What’s the Deal with Nuclear?

Some people think nuclear is the best solution for climate change, and others want it gone tomorrow. What’s the deal? Source: Burghard

As the world strives to reduce its carbon emissions, massive efforts are being undertaken to decarbonise electricity. In most developed countries, fossil fuels like coal are on the way out, being gradually (albeit slowly) replaced by renewables such as solar and wind. However, keeping the lights on while generating most power from weather-dependent renewables comes with significant challenges (see a previous article that discusses this in more detail). The key difficulty arises because electricity supply and demand must always match perfectly. Traditionally, this involved adjusting power plant output to meet demand, including rapid spikes or dips. In fact, grid operators tune in  to popular TV shows to ensure supply is increased exactly as thousands of people turn on their kettle at the end of an episode.

A famous graph showing total UK electricity demand during the 1990 World Cup Semi-Final against Germany, with spikes at times when watchers massively turned on their kettles. Source: National Grid

Weather-dependent renewables make this balancing act more difficult since generation levels are controlled by e.g. the wind or sun and cannot be adjusted as required. In fact, the supply-demand balance requirement means that, in countries without the possibility of hydropower (requiring mountainous and rainy terrain) or geothermal power, it is virtually impossible to go 100% renewable without drastically increasing electricity prices. This is sometimes referred to as the energy trilemma: in most regions, only two of supply security, affordable energy and environmental sustainability can be satisfied. Two of the most promising solutions, grid-scale storage (storing excess renewable production at times of high supply and using it when supply is low) and carbon capture-and-storage (storing carbon emissions before releasing them into the atmosphere), are unproven and not yet economically viable. For this reason, most countries still generate most of their electricity from fossil fuels — it’s too difficult or expensive to match supply and demand any other way.

In this backdrop, nuclear power seems perfect: fully controllable output levels without any greenhouse gas emissions. It’s also a proven technology, generating electricity from the United States to Pakistan. Nonetheless, the future of nuclear power is a contentious issue. From this author’s personal experience, the UK energy community seems to be in a perfect dichotomy between those who think nuclear power should be the strategy to mitigate climate change (at least in the short term) and those who think all reactors should close tomorrow. Why all the disagreement? This article hopes to give a balanced account of the advantages and disadvantages of nuclear power, and the controversy surrounding it.

Firstly, there are ethical arguments. Current nuclear technology produces poisonous nuclear waste that must be stored safely for thousands of years. Nuclear detractors question the morality of leaving behind toxic material for future generations to take care of, while nuclear supporters opine that the social costs of unmitigated carbon emissions are much higher.

Secondly, there are political factors. For a number of reasons, decisions regarding atomic energy are typically made at government level. The first is scale; nuclear power plants are so expensive that energy companies are unable or unwilling to take the risk building them. They are usually built either by governments themselves or involving some government financial support. And even when market players do build new plants, the extensive planning permissions mean that, in the end, it is usually the government who decides. For this reason, decisions regarding nuclear power are susceptible to the whims of political sentiment, and this explains many of the trends in the sector.

Politicians (especially in democracies) are concerned with public opinion, and the general perception of nuclear power is a complicated topic. It’s reputation has been tarnished by a number of high-profile disasters, most notably Chernobyl (former USSR, currently Ukraine) and Fukushima (Japan). Both contaminated the surroundings, left areas uninhabitable for decades and required hefty cleanup costs. The United States had its own accident at 3 Mile Island, of comparably smaller impact but nonetheless negatively affecting the perception of the safety of nuclear power.

Nuclear power: contentious around the world. Source: capotian

Nuclear proponents sometimes argue that the technology’s nature gives it an intrinsic disadvantage in public opinion. Disasters can be of almost biblical scale, and images of atomic explosions or radioactive ghost towns appeal to human emotion more than e.g. a gradual rise in temperature or the lives lost each year in coal mine accidents. Furthermore, public perception of nuclear energy is often based on emotive imagery as much as reasoned analysis. One US study indicates that support is higher among those either better informed about it or living in close proximity to a nuclear power plant, and that the majority of opposers can be convinced of its merit just by telling them that it is the “only electricity source that provides both clean air and 24-7 electricity”.

When nuclear power goes wrong, it really goes wrong, as the ghost town of Pripyat (near Chernobyl) shows. Source: Amort1939

The effect of public sentiment can be seen in Germany’s 2011 decision to phase out nuclear power, taken in the wake of the Fukushima disaster. While widely supported politically, energy scientists point out that it delayed Germany’s energy transition multiple years by requiring coal plants (with the highest carbon emission of all major generation technologies) to stay open. For this reason, despite a slightly higher renewable electricity production, Germany’s carbon emissions per unit electricity are around twice as high as the UK, where coal power has almost totally disappeared.

Despite all this, nuclear’s high cost is broadly considered the main driver behind its decreasing role in world energy supply. For the Hinkley Point project, aiming to build the first new UK plant in decades, the government has agreed to purchase electricity at around twice the current average price. This has been described as “ridiculously expensive”, especially in the face of plummeting renewables costs. Supporters argue that the ability to generate when needed (as opposed to only at sunny or windy times) justifies the higher price, but the fact remains that nuclear power cannot compete on a pure cost basis . Furthermore, its economics worsen in combination with renewables. Nuclear power plants are expensive to build, but cheap to run, so should be run as often as possible. Since renewable-heavy grids only need backup power at times of low renewable output, it becomes more difficult for nuclear plants to “earn back” their considerable construction expense with low generation costs.

