# Can I Exercise or Run in this Pollution?

Short answer: no. Longer answer: only if it is raining or just rained.

It's been two months since a post. Sorry, been working on a low-cost solution to fix stuff discussed herein, applying for grants, and continuing my PhD. Back on track for one per month after this post, though.

So. Air pollution. It's comprised of four major life-threatening pollutants: PM2.5 (particles 1/30th the diameter of a human hair), SO2, NO2, and ozone. SO2 becomes battery acid in your lungs, so that sucks. NO2 becomes nitric acid, which can strip lead from glass. Ozone is great high up in the sky cause it blocks UV, but on the ground it's toxic and kills plants and hurts humans.

All of these things absorb into rain and then fall to the ground. In other words, a rainstorm scrubs them out. That smell in the air after a rainstorm? Often it's the smell of clean air. It's what air is supposed to smell like. This is why we get acid rain. All that stuff goes into the rain, and that rain can cause pits in statues. Imagine what all that pollution does in your lungs if it can pit statues from being in rain.

The sky in Beijing after rain (right) is cleared of pollutants. Rain removes most pollution.

The rest of the time, if there is pollution, here is what happens:

Exercise involves breathing more than not exercising. You breathe more, you breathe deeper. Deeper into your lungs. So if you exercise, you are exposing more of what you breathe deeper into your lungs. Breathe in pollution, mess up your lungs.

Exercise. You live in a developed country? It's likely that every minute of exercise adds more than that amount of time to your life. What about if you are in a polluted area? The jury is still out. Most mortality studies are based on widely available statistics, and are inexpensive. If you want to start studies specific to exercising air pollution, that becomes more expensive. So there is not much data on it.

You breath up to 3x as much volume when you exercise. It penetrates deeply and rapidly into your lungs. Moreover, you are breathing 3x the volume in through the exact same amount of nose, mouth, and lungs that you always have. That means air is moving a lot faster. Many of our defenses, like the mucus that lines our airways, becomes less useful if pollutants are moving so fast past them that it can't be captured. So we breathe faster in exercise, making air move 3x as fast, reducing our ability to filter things.

That's what I like to call a hand-waiving argument. I offer few hard, tested facts. Unfortunately, I can't find solid sources one way or another on this. Most experts, however, indicate that exercising in air pollution is a bad idea. A few doctors disagree, but I've yet to find a pulmonologist (lung doctor) who disagrees. In other words, the actual experts I've talked to all think that exercising during awful pollution is bad.

The Chemistry

Okay, let's get more detailed. Many pollution masks filter PM2.5. I'm skeptical of their sealing ability during exercise (if you don't have a good seal, you breathe in non-filtered air through the leaks, and you aren't filtering anything). Moreover, no one filters SO2 and NO2. So pretty much, go ahead and filter your PM2.5. You're still making battery acid in your lungs. In other words, don't exercise without a gas mask that can filter PM2.5.

Some say to exercise in parks. Why? It turns out that trees and plants can "filter" PM2.5 and other chemicals by pulling them out of the air. This works great if you are in, say, the US or Sweden, two of the cleanest countries in the world. In China, or worse yet in India, this filtration will be overrun rapidly. So pretty much, don't exercise in parks.

How about gyms? In the western world, gyms do a pretty good job of filtering outside air of PM, but they do not filter SO2 and NO2. In the developing world, not so much. They might run their air through ACs, which have filters, but it's unreliable to assume that they spent the tremendous amount extra to get ACs that do filter air pollution. So, still dangerous.

What to do? It depends on where you are. It turns out that pollution in Northern China (represented by a whopping 500 million people living there) is heavily SO2 impregnated in winter, and less so in summer. In other words, don't exercise in winter. Great, right? We all already get fatter in winter. Now we have that pushing us. Pollution in summer is not as bad with the SO2. If you trust vogmask to get a good seal (I don't), then get a mask and run with it. Again, I wouldn't recommend that.

So, in short, wait for low air-pollution days to exercise, and then get it all in at once. Or wear a gas mask. Or wait til I come up with something better. Cause that's coming.

- Jason Munster

# Remedying air pollution, one person at a time

One of my friends once told me, "If you are complaining about the government and aren't doing anything to solve the problem, then you are part of the problem."

I decided to do more than write about pollution associated with energy, and have started a side project to build a breathing filter (and mask that it will go with) for people living in and visiting countries with significant air pollution.

My apologies for not posting this sooner, I wanted to wait until I had finished a major milestone on my PhD that was taking literally all of my time. In other words, I didn't want to post about "working on" something that I had no time to work on. I hope to become active again in posting related articles now that I've a bit of free time again.

20,000 people die every day from air pollution. Most of them cannot afford current filters. It's time to change that.

So. China and India are not going to institute US-level air pollution controls on their power plants. So if they aren't going to filter the entire sky the way we do, the next best thing is to just filter the parts that people breath. By filtering it just before they breath

"But Jay," you say, "Aren't there other masks on the market already?"

