Visualizing the material needs of wind and nuclear

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electricity, energy, environment, materials, nuclear, renewables, technology, wind

Check this out!

A large wind turbine and a single nuclear fuel assembly put out the same amount of electricity over their respective lifetimes.

Ok, so why is this so cool? It’s often hard to visualize how much impact our energy system has, so it often comes down to charts. But when two concrete items can be visualized that put out about the same amount of juice, it’s easier. Imagine all the steel that goes into building a giant wind tower taller than the Statue of Liberty and the fiberglass for three blades almost as tall. Now imagine a 4 meter (13 foot) tall fuel assembly, 30cm x 30 cm (1ft x 1ft). Sure, it’s uranium and zirconium instead of steel and fiberglass, but the total weight must be a thousand times smaller! (300 tons vs. 0.4 tons actually.) That roughly translates to a thousand times less mining.

First, let’s calculate the output of a single 2.5 MWe wind turbine. The U.S. Energy Information Agency’s (EIA) 2018 capacity factor for wind is 0.374. That means wind turbines output their rated capacity (e.g., 2.5 MWe) about 37.4% of the time. Wind turbines are designed to last 20 years, and will have a slight decrease in output of 1.57%/year. That gives an average wind turbine a total electricity output of 142 GWh over its lifetime.

Now, let’s look at nuclear energy. Nuclear power plants come in two varieties – roughly 2/3 are Pressurized Water Reactors (PWRs) and 1/3 are Boiling Water Reactors (BWRs). Their fuel looks very similar, but a fuel assembly is how individual fuel rods are bundled together and nowadays PWRs go with a 17×17 square assembly and BWRs go with an 11×11 square assembly. This means that a 1.2 GW PWR contains around 200 assemblies while a BWR with the same rated capacity might have 750 assemblies.

An engineer inspects a new PWR fuel assembly.

The EIA’s 2018 capacity factor for USA nuclear is 0.926. Nuclear fuel stays in the reactor producing power for about 5 years. Combine all that and you find that each PWR fuel assembly puts out about 227 GWh over its lifetime, and each BWR fuel assembly puts out about 75 GWh over its lifetime. Weighting those two outputs to the fraction of each fuel assembly type in the USA fleet yields an average nuclear fuel assembly output of 127 GWh over its lifetime.

Wow!  Each wind turbine generates 10% more electricity than a fuel assembly, but needs 1000 times more material!

Sure, this is just an estimate. I’m not counting the huge amount of concrete involved in either technology, and yes, a reactor is a huge, thick metal cylinder that requires mining inputs, too. But over its 60 year lifetime, a nuclear power plant will spread those material costs between 8,000 assemblies for PWRs or 23,000 assemblies for BWRs. I’m sure there are other nuances, so please bring them up in the comments!

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Pre-print of my GLOBAL Conference paper

NEUTRONIC ANALYSIS OF A LIQUID SODIUM FAST REACTOR EXPERIMENT FOR THE LARGE-I POSITION OF THE ADVANCED TEST REACTOR

File download: global-fast-loop-paper-preprint

Abstract:

Material testing experiments are needed to enable the next generation of nuclear power reactors. This paper discusses the neutronic analysis of using a modified Boosted Fast Flux Loop (BFFL) design. This Fast Loop design features both booster fuel plates and a thermal neutron filter.

Attila is a 3D multigroup deterministic neutron transport code. It is used to mesh CAD model geometries for use in both the Attila deterministic calculation and the Monte Carlo calculation. MC**2-generates a multi-group fast reactor cross section library which is converted to a form that is used by Attila for deterministic numerical solutions. Monte Carlo neutron transport results generated by MCNP are used as reference solutions for comparison.

The Large-I position Fast Loop fast neutron (>0.1 MeV) flux magnitude is 2 x 10^13 n/cm^2-s, which is significantly less than the minimum BFFL experiment criteria of 3 x 10^15 n/cm^2-s. The fast to thermal ratio of 8 is also below the minimum criteria of 15. Further design iteration is necessary to achieve adequate materials testing performance in the Large-I position. Attila default thermal library calculations yielded group-by-group errors of <±50% compared to the MCNP reference solution while Attila-MC**2 calculations had significantly reduced errors (<±15%).

