Solving the Climate Problem

I started this site to get practice in writing science for the general populace. I've slacked off because I am a bit bored of reaching for topics. More importantly, I've been playing rugby with HBSRFC.

So here it is. A generalized and very incomplete version of my view on climate change, who it will affect most, and what we can do about it.

CO2, The Ugly One That Won't Leave You Alone

CO2 stays in the environment for more than 40,000 years. That is longer than nuclear waste lasts. Moreover, its effects are experiences by every person on the planet. What we do now has an effect on the entire planet. Luckily, technology will probably be able to fix this eventually. We can't count on this now, though.

Energy and Climate Change, How They Relate

Climate change is caused by emissions of CO2 by energy use, methane by agriculture and other things, and a host of other very powerful chemicals that are emitted from industry.

How do we solve climate change? The answer is straightforward, but far from simple: use much less energy from sources that produce CO2. Either switch to "green" tech, or conserve. Buy less things that require all the energy to produce. Travel less, or travel in ways that produce less greenhouse gases. Make fewer babies. None of these are easily accomplished, unless you are poor and can't afford any of them. Even then, everyone is striving for a wealthier, more CO2-heavy lifestyle.

So let's assume for a second that people aren't going to change their lifestyles and conserve. We need ways to get energy without belching CO2 everywhere.

Live in Smaller Houses, Buy Less Stuff

You can't convince Americans to live in houses that are the size that Europeans live in and you can't convince them to give up their cars to take public transportation and live in cities (at least in the short term). Houses require energy to heat and cool. Smaller houses mean fewer drafts, leading to less heating and cooling needs.

How about green energy? We have reviewed those technologies. There isn't enough wind to provide sufficient wind power, and the wind isn't always blowing, so sometimes we won't have power when we want it. Hydro power is pretty much fully tapped. Tidal power is a joke in the big scheme. Solar could be an option, but it is currently far too expensive. It is not "deployable" in that with solar, you only get what the sun decides, so we will always need some backup power that can be turned on when we want. Solar doesn't work well at night, for instance. Moreover, the best places for solar are far from cities, so figuring out how to get the electricity from the countryside to the cities is a monumental task, especially in the US (even with eminent domain, getting the land to be the transmission lines through several states would be nearly impossible). So here we stand with three good reasons that solar won't solve our problem in the near future, and with the other resources insufficient. Pretty much, even if we do use solar to solve a lot of our problems, we still need some other energy source to provide baseline power.

Too small! Turn back!

What about buying less stuff? The amount of CO2 that goes into making cars, laptops, etc., is pretty big. How much stuff do you buy that you never use afterwards? Or you maybe use once a year or two? All of that, you could have rented, saved money, and saved space. Even better? The things that go into making electronics like cellphones are not easy to pull out of the ground. Tantalum in your cell phone is pretty much produced by indentured servitude in Africa. The other stuff that goes into electronics, the rare earth metals, these are not so rare. It just turns out that it is difficult to produce it without destroying the environment. The US has plenty of rare earth's the reason it is done in China is that they don't mind wrecking the environment and their workers (see bottom of that post). Yeah, we need electronics to communicate and keep things moving. We don't need a new iphone every 6 months. Those things last at least 2 years.

Energy for Transportation

This is a much larger hurtle. 35% of US energy consumption is in transportation. Transportation requires that the energy source be within the vehicle (unless you are in South Korea, where the energy source is induction and is beneath the road. Pretty badass, if you ask me). Batteries currently weigh a lot, don't have nearly as much energy per pound as gasoline, and require a long time to charge. The problem is not as bleak as it seems, however. Most driving in the US could easily be done with all-electric cars.

Your bus is ugly, but it charges while driving without producing its own CO2. Well done, South Korea.

Cars

I've also written about Electric Cars.