Indeed, my friend, there are. Except most of them fail in one way or another. Nearly all of them fail to achieve a face-seal. This means that there are small leaks. Small leaks are fine when you are filtering large particles like water droplets (think viruses that travel on sneeze particles), because the leaks are often at 90 degree angles. The droplets can't make those 90 degree bends, and they get absorbed by the mask or deposited on the skin. This is why doctors masks can be fairly effective. PM2.5 and chemical pollutants, however, are small. PM2.5 is 1/30th the width of a human hair in diameter. It can easily make a 90 degree turn through a leak in a mask, and get into your lungs where it penetrates deeply, creates scar tissue, and then gives you asthma and lung cancer until it kills you. The other pollutants are literally molecules. They have no problem making any bend of any sort. If there is a leak, they are getting through.

Gas mask. The only true way to ensure there is no leak.

What's the easiest way to tell if your mask leaks? Take a deep, sharp breath. If your mask doesn't push against your face from suction until the pressure equilibrates, you don't have a good seal. So pretty much, every mask short of the one pictures above doesn't work.

So this is one part of what I will address. I've a few methods to ensure no leaks while maintaining low costs for masks. I'm not exactly going to be open on how I will do it, but this is happening.

So, if you plan on traveling in China, India, or near LA (heh) next year and need a breathing filter, be sure to talk to me.

- Jason Munster

# Air quality limits, Geographic Air Pollution Causes

Hi everyone! Last week I wrote about air pollution, where it is bad, what causes it, and the main harmful components of air pollution.This week I am going to give you some exact numbers. First, though, let's start with a scary fact. Then I'm moving into how pollution goes away once it is in the air.

US limits on PM2.5 are 12 micrograms per cubic meter averaged over a year. In Europe, the limit is 25. Note that for every increase of 10 micrograms, there is an associated 9% increase in lung cancer incidence, and a .6 years decrease in life expectancy. Scary, right? China has an annual average limit of 40, and India has an annual average limit of 50. They don't do so well in some cases. Beijing averages 56, and Delhi averages 150. In other words, Delhi's population has somewhere in the vicinity of 10 years less of life from air pollution alone.

What about other pollution? SOx, NOx, and ozone tend to accompany each other. Wherever you have SOx, you have the other two. Even clean-burning natural gas power plants produce NOx, just as a by-product of combustion is our nitrogen atmosphere. NOx becomes ozone and smog when mixed with sunlight and organic radicals (the latter of which exist just about everywhere). In other words, these three things are difficult to separate. Moreover, they are often accompanied by PM2.5. Research is having trouble teasing them apart and figuring out what might cause what. But, again, SOx and NOx become strong acids when they react with the water in your lungs, and ozone is toxic to life at ground level (always remember, ozone 15km overhead blocks out the bad parts of the sun, ozone at ground level damages living things).

SOx and NOx, once emitted, are typically cleared out by rainstorms, creating acid rain. It's better than breathing it in, right?

The US has pretty good air quality overall. But if you look at the US government website that shows current levels of pm2.5, you'll see some cities in the US are straight up awful. While their annual average might be around 20-25, on the day I checked, San Bernardino, CA, had 137 micrograms per cubic meter. This is absurdly high. On days like this, people will have difficulty breathing.

Los Angeles on a polluted day. Thanks Curtis Barnes for the correction! Site.

In other words, you can go almost anywhere in the world and find places that are tough to breath in. That being said, there are some countries that are really bad almost everywhere. Bangladesh, India, Nepal, China, and Pakistan are all very polluted. Much of the middle east is as well.

So what makes these things hang out? The most common reasons are inversions. It's when warm air sits on top of colder air. Since air likes to rise when it is warm, if there is a layer of cold air that is polluted that also happens to be capped by warm air, that cold layer will sit there and stagnate. Instead of blowing up or away, it will simply accumulate pollution. Another cause is being surrounded by mountains. Mexico City, for example, is right in the middle of a bunch of mountains. The pollution cannot rise above the mountains, so it lingers and builds. It is also common for coastal areas, or areas next to high deserts, to have times when air refuses to vacate. Those mechanisms are a bit complicated, so we won't discuss them. Finally, being near 30 degrees North or South latitude tends to make air pollution stick around. LA, for example, is at 34 North. The reason for this being bad is that the Earth has the giant airflow patterns. Air is heated at the equator by the sun, then it rises. Eventually it cools and falls near 30 degrees north. The result is that inversions happen more frequently, cause there is air pushing down on the cities.

Diagram of temperature inversion. Site

That's about it for the major causes of air pollution buildup. Of course there has to be pollution to start with for these effects to matter.