Nuclear reactors have been around for 2 billion years

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gabon, moderator, nuclear, oklo, reactor, U-235

We get nearly all our power from nuclear reactions. Solar energy is nuclear-based. From 150,000,000 kilometers away, the sun sends us the energy released from fusing atoms. For millenia, the sun has heated our homes. More recently solar energy has been used for passive cooling and electricity production.

credit: macdonaldarchitects.com

The sun also drives evaporation which eventually enables hydroelectric dams. However nuclear reactions in the sun also released the energy now stored in fossil fuels. Closer to home, radioactivity within the earth nearly matches the energy consumption of humans on the surface. Around 20 TW of heat is generated by radioactive decay, while 17 TW was consumed by humans in 2013.

In modern nuclear reactors we can sustain nuclear fission reactions by bringing certain materials together in the right proportions, but did you know that earth also had its own fission reactors about 2 billion years ago?

In the central African country of Gabon, in a region called Oklo, miners discovered that the uranium ore they were mining was deficient in the U-235 isotope. That was the first clue. U-235 is the natural isotope responsible for most of today’s nuclear power. Besides fuel though, a reactor needs a moderator. The moderator slows down neutrons to speeds where they can split additional atoms.

Today, most reactors use light water which is just water with hydrogen nuclei that consist of a single proton. Using this moderator, it is necessary to enrich U-235 to around 3% before it can sustain a fission reaction. Natural uranium today is only 0.7% U-235. However U-235 decays faster than U-238. 1.7 billion years ago, the U-235 fraction was around 3%.

This enabled the reactors at Oklo to periodically “switch on” when water was present. The uranium deposit would generate a lot of heat and the water would eventually evaporate or otherwise escape. The reactor would “switch off” and cool down. When the water returned, the reactor would cycle again.

credit: gsapubs.org

Besides being an interesting puzzle, the Oklo reactors can and have informed today’s nuclear engineers and scientists. Since they operated for thousands of years without destroying themselves, the reactors can inform modern reactor design. Additionally, they can tell us how radioactive materials can be immobilized for billions of years. Scientists have even used Oklo to test whether the fine structure constant has changed over time.

Are we really expecting a miracle?

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carbon, fossil fuels, Germany, GHGs, miracle, nuclear, renewables, world

Check out this figure. It shows actual energy consumed by fuel type worldwide. If you look at the chunk provided by low-carbon technology (nuclear, hydro, and other renewables) in 2015, note that the world demand for energy has increased by this much since just 2005. That’s right. In ten years low-carbon energy use has grown 20%, but energy demand has grown by 125% of all low-carbon energy consumed in 2005.

credit: vox.com

This means we are using more fossil fuels every year. Even though renewables have high rates of growth, they are growing from a small base. Even Germany is struggling with its renewable goals because it simultaneously wants to stop using nuclear power.

With population growth and increasing affluence in many parts of the world, we can expect energy demand to keep growing. The obvious choice for many countries is fossil fuels because they are cheap and dispatch-able.

The truth is that a significant fraction of people will never opt (= pay more) for intermittent power or consume less of certain things (e.g. air conditioning, washing machines, mobility, and food). What we really need is a radically cheaper energy source that can do everything that fossil fuels can but without the CO2 emissions. Then we need the infrastructure and expertise for it to grow incredibly fast over the next several decades.

Perhaps the best way to achieve this is to get more people out of poverty and educated. It might take only a few geniuses to come up with the miracle technology. We know lowering consumption and artificially increasing the cost of energy could reduce greenhouse gas emissions, but our economic and social systems prefer to ignore this. With the added strategy of fostering innovation in the energy sector, we stand a better chance.

Hopefully, we can make more miracles happen instead of just waiting for one.