This is an area with a lot of potential. 120 million Americans commute to work by car. The average person lives fewer than 20 miles from work. Substantially all of them commute alone. The Nissan Leaf gets 75 miles before it needs to be recharged. The Tesla model S goes about 275 miles. No matter what the source of energy for an electric car, it produces less CO2 than a normal car. Going by the numbers available on these cars, we see that with the standard US energy mix (some renewables, lots of nuclear, a whole lot of natural gas), they produce between 33% and 50% the CO2 as a combustion engine.

Bicycles

I've written about bicycling. It's good for you, and saves the environment. Unless you eat only beef. Then you have other problems.

Power Generation: What Works

Wind power makes sense everywhere that there is a lot of wind, as long as it is onshore. Wind is pretty much going up everywhere that makes sense. It costs less than a new coal power plant, and is far cleaner.

Solar power is expensive. Is there anywhere it works well? Sure, just take a look at the electricity rates paid by different types of consumers. Commercial real-estate (stores, offices) and residential places (our homes) pay a huge premium on electricity. In most states, residents and commercial consumers pay nearly 15 cents per kwh, while industrial consumers pay closer to 7 center for a kwh. How does this stack up to costs to produce? Let's return to my favorite chart:

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
 

Solar PV costs less in sunny areas than buying from the grid, as long as you are residential or commercial. A big industrial complex gets really cheap power, so they will never use something as expensive as PV.

The Future of Solar

Even if solar power is widely deployed in the future, it doesn't work at night. A lot of people in Houston, and other places that are unlivable without modern tech, would be unhappy if they couldn't sleep in AC. We don't have massive-scale battery tech  to compensate, so we will still need baseload.

Baseload Power

There are two viable places to get baseload power. The first is nuclear power. The second is burning fossil fuels and then catching their CO2 and putting it underground.

Carbon Capture and Storage

This is a very unproven technology. We don't know if we can hold the CO2 underground forever (which is what would be necessary) or whether we can find a place for it. And there are only a few test cases for it. The numbers above are completely unreliable in terms of cost. This might be better in the future, but I would guess that it isn't viable for at least 15 years.

Another issue? You can't just start capturing CO2 emissions from any old power plant. Retrofitting the plant is expensive or impossible. Power plants are built to last 50 years. Even when we figure out carbon capture and storage, we can't easily retrofit old plants to make them work well.

Baseload?

So we need baseload. There are no green baseload sources. Making coal based powerplants green is not currently viable. Nuclear power doesn't produce much CO2, but it has nuclear waste. Nuclear waste lasts a long time. But it is the only power source that contains all its waste. It's manageable. And it decays faster than the Earth will take down CO2.

nuclear power plants are my favorite

What's the biggest problem with nuclear? I'll describe this in more detail later. The long version: it can't get financed. Short version: people are afraid of Nuclear. Cause three powerplants have blown up. Fukushima was completely preventable. The US literally told Japan twice to get their house in order, cause there was trouble.The USGS warned that the walls of Fukushima were not high enough to prevent tsunami flooding years ago. Had they followed through with the USGS recommendations, Japan would not be spewing radioactive waste into their groundwater. Moreover, the US Nuclear Regulatory Commission told Fukushima and Japan that they had a groundwater problem, and that a breach would cause widespread contamination; that if it ever melted down, it would dump nuclear waste into the ground through the water. They indicated Japan should divert the flow of the groundwater to prevent this. Still, no one died in this meltdown.

When Russia melted down a nuclear plant, it was a big mess.

When the US melted down a nuclear plant, no one was harmed and not much was released. It was just expensive to clean it.

Short version? The US is good at nuclear. Korea seems to be good at it. People shouldn't be afraid of it.

But they are. So the plants don't get financed, they don't get built, they aren't allowed to go forward.

As a result, if someone did want to finance them in the US, they would have to pay such massive interest rates that it would never pull a profit.

You know who is building them? Korea. China. Korea is also building power plants in the middle east. Other countries will follow suit. We need to get our house sorted out so our country can build power plants here and elsewhere, too.