Hokay, so, what makes PM2.5 go away when it starts hanging around? Either a wind comes through and blows it out, or a rain comes through. Rain scrubs PM2.5 by absorbing it, and it chemically converts SOx and NOx to acids that become solutes in the rain. Hence acid rain. Also hence why skies are most clear after rains, and how they can smell so fresh and clean after rain. So, if you are going to go for a run in Beijing or Delhi, wait til after a big rainstorm 🙂

Let's talk about that last point a little bit more. China is dry nearly all the time. It doesn't rain much there, so it has a bigger problem of building up air pollution. India has the monsoon season, but is also fairly dry otherwise. What about LA? If you have ever driven in a slight rainstorm in LA, you will see that everyone freaks out and has no clue how to drive in the rain. It's hilarious for about 5 seconds until you realize you are now in a traffic jam. It doesn't rain there, either.

So. Your most polluted places will be near 30 degrees latitude, potentially on the coast or in mountains, dry, and in the vicinity of polluting vehicles, industry, or power plants. Neat. right? I bet you thought it was just pollution alone that caused pollution to linger.

Hokay, that's all for now. Thanks for reading!

- Jason Munster

# Which Country has the Worst Air Pollution in the World?

Before I get into anything, this is a first in a series of three articles I am going to be releasing. Instead of my monthly release rate, I am going to be releasing them one each week. If you are traveling to or live in a polluted environment, I highly suggest you subscribe to the blog or do it as an RSS feed.

Now to the article!

If you guessed China, you guessed wrong. Did you get it wrong? If you say you didn't, I am going to call you a liar. Every person I know, when asked which country in the world has the worst air pollution, answered China. This includes experts on China, experts on air pollution, and experts on countries that are more polluted than china.

Also, the number of people that die per year from air pollution is staggering, more on that after the math.

China isn't even close to being the country with the most fouled air. That distinction belongs to India, by a huge margin.

Okay, well, let's delve further into it. Of the top 20 most polluted cities in the world, how many would you guess are in China? Okay, that was a trick question. China doesn't have any of the top 20 most polluted cities in the world. And India holds the distinction of having at least 10 of them.

A gate in India that can't be seen through air pollution.

Before getting to the science grit, one more important thing. Owing entirely to city air pollution in India, at least one study shows that Indian citizens living in cities have 30% less lung capacity than Europeans living in cities. So, pretty much, pollution makes it so

Okay, let's back up and discuss air pollution a bit.

What is Air Pollution? (This is the technical part of the post)

In this above mentioned study, air pollution is strictly PM2.5. Why is that? Because PM2.5 is particulates smaller than 2.5 microns, roughly 1/30th the width of human hair. They are small enough that they penetrate deep into the lungs, where they cause permanent damage and can lead to cancer. PM2.5 is produced by powerplants (mostly coal-fired) and any combustion-based motor vehicle. The EPA has a great guideline for PM2.5 if you want to read more.

There are other pollutants that everyone seems to ignore. Back in the day, you heard a lot about acid rain. Acid rain is caused by $SO_2$ and $NO_2$ . Combusting anything creates NO, cause there is so much $N_2$ in the air (78% of the stuff we breath is $N_2$ ) that some of it combines with oxygen during combustion, creating NO. NO reacts with $O_2$ to produce NO2 and O-, the latter of which produces ground-level ozone (more on that soon). Let's look at what happens to $SO_2$ and $NO_2$ in air:

$2SO_2 + 2H_2O + O_2 \rightarrow 2H_2SO_4$

So that's sulphuric acid.

$2NO_2 + H_2O \rightarrow HNO_2 + HNO_3$

And that is nitrous and nitric acid. Another fun reaction is:

$NO + VOC + sunlight \rightarrow O_3$

VOCs are Volatile Organic Carbons. It pretty much means organic matter in the air. It comes from plants. $O_3$ , or ozone, is bad for people and plants at ground level.

So let's review what happens here. Power plants burn fossil fuels, they produce PM2.5 which causes cancer, coal-fired powerplants produce $SO_2$ which becomes acid in your lungs, and all combustion plants produce $NO_2$ which also becomes acid in your lungs. PM2.5 is the worst, but the other pollutants are also bad. Burning coal causes the most of all of these pollutants. Lower grade coal, the stuff burned more often in China and India (the US has high grade coal), has less energy relative to pollutants, so it makes more pollution.

Now, exactly how bad are ozone, NOx ( $NO_2$ ) and SOx ( $SO_2$ )? They are all similar, so lets just look at SOx health effects according to the EPA. In short, exercising in an environment with this stuff is bad for you, and sends people to the emergency room. In the worst case scenario, it exacerbates or triggers asthma, heart attacks, and aneurysms, killing people nearly instantly. Long term exposure increases asthma and other health hazards. Now keep in mind that this stuff is considered less of a problem than PM2.5.

Back to the Qualitative

Okay, now that we know what the stuff is and what it does, let's get to some specific numbers. The World Health Organization indicates that air pollution is "single biggest environmental health risk in the world" the largest health hazard in the world, killing 7 million people per year.

