plants are designed to prevent these accidents from happening. Three Mile Island Three Mile Island occurred in 1979 in PA. A problem began, and human error allowed it to persist. A pressure release valve was stuck open. The valve allowed some irradiated coolant to escape. A poorly trained operator was not familiar with the interface and confused the warning for the loss of coolant (the human-computer interfaces were new and not well designed). When the reactor began to overheat, the control rods were fully inserted. Remnant decay heat persisted, but the chain reaction was halted. Unfortunately, the plant had its emergency cooling pumps shut down for maintenance. You would think that there would be a rule saying that if the emergency cooling pumps were shut down for maintenance, that the plant itself should shut down, right? Well, there was such a rule. It is one the the key rules that the Nuclear Regulatory Commission laid down. The plant was in violation of this key rule. A series of events followed where the cladding of the nuclear fuel rods melted. Some radioactive gas was released into the environment. The average person living within a 10 mile radius was dosed with about 8 millirem (a measure of radioactivity). This is the equivalent to a single chest x-ray. The average person living in a high altitude city, like Denver, CO, gets 100 extra mrem a year just by being closer to the sun. The average US citizen gets 300mrem a year from the environment. A round-trip flight from New York to Europe will dose you with 3mrem. In other words, this was negligible. The consensus of epidemiological studies since shows no increase in cancer rates from this event. One a 1-10 screw up scale, this was about a 6. The operators failed to recognize it as a loss-of-coolant event, and allowed the core to overheat. Not a single person died as a result. All the containment methods, which are 1970s technology and design, worked. The only loss was an economic one. To the tune of about$2 billion.

Chernobyl

Location of the Chernobyl plant, and the spread of radiation contamination afterwards

Chernobyl. April 26, 1986. A real, unshielded nuclear meltdown occurred. Chernobyl did not have the containment building that most other reactors had. In other words, outside of the reactor pressure vessel, there was nothing to contain leaks or explosions. 31 people died that night, and most serious epidemiological studies indicate the total death toll (counting increased incidences of cancer) has caused about 5000 premature deaths in Europe to date. Total increase in cancer by 2065 is estimated to be about 40,000 (not all of these lead to death). Let's be very clear on this. The worst nuclear disaster in history, which has proven to be avoidable just by building a concrete building around it, will have caused 40,000 cancer-related premature deaths in 80 years. This also happens to be the sum total of deaths caused by nuclear. If you look at actual deaths caused in the US alone by coal in the past 80 years, you are looking at numbers close to 1.6 million (about 20k deaths annually in the 70 years prior to strict limitations in 2004, 11k annually since then). This is a conservative estimate, not accounting for likely increase in death through the years when there were no emissions limitations. The number of heart attacks caused by coal emissions over this period is likely double this. Also compare those 40,000 increased cancer incidences to the literally hundreds of millions of unrelated cancer cases that will have occurred over that same 80 year period in Europe alone. 40,000 compared to 1,600,000, the latter produced in an era of much lower population, is pretty staggering. These numbers speak for themselves. Also compare this to the 17,000 deaths that have occurred from airplanes in the 13 years of 1999-2011.

Now that we know the death toll of Chernobyl, and we have a comparison of other deaths, let's talk about this catastrophic failure. It was a very complicated series of events, one that I could write several posts about. Instead, I will direct you to the Wikipedia article. The short version is that they were running some safety tests. They were instructed by Kiev to hold off their tests by 12 hours, making the test run during the overnight shift instead of the shift that was trained to run the test. At the end of the safety tests, they tried to insert the control rods back into the core. Because of several anomalies caused by having moved the test time, there was a minor explosion in the core as the rods were inserted. They were only 1/3 of the way in, and they broke off, preventing full insertion. Unlike modern control rods, these control rods were made of graphite. Graphite is a good moderator, but it also burns really well at high temperature. The lack of control rods allowed a small nuclear chain reaction to happen. This reaction was self-limiting; the energy from the reaction blew the fuel rods apart, making it so there was not enough uranium in one place to continue the reaction. The explosion, however, ripped through the pressure vessel and allowed atmosphere to come in. Air contains O2. Graphite is carbon. Carbon is what burns in coal to produce heat. The heat of the overheated reactor combined with the influx of oxygen was enough to make the graphite burn. This helped spread out the radioactive material. There was no giant concrete containment structure to contain it (remember how Three Mile island had a containment structure, and it worked? So did Fukushima.). The burning graphite spread radioactive material very far.

On a 1 to 10 scale of screw up, this was a 10. Bad idea to do safety tests.

Fukushima

The reactor that blew. https://share.sandia.gov/news/resources/news_releases/images/2012/Fukushima.jpg

Fukushima is still being studied. The latest reports indicate that people living within the immediate vicinity of the plant received 10mrem dosing. Again, this is the dosage a person gets every 10 days just for living on Earth. There have been no increases in cancer, nor is there expected to be any. There are some serious ecological impacts to be dealt with. There are some regions in the immediate vicinity of Fukushima that won't be able to produce agriculture for as much as 20 years. Other areas are uninhabitable for that amount of time. The region groundwater around Fukushima Daiichi is still contaminated and likely will be until a 100 foot deep wall of concrete and steel is built as a containment wall around it. It still leaks radiation into the ocean today. Nonetheless, no one has died from the incident. It could have easily been prevented in two circumstances. An event like this wouldn't even be possible in a modern nuclear power plant, as we will see.

Fukushima Daiichi's emergency backup generators kicked in after the 9.1 magnitude earthquake shut down the power grid. The ensuing tidal wave washed over the protective barrier of the power plant and inundated the generators. They shut down. The emergency backup batteries lasted 8 hours. Then cooling pumps stopped. This is known as a triple power failure. It is something that had been written about in the past for many plants, with measures taken against in. It was something written about with this particular plant, with no measures taken against it. TEPCO was warned by a governmental agency two years prior to this event that their sea walls were not tall enough.