3 minutes to midnight

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bioweapon, climate change, disease, end of the world, midnight, nuclear, population, war, weapons

People have been predicting the end of the world since the beginning of the world. Christians have expected the apocalypse since the Book of Revelation was written. Even scientists like Paul Ehrlich predicted the end would arrive by the 1970s. However, it might be time to take the idea more seriously.

credit: playbuzz.com

The “end of the world” can be defined in various ways. My definition? I define it as the large loss of human life and knowledge. Even a 10% loss would be tragic beyond imagination. Many environmentalists are actually concerned about human suffering and our continued civilization.

There are many disasters that might cause the “end of the world,” but I find several both interrelated and too probable. These are nuclear war, climate change, and infectious disease. Big organizations are beginning to take them seriously and you should too.

Infectious Disease

Humans have been fighting bacterial and viral infections since the beginning of our species. Even with all our medical expertise today, it’s far easier for a pathogen to kill huge numbers of us. Partly this is because we are moving to cities and partly this is because mobility (think air travel) is now so easy. However another factor is antibiotic resistance. The World Health Organization has issued a report warning of the huge danger of over-using antibiotics (especially in livestock). Another grave concern is an engineered bio-weapon that escapes control.

Climate Change

The British medical journal The Lancet has issued a new warning discussing the impacts of climate change on human health. Climate change affects the availability of such rudimentary needs as water, food, and shelter. Not only that, but climate change means that disease carriers like mosquitoes will be more prevalent and widespread. The NRDC argues that once rare infections in the US are on the rise. Climate change even threatens developed cities due to changes in water availability. This article discusses a UN report and 8 world cities that face water scarcity in the near future.

Nuclear War

This is a big one, because if it happens the “end” comes pretty fast. A generation ago, a betting man might have picked this one as the most likely. The USSR and USA repeatedly came close to destroying the world. Even now, the US and Russia are modernizing their arsenals and maneuvering each other into more dangerous stances. Further, climate change may exacerbate certain situations. India, Pakistan, and China all rely in part on Himalayan glaciers for water supply. As populations grow and climate change stresses water and food resources, the unthinkable might be considered. Even a few weapons exchanged in a “small” conflict would drastically alter the climate, further exacerbating resource scarcity.

Midnight nears

A doomsday clock was conceived to convey the danger we face from nuclear war back in 1947. It has since widened its scope to climate change and other threats. The clock is updated periodically, but in January this year we moved to 3 minutes to midnight. Since its inception 68 years ago, we’ve only been closer to midnight only once (in 1953).

These are big organizations warning about BIG impacts. In the past, we’ve largely relied on good luck and timely technological inventions to avoid catastrophe. We need more discussion and engagement with these issues. We have the power to change our future and to make it better for all life.

The pope is right for once (at least partly)

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carbon, climate change, consumer, consumption, countries, economics, energy efficiency, overconsumption, pope, technology, world

I don’t generally agree with religious leaders, but Pope Francis has been making some good arguments lately. Besides pointing out that weapon manufacturers aren’t very Christian, he’s released a letter arguing that climate change is a looming world issue.

Climate change is a global problem with grave implications: environmental, social, economic, political and for the distribution of goods. It represents one of the principal challenges facing humanity in our day.

Of course he ignores addressing the growing population, but he does argue that rich countries have consumed too much at the expense of the less powerful. Wealthy countries need to reduce consumption and support clean energy development of poorer countries.

The developed countries ought to help pay this debt by significantly limiting their consumption of non-renewable energy and by assisting poorer countries to support policies and programmes of sustainable development.

While I do think putting a price on carbon emissions will be a HUGE step towards addressing ecological-societal catastrophes, we also really need to consume less. Without addressing consumption, we are delaying our problems in the hope that technology will fix them some time in the future.

100% clean energy transition?

A couple of academic groups in California were back in the news last week. They argue that every state can economically transition to 100% clean energy. I first heard about their project around two years ago and was understandably enthusiastic.