What's the best way to deal with this stuff? Staying indoors helps a lot. Your house acts as a good barrier against it. Having a filter also helps. If you live in China or India, build one of these at your home. The filter will stop working eventually, so it will have replacement costs, but you can probably get clean air for around $100 per year for a single room in your house. Now keep in mind, this is a HEPA filter, which filters out only particles. Good luck with that SOx, NOx, and ozone. The guy who stapled together the filter and the fan states that it's the only thing you need for clean air in his blog. Clearly the PhD he is learning in psychology does not qualify him to know a lot about air quality. It doesn't disqualify him from knowing about it, but being completely unaware of the chemicals I described above does. HEPA + fan. Good for PM2.5, useless vs. ozone, SOx, and NOx. In other words, this filter will work inside, but you are still going to get bad chemicals living in your lungs. If you want to filter more, be prepared to shell out thousands of USD. Also, if you plan on going outside, or you want to exercise, if you work outside, you're pretty well screwed. There are a few masks that work, but all have their flaws or are expensive. More on this later, we've hit 1000 words and it's time to go. Before we let me repeat one thing. If you are in a polluted area: Do. Not. Exercise. Anywhere. That. Isn't. Filtered. And no mask on the market filters out SOx, NOx, and Ozone. Thanks for reading! - Jason Munster # Solar Roadways: Full of Crap and Bad at Math First of all, sorry it has been over a month since I've posted. I've decided to get together a few people to start addressing some of the things I write about, and that has taken my time up til now. I'll be posting once per month from here on out, on the first Sunday of every month. Today's post is a long one, but one of the most interesting I've written by far. This is the one time where I will say the following: if you are short of time, skip directly to the math section. It shows a serious glaring deficiency of either forethought or disclosure on the part of the founders of Solar Roadways. Moreover, it shows they can't do basic math. Never trust an engineer who can't do basic math. It's a very crackpot idea. Here We Go! I've heard a lot of talk about Solar Roadways recently. I'm going to use it as an example of how to analyze some "science." After you follow the very basic math below, you will see that the team at Solar Roadways does not know what numbers to run*. A much larger problem: they suggest that solar roads can replace fossil fuel power, while simultaneously and surreptitiously admitting that they need a ton of grid power to make this work. So pretty much they are either dumb or straight up liars. First, let's talk about why these roads might be good, from their point of view. Being a by-the-numbers type of guy, the first thing I did was check the "numbers" section of their website. While their assumptions are dubious at best (more on that later) They say that their roads could provide 3x the energy that the US needs, in kilowatt hours (kWh is a useless measurement here, cause it will be intermittent power. In other words, it produces no energy at night, and will need to be supplemented by fossil fuel power. More on that later). Also, the roads look a lot cooler, with light-up sections, and ability to melt snow so that road maintenance is reduced. So the thing is wired to the grid so that if it snows, it can use heating elements to melt the snow instead of plowing it. But doesn't snow take a lot of energy to melt? Would it take less energy just to push it with a plow? Time for the math! Math of Melting vs Pushing Snow Plow trucks to be replaced by Solar Roads? Not happening. Okay. Let's assume middle-case scenario of 8 inches of snowfall, being removed with one sweep by plow trucks, and that this is between powder and heavy snow in consistency, which means 1" of water equivalent. A DOT snowplow clears 10' width of snow, or 120 inches. In one foot of movement forward and plowing 8" of snow it moves the water-weight of 1"x120"x12" or $1 \cdot 120 \cdot 12 = 1440 in^3$ Now we have to figure out how much energy cost this took in fuel, so we will later relate this to the mileage efficiency of a DOT truck. First, let's figure out how much energy it takes to melt this much snow into water. Do do this we need the latent heat of fusion, or the energy it takes to transition from ice to snow. It's 334 Joules/gram. How do we convert from cubic inches of water to grams? Easy. Because the metric system makes sense, one $cm^3$ of water = 1 gram. There are 2.54 cm per inch, so: $1440 in^3 * (2.54 cm/in)^3 = 23600g$ Okay, we have grams, now let's calculate the energy to melt as much snow as a plow moves from driving 1': $23600 g \cdot 334 \frac{J}{g} = 7,880,000 J$ Or ~7.8MJ. Per foot. Or, for a mile: $7.8 \frac{MJ}{ft} \cdot 5280 \frac{ft}{mile} = 41184MJ/mile$ to melt 8 inches of snow. Okay, so, a plowtruck uses diesel. Each gallon of diesel has 136.6MJ. Very conservatively assuming a plowtruck gets ~5 miles to a gallon (I'm guessing it's more like 10, someone who has driven one, correct me and I will correct these #'s), it would take 27.3 MJ to plow one mile of snow. Compared to 41,184MJ to melt it. It literally takes 1500x as much energy to melt is as it would to move it. This is what you would call a very very bad idea. Engineers as cofounders should know better than to let this slide as a potential solution. End of Math Section Okay, so now that we've completely dismantled the case of using these things to melt snow, lets move on to some other issues. We'll skip the minor issues, because that's just nitpicking, and move straight to the parts where they just don't know what they are talking about, and finish with things they clearly know about, but are purposefully misleading people with in order to get more money. Finally, we will close with me realizing that Nathan Fillion is a fool. Okay, to the problems with this solar roadways project: Dubious assumptions: Things they don't understand: the supply lines of a very basic input. REE mining in China is not a clean thing. Nor was it great in the US. Right now there is not enough world production to make enough of these solar roadway tiles. Look at this article to see more pictures of REE production in