Summing it Up

Live in smaller houses, it won't make you less happy. Buy less stuff, it also won't make you less happy. You also don't need to drive an SUV. Or drive as much as you do. Commuting sucks anyways.

Until all that happens, we still need a ton of electricity. Nuclear is probably the best way to do it for now.

That's my rant

Seriously. I'm pretty much done.

Thanks for reading all along. There might be a few more posts on this stuff.

- Jason Munster

Electric Cars

Electric Cars

Electric Cars. Are they really all they are hyped up to be? The short answer: hell yeah. These things are sweet. I want to get my hands on one right now.

Energy flows in the US.

Energy flows in the US. Transportation accounts for 28% of all energy use, primarily from burning petroleum. 

35% of US energy consumption is in transportation. Transportation requires that the energy source be within the vehicle (unless you are in South Korea, where the energy source is induction and is beneath the road. Pretty badass, if you ask me). Batteries currently weigh a lot, don't have nearly as much energy per pound as gasoline, and require a long time to charge. But if we could replace a huge percent of this with more efficient electric cars, it would go a long ways towards arresting GHG emissions.  

120 million Americans commute to work by car. The average person lives fewer than 20 miles from work. Substantially all of them commute alone. The Nissan Leaf gets 75 miles before it needs to be recharged. The Tesla model S goes about 275 miles. No matter what the source of energy for an electric car, it produces less CO2 than a normal car.

How does an electric car produce less CO2 than a gas one? No matter the source of the electricity, even if it is an old inefficient coal plant, the conversion efficiency of an electric car will result in lower CO2 emissions per mile than a gas powered car. The EPA estimates that the Nissan Leaf gets an estimated 125mpg using CO2 equivalent of gasoline. The recent fleet average for the US is about 30mpg for passenger cars. So electric cars emit only 25% the CO2 of your average normal car. Lets be generous and say they emit 40% the CO2 of your best gasoline powered cars.

Commuters would make a very significant difference in emissions if they changed over to electric cars.

Power

Most Americans base the acceleration needs of their car on the idea that they someday need to accelerate down on onramp to get to 65mph on the highway. The amount of power a car has is typically listed as horsepower (hp). This is a terrible measure. The real measure of power of a vehicle is Peak Torque.

Allow me to explain this concept. Roughly speaking, torque is the force going into a rotation of an object. It makes sense to use torque to describe cars, cause they have rotation parts. Think of it as the amount of energy going into the car from the tires rotating on the road.

 \tau = r x F (yes, that is a cross product) where r is the radius, or distance from the center of rotation, and F is the force. For the most part, the torque of a vehicle is entirely determined by its engine. It directly translates to how fast you can accelerate. More torque yields less time from zero to 60.

My motorcycle. Pretty, eh?

Let's compare some examples. First,  my favorite. My bike, a Kawasaki VN750, vs. a Hayabusa (fastest production bike in the world) and an electric bike from Zero Motorcycles, the Zero DS. The electric motorcycle gets up to the equivalent of 400mpg. Compare to a normal bike of around 40-50mpg.

VN750 Hayabusa DS-electric
Style Cruiser Sport Sort of cruiser
Weight 500 lbs 563 lbs 400 lbs
Torque (ft-lbs) 47 99.6
69

Before comparing, let's talk about peak torque. Peak torque is the maximum torque an engine can put out. For a gasoline engine, it is pretty much right before it redlines. So the numbers of 47 and 99.6 you see for the first two bikes means that it is the best they can do. You can think of an electric motor as pretty much always putting out peak torque. In other words, the hayabusa has to jump up to 6500rpm before it can be at full power, then it shifts up a gear, and drops back down out of its full power range. The electric bike doesn't shift gears, either.

Let's look at the Hayabusa power band to illustrate this difference.

Hayabusa power band in yellow. It is not a flat line.

As you can see, the torque output of a gas engine changes with RPM. You will notice the Kawasaki ZX-14 has more max torque, but less torque at the lower end. This is one of the main reasons the 'Busa is considered faster. It comes off the line far faster than other bikes, cause it has higher starting torque. Compare this to an electric engine, which has max torque from 0 RPMs up. You probably see my point about how sweet electric engines are.

