Think of the industrial revolution of 18th century Britain. What started it, and what kept it going?
The answer has to do with natural energy supplies. This meant a stable supply of coal to power up complex machinery and an economy based on mining and international trading. The historical availability of one type of fuel across various geographical locations has shaped populations as we know them today. Fuel shortages, also known as energy demands, especially in remote areas, would instil energy conservation habits. Fuel richness, where there is a surplus of energy supply, on the other hand, would encourage higher energy consumption. Both energy supply and demand have their own advantages and disadvantages.
The definition of energy supply and demand
Energy is generated at power stations and transported through the national grid to substations. From there, it is supplied to customers through a network of cables and transformers (the transmission and distribution lines).1
The demand for energy fluctuates throughout the day, and the supply must be carefully managed to meet this demand. To achieve this, power stations can adjust their output or supply in response to changes in demand.
Our society functions on different energy mixes. An energy mix is made of different types of primary energy sources such as crude oil, nuclear or sunlight.
Some countries, such as Australia, have more annual sunlight to work with and convert into thermal energy or electricity than others, like Sweden.
This energy is obtained through specific technologies which can use different types of fuel:
Fossil fuels: internal combustion engines used in cars, aircraft, boats, etc.
Nuclear power: usually converted into electricity by commercial nuclear stations.
Renewables: usually converted to electricity, heat or kinetic energy by wind turbines, solar thermal tubes, etc.
Industrial energy use
The industries we have on Earth range from agriculture and mining to education, transport and telecommunications. Heavy industries are incentivised to use combined heat and power systems to ensure that electricity generation and its resulting heat don't dissipate and thus get wasted.
Some sectors, such as education, are less energy-intensive than others, such as mineral processing.
Extracting a material or energy source, such as uranium (U) or iron (Fe), from higher-purity ores is less energy intensive than extracting them from low-purity ores.
Methods of energy conservation and management
All methods of energy conservation help reduce energy consumption, greenhouse gas emissions and improve comfort levels. They also help to manage the energy infrastructure better.
Both the industrial and domestic sectors employ the following methods:
Controlled habits: carpooling or turning off appliances and lights when not in use. This can be done using energy-efficient appliances, bulbs, timers, or motion sensors to control lights.
Insulation in the form of fibreglass and foam is industrially applied to pipes carrying hot, cold, or generally thermally sensitive liquids.
Cheap but efficient insulation, in the form of adobe, cob, straw or animal manure, is domestically applied to insulate households.
Exchange and recycling: energy, such as heat from industrial processes of burning, cremating or melting, can be harvested and prevented from escaping in closed-loop recycling facilities. Additionally, the heat generated by one industry can be used by another.
Some proposals spark controversy. The intense heat of a crematorium heats one pool in Worcester.2
The difference between primary energy supply and primary energy demand
The primary energy deficit or surplus is the difference between primary energy supply and primary energy demand.
A primary energy deficit exists when the primary energy demand exceeds the primary energy supply.
A primary energy surplus exists when the primary energy supply exceeds the primary energy demand.
Various factors can cause differences between primary energy supply and demand, including technological changes, economic growth, and demographic changes.
Primary energy supply (PES) is the total primary energy available in a society, region, or country.
Primary energy demand (PED) is the total primary energy required by the end-use sectors of an economy.
PES includes both renewable and non-renewable sources of energy. PED can be expressed as the product of three factors:
the number of end-use sector energy users
the users' average primary energy use per unit
the level of end-use service demand3
Some countries mine or harvest a primary resource, but others may have a greater demand for the same resource and wish to buy it. Kazakhstan and the USA are compared below:
Kazakhstan produced 45% of the world's uranium in 2021. Uranium is a primary energy source in high demand. Despite that, Kazakhstan has no commercial nuclear reactor in the country.4
The United States only mines 0.02% of the world's uranium on their territory but has 93 commercial nuclear reactors as of 2021.
Other countries may appear to be significant energy consumers, but looking at their industries, what they produce, and their actual per capita energy consumption is important.
As of 2021, China is the world's largest primary energy consumer.5 However, 30% of the world's manufacturing processes also take place in China.6
There is also a difference between secondary and primary energy supplies.
Primary refers to the unrefined type of fuel as found or obtained from nature.
Secondary energy fuels include what derives from or is given off by the original source.
Secondary energy sources include:
"green" hydrogen (H) (primary source: water)
biological methane (CH4) (primary source: biomass)
kerosene (primary source: crude oil).
electricity (primary resource: nuclear ores)
Energy storage systems are used to manage periods of intense energy use. Some electricity grids can become overwhelmed, and it is important to redesign grids to allow them to accommodate high voltages. "Peak shaving" is also used, which requires the consumer, such as a big company, to scale down production for a limited amount of time, or use their own energy sources, for example, generators. Methods include:
Pumped-storage hydropower: water in a higher-up basin can fall during the day and is moved back up during the night when electricity is cheaper. e.g. the Dinorwig Power Station, Wales, UK.