China. They assume an 18.5% efficiency of the solar panels. These are panels that use Rare Earth Elements (REEs). On their FAQ, when someone asks if they are using REEs, they state (paraphrased), "Our electronics don't use silver or gold" (neither of which are REEs, so they are either changing the topic or don't know what question they are answering) "but we can use any solar cell." Good that they can use any solar cell, because there is not enough REE production in the world to produce solar at the scale they need to even replace one major highway with these. Bad they they use 18.5% as their assumed efficiency, because solar cells in this range of efficiency use REEs. REEs are pretty much only produced in China, because producing them make a massive amount of pollution. Decades ago every other major country quit producing REEs because of the pollution they cause, and because China didn't care about pollution or health hazards, so the world was happy to let them pollute themselves and take their REEs. It's been so long since the US produced REEs that we literally don't know how. Solar Roadway's answer is "let's leave this to the government." They aren't addressing the problem at all. While other countries are looking to have their own production, it will take a very long time for this to come to fruition, and the production rate still won't be enough for a second-rate harvesting design (flat roads with bad optics vs. tilted panels with great optics to concentrate light perfectly). At best, they can go with non-REE solar cells, which have about an 5-10% efficiency. That means that each of their hexagonal panels will produce half the power anticipated, and thus will make half as much money toward recuperating their costs. In other words, these non-REE solar panels need more basic raw materials (in terms of roadway) per kwh produced, and thus will cost more per unit energy, in an already material-intensive design for a solar cell. This shows that the project is lacking in any real expertise or understanding of the core problem they are trying to solve. Keep in mind that these are not dealbreakers. The team could hire an expert, or consulting, to fill in their knowledge gaps (likely the former, consultants are expensive, and they really need long-term help to bring this to fruition). Also, it doesn't negate all the other benefits of the solar roadways. Finally, non-REE solar panels are a hot topic in research. If the rest of the solar roadways tech is developed, and they are just waiting for good solar cells, it will rapidly enhance future deployment. In short, the solar cells are a slight additional benefit to whatever holds them in this case of mass-distribution and inefficient use of cells. So if this new road itself doesn't compare favorably to asphalt, the project is sunk in the water. Things they are just completely wrong/misleading about: melting snow, shutdown of fossil fuel, price of energy We discussed the melting of snow. They suggest it replace snowplows. Bad idea. It's clearly not going to work, energetically speaking. They keep talking about how 50% of US electricity use is from fossil fuels, and how these roads are going to replace it. This is so wrong that it is hard to debunk in one post. But here goes: First, only 40% of US primary energy (my link, please read it for background if you feel a bit lost, it is far briefer than this post) is for electricity. Second, only 66% electricity of this comes from fossil fuels. In other words, 26.4% of US electricity comes from fossil fuels (if we change all our transportation over to electric, these numbers will change, but that would require these roads to have induction power installed - AKA roads that provide the car with energy for driving so they don't have range issues). This is the total amount of emissions that could be replaced by solar roads in their current design. Primary energy in the US. As detailed by the math above, only 25% of primary energy in the US can currently be replaced. So, pretty much they are off to a bad/misleading start there. But this is nitpicking. The real issue comes in when they talk about replacing fossil fuels. First, they talk about heating the roads. This means they will have to put energy into the roads. Where will this energy come from? Power plants. So much for shutting down fossil fuel. But wait, there's more! Solar power is intermittent. It doesn't even work at night, so power plants also have to be on then. So pretty much, their idea of shutting down power plants is completely shot out of the water by these two things. Can solar roadways still be part of a larger energy solution? Well, not if they are heating roads to melt snow. That just takes far too much energy. If they scrap the melting snow idea and go to just producing energy? Yeah, it might help some. But let's get to one last funny part, the one that shows they know that they won't be shutting down fossil fuel power any time soon. Energy storage. From their FAQ, they mention that there will be "virtual storage" in that during the day they will add power to the grid, and at night they will take power from the grid. This is double-speak to mean: during the day we will provide power that can offset coal and natural gas power plants. At night when we aren't producing, natural gas powerplants (again, my link) will fire up to power our roads (nuclear is not an option for power phasing like this, nuclear powerplants don't spin up or wind down on half-day timescales). In other words, they fully well understand that they aren't going to do away with the rest of the power grid, and that they aren't going to replace all those fossil fuel emissions. So pretty much, saying that these can replace our power grid is double-speak sales points. The final problem? They don't understand energy distribution. Electricity is produced at about$0.03 to $0.08 per kwh at a power plant. By the time it arrives to us, we pay$0.13 to $0.25 (or$0.50 in Hawaii), because distribution costs a lot of money. Solar panels on our roofs produce power that costs about $0.15 to$0.20 cents per kwh, give or take. So the end-user cost of grid power is the same as that of house solar. But if you run that solar power through the distribution channels and add that price, suddenly you're talking $0.25 to$0.40 power. So, unless they are giving this power away for free, it's probably not gonna be a great solution.

