The New Gastronome
Energy Systems 101
by Cinta Peerdeman
by Cinta Peerdeman
It’s evening. I have just stopped working for the day and close my laptop before heading to the kitchen. I walk to the fridge to pour myself a glass of cold, filtered water. Outside, the sky is slowly growing darker, so I switch on the lights. I do all of these things daily, often without even thinking about them: they are habits, part of my day-to-day life, and they all consume energy.
But not every country has access to electricity 24/7. In fact, in most parts of the world, people have to live with frequent blackouts or worse. Thirteen percent of the population (940 million people!) do not have access to electricity at all, and 40% (three billion people!) have to live without clean fuels for cooking (Ritchie, H.; Roser, M., 2020). While most of the Western World pays their energy bills monthly, other areas use a prepaid system for their electricity. Once the money runs out, so does their access to power.
Furthermore, data shows that energy access is strongly related to income. Poorer households are more likely to lack this access (Ritchie, H.; Roser, M., 2020). On the flip side, energy also enables opportunities. It does not only power our phones, laptops and internet routers, but it also gives us light, which allows us, among many other things, to study and work at night. Imagine how much harder it would be having to study by candlelight … .
We also need energy to produce food. First of all, the energy from the sun which kickstarts the photosynthesis process in plants, but also energy used for machinery, transportation, conservation and preservation of our food. Even our food waste consumes energy and creates energy loss.
Let’s take a closer look at all the energy systems at play behind the scenes of our daily life:
Energy and Emissions
Energy comes in different forms. Fossil fuels, nuclear energy and renewable energy build the basis from which electricity and heating can be developed. Fuels can refer to fossil fuels and biofuels. Most electricity is (still) produced by burning fossil fuels, which are the biggest cause of greenhouse gas emissions and climate change.
If that’s not reason enough to stop burning them, we need to consider that fossil fuels are a finite resource. It’s estimated that there are about 115 years of coal left, as well as about 50 years of both oil and natural gas (Statistical Review of World Energy of BP, 2016). Since energy is needed to mine these resources, they will continue to become more expensive. Fossil fuels are not only used to produce the energy to fuel our cars but clothing, soaps, creams, plastic for packaging, and much more are created from them as well. Furthermore, expensive energy could cause a threat to food security as food prices will start to rise along with it, making them less affordable for people to buy or produce.
Greenhouse Effect and GHGs: Fossil fuels emit greenhouse gasses (GHGs), mostly carbon dioxide (CO2). These GHGs form a layer in the atmosphere, which prevents heat from the earth to leave the atmosphere, which, in turn, causes an increase in global temperatures. This is called the greenhouse effect.
The most emitted GHGs worldwide are CO2, methane (CH4) and nitrogen oxide (N2O). How ‘strong’ a GHG is depends on its ability to absorb energy and radiate it, as well as its atmospheric lifetime; this is often calculated over 100 years. To compare the different GHGs, the measurement Global Warming Potential (GWP) is used with the unit carbon dioxide equivalent (CO2-eq). This means that the different GHGs are compared to CO2, so CO2 is 1 CO2-eq. Methane is a 25 times stronger GHG than CO2, so it has a value of 25 CO2-eq, and N2O even has a value of 265 CO2-eq (IPCC, 2014).
Renewables are the future. Examples of renewable energy sources are wind, sun, water and biomass.
Wind energy is harnessed with wind turbines, which can be situated onshore or offshore. Their blades are connected to a rotor, which, in turn, is connected to a generator. In this way, kinetic energy from the wind makes the rotor spin (mechanical energy), and the generator turns this into electricity. You can compare this system with a dynamo on your bike.
Most large wind turbines – the larger the turbine, the more energy can be generated – can be found offshore as wind speeds are higher at sea, and there are no physical obstacles that can interrupt the wind flow. Furthermore, the wind is more consistent at sea. On the other hand, it is harder and more expensive to build and maintain wind turbines offshore, as salty seawater can damage the turbines through corrosion. Floating wind turbines are one of the innovations created to deal with these problems, as they can be towed to land and repaired there. Since they float, there is also no need to build a foundation on the bottom of the sea, which is difficult and expensive to do.
Solar power can be harnessed with photovoltaic cells (PV), which are the main component of a solar panel. The photovoltaic cells convert sunlight into electricity. The sun provides us with light and heat. This heat, in turn, can be harnessed with a solar thermal collector (T) absorbing the sunlight. Typically, solar panels transfer the heat to water (or another fluid) in a tank. There are also solar panels that can generate electricity and store heat at the same time. These are called photovoltaic thermal (PVT) collectors.
