Electricity Basics (and some advanced)

I received my second request for a post! This time the submitter asks for information about electricity, transmission, and how intermittent renewables like wind and solar fit in.

So, the first question:

1. Electricity, for the most part needs needs to be consumed the instant it is produced?

Yes. Storage of electricity can be done in batteries, or with pumped-water energy storage, but these are all just ways of being able to make electricity at some moment later in time. In short, electricity, once produced, is either used immediately or stored. Massive storage is not practical at the moment, so it's used.

2. Wind or Solar electricity is essentially in addition or parallel to the base load, and do little to lessen the use of coal, NG, or nuclear derived electricity!

This bring up an interesting point about electricity production. In the US, we have 60hz electricity. It's made 60hz by the generator design (in the US, Europe and other places use 50Hz power). Thermal power plants, those that burn things to produce power, rely on spinning a turbine in a magnetic field to produce power. The magnetic field is part of the turbine design, and is too complicated for this post to discuss in further detail. The turbine is spun because water, turned into steam by the heat from burning things or other reactions (coal, natural gas, or even heat from fission), expands rapidly from water to steam. It creates pressure, and then pushes through the turbines to spin them. The turbines spin at the exact rate they need to in order to produce 60hz electricity.

If we produce slightly too much electricity, the turbines start spinning slightly faster. To keep the grid at the right speed, electricity production is reduced at plants. If there is too little electricity, the turbines will slow down, and we'll fall below 60hz. There is a constant dance of the power plants and the electricity users to make everything balance. It's mostly automated, and happens very quickly.

What does this have to do with solar and wind? A lot. Solar and wind power output can be predicted, but not perfectly. If we want to maintain a perfect 60hz grid, we need to be able to adjust for wind and solar output. Because, again, electricity is used when it is made, and not stored. Coal and nuclear power plants aren't great at changing how much electricity they produce in a short timescale, so if we are going to have power plants to make the balance necessary, we need hydro and natural gas to account for the variability of the solar and wind. There isn't enough hydro to do that all over the country.

In  other words, if we want to maintain a 60hz grid, we are always going to have some amount of natural gas power plants.

But beyond that little wrinkle, solar and wind power absolutely offset coal-fired power plants. The more solar and wind we have, the less nuclear and fossil fuel power we need, in general.

In practice, do renewables offset much? See the chart below.

US primary energy consumption. Source: eia.gov info

Short version: Wind was about 1.2% of primary energy (primary energy counts burning oil for cars as well), and solar is 0.16%. So wind and solar can replace coal and nuclear, but it barely does currently.

Longer version: We can let the 60hz grid go from exactly 60hz to let it slide between 58 and 62. And then we can fairly easily do away with a lot of other power plants, as long as we have enough wind and solar. Note, however, that there aren't enough good wind sites in the US for this, and solar is currently too expensive and resource-demanding to replace fossil fuels.

3. Electricity is bought and sold just like a commodity?

In some ways, yes, but not exactly! There is a complicated daily bidding process, and several factors are brought into play.

This one is a bit confusing. I'll do my best. Power plants bid on the day-ahead market. They submit their bids to what is typically called an ISO, for Independent System Operator (some places call it differently, like RTO for Regional Transmission Organization. The ISO/RTO looks at the bids, looks at their best guess for power the next day, and then figures out how many of the power plants they need to hire for the day. Those that don't get hired don't actually burn anything or produce power. Those that do get hired, get hired at the rate of the highest bidder. Let's do an example to explain better.

Note that a MWh is one hour of one MW production. So a 600MW plant produces 600MWh in one our, and 1800MWh in 3 hours.

A plant says, "I can produce this many megawatts at this many dollars per megawatt." Power Plant 1 might say, "I can produce 600MW of coal power at $80/MWh." Power Plant 2, "I can produce 1000MW of natural gas power at $100/MWh." Power plant 3, a nuclear power plant, doesn't shut down. They just keep running. They say, "I can produce 1200MW at $0/MWh." Why? Cause they have to run anyways. They are delivering that power at any price. Power plant 4 is an old coal-fired power plant that has already paid for itself, so it's really cheap, and says, "I can provide 300MW at $50/MWh"

Let's assume it is determined that all of the less expensive power plants, along with Power Plant 2, need to run in order to satisfy electricity demand. They want $100/MWh. Power plant 1, despite bidding in at $80 per MWh, gets $100/MWh, nuclear plant 3 also gets $100/MWh, and coal plant 4 also gets $100/MWh.

On another day, it is determined that only enough electricity is needed for power plant 4 (and all the ones who bid below it). So Power plants 1 and 2 do not produce electricity, power plants 3 and 4 each get $50/MWh.

Should inputs become more expensive, then the power plant has to raise its price. Natural gas, for example, became a lot less expensive in the past 5 years. So they now produce electricity for less than a new coal fired power plant would. So they bid in for less.

A bit confusing, right? It gets more complicated than that. This is a great example to show that electricity is not exactly treated like a commodity.