Some Solutions

I've softened my usual tone quite a bit for this writeup, cause I don't want to be a complete naysayer of something who is trying to do something positive (sorry, I know how much you all know and love my biting sarcasm and scathing reviews).Outside of their false solution of trying to solve the energy/climate issue, this idea has some potential. On that note, rather than pointing out problems, I've come up with some great solutions.

My suggestions:

1: Nix the whole melting of snow concept to replace plow trucks. Energetically, it doesn't work. Plow trucks should still exist. Instead of replacing them, replace the salt and sand they need to spread. Make it so plowtrucks plow all but the last 1/8" of snow, then melt that (note, this is still a tremendous amount of energy, but stay with me). This will have a few benefits:

• No more salt and sand on roads means less salt and sand damage to vehicles, making vehicles last longer
• No more salt and sand on roads means that DOTs can save money buy not buying these things
• ... no salt and sand runoff, which pollutes local waterways
• ... animals that go to roadways in the spring to lick off accumulated salt won't do that, reducing traffic accidents from moose and deer, etc.

2: Get a bit more cognizant or REEs and their limitations. Don't use bad assumptions that are easy to poke holes in.

3: Stop selling people on false promises of doing away with fossil fuels. It makes the whole green movement look bad when prominent people are lying or severely misinformed.

4: Focus on the real potential of making these have inductive energy for electric cars. This could eliminate range anxiety (people fearing their electric cars will run out of energy and leave them stranded). Electric car sales will move a lot faster if people can drive from LA to SF, or between Boston/NYC/DC. The potential partnerships include every major car company that markets in the US. Also, this could reduce oil use, and drastically reduce air pollution from cars in these busy areas by further replacing combustion engines with electric ones (even if we power them with electricity from coal, a well-scrubbed coal plant produces fewer bad things than a car). Moreover, since people won't need fuel, they could be assessed a charge per mile driven instead. By whoever owns the roads. Here is your real money-maker for the roads, fellas. It will be far more lucrative than producing tiny amounts of electricity. Please get on this. It will lead to more electric car research, and more rapidly drive forward battery development, and it turns out that cars make a bunch of really bad pollution that causes harmful side effects like death.

This last bit, changing your startup's tack when a better model comes along, is important. And solar roadways needs to do that for a viable product, because their core solution faces a lot of headwinds (yay, sailing puns!) in break-even with their current model.

So, overall, these roads could be an excellent idea. The solar part, their main selling point, is BS because of cost, efficacy, and the need for gas-fired power plants to supplement them. The shutting down most fossil power plants is a lot of nonsense for the same reason. Making the environment better by reducing salt and sand use? Decent. Potentially by making most cars electric? Game-changer, but they are barely looking at that aspect right now. Probably cause they are too busy counting the piles of cash that indiegogo just threw at them (or, more likely, answering the insane number of emails that comes from this sort of campaign).

Hokay, that's my piece. Thanks for reading this long one.

- Jason Munster

Extra stuff!

Some background about Solar Roadways initial funding: They were funded by government SBIR. This stands for Small Business Innovative Research. It's for high-risk, high-reward research. In other words, this was considered high-risk from the start. They got a phase II, which means they did well. It's clear they still have issues and are still high-risk. But I'm glad someone is paying for research and innovation like this, especially because if it pays off, it could result in more jobs and more taxpayer base. That being said, they haven't received more funding or any grants to build this out further. Possibly cause it's a big, crazy idea. Elon Musk can pull off big, crazy ideas, because he is a brilliant manager and has a very strong personality. These guys are going to need some bigger guns on their team if they are going to make something of this project.

Second, Nathan Fillion is a bit of a fool. In touting Solar Roadways, he displays why pop culture heroes shouldn't get involved in matters outside their field of expertise (mainly, looking good in front of a camera, and pretending to be someone who they aren't in front of a camera). His adoration of something he doesn't understand falls deep within the territory of religious fervor. Nerds: just cause one of your heroes likes something doesn't mean it actually is plausible.