Unfortunately, they argue that energy efficiency can take care of a large fraction of the transition. They expect demand to decrease 40% in Oregon by 2050. Other states are similar even though US population is expected to grow from 320 million to 438 million in the same period. While some of the demand decrease is associated with changing power sources, much of it relies on more energy efficient buildings and cars.

However, the study I discussed three weeks ago suggests that energy efficiency savings may be highly exaggerated. This article expands on that argument saying that we should compare solutions based on economic cost, and therefore energy efficiency is not cost effective (at least within the study’s scope).

Recycling will fix everything?

Another article suggests that though our technology has light-weighted products and decreased waste generation on the front end of the consumer cycle, we’re having a hard time making gains with recycling. These articles may tiptoe around it, but the fact is that we CANNOT continue to consume so much.

credit: guardian.com

The pope is arguing that we can improve technology and modify our economic systems, but that won’t be enough. We ultimately must change our over-consumption behaviors. We must make hard decisions to live with nature- not exploit it, and to value human life- not human riches. These decisions are hard because they change entrenched behaviors and societal norms. However, if we can muster the courage to change, our environment with humans enmeshed within will ultimately come out as the winners.

Risk taking (or how I learned to stop worrying about shark attacks)

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air travel, impact, motor vehicle crash, probability, risk, sharks, showers, stress

Several shark attacks occurred recently in North Carolina. While definitely scary, should the average person worry about getting attacked by a shark?

People often contemplate risks like these, but usually our thought process doesn’t reflect reality. We often focus on unlikely horrific scenarios rather than frequent mundane ones.

One way to better judge risks is by separating risks into two components. The first is impact, or the amount of damage that might occur. The second is probability, or how often you might expect a situation to happen. The risks we focus on should be both high-impact and occur often:

credit: project-management-knowhow.com

As an example, let’s look at the risk of getting injured due to slipping in the shower. I might expect to take a shower every day, but I might expect to slip only once every 100 showers. I’ll call this a medium probability. What about the impact? If I slip, chances are I might catch myself or just get a bruise. The impact is very low. I would classify this risk as low priority.

However, consider a healthy person around age 75. Both the probability of slipping (eg. less motor control) and the potential impact (eg. broken bones) increase. This risk has moved from a low priority to a high priority over a lifetime. Using this framework, we see that a mundane every-day task can still be very risky.

The National Safety Council has calculated the probabilities of dying from different causes. Note that these figures are lifetime odds for the whole US. The odds a person might ultimately die in a motor vehicle crash are 1 in 110. The chance of dying from an air travel incident is 1 in 8,000. Yet we’re fascinated by and benchmark our fears with plane crashes.

If we don’t acknowledge this framework or recognize that risks can change over time, we’ll be wasting resources trying to fix the wrong situations. We may have evolved to fight or flee from lions and tigers, but today exposure to stress or sitting too long might be a bigger risk.

Many of the risks we face are mundane and repetitive while many of our worries are caused by unlikely (but media-fueled) disaster scenarios. Make sure that you are taking care of yourself and reducing those long-term every-day risks!

How to recognize climate change denial and alarmism

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alarmism, climate, denial, sea level, sea level rise

I recently finished a free on-line course through edx.org called Making Sense of Climate Denial. I highly recommend the course to anyone interested in climate change and especially those interested in what science says about communicating the science of controversial issues.

One example is that presenting myths in the wrong way can create more belief in the myth even if the author is trying to do the opposite. My attempt at debunking a sea-level-rise myth is below. While many of the impacts of climate change are under-estimated by many people, I chose one claim that could be called “alarmist.” That means that the myth overestimates the impact. To learn more about the fact-myth-fallacy structure, please check out the course!

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FACT: Climate scientists expect global sea level to increase between 0.26 meters (0.85 feet) and 0.98 meters (3.2 feet) by 2100.

In the 2013 IPCC report, estimated sea level rise by 2100 is estimated to be between one and three feet. This compares to a 0.2 meter (0.6 feet) increase from 1901 to 2010. The main contributors to sea level rise are thermal expansion of oceans and glacier melting. Another increasing contributor is ice sheet melting.