So now we can compare electric vs gas based on torque. The electric motorcycle trounces my motorcycle all the time. In the first few moments, it will likely nearly match the Hayabusa. In fact, until the 'Busa hits 3000 RPM, the electric bike won't look too shabby. Why? First, cause it has the same torque as the 'Busa up til the Busa hits 3000rpm. Second, cause it weighs 150 lbs. less. In short, a smaller electric bike kicks butt. (note that the electric bike doesn't have super wide tires to accommodate all its power, so it might slide around a bit when you hammer down).

Where does the electric bike fall short? Range. This bad boy will only go 75 miles on the highway between charges. Funny enough, it'll go 125 in the city. This is all owed to wind resistance.  Back to the point, you can't refill this guy as easily. You need to plug it in. It takes a while to recharge. You can just fill up a motorcycle and go on your way. This bike is pretty much for commuting or visiting friends in nearby cities.

(*2017 update! New electric motorcycles are capable of going 200 miles. Then they have to recharge for a long time. But 200 miles is a long trip).

Also, let's admit it, both my bike and the 'Busa are sexier.

The cars.

Audi A5 Nissan Leaf Tesla S
Cost $38k $21.3k 62,000
MPG 22 102 90
Peak Torque 258 210 443
Weight (lbs) 3549 3354 4650
Range (miles) unlimited 75 275

As you can see, if you are commuting the Nissan leaf makes a lot more sense in every possible way. It costs less to buy than most cars, it has the acceleration potential of a high-end Audi A-5, and the range you need to get to work and back. This beast will accelerate onto the highway just fine. Also, there is the whole power band thing. These electric cars have peak torque all the time.

Overview

Electric vehicles. These puppies accelerate as fast or faster than most vehicles in their class. The shorter range ones are less expensive to buy than most cars, and the cost of making them move is lower. Oh, and they save the environment relative to normal cars.

Whats the drawback? Range anxiety: the other event people think of when they don't want an electric car. Visiting Grandma. People want to buy one vehicle that can do everything they want. There is also the concern of "what if I am in an emergency and really need a car that can drive far right away?!?" How many times has that happened to you in your life? For me, the answer is 0. Any family emergency I had, I took a plane or a bus to.

Most families still own two cars. At least one should be electric. Here's an idea: get one gasoline car to visit grandma when you need, and then get an electric for your commute. Here's another idea: get an electric car or two, and rent a car when you need to go visit Grandma. You will save money either way.

The ridiculousness that is trucks and SUVs? Get a subaru with a roof rack, and rent the trucks and SUVs otherwise. Why the heck are you in a vehicle getting 12 miles to the gallon when gas is expensive, and when burning that gas helps wreck the environment? You, person who commutes to work in a pickup, are a selfish person.

Grid Stabilization

In the Solar and Wind articles, we read that these technologies produce intermittent power. In other words, they can't provide power on demand or at night. Imagine, if you will, that those 120,000,000 commuters all had electric cars. And that they all had excess batter capacity. They could charge up while the wind was blowing and the sun was shining, and discharge while the sun was sleeping and while the wind was lazy. Suddenly part of the problem with wind and solar has some help. This is a huge topic, though, and I won't go farther into it.

Shortest version:

Get an electric car for your commute.

Hokay, that is all for now. I will edit this as I get comments. Thanks for reading!

Jason Munster

Geoengineering

So. Science can fix anything, right? Only if we have lots of time and money. And grad students that function as indentured servants in a pyramid scheme to get tenure.

Back to the point. The truth is that science can't fix everything on short time scales. Climate is one of them. Geoengineering can help to a degree, but it will only get us part of the way there to avoid the worst consequences of climate change. Let's discuss some.

White roofs, white roads, white buildings.