One final-final note: I know that this post is 3x longer than my rest. I assure you, it's far shorter than I wanted it to be. I don't believe in two-part posts very often, though. If you have read this far. please leave a comment so I can appreciate you forever 🙂

*Engineers who don't know what numbers to run are a bad investment. For my own company, all business types are skeptical of how much I know (or want to take advantage of me fully) until they find out that I used to be in finance and have a really good idea of the big picture of most things. In short, this company has a lot of potential once they take on broader experts.

# China's Water Shortage and Power Plants (their power plants definitely have a drinking problem)

In the previous post, I described how thermal power plants use a massive amount of water. This time we are going to explore a specific case. As usual, it's China.

Power plant water use can be a problem in a water-stricken area. Let's look at a case-study. China is a water-stricken area, and has a lot of thermal power plants. In fact, China uses more primary energy than any other country in the world. Unfortunately, their power plants are far less efficient than they should be. So they are wasting water, and this is unsustainable. Moreover, China has 1,350 million people. The US has 314 million.

First, let's look at the rainfall of China, compared to the US:

Rainfall in China, in inches

Rainfall in the US, in Inches

Looks pretty similar, right? Now recall that the US has 1/4 the population of China. And pretty much the exact same amount of area. Keep that in mind while we look at China's powerplant locations:

China's water stressed areas, compared to where power plants are planned. Source,

So. The places that have the most people and need the most power are the same as the dry places. In other words, China is building the bulk of its thermal power plants in the area that can't provide sufficient water to cool the power plants.

Before coming to the complete picture, let's check out the water use:

Fresh Water Use in the US.
source

In the US, 80% of water use is to grow food and to make electricity.

Finally, where is all this water coming from? Rain alone isn't enough, it comes from the ground. Fresh water from the ground is not unlimited, and we are running out of it. It's called Fossil Water, and here is what the situation looks like in the US:

Water withdrawals in the US

In other words, a huge chunk of our country is relying on water that will not exist in a few decades.

And looking at China:

China's groundwater depletion rate

In the US, the scale of groundwater depletion tops out around 400 cubic kilometers. In china, it tops out at 3,000 in regions. That's not to say that the US won't run out. It just says that China is in serious trouble.

Again, 80% of water use is for electricity and agriculture. And China has 4x the people of the US. There is not sufficient water. Would you rather run out of electricity, or run out of food? It's not an easy choice, but food can be imported. That being said, someone has to grow the food, and that country better have a robust water supply. Moreover, food growth is a low income industry. A country that marries itself to being a food supplier, unless it charges gouging levels of prices, is marrying itself to never being a high-income country. But charging price-gouging levels is a bad idea.

While this mental exercise was fun, let's look at some examples.

First, while Californians probably shouldn't have been growing water-intensive almonds in a dessert in the first place, running out of water has imperilled the world supply of all sorts of nuts and things. They are tearing up their farms because of lack of water.

That's only the start. Drought in Syria helped bring about war there. Syria is a tiny country that doesn't matter on the world scheme. India, China, and Pakistan face water shortages. Combined, they have 1/3 the world population. They also happen to hate each other. As climate change progresses, and some countries face droughts, people may not want to choose between food and electricity. They may try to divert water supplies, sparking tensions and even war.

So. Does your power plant have a drinking problem? If you live in China, it definitely does, and it's causing all sorts of strife.

Wrapping it all together: Yes, a country can import food. But you know how much of the world relies on the middle east for oil, and we talk about energy security? That's just stuff that makes your cars move. Remember how Russia threatens to shut off natural gas to Europe if they don't get in line with Russia's plans, and so much of Europe is cowed? That stuff keeps homes warm, but it isn't as important as food. Imagine a powerful country that is mostly reliant on other countries for food to stay alive. That's a really bad situation. The country in this situation has to either take dictations from whoever feeds them (not really a problem if you are getting your food from non-powerful nations, but still irksome), or has to take over a food-producing country.

One potential solution: Chinese power plants are notoriously inefficient. If you have a 25% thermodynamically efficient powerplant, it uses 30% more water than a 37.5% efficient power plant. China should either shut down inefficient plants and require new construction that is efficient, or require retrofits of old plants. It would be very expensive, but less expensive than the social and political cost of running out of water too soon. What about the US? Most of our plants are pretty efficient already. Especially our Natural Gas plants that much of the country runs on. We probably spend too much water on watering desserts to make food, but that's another story.

An almost-final note. While solar power and wind power use water in construction, their water use is minimal compared to that of thermal power plants. Barring solar-thermal (it's thermal, it uses water), these renewable resources are the only answer to the reducing the choice between electricity and food. In other words, expansion of wind power and solar PV is the only cheat code we have to deal with this impending water shortage.

One last thing. Why did I single out China? Only because I know a lot about China. Pakistan will have water shortage issues, but they already don't have electricity. In the summer, they have blackouts for up to 20 hours a day cause they can't produce enough electricity. This is a country of 180 million people, bordering India, and sharing a strong mutual resentment with India. More on this later, though.