Hydropower is harnessed with a hydroelectric generator that generates energy from falling or fast-running water. It works similar to wind turbines, but in this case, the rotor is moved by water instead of wind. Hydropower can also be used to store energy (pumped storage).
Biomass are natural materials (from plants or animals) which can be used to produce electricity or heat. It can be used directly as a fuel but can also be transformed into biogas or biofuels. In a way, biomass can be considered renewable energy as the natural materials will grow back in time, but I would not say that it is particularly sustainable – especially, in large scale models. The rate at which biomass is used is higher than the time it takes for it to grow back, which means more CO2 is released than what is captured by the plants.
Biomass also incentivises natural ‘waste’, which does not exist in a circular economy model, as resources should be reused instead of being burnt. I believe that small-scale biomass usage, for instance, on a farm, can be sustainable, but it sounds like greenwashing to me when it comes to large-scale use. Let me give you an example from the Netherlands: in coal-fired power plants, biomass pellets – small, pressed pills of biomass – are added to ‘improve the sustainability’ of the energy production. The particular pallets used in the Netherlands were made from trees that were shipped from Canada since there was not enough ‘waste’ biomass. However, adding biomass improves the sustainability of coal-fired power plants only on paper, as only the generation of truly sustainable energy improves a country’s energy mix and GHG emissions. In this case, it just seems a convenient justification to keep using old technologies, such as coal-fired power plants, washing them green rather than creating real sustainable change.
Most renewable energy worldwide is generated by hydropower (60%), followed by wind energy (20%) and solar energy (10%). Currently, renewables do not even count for 20% of the world’s primary energy generation (Ritchie, H.; Roser, M., 2020). Since 2019, however, renewable energy has started to become cheaper per kWh than energy from fossil fuels.
Another advantage of renewable energy is that it lends itself very well to use in decentralised off-grid and mini-grid systems, enabling disadvantaged communities and remote areas access to electricity.
Balancing the Electricity Grid: Energy supply and energy demand need to be equal on the electricity grid. Otherwise, blackouts occur. To balance energy supply and demand, Transmission System Operators (TSOs) balance the grid. When the demand is low, power plants need to be switched off and vice versa.
Energy storage will be very important since renewables are less predictable and highly dependent on the weather. Examples of electricity storage are pumped storage hydropower. Here, water is pumped to a higher level, using surplus power to do so. When the demand is higher than the energy supply, power can be (re)generated by water that moves down through a turbine. Other examples are batteries or hydrogen (surplus electricity can be transformed into hydrogen with electrolysers). Heat can be stored too, for example, under buildings, in the ground, or heat exchange can also be done with water reservoirs.
You might think: What about nuclear energy? Indeed, nuclear energy does not emit carbon dioxide, but the by-product of nuclear energy is radioactive waste, which needs to be stored safely for about 1,000 years. Even if we would accept all the risks connected to nuclear energy, uranium is, like fossil fuels, a finite resource, which means that, unlike wind and solar energy, it will run out someday. Another disadvantage of nuclear energy is that it takes about three weeks to switch off a nuclear plant, making it harder to balance the grid. In comparison: a gas-fired power plant can be switched off in about 15 minutes.
Risks of Nuclear Energy and Uranium Reserves: High-level radioactive waste is still thermally hot, highly radioactive, and takes about 1,000 years before it reaches the level of radioactivity of naturally occurring uranium ore, though it would still be more concentrated (Möller, D., 2007). Besides the risks of nuclear waste, there is the risk of nuclear meltdowns (explosion of the reactor when the chemical reaction is not controllable anymore) and plutonium (a by-product of nuclear energy) which can be used to produce nuclear weapons. Mining uranium is dangerous because uranium ore emits radon gas, which can cause lung cancer when inhaled in large amounts or over longer periods of time.
Furthermore, the generations that benefit (and benefited) from nuclear energy are not the generations that have to deal with the waste, which is neither sustainable nor fair.
There are many sources that estimate current uranium reserves at between 80 and 230 years of uranium left on land. There is more left on sea, but it is much harder and more expensive to harvest, and the question is if it can compete with the low prices of renewable energy.
The global energy system and the global food system are both large, complex systems that are interconnected. Both systems are, currently, not very sustainable, so, in my opinion, we should transform them both and aim for more sustainable development.
In 1987, the World Commission on Environment and Development (WCED) published a report entitled “Our Common Future”, where they defined sustainable development as follows: “Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” This was the first time that sustainable development was defined, and this definition is still used in current (international) energy and food policy.