Nuclear power — on the way out? Even while global electricity demand has grown, nuclear production has stalled since around 2000. Source: World Nuclear Association

A fantastic website, electricitymap.org, shows real-time greenhouse gas emissions from electricity generation in many parts of the world. The data displayed serves as a good indication of the present reality. There are essentially two ways to generate power without emitting greenhouse gases. The first is hydropower, which countries like Norway use for almost all their electricity needs. The second is nuclear. Indeed, the only country with a population over 10 million people consistently emitting less than 100g CO2 per KWh of electricity without major hydropower is France, which generates between 60% and 80% of its power from atomic fission. For many countries, going nuclear is the only way to decarbonise electricity.

The greener the country, the lower the carbon emissions per kWh of electricity. Only three countries in Europe are really green: Norway (majority hydropower), France (majority nuclear power) and Sweden (combination of  hydropower and nuclear power). Source: electricitymap.org

However, something currently being true does not mean it will be forever. Much of the difficulty in nuclear decisions relates to uncertainty about the future. With Hinkley Point, the UK government agreed to pay, for multiple decades, a price that may seem unjustifiably high. Nobody knows what will happen in those decades. If breakthroughs in grid-scale storage or carbon capture-and-storage allow rapid decarbonisation of electricity, then Hinkley Point will probably be viewed as a mistake. If not, its construction may prove essential to meet climate goals. Some of the uncertainty comes from uncertain future developments of nuclear technology itself. One example is the development of small modular reactors (SMRs), essentially mini-reactors, that are easier for private companies to finance and build. Another is to (finally) harness the power of nuclear fusion, which produces almost no nuclear waste but has been “ten years away” since the 50s. The commercialisation of either of these may yet provide a nuclear resurgence.

All in all, a Grantham Institute briefing on UK nuclear power perhaps summarises the future of the technology most aptly:

“Nuclear power will be essential for meeting the UK’s greenhouse gas emissions reduction target, unless we can adapt to depend largely on variable wind and solar, or there is a breakthrough in the commercialisation of carbon capture-and-storage. […] We may regret building nuclear power stations if the cost of renewables continues to fall and we find solutions to the problem of the variability of these generation sources. On the other hand, if progress in reducing the costs of energy storage is insufficient, we may not be able to achieve climate targets without new nuclear generation capacity.”

The somewhat unsatisfying answer is that decisions made about nuclear power now can’t be evaluated for years. One the one hand, massive investments now will look foolish if technological breakthroughs allow power systems to decarbonise by other means or if a major nuclear disaster occurs. On the other hand, not investing will be a mistake if it turns out carbon emissions can’t be reduced without it, and the effects of climate change really start to hurt. Simply waiting is not an option: nuclear power plants take more than 10 years to build, so decisions must be made now to ensure carbon emission reduction targets are not missed. For the future climate, electricity bills, and the challenge of keeping the lights on, the next few years will be telling.

What are air masses?

One of the most admirable (or most irritating) aspects of children can be their thirst for understanding. This often manifests itself through a seemingly never-ending chain of questions beginning with “why…”?

Trying to explain the weather on a particular day can feel a bit like this. Every answer leads to another question, which can turn the process into a fruitless task! However, inspired by the name of this blog, this is the quest that we would now like to set upon.

This post is meant to launch a series of blog entries, with the eventual goal of untangling the causes of weather on a particular day. For the moment, we’ll just focus on the weather over London.

However, in order to reach our goal, we need to first provide answers for several of the most common `why` questions. We’ll then be able to refer to these when trying to justify the weather each day!

The first concept in this series concerns air masses. This is possibly the most important aspect in determining what the weather is like.

What is an air mass? Simply, it is a large body of air – thousands of kilometres in extent. The crucial point for the weather in the United Kingdom is that there are different types of air mass that can move over the country.

Typically these air masses can be categorised by the direction from which they’ve come. Each of these types of air mass will have different characteristics, and are related to different types of weather.

The UK Met Office website lists six types of air mass that affect the UK. These are labelled by the direction from which they come and whether it was from land (continental) or sea (maritime).

Each of these air masses has characteristic temperatures and humidities – i.e the amount of moisture they contain (for instance maritime masses bring more water with them). They also tend to occur at different times of the year. 2018 has been a year of extreme weather in the UK: the cold and snowy February was associated with polar continental and arctic maritime air masses, while the very hot summer featured tropical continental air.

Air MassDirectionAssociated Weather
Arctic MaritimeComes from the north, from the Arctic.Cold, snowy weather in winter, particularly to Scotland.
Polar MaritimeComes from the north-west, from Greenland and the Arctic sea.Generally brings frequent showers. In winter these are often over the western and northern sides of the British Isles, but in summer the showers are heaviest of the east. This is the most common air mass to affect the British Isles.
Returning Polar MaritimeOriginates over Greenland and Arctic sea, but comes from the west via the Atlantic ocean.This air has travelled further over the Atlantic ocean than Polar Maritime. It is usually dry but can bring a lot of clouds.
Tropical MaritimeFrom the south-west, from over the Atlantic sea.Warm but moist air, bringing low cloud.
Tropical ContinentalFrom the south-east, with air originating over North Africa.Hot dry air. Most common in summer.
Polar ContinentalFrom the east or north-east, with air originating over central or north-eastern Europe.The air is very cold but dry. Can bring clear skies and severe frosts, or if it travelled over the North Sea brings rain or snow showers.

You can read more about these air masses on the Met Office website:

https://www.metoffice.gov.uk/learning/atmosphere/air-masses/types