Two articles back, we discussed albedo, or reflecting sunlight. Ice reflects 90%, water reflects 90%. Whatever is reflected tends to go to space and not stay in the Earth system and warm it up. In fact, whatever is absorbed then gets in the greenhouse trapping loop, warming up the Earth a good bit. Dark surfaces (our roofs, our roads, most of our buildings) reflect little and absorb a lot. So, paint them all white, and more light is reflected. Excellent!

"But Jason," you say, "Cities are only a small percentage of land area. How could this possibly help? I mean, the rest of the Earth will still absorb just as much heat. Right?"

And to you I say, "Excellent, sir! That is true. Making all our stuff white won't do much for the overall heat budget of the Earth. I am so proud of you for reading most of my website so you quickly figure stuff like that out."

So what does it do?

 

The heat island effect is based on the fact that cities are covered in dark buildings and pavement, and have a very low albedo, so they absorb heat

Cities are fucking warm. They suffer from this thing called the "heat island effect." That is a fancy way of saying that they are so dark, they absorb the sunlight and are easily 10 degrees F (around 5 degrees C) warmer than they should be. Turn everything white, and you can cool the city. This will actually have a very large effect on how hard our AC units have to work in the summer. Imagine if your city was suddenly 10 degrees F cooler. How sweet would that be? I posit that it would be pretty rad.

This one seems to help a bit, but we will still be using tons of energy and producing CO2 in all other ways. Moreover, it won't solve the problem of the agriculture, ice caps, and acidifying ocean.

Putting CO2 in the ground

There are two ideas of sequestering CO2 in the ground. The first is capturing it at the source. Like power plants. This sounds like an easy idea, but the first problem is the energy it takes to capture it. Thermal power plants take in atmospheric air. Which is 78% nitrogen, and 21% O2. Even if all the O2 were converted to CO2, what comes out of the power plant stack is still 78% nitrogen. Separating the two to store the CO2 takes more energy. In fact, the power plant is roughly 30% less efficient. So it needs to burn a lot more coal or natural gas to produce the same amount of power, and will cost a lot more to build. And any fancy idea you have to get around this 30% efficiency hit won't work. No matter what, you either have to pre-concentrate O2 to get a pure stream of CO2 on the other side, or separate the CO2 on the emission side.

The next problem is where to store it once you get it. Gases like to leak out of things. Some companies are trying to store the CO2 underground, much like petroleum is stored underground in a lot of places. This is why you need to separate it from the nitrogen in the air. There just isn't enough space to store both the CO2 and the nitrogen, and also it is expensive to pump stuff underground. Another issue is that it is unclear how long storing CO2 will last in the ground, since it more or less needs to be done indefininately.

Finally, since 35% of our energy use is from cars driving down the road, and it is impossible to capture that CO2. So Carbon Capture and Storage (CCS) from the source still won't do everything we need.

Direct Capture
The next idea is to capture CO2 directly from the air. We have increased CO2 in the atmosphere from 280 parts per million (.028%) 400ppm. The idea of direct capture is to do the opposite. Draw down the CO2 and then store it somewhere. Some might suggest we store it in trees, but that is an awful lot of trees, and unless we bury them trees somewhere underground, they are just gonna get consumed by bacteria and become CO2 again. Other options are to mechanically and chemically separate CO2 from the air, and them store it underground as above. This is very expensive. It might work in the future, but for now it won't.

The bonus of this, if it ever works, is that it is the best way to reverse our issues from an engineering standpoint. We can turn back the clock.

Stratospheric Injection

Injecting small sulfur or other particles into the atmosphere cools the entire globe by reflecting some small portion of sunlight before it hits the rest of the Earth. We know this cause when mountains like Pinatubo and St. Helens explode, they launch particles into the stratosphere and we get a cold year.

SO2 increase in the stratosphere by exploding volcano

Some people have suggested that we could do this. Just inject stuff into the stratosphere to reflect sunlight. The problem? It turns out that everything small enough to cause the proper scattering just happens to be the right size to promote adsorption of water particles. Which then allows for rapid recycling of CFCs in the stratosphere.