Now what about solar and wind? Pretty much, if solar and wind is produced in the US, it is purchased, pretty much outside the normal bidding system. What happens to the bidding system if all power becomes solar and wind? There probably will still be some version of it, changed to fit the new system!

That's all for now, 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.

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 China, in inches

Rainfall in the US, 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,

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

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.

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

Power Grid

I was struggling to write a post about PV solar panels (the struggling part came in while trying to describe the quantum mechanics that take place), and realized that I need to describe how our power grid works in far greater detail than I had before. What follows is the gory details about how power is transmitted to your home. This is important because while solar power costs 5x as much as coal on the wholesale market, it only costs about 2x as much as coal at your house. Sometimes less. This is because coal-powered electricity is wheeled and dealed through several players as it reaches you, and is marked up every time. Solar power dumps straight into your home. Some of you are gonna love this article, others have already closed it.

power_grid_300

On a logistical note, I haven't posted in the last two weeks cause I am too busy with life things to write both the blog and play computer games. Computer games sometimes win out. Thanks, X-Com: Enemy Unknown.

Generators, LSEs, Home Energy

Generators are all the different types of power plants we have discussed. They produce power, and in a deregulated market, sell the power to the grid. They are given a price based on demand. We have discussed how each power plant will "bid in" a day ahead and say how much power they can produce at which prices. As more power is demanded, the price will rise to bring more expensive power online. No matter what the power plant bids in, if they are online, they will get the per-MWh payment of the most expensive plant to come online. In other words, the marginal cost of energy production is what each power plant gets paid per MWh. If an expensive power plant is brought on-line for $1000/MWh, for instance, every single plant that is operating will receive that.

Okay, we have also seen the cost to produce power in several posts. It makes sense to repeat it here.

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

So the cost to produce is the total system levelized cost (and now you should realize that producing power for $1000/MWh is ridiculously high. Except it has happened recently and momentarily in New England).

People at home don't see the price that a generator gets. Do you notice that you pay about 20 cents per KWh in MA (I use MA cause apparently all my readers are here), it is $200 per MWh. What gives? All these power plants are producing power for way less than that. Except for solar thermal and offshore wind, which both suck and are expensive.

The reason for this is that home/commercial retailers do not buy from the generators and from the wholesale market. Things called Load Serving Entities (LSEs) buy from the wholesale market. Often they will just be your utility company. They then distribute it to end-users or to other complicated things that we don't care about. The end users are your households and commercial things like shopping malls and stores and offices.

Sidebar: One important thing to note is that industry usually buys directly from generators. So while we pay $200/MWh for electricity, a Ford power plant might pay $60/MWh. This has implications that we will discuss later.

So, the LSE buys electricity off the wholesale market. And then marks it up and sells it to consumers. That is why you pay $200/MWh.

RTOs, system management

This section is getting specific, some of you may want to skip to the end of the article, the implications part.

Who tells generators when to come online and manages the wholesale market? Regional Transmission Operators. In New England, our RTO is called ISO-NE, for Independent System Operator of New England. They take bids and determine which power plants produce. They have important things to consider, like making sure a regional power line isn't too congested.

Line Losses

Nearly all power lines lose a percentage of their power as heat. Transmitting long distances loses around 8% of power. This is because there is always some resistance to the flow of electricity. It is like friction for the flowing of electrons. Power lines also have a limit to how much power can flow through them. If you try to go past the limit, they heat up rapidly and lose a ton of power.

The latter is something that the RTOs manage, to make sure that there won't be problems. The former has massive implications for renewable energy. Most of our renewable energy is wind and solar. Like wind in the sparsely populated midwest. And solar in completely unpopulated deserts. Transmitting this power to cities incurs huge line losses. With current capabilities, transmitting power from Iowa wind farms to NYC would make power more expensive than just building the wind farm near NYC, despite that wind in NY sucks (heh, punny). I don't have a source for this, I just saw it at a talk at Harvard.

Implications for installing renewables at home, commercially, and in industry

boa_photo1

We pay $200 per MWh of power as residents in Boston. Solar PV in the best cases is $144. This will be in deserts. In MA, we don't get as much sunlight. But for the sake of argument, lets say that the average cost of solar in MA comes out to be $200-$250. With subsidies, it will be less. So would you pay $200 per MWh from your utility, or $200 per MWh to produce your own energy and stick it to the man? Also your own power would be clean, with far less CO2. With subsidies available in places like MA and NJ, solar comes out to less than $200/MWh at home.

Next lets consider commercial places. They also buy from LSEs. This is why you see a ton of them building solar panels. It makes sense economically and gives them a good vibe that the public likes.

Finally, let's consider industry. They buy directly from the wholesale market. So they pay closer to $100/MWh. They won't give two shits about renewables. Because they won't save money by installing renewables on their sites.

And this, my friends, is the trend we see. On-site renewables are adopted by commercial real estate and by residents, and industry is highly unlikely to ever embrace it. Interesting, eh?

Thanks for reading!

-Jason Munster