- Jason Munster

# Your Power Plant Might Have a Drinking Problem

While at an energy conference (ARPA-E, 2014) I found out that power plants account for 40% of water draw in the US. Simply put, they use a lot of water. The good news is that it doesn't have to be fresh water. Brayton Point, for instance, uses grey water. In other words, it uses water that came from your toilets and sinks that has been reprocessed. Others use saline water from oceans (all water in the oceans is saline, cause it is salt water).

No math this time, just review the math from my thermal power plants post.

Why do power plans needs water? Cooling purposes. The way a turbine works is that high-pressure air has to drive through it. The way this happens is water is flashed to steam. Steam takes 1600x the space at 1 atmosphere compared to water. So it creates a massive pressure differential on one side of the turbine, turning the fans, turning the turbine, and generating electricity. The steam needs to be cooled on the other side to either create the vacuum that drives the pressure differential to turn the turbine, or, if it's a close cycle and the same water is used, to cool the steam back to water. It needs to be water again, otherwise it cannot expand and drive the turbine.

Schematic of a thermal power plant. It needs water to cool the water used to drive the turbine.

Okay. That was complicated. Let's break it down further. This section if very detailed, and most of you will want to skip this paragraph. Here goes: There are two major ways to run a thermal power plant. Combined cycle, and single cycle. Combined cycle is more efficient. How? It uses several turbines to extract energy rather than a single one. Think about it this way: when you have 300 degree celcius steam coming from the coal-burning reactor, it is all steam. There is no water-phase droplets in it. This is called dry steam. It can be directed to special high-efficiency turbines that can extract a lot of energy. The steam then loses pressure and temperature, and some water droplets begin to form. If this mix of steam and water were directed at the same turbine, it would pit and tear at the turbine blades, destroying it. Two things could be done with this steam. Either it could be directed to another turbine, or it may not be reused. The second turbine will be designed differently for steam that is lower pressure and lower temperature. Having multiple turbines like this increases efficiency. Inefficient plants use only one turbine

(everyone else should join back in now) Eventually you end up with a mix of water a steam. As I said before, this has to become water again, so it can expand to steam and drive turbines. Or, if a plant is doing a once-through cycle and expanding water from a stream, it needs to dump the water back into the environment. Dumping near-boiling water into the environment is a terrible idea. That would be a bit of a disaster. So, in either case, you need a lot of water from the environment to cool the water used for the steam cycle in the plant. An alternative scenario is using evaporative cooling towers. They evaporate water, which requires heat to go into the water, which then cools other water. No matter what, cooling a plant requires a lot of water.

So here we come back to the end point. Power plants use an insane amount of water. "Ahh, but Jason," you ask, "these are just thermal power plants. I use solar power. So my plant is water-efficient!"

Not so, I say! Solar plants also use water for cooling and cleaning. And this is from NYT, an ostensibly liberal paper that likes solar. This is because major solar plants use solar thermal, rather than solar PV. Solar PV is pretty much water-free, other than for cleaning mirrors. But that electricity is too expensive to be useful at the grid scale (recall from a prior post that it costs about 3-7 cents to produce a kwh of electricity, but we buy it for 20 cents, so it makes sense for us to put solar panels on our houses at the cost of 20 cents per kwh, while it doesn't make sense for power companies to use solar panels since they mark up prices 3x to get power to us).

How does this compare to coal? In the link above, we have solar power using 1.2 billion gallons a year to produce 500mw of power. Your average coal plant produces 600 watts of power. A once-through plant draws "between 70 and 80 billion" gallons a year. But a closed-cycle plant, the one that uses the same water in the plant and only uses other water for cooling at the end of the power cycle, uses 1.7 to 4 billion gallons a year. So the efficient ones are comparable to solar in water use.

So here we have a chart showing all this:

Water use by power plant type, source

Note that you can find different graphs using different information sources, but the general point always remains: power plants use a lot of water.

Wind power, however, doesn't use water. Unfortunately, wind power is only available in a few places. How about hydro power? It passively uses water, so it doesn't really count. Great, right?

Not so fast. How much of the US power generation comes from thermal and solar sources? According to the EIA, 87%. I reproduce the info here:

In 2012, the United States generated about 4,054 billion kilowatthours of electricity.  About 68% of the electricity generated was from fossil fuel (coal, natural gas, and petroleum), with 37% attributed from coal.

Energy sources and percent share of  total electricity generation in 2012 were:

• Coal 37%

• Natural Gas 30%

• Nuclear 19%

• Hydropower 7%

• Other Renewable 5%Petroleum 1%

• Biomass 1.42%
• Geothermal 0.41%
• Solar 0.11%
• Wind 3.46%
• Other Gases < 1%

So yeah. Your power plant has a drinking problem.