"But Jason," you say, "I thought recycling was good!"

Recycling plastics is good. Stratospheric recycling of CFCs is bad. Cause what happens is a CFC reacts with ozone, breaking it apart, wrecking the ozone layer, and then usually is all like, "Man, I am exhausted from catalyzing that reaction, I am gonna take a break." But that water that adsorbed onto our reflective particle provides an excellent place for it to re-radicalize. Which means it is ready to take out another Ozone particle. That's right, our CFC goes to chill out on some water droplets, effectively taking a restful timeout at a pool, and gets ready for work again destroying the ozone layer.

Let's pull this all back together. We try to put stuff in the upper stratosphere, if could make CFCs more effective at destroying the ozone layer, and then we are all screwed in a much much larger way than climate change. Cause the ozone layer is what protects us from getting fried by a lot of UV rays.

Here's where things get fun. Imagine you are a small country of 1 million people living on an island. And that island is going to get inundated with water in 20 years unless climate change is reversed. You don't give a damn about a chance of destroying the ozone layer. You only care about saving your people and your country. Stratospheric injection isn't exactly nuclear science. We aren't going to have rogue nations stumbling through how to do this, and failing all the time.

I'll leave you to ponder what all that means, cause it is more fun that way, and we are already at 1200 words.

The upshot of this is that it also fails to solve the acidifying of the ocean, we don't know how well it will work, and we don't know what will go wrong.

Solar Reflector

Another idea is to put huge mirrors in space and reflect a chunk of the sunlight coming in. This could work. Wasn't this a plot in some Bond movie, though? Also, it would be mad expensive. Probably much more expensive than some other options. And much like the option directly above, we still acidify the ocean.

Review

Hokay, so. Most of the technologies for fixing our problem don't exist, don't work, are too expensive, or could kill us all. And if they do work in the future, they won't solve all the problems we are creating. Even the one that does solve all the problems, direct capture from the atmosphere, won't do crap for our plight if we rely on that alone. As a species, we can easily outstrip any CO2 removal measures just by burning more things. Even if after rigorous testing proved all these work, we would need to some combination together to get anywhere. And even with that, we need to reduce the continued growth of emissions worldwide, otherwise no science or engineering solution will stop climate change.

Depressing, eh?

Thanks for reading,

- 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:

 E = \frac{1}{2} A \rho v^3

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.

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

 E = \frac{hc}{\lambda} where \lambda 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.

Thanks for reading.

-Jason Munster

Some dams

Dams. They provide clean electricity. Sometimes they cause earthquakes that kills thousands of people.

As I mentioned before, hydro is a tapped resource in all places except Asia, Africa, and South America. In other words, it works great in developing countries. It is not an option for developed countries.

Despite that I provide references where I can, this post is pretty unprofessional. Also, since I didn't post last week, this will be a mid-week post. It is as close as I will get to a blog rather than a collection of science-based articles.

Hydro Plants Causing Earthquakes

Three gorges dam represents the domination of Man over Environment like nothing else on the planet.

Remember that earthquake in Sichuan earthquake in 2008 that killed 60,000 people? This earthquake was likely caused by the three gorges dam.

three gorges dam! "I cause Earthquakes" says Three Gorges.

How do earthquakes happen in general? Stress builds up in the Earth, usually from shifting tectonic plates. Loading a massive amount of water in an area increases the stress by huge amounts. Dams load billions of tons of water into an area. Dams are not the only way to do load the environment to prime it for an earthquake. Downtowns of cities with skyscrapers also do a pretty good job of it. But dams are way better at it.