Batteries: rechargeable, one-time use, etc.
Compressed air: surplus energy is used to compress or turn mechanisms (kinetic energy), energy which can then be released slowly.
Molten salt: heated salt cools down very slowly.
Chargeable vehicles: electric car batteries can store energy and return it to the grid when necessary.
Power to gas (P2G): additional energy can be used for water electrolysis, which produces hydrogen gas.
Renewable and non-renewable energy
Renewable energy resources include hydropower, biofuels, and wave power. They tend to re-form quickly or be inexhaustible but can be intermittent (fluctuating).
These fluctuations are tied to weather patterns and people's activity patterns. For instance, most solar energy can be obtained at midday.
Non-renewable energy resources, such as coal and nuclear, are denser in terms of energy output but also take a long time to form.
Diagenesis and catagenesis are two processes that naturally turn biological sediments into what we know as fossil fuels, which happen over millions of years.
Renewable energy supplies are typically regarded as sustainable but can also have drawbacks, including:
Hydropower dams and water harvesting techniques usually change river fauna, flora, water flow and speed, sedimentation rates, etc.
The technology that captures renewable energy may need rare earth minerals that are difficult to mine or process.
Interestingly, most energy-forming processes on Earth are driven by the sun's power, which is caused by nuclear reactions (fusion) in the Star's core.
Hydrogen (H) turns to helium (He)... you know the story!
Some renewable energy sources, such as geothermal and tidal, tend to be more predictable and stable. Geothermal energy is fuelled by magmatic processes warming up water and pushing hot steam through fissures in the crust. Tidal energy is driven by the moon's gravitational effects on a large body of water.
Worldwide, the most energy produced (measured in terawatts per hour) comes from the following reported renewable technologies:
A country or region that can efficiently harvest solar power from electromagnetic radiation requires a high solar irradiance index. On the other hand, places that can harvest geothermal energy require volcanic processes near the surface.
Population and energy demand growth
Energy demand grows with the population. The energy calculated "per person" tends to be expressed as "per capita" in English, a term borrowed from Latin and employed in statistics.
The emissions from the energy sector are a major contributing factor to climate change. These emissions contribute to atmospheric pollution with the following:
Gases: ground-level ozone (O3), oxides of nitrogen (NOx), methane (CH4), etc.
Particulate matter (PM): PM with a diameter between 2.5 and 10 microns (tiny soot or plastics which can get in our lungs).
The greenhouse gas potential of different gases is expressed as CO2e (carbon dioxide equivalent) for calculation purposes. These gases are summed up to obtain a CO2e number.
The energy sector accounted for 76% of all CO2e emitted worldwide in 2020.8
Couple this with the fact that fossil fuels still supply 80% of all energy used as of 2022.9 It may be easier to understand why society is trying to move away from being dependent on one single class of fuel.
Energy loss is sometimes unavoidable. Adopting concepts from the circular economy are efficient in closing "open loops" and waste streams.
Biodigesters host bacteria that process food scraps and produce valuable fuels, such as methane gas.
Energy Consumption and Economic Development
Energy consumption is strictly tied to the state of the economy. Cheap fuel almost always means more of it can be used, although it depends on whether it is safe. Additional factors that influence energy consumption include:
| Factors | Details |
| Geopolitical | - Trade deals allow better access to foreign supplies and exchanges of surplus energy or resources.
- Financial grants and support.
|
| Historical | - Past misuse of an energy resource may make people more apprehensive about its present use.
- e.g. the effects of nuclear weapons.
|
| Demographic | - Per capita consumption increases as long as the country can keep up with a growing population. Faulty allocation of resources may decrease per capita consumption too.
|
| Environmental | - The environmental awareness of people has changed, and they recycle more, throw less non-biodegradable waste into nature, modify their food and vehicle choices, etc.
|
| Technical | - Ease of storage, and current applications.
- e.g. hydrogen gas is promising but difficult to store and transport due to being lighter than air.
|
| Economic | - Calculating the full costs of energy use, including pollution, effects on health and all running and operational costs.
|
The energy type that society depends on the most is electricity. Crucial systems that rely on electricity include:
Telecommunications (anything linked to satellites: internet, radio, mobile, etc.), lights, electronic and electric systems (computers, gadgets, blenders, electric stoves, boilers, etc.), refrigeration, automated doors and security cameras, machinery, life-support systems, etc.
Only very few of our commodities could use raw energy harnessed from nature. Therefore, we usually have to refine it first.
By understanding how energy is supplied to customers, we can make informed decisions about using energy more efficiently and develop cleaner, more sustainable energy sources for the future.
Energy Supply and Demand - Key takeaways
Transmission and distribution lines, power stations and facilities, and the grid support our economy and satisfy end consumers' energy needs