Chapter Eleven

Energy Density

If there could ever be a lesson learned that can make a person recognize why we need nuclear it is the case for energy density. All of the energy choices have small outputs compared to nuclear. We are going to look at how various energy forms differ by the quantity of fuel per unit and in the case of wind, solar and hydro their energy footprint that needs to factor in efficiencies and dependencies.

There are two ways to look at energy density. One is by looking at how much energy is produced per unit of fuel. Nuclear fuel is as compact as you can get. The power contained in several pellets of Uranium is literally very dense. The other is how much energy is produced by the resource equivalent whether that be wind, sunlight or water. The energy produced per unit of fuel is easy to calculate.

The energy produced by wind, sunlight and hydro are trickier values to calculate. Wind and solar are more of a problem to sort out because they are dependent on things that are less predictable like the weather or daylight. Their dependncies are also hard to ignore. Both wind and solar energy depend on other energy types whenever the wind stops blowing or the sun stops shining. But which type of energy source gets used to replace the missing wind and solar energy? In the U.S. its natural gas. Other places that find natural gas too expensive are more likely to use dirtier sources of energy like coal. If the local land formations allow it pumped storage power plants can be used but they are not available everywhere.

The Levelized Cost of Electricity (LCOE) helps compare their value.

“The levelized cost of electricity (LCOE) is a measure of a power source which attempts to compare different methods of electricity generation on a comparable basis. It is an economic assessment of the average total cost to build and operate a power-generating asset over its lifetime divided by the total energy output of the asset over that lifetime. The LCOE can also be regarded as the minimum cost at which electricity must be sold in order to break-even over the lifetime of the project.”

From Wikipedia: https://en.wikipedia.org/wiki/Cost_of_electricity_by_source

“Roadmap to Nowhere” is a chapter from a book called “Power to the Planet” by Mike Conley and Timothy Maloney that helps illustrate what the problem is with so-called renewable energy.

Four bottom lines up front:

  • It would cost over $29 Trillion to generate America’s baseload electric power with a 50 / 50 mix of wind and solar farms, on parcels of land totaling the area of Indiana. Or:
  • It would cost over $18 Trillion with Concentrated Solar Power (CSP) farms in the southwest deserts, on parcels of land totaling the area of West Virginia. Or:
  • We could do it for less than $3 Trillion with AP-1000 Light Water Reactors, on parcels totaling a few square miles. Or:
  • We could do it for $1 Trillion with liquid-fueled Molten Salt Reactors, on the same amount of land, but with no water cooling, no risk of meltdowns, and the ability to use our stockpiles of nuclear “waste” as a secondary fuel.

One estimate my colleague Mathijs Beckers is that if the U.S. were to go 100% renewable the rest of the world would have no resources left to do the same. That’s how much we would need in materials such as steel, concrete, aluminum and copper wire. China and India would be stuck burning fossil fuels.

Despite Germany’s plans to shut down nuclear power plants they will have trouble shutting them down. They boast about their plans to make renewable energy the dominant energy source regardless of the fact that they have achieved only a 15% share in the energy mix. Misguided intentions considered, they are not tsunami prone like Fukushima was in Japan. Energiewende cannot shut down nuclear power easily because currently they provide so much of the missing energy. Unlike the U.S. natural gas is more expensive in Europe because they don’t have the geological conditions for natural gas. What they do have ironically is coal which has been added to their energy mix. The dirtiest kind of coal fleet called lignite is now expanding in Germany. In fact it makes up over 50% of their electricity in the country cited as being largely renewable.

Energy density of nuclear energy is precisely why it is by far the most significant factor in reducing Carbon emissions. We all know that nuclear power is mighty. We think of phrases like “harness the atom” and “split the atom.” What is hard to grasp about nuclear energy is just how much energy is contained in uranium, plutonium or thorium. It is because of this huge amount of energy created per unit of fuel that makes it so appealing and after comparing you will see that it is necessary.

Being energy literate you will begin to see why nuclear energy is so desperately needed. Being painfully aware of the threat carbon dioxide has become and being energy literate we realize its the facts that matter.

We know coal is by far much more harmful and deadly than nuclear. The nuclear safety record is the best. To illustrate the point let’s try to imagine an impossible scenario that for all the planet’s nuclear plants we managed to produce one chernobyl accident a day. First remember that depending where you heard about Chernobyl the numbers will vary. But we would still be doing better than the current damages being done by coal pollution. Coal kills 1 million people a year worldwide. That’s 2700 a day worldwide. Looking at just the U.S. that’s  24,000 a year or 67 a day. Considering Chernobyl’s official death toll is 60 people it is fair to say that nuclear energy in a worse case scenario is still a better choice than coal.  Also consider that nuclear accidents are very rare. Count the coal mine accidents, the natural gas explosions, the oil spills, the hydro dams bursting, even the repairing of wind turbines and installation of solar panels has had more accidents than nuclear plants. But everyone remembers the three nuclear plant accidents over the entire history of commercial nuclear plants that killed less than 100 people combined and that was all in Chernobyl. 

