Indirect Income: Load Following, Potholes, and the Elderly

Dear Mom, please ignore the next paragraph. Just move on to the third one and pretend that that is the real beginning of this post.

Fuck potholes and all their horrible children. Avatars of the impermanence of mans creations and active forces of entropy that love to do nothing more than wreck tires, throw steering out of alignment, and light the cash in your wallet on fire. The only bass beat I should hear in my car should be from the drums in Fat Bottomed Girls by Queen, not the thump thump of my wheels jumping in and out of a street that looks like it was lifted out of the French countryside circa 1917.

No matter how careful you are, it is likely that if you live anywhere in Canada where it gets below zero for the winter (screw you Vancouver and Victoria), you’re going to hit a pothole sometime this year. Honestly it’s probably going to be sometime this week.

You can just feel your soul leave your body when you hit something like this. Which you will, because it’s hiding under a puddle that covers the street.

But what does this all have to do with nuclear energy? Well I’m going to have to back up a touch, and talk about something completely unrelated, load-following. For people that don’t really follow energy policy, load following is the practice of ramping a power plants output up or down to match the demands from the grid. Ostensibly so that we don’t overload any section of the grid, but also to minimize fluctuations in the prices of energy hour to hour, day to day, and month to month.

People seem to be under the idea that nuclear plants can’t load-follow, which is one of the reasons you hear people refer to it as base-load power. Whether it is used as a disparaging term or as a positive description depends on which side of the argument that person is on. But it doesn’t matter because people that claim that nuclear can’t load follow are wrong, or at least misinformed.

Nuclear plants most certainly Can load follow. They just Don’t. Load following is easy for a nuclear plant, output is controlled by the control rods which I’ve mentioned before in a couple of posts. The problem is that the core takes a long time to lose the heat from running at full power even down 20%. Think about how long it takes for a big bathtub to lose its heat. Then make it 200x the size, insulate it on all sides and put a water heater inside it still running. So if you are going to want to ramp power up or down you need to get that whole tank of water up to the temperature that will make the right amount of steam to turn the turbine at the right rate.

Way easier to get the perfect temperature in one of these than in a reactor core. More comfortable to use too.

Now this is for current solid fuel reactors like CANDUs, PWRs and BWRs. A funny thing happens with liquid fuel reactors that I am looking forward to getting more in-depth with in hopefully my next post, but suffice to say that since liquids can expand and contract with temperature they are even easier to make load follow.

The reason that nuclear plants Don’t load follow (not Can’t, very important distinction) is economic in nature. Since we in north america currently suck at building plants on time or on budget, and since nuclear plants are capable of running at very high capacities anyways, running them at less than full capacity is like leaving money on the table. And of course since it doesn’t make economic sense for nuclear plants to load follow once they reach a level of production equal to the average minimum production of their local area building any more becomes less and less profitable or attractive.

But load following isn’t just an hour to hour thing. It’s also a seasonal thing. in Alberta, electricity usage usually peaks in the summer months when everyone shields themselves from the sun with air conditioning, while gas usage usually peaks in the winter when we are all trying to not freeze to death. However! Nuclear power plants make heat as well as electricity. in fact they usually make a lot more heat than electricity due to them not being very high temperature so their steam turbines are fairly low efficiency (~30-35%).

I’m sure they don’t need All that heat for electricity….

So what does this have to do with potholes? Well, at least up here in the vast frozen fields of Canada (and much of the northern United States) potholes are formed by the freeze/thaw cycle of water. Snow falls, melts, refreezes, expands, and breaks all our roads into horrible chunks of steering column jarring crap. But what if it didn’t refreeze? What if we made it so that when the snow hit the streets and sidewalks and driveways it melted and then just drained away down the storm drains like it does all the rest of the year?

If you could use the heat from a nuclear plant to heat streets, sidewalks, alleys, parking lots, and driveways you could prevent the formation of potholes and icy roads. This could save tens of millions of dollars per year on road repair and snow removal. For example, Edmonton budgeted over $750M for road maintenance, repair, and construction for the 2019-2022 budget not including snow removal, which cost $64M in 2017 and covered almost 12,000 km of roads and side streets. And this heat could almost be the waste heat of the power plant rather than intentionally produced heat, meaning it would still be earning its regular income from producing electricity. If extra heat is required that could be purchased by the city by reducing electrical capacity during off peak hours to make more heat, because remember, nuclear powerplants can in fact load follow if they have foreknowledge.