Energy and Food Policy: In 2015, during COP21 in Paris, the Paris Agreement was ratified by 150 countries. In this agreement, the countries promised to take climate action with the aim of not exceeding a global temperature rise of 2°C, but preferably 1.5°C. This is called the tipping point. After exceeding a maximum global temperature rise of 2°C, there is a large risk for irreversible global temperature rise, with multiple causes such as melting glaciers that no longer reflect the light (albedo effect) and peri frost that continues melting, emitting large amounts of methane (CH4).
In July of this year, all 27 EU Member States committed to turning the EU into the first climate-neutral continent by 2050. The so-called European Green Deal focuses on eight sectors, of which three are directly related to sustainable energy and food production.
Food and Energy
A recent report of the FAO in collaboration with the European Commission’s Joint Research Centre, with data of over 245 countries, states that, in 2015, food systems accounted for 34% of global greenhouse gas emissions (18 Gt CO2-eq per year globally). The biggest emitting countries are, in order of magnitude: China, Indonesia, the United States of America, Brazil, the European Union and India (Crippa, M.; Solazzo, E.; et al., 2021).
The biggest contribution to GHG emissions in the global food system can be referred back to land use (65%), followed by energy use, fossil fuels (21%), food waste (10%), and industrial processes (4%), visualised in Figure 1.
Food Production and Energy
Energy is used throughout the whole food supply chain, but in some areas, energy consumption is more visible than in others.
Farmers who work in the field deliver physical labour, pumps are used for irrigation, and equipment and machinery such as tractors, combines, and harvesters that work the land use diesel. If we go one step back, we can think about the energy needed to produce these machines. One step further and we look at the energy required to generate electricity and, even before that, the energy needed to extract fossil fuels. We can also think about the energy and resources (both fossil fuels) needed to produce agrochemicals (fertilisers, pesticides, insecticides, fungicides, etc.) used in conventional agriculture.
Agriculture, land use, and land change activities are the largest contributing factors to GHG emissions of the global food system, namely 65%. More than half of it (34%) comes from production stages, including fertilisers and other agrochemicals that are the largest contributor to the overall food-system emissions. Land use and land change contribute to 32% of the total emissions, mainly caused by livestock production. (Crippa, M.; Solazzo, E.; et al., 2021).
There is a (slow but sure) trend noticeable for green hydrogen. Green hydrogen is hydrogen produced with surplus energy from renewable sources, such as offshore wind energy. Hydrogen is a fuel (liquefied by compression) that can also be used to store electricity. I’m expecting large machinery, such as tractors, to run on hydrogen in the future – some can already be seen in the Netherlands. Meanwhile, the Nikola Motor Company has developed trucks that run on hydrogen, and even hydrogen-powered ships, trains and planes are being developed. Hydrogen is a so-called fourth-generation biofuel.
Biofuels: 1) First-generation biofuels are made from crops grown on arable lands, such as cane sugar, corn, or potatoes. Sugar, starch, or oil from these food crops is converted into biodiesel or bioethanol. First-generation biofuels can compete with food security. 2) Second-generation biofuels are produced from woody biomass or agricultural residues, such as straw, grasses, waste vegetable oil, or municipal solid waste. 3) Third-generation biofuels are algal biomass. Algae can be produced in ponds or tanks on land, but also at sea. Its production requires large amounts of fertilisers and energy. Until now, there are no great successes booked since algal fuel degrades faster than other biofuels, and it does not work well in colder conditions. 4) Fourth-generation biofuels are electro fuels (e-fuels), synthetic fuels, made by storing electrical energy from renewable sources in liquid or gas fuels, such as hydrogen.
Food Transportation and Energy
Most foods are transported multiple times before they end up in your house, for instance, from the field to the warehouse, from the warehouse to a factory, from the factory to a distribution centre, from the distribution centre to another warehouse, from the warehouse to a supermarket and finally, from the supermarket to your house. These movements are done by trucks, ships, trains and planes, which almost always run on fossil fuels.
A large share of the GHG emissions from energy consumption in the global food system comes from transportation, namely 22% (which amounts to 4.7% of the global food-system emissions). This share is growing and is expected to continue doing so (Crippa, M.; Solazzo, E.; et al., 2021).
Packaging (plastics made from fossil fuels, heating for glass production) contribute to even more emissions, namely to 25% of the energy emissions (which amounts to 5.4% of global food-system emissions). The intensity largely varies by product, so wine and beer account for quite a large packaging impact due to the heat needed for glass production, while bananas and sugar beets have higher emissions for transportation, as they get shipped over large distances (Crippa, M.; Solazzo, E.; et al., 2021).
Nowadays, we are used to buying every type of fruit and vegetables all year long, even though they are not in season at all times. When certain fruits and vegetables are ‘off-season’, they are shipped from faraway places where they still grow or are produced in greenhouses. The decentralisation of food production and eating seasonally would minimise food transportation.