The countries of China and India dwarf our North American countries. They are desperate to come out of poverty. Will they listen to the brats marching for green power. Those who march in the name of renewable energy and conservation have never lived without energy for any length of time that matters.

https://en.wikipedia.org/wiki/Environmental_impact_of_the_coal_industry

Why can’t weather dependent wind and solar solve our problems?

Wind and solar power are diffuse and unpredictable. We know when the sun shines if there’s no cloud cover. And there are regions that have more wind and there are regions that have more sun but they are not the norm. Last century the countries that had power mostly ran on reliable power. Our grid is geared to handle reliable power. We call reliable power base load power like nuclear, hydro, natural gas, oil and of course coal. Over 400 coal plants exist in the U.S. and we keep saying we need to stop coal plants. 60% of American electricity comes from coal.

Does running a lemonade stand in front of your house as a child prepare you for the retail business? Hardly.  

Here is a quote from Alex Cannara who keeps his group members primed for encounters and this is a simple to understand explanation:

“Ok gang, here’s the pinky story: Hold up a pinky.  If the top two joints of your pinky were Uranium 235, it would run your profligate American life for 10 years.  That would give you two pinkies of ‘waste’ including a teeny amount of the long lasting kind like Plutonium.

That “waste” is usable in advanced reactors and they decay to ordinary elements taking anywhere from seconds to a few centuries.  So every decade, that individual would have to find a pill bottle to put the waste in and bury it next to the prior decade’s bottle in their back yard.  Each bottle could indicate when it can come back out.

Wade Allison & some other sensible Brits in an attempt to show their confidence of the safety of such stored waste offered their gardens as a place for the “waste.”

One pinky’s worth of pure fissile Uranium produces enough energy to supply a single

person for 10 years leaving behind two pinky sized pellets of so-called “waste” fission products (much of it is reusable). Producing the same amount of energy from coal would take 286 refrigerator loads to produce 20 refrigerator loads of coal ash. ”

From Booklet on IAEA website Energy density comparisons (fuel and land requirements)

The quantity of fuel used to produce a given amount of energy – the energy density – determines in a large measure the magnitude of environmental impacts as it influences the fuel extraction activities, transport requirements, and the quantities of environmental releases and waste. The extraordinary high energy density of nuclear fuel relative to fossil fuels is an advantageous physical characteristic.

One kilogram (kg) of firewood can generate 1 kilowatt-hour (kW•h) of electricity. The values for the other solid fossil fuels and for nuclear power are:

1 kg coal:

3 kW•h

1 kg oil:

4 kW•h

1 kg uranium:

50,000 kW•h

(3,500,000 kW•h with reprocessing)

Consequently, a 1,000 MW(e) plant requires the following number of tonnes (t) of fuel annually:

2,600,000 t coal:

2,000 train cars

(1,300 t each)

2,000,000 t oil:

10 supertankers

30 t uranium:

reactor core

(10 cubic metres)

The energy density of fossil and of nuclear fuel allows relatively small power plant areas of some several square kilometers (km²). The low energy density of renewables, measured by land requirements per unit of energy produced, is demonstrated by the large land areas required for a 1000 MW(e) system with values determined by local requirements and climate conditions (solar and wind availability factors ranging from 20 to 40%):

Fossil and nuclear sites:

1–4 km²

Solar thermal or photovoltaic (PV) parks:

20–50 km²

(a small city)

Wind fields:

50–150 km²

Biomass plantations:

4000–6000 km²

Comparing the energy output difference of Uranium to Coal

Comparing the energy output difference of Thorium in Molten Salt Reactors to Uranium to coal

Who’s the Fairest of them All

There was a time when Nuclear Energy was the cheapest going by the accounting. In fact it still is over long periods of time.

Looking at figures from 1982 page 98 The Environmental Case for Nuclear Power

Kirk Sorensen explains how energy dense a Thorium Molten Salt Reactor based on his LFTR design would be.

“A mere 6,600 tonnes of thorium could provide the energy equivalent of the combined global consumption of 5 billion tonnes of coal, 31 billion barrels of oil, 3 trillion cubic meters of natural gas, and 65,000 tonnes of Uranium”

Hydro uses kinetic energy from the flow of water. Wind uses kinetic energy from the flow of air. Solar uses electromagnetic radiation from the fusion reactions on the sun. 

The different fuels we use as energy sources are either combustible or fissionable. The combustible type is the breaking of chemical bonds called an exoergic or exothermic reaction. 95 percent of the world’s energy is created from combustion of coal, oil and natural gas.

That leaves us with nuclear energy which relies on another type of energy release from breaking a nuclear binding force. The reaction depends on using uranium or plutonium. Thorium is still experimental but could prove to be an indirect fuel that goes through the thorium cylcle to produce uranium.  Thorium has advantages based on its abundance 4 times more plentiful than Uranium, better fission products than Uranium. As Kirk Sorensen explains the real advantages of Thorium are a real game changer when the reactor is using the molten salt reactor as it’s design. It is the fluid that makes all the difference. Hot fluid mixture allows nearly full utilization of the fuel.