Running several scenarios including atmospheric CO2 concentrations greater than 700 ppm and including “ice-sheet dynamical changes”, models suggest that sea level rise will likely not be greater than 0.98 meters (3.2 feet) by 2100.

There *will* be regional variation in sea level rise as winds, ocean currents, and landmass change. Some areas will experience greater change and others will experience less change or even sea level decrease. However, average global sea level rise by 2100 will be moderate – not extreme.

The reports adds that with medium confidence, extra sea level rise from collapse of the Antarctic ice-sheet would contribute less than several tenths of a meter (1 foot) additional sea level rise by 2100.

One myth suggests that expected sea level rise will be 20 feet (6.1 meters).

This myth doesn’t include a time frame. However, it implies that this may happen in a single lifetime. This myth cherry picks from the model results because sea level may well reach this magnitude, but not for at least 500 years. Even in the worst scenarios considered, global sea level in 2100 will only reach 1.3 meters (4.3 feet).

People who cite this 20-foot-rise statistic are trying to make this impact seem scary, but other factors like changes in storm surges and increased weather extremes will have more worrisome effects.

So the next time you stand on a beach with your toes in the water, imagine the ocean at waist level in 2100. This is definitely worrisome, but the sea level will *not* have increased by the height of a two-story house.

Bad news about your favorite “green” tech: biofuels, energy efficiency, and subsidies

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biofuel, biomass, carbon fee, carbon tax, climate change, electric cars, Elon Musk, energy efficiency, environment, government, solar panels, subsidies

Sometimes government programs don’t achieve the best results. Several recent articles illustrate this point. These three articles discuss programs that aim to reduce environmental impacts of energy use, but have unintended consequences that could be avoided.

Biofuels and biomass

Southwest US forests are producing biomass for Europe. We have to be very careful when considering the use of biomass and biofuels to replace fossil fuels. Governments have set up incentives or mandates to encourage the use of, among other sources, biofuel and biomass (sometimes called renewable portfolio standards). However, the net effect on human and environmental health is questionable.

• Biomass can be transported long distances that might cause life cycle greenhouse gas emissions to be high (the standard mentioned in the article requires that the biomass emit 60% less carbon than coal, but that’s still 40% from being a sustainable solution)
• Biomass emits more non-CO2 air pollution than coal; humans near power plants would experience more detrimental health effects.
• CO2 is collected slowly by plant mass (especially trees), but released rapidly; this means that short-term emissions could be high and outweigh long term reductions.
• Biomass is less energy dense and more expensive than coal; it is unlikely to become cheaper than coal.
• Biomass is being harvested from areas with high biodiversity and ecosystem services; monoculture farming would have an even worse impact.
• Biomass farming can require using land otherwise devoted to growing food. This can lead to higher food prices and instability in areas that can’t afford these increases.
• Some biomass crops require fertilizing and pesticides. These can contribute to further detrimental environmental effects.

To be sustainable, biomass use must incorporate best growing practices and can only supply very-local small power plants.

Energy efficiency

A randomized control trial showed that weatherization funding from the 2008 stimulus was rarely effective. Energy efficiency programs, including weatherization, seem like win-win scenarios. After the initial investment, households can expect money savings and less energy consumed means fewer environmental impacts. However:

• Participation rates, even with heavy outreach, were only 6% (1% without outreach)
• While there were some energy and cost savings, “by most measures, savings did not exceed the cost of the improvements.”
• Projected energy savings were probably over-optimistic compared to reality.
• Most carbon mitigation plans include large energy efficiency savings that might be much harder to realize than previously thought.
• As people save money, those extra savings will often be used to increase consumption in other ways.

For energy efficiency measures to be truly effective, we must in tandem make energy use more expensive. This means people to choose to consume less.