Food Transformation, Conservation, and Energy
Large amounts of water and energy are used to transform our food. Heat, in particular, is used for many processes, for instance, to dry crops, produce beer, and bake bread.
Instead, for food conservation, cooling is important. In industrialised countries, the emissions of fluorinated greenhouse gases (mostly used in refrigeration) have increased significantly. These are the most potent and long-lasting GHGs emitted by human activity, and they have a very bad effect on global warming (Crippa, M.; Solazzo, E.; et al., 2021).
Almost half of the energy consumption of the retail and supermarket sector comes from refrigeration. Since 1990, these emissions caused by refrigeration have grown more than 400%. Worldwide cooling accounts for about 5% of global food system emissions, and this number is likely to increase further (Crippa, M.; Solazzo, E.; et al., 2021).
I remember that my grandparents had a closet in their house with little stairs that led to some shelves at basement level, where it was dry, cool, and dark. This is where my grandmother kept all her jars of homemade pickled vegetables and fruits. It was a natural refrigerator. Most old-fashioned conservation methods are more sustainable than their modern counterparts. Storing food underground does not consume any (cooling) energy. After correctly drying, pickling, or preserving something in oil, vinegar or honey, food can be kept for years without the intervention of a fridge or freezer.
In the previous paragraph, we saw that packaging has quite a large contribution to global food-system emissions. Its main function is food conservation, but, currently, almost only single-used packing is used. Plastics and packaging made of combined materials are especially polluting, the latter being almost impossible to recycle due to the difficulty in material separation.
It is possible to shop packaging-free in more and more places, where you can fill up your own jar or bag. Farmers markets are also a good place to shop packaging-free. Meanwhile, the industry is developing more and more compostable materials and innovations to avoid so much waste.
Food Consumption, Food Disposal, and Energy
After all the previous steps mentioned, the food has finally arrived in your kitchen. What now? You will most likely store some of it in the fridge and maybe freeze some things for later.
There are many ways to prepare food, such as cutting, boiling, frying, steaming, smoking, and so on, and so forth. Most of them consume energy, such as wood, natural gas or electricity.
Around 931 million tonnes of food go to waste each year (17% of the global food production!), of which 61% is related to households, 26% to food services and 13% to retail. This accounts for almost 10% of global food-system emissions (UNEP, 2021). At the same time, 690 million people (8.9% of the world population) are estimated to be undernourished (FAO, IFAD, UNICEF, WFP and WHO, 2020). This is not sustainable, not energy efficient, and also not fair.
So, What Can We Do?
You might ask yourself: what food should I buy if I want to eat more sustainably? It would be great if there were Life Cycle Assessments (LCA) available for every product to make our choice easier. But still, even if they would exist, LCAs can be done in different ways and are very time-consuming; plus, the social/ethical part of food is not considered.
The best rule of thumb, for now, is to choose good, clean and fair food (Sounds familiar? Yes, it’s Slow Food’s slogan). So, food that tastes good, preferable food in season; food that is produced in a clean way, ideally organically, biodynamically or in permaculture; and food produced by people who have fair working conditions and a fair salary. Bonus points if you can apply all these points to locally produced food, so you can also support your local economy at the same time. You can further reduce your carbon footprint by producing your own food, a nice hobby that can help you save some money and is also very meditative.
The easiest option, by far, is to buy just enough food and preserve anything you might have left, thereby reducing food waste. Eating less meat and dairy products is also always a good way to start.
With all of this said, what’s most important to remember is the following: it’s way more important to have many people working on these issues imperfectly than few who tick all the boxes. Rome wasn’t built in a day, so take one step at a time, and your support will have a global impact, even if it doesn’t seem like it. In the end, food should not add to our stress but be something that can be enjoyed with our loved ones.
BP (2016). Statistical Review of World Energy 2016.
Crippa, M., Solazzo, E., Guizzardi, D. et al. (2021) Food systems are responsible for a third of global anthropogenic GHG emissions. Nat Food 2, 198–209.
FAO, IFAD, UNICEF, WFP and WHO. (2020) The State of Food Security and Nutrition in the World 2020. Transforming food systems for affordable healthy diets. Rome, FAO.
Hannah Ritchie and Max Roser (2020). Energy Mix.
IPCC (2014): Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, R.K. Pachauri and L.A. Meyer (eds.)]. IPCC, Geneva, Switzerland, 151 pp.
Möller, Dietmar. (2007). Storage of High Level Nuclear Waste in Germany. Acta Montanistica Slovaca. 12.
United Nations Environment Programme (2021). Food Waste Index Report 2021. Nairobi.
Photos ©Aarón Gómez Figueroa