Pros and Cons of a hydro plant

Let's look at more information on Three Gorges. I've recommended y'all read When A Billion Chinese People Jump. In that book, we find that the past several presidents of China have been hydrological engineers. The most recent one didn't show up at the opening of Three Gorges because, because in some ways, it is very controversial. It has very strong benefits and issues. Despite negative effects, it produces 22.5GW of electricity. In other words, it replaces 22 very large coal fired power plants. And in China, that means 50 years of 22 unfiltered powerplants not belching harmful pollutants into the atmosphere. In case you haven't heard, China in general and Beijing have some of the worst air pollution in the world. Before you start judging, remember all those jobs that are being outsourced to places like China? This is the result of that. We are exporting our trash and our pollution to poor countries, where environmental regulations are more lax. Getting back to the point, those 22 coal fired power plants that are being replaced would probably have caused more long-term deaths than the earthquake. Moreover, China is a very dry country. Like most dry countries, it is prone to flooding without controls. Containing the river behind the three gorges prevents the downstream from ever being flooded again. So they saves the homes and such of millions of people, but had to move millions behind the dam, and it also flooded historic areas. How's that for controversial? Serious positive and negative implications. No dam embodies the pros and cons of building a dam more than Three Gorges.

Other uses of dams

It turns out that producing electricity is only a small part of what dams do. Many are used for irrigation, for flood control, for reservoirs, and to protect the environment. We are mostly an energy blog, so we don't give a damn about all that stuff. Except one major point: electricity is less than 10% of the economic benefit from dams. A huge amount is in flood control, irrigation, and recreation.

FEMA says these are the benefits of dams. Notice that hydroelectric is tiny.

Hoover Dam

Hoover "meh" Dam

When you think of a huge American dam, you think Hoover. This is silly. It is a 2.5GW dam. It is 10% the size of Three Gorges. It is like comparing Bangor ME, to Boston, MA. One is just tiny. Why do people care about Hoover? I dunno. Maybe after spending too much time in Vegas they decide they want to see something natural? Hoover dam is tiny. It only replaces 2 or so coal plants. Hoover Dam, you are not worth wasting words on.

Grand Coulee Dam

Grand Cooulee Dam is one of the largest dams in the world. Notice the size of the houses for scale.

Grand Cooulee Dam is one of the largest dams in the world. Notice the size of the houses for scale.

You know which dam is an American dam? Coulee Dam. This dam produces 7GW. Fully 3x of Hoover, and near 1/3 of Three Gorges. It is also in Washington state, which, compared to Nevada, is better in every way except for gambling and prostitution. Which shouldn't be family activities. Why don't more people visit Grand Coulee instead of Hoover? This is not a rhetorical question. Someone please tell me.

Grand Coulee has this other sweet feature I already discussed. They have pumped hydro storage. In other words, they pump from the area behind the dam to another dam that is far higher up. This is a great way to make a giant battery. It recovers about 60% of the electricity that is put into it.

Interesting note: While scouting around the interwebs looking for information on the pumped hydro storage at Grand Coulee (it is really difficult to find), I stumbled across a blog that already has written posts that are way more in-depth maths about many of the things that I write about. If you are one of my sciencier readers, you might want to check his page out. I will poke around there some and give you more info on it later.

Dams produce clean power. They are environmentally friendly! Or not. 

We have discussed how dams get backed up and leave heavy metals in the sediment, and more or less create environmental issues. And how they block fish from swimming upstream. I wanted to touch on one thing again. In China, many places that built clean hydro plants attracted industry, cause industry loves inexpensive power. And hydro power is amongst the cheapest. So the skies and waters became quickly polluted with industrial wastes. Like, red polluted.

Image from the link above. It looks like the Earth is bleeding. I don't think this is healthy. And all my Boston readers are afraid of the Charles.

Outsourcing manufacturing seems even a bit crappier than it used to, doesn't it? Sure, we lose jobs, but they lose lives and the environment.

Alright, that's about it for my quite unprofessional rant. Thanks for reading.

-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.

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

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 ^2 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:

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
Solar thermal is expensive. And the capacity factor is junk. There are places for it, but those are so few that it is not worth further exploring this technology.
That's it for now. Thanks for reading!
-Jason Munster