Subsidizing technology

There is a good reasoning behind subsidizing certain technologies. Established technologies (like coal plants and gasoline-powered cars) benefit from decades of incremental improvements that have made their production and use cheap. Governments can provide incentives to develop new technologies through subsidies like “grants, tax breaks, factory construction, discounted loans and environmental credits”.

After a short time, the hope is that the technology can stand on its own without government help. The government is basically making a bet on which future technologies will be effective. Elon Musk may recognize this and has been effective at securing at least $4.9 billion in government subsidies for his companies. However:

• Electric cars could perpetuate the car and highway system when something else might be much more effective (eg. train systems and walkable cities).
• Subsidizing solar panels might encourage suburban sprawl so that each house can generate enough power for itself while other options might be more environmentally benign (eg. urbanization).
• These incentives usually benefit the relatively wealthy (stockholders or households that can afford Tesla cars) further exacerbating wealth inequality.

So while these subsidies might be working towards cheaper clean energy and less pollution, I would rather see a carbon fee implemented. This would have the same effect, but wouldn’t exclude other potentially greener technologies.

With simpler policies, we can drum up bipartisan support and achieve better results!

Are LNG export terminals good or bad?

Tags

CO2, export terminals, fossil fuels, GHGs, LNG, methane, natural gas, oregon

The US has widely adopted hydraulic fracturing (fracking) which has domestically led to cheap natural gas. Since natural gas is 2.5 to 3 times more expensive worldwide, many expect that exporting natural gas could benefit both the US and other countries. However transporting natural gas is more difficult than oil. Companies need either pipelines or liquid natural gas (LNG) facilities/tankers to economically transport it.

credit: ihrdc.com

LNG facilities compress and cool natural gas to its liquid state (124 kPa, -162 degrees C). This allows for ocean tankers to hold 600 times as much natural gas for a given volume. While it might seem energy intensive to make natural gas that cold, keep it cold, and transport it thousands of kilometers, most GHG emissions (90%) still come from extraction and combustion.

There have been several proposed export terminals throughout the US, but two in Oregon. One in Coos Bay and another in Warrenton. While there are many other pros and cons, I want to highlight a few important ones.

Greenhouse gases

A recent study has found that natural gas exports could reduce GHG emissions. The authors assume that LNG could be used to replace coal in Asia or Russian natural gas in Europe. In both cases, there is a net reduction in total GHG emissions. This essentially supports the “bridge fuel” argument. It says that natural gas can serve as a fuel as we transition from coal to low-carbon technologies for electricity production.

However, natural gas can be used in other ways such as plastic production or home heating. These activities have less clear benefits. Also, US exports could lead to increased domestic fracking and even increased domestic coal consumption as natural gas prices increase. In addition, another study has shown that natural gas as a “bridge fuel” could increase electricity consumption, increase methane emissions, and/or delay investment in truly low-carbon technologies.

Social impacts

Domestically, a few jobs would be created. Some US companies would prefer to keep cheap natural gas prices to themselves, but LNG exports would certainly boost world economic output. Exports could provide Asian markets with cleaner-than-coal cheap electricity. It is important to acknowledge that the US and Europe grew wealthy by exploiting fossil fuels and that we don’t have the right to demand that poorer countries abandon fossil fuels immediately.

Other environmental impacts

As new pipeline must be laid to get natural gas to the export facility, significant impacts could occur. Construction and maintenance of the pipeline would necessitate a clear swath through forests (public and private) and construction that may temporarily disrupt waterways.

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We should immediately work to reduce fossil fuel consumption; we can afford the extra costs and we are responsible for most of the current climate change. Ultimately we need an effective carbon tax. This is necessary to address climate change and could displace other taxes. It would still allow for exports when it makes sense for all parties. We’ve recognized that fossil fuels are a problem and ways to mitigate their use. We now need the political will to implement these solutions.

Today, there is a rally in Salem, OR to protest the proposed LNG export terminals. Please consider joining us, contacting your representatives, and please just discuss these issues with your friends.

Further reading

• Portland propane terminal pros and cons (environmental emphasis)
• US LNG export pros and cons (economic emphasis)