Now granted, the technical challenge of turning every concrete and asphalt public surface in an entire city into the equivalent of a radiant floor is a non-trivial challenge, but the benefits start propagating out very quickly among the population. If we keep the streets from dropping below say 5C then we cut the shrinkage of the streets by up to half of their currently designed tolerances (Edmonton can go from more than +30C to sub -40C, it’s not fun) which mixed with the drastic reduction in pothole formation would bring our road surface lifetime up to approximately the same level of our more temperate cities like Victoria and Vancouver. In a corollary to being able to heat streets to prevent freezing, having heat exchangers under a road surface could also be used to prevent excessive heating, preventing expansion from damaging the surfaces and also having the side benefit of potentially preventing our super cute doggos from burning their paws on walks!

We would do anything for our cute 4 legged friends, yes we would. Yesh we Would! Who’s a good puppy?

No snow and ice means fewer accidents on the road due to poor grip conditions, which means fewer injuries and fatalities during winter driving in the city. It also means that there is no reason to use salt or sand on the roads in winter, which have potential environmental concerns from chemically concentrated runoff flowing out of a city and into the larger ecosystem (plus it would prevent our cars from rusting out from underneath us).

It would also protect our elderly and infirm as there would be far less ice to cause slips and falls that would potentially take them to the hospital for broken bones. Not to mention help prevent your father or grandfather from over exerting himself trying to shovel 10 billion tonnes of white bullshit off the driveway and having a heart attack. But of course these aren’t immediate sources of income so they are not taken into economic account when talking about nuclear power. There is also the fact that preventing snow ploughs, sanding trucks, and transport trucks that haul away the snow from having to operate removes a fairly intense source of CO2 emissions from our city.

Nuclear power is intense enough to start opening up opportunities and options to improve day to day life in ways that are minimally impactful to the environment. This level of energy use can’t be done with solar power because it can’t be done with the sun itself. We can use nuclear for more than what we currently use energy for because it produces so much extra in such a small package. We could afford to start getting a little weird with its applications in pursuit of better, more practical, and simultaneously more whimsical lives for ourselves and our loved ones, no matter how many legs they have.

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4 thoughts on “Indirect Income: Load Following, Potholes, and the Elderly

Add yours

  1. Energy requirement is a bit realistic, if I’m correct:
    Length * Lane width = 1km*3.25m
    Ice thickness on a cold day = 5mm
    Volume = 16.25 cubic meter
    Weight = ~15,000kg
    Assume ice temperature as -10C. Specific heat + Latent heat = 15,000*2*10+15000*334 = 5,310,000kJ
    If 5mm ice falls in 1 day power needed to melt ice on 1km of single lane = 61.5kW
    12,000 km of 2 lane roads: 1476 MW
    12,000 km of 3 lane roads: 2214 MW
    If 10 billion tonne of ice accumulates in a month, energy required is unrealistic.
    Energy required to melt 10 billion tonne: 3.54*10^15 kJ
    Power capacity to melt this in a month: 1366 GW
    World nuclear thermal capacity is around: 1200 GW
    What about new heated road infrastructure cost?
    If trains do not have this problem, it is better to build more railway lines.

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    1. oh yeah, it really doesn’t work if you let the snow accumulate first. The ideal way to do it would be to have it always on so that the surface temp never gets below say 5C. That way you only need to melt the snowflakes as they land which is significantly easier than trying to melt through the solid snowpack. and the “ten billion tonnes” is a bit of an exaggeration based on this little news story that always makes me laugh http://fmobserver.com/fargo-man-arrested-for-clearing-snow-with-flamethrower/# The heaviest snowfall of recent memory was a bit over 1 meter of snow for the season which for your calculations would be about 2.1 Billion tonnes over the course of 6.5 months. which puts the energy requirements at about 1/33 of the energy considerations you have. (that’s still like 41 GW, but that’s for an always-on system) I’m sure that proper management of the system to tie into weather forecasts could reduce that load even more. Also, nuclear thermal capacity is significantly more than 1200 GW as nuclear energy supplies about 11% of the worlds 14TW of electrical needs and the thermal output of a powerplant is generally a 3:1 ratio with its electric output currently. which puts the world thermal output at about 4700 GW.

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      1. I think you have counted world fission thermal capacity as electrical. So to get your 4700-GW figure you have divided the electrical capacity, ~400 GW, by the square, not the first power, of typical 0.33 heat-to-electricity efficiency.

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      2. wow, I have been grossly misinformed for a very long time. I guess I’ve always heard the 14TW figure and assumed that people were talking electricity but I guess that it is, in fact, energy total. thanks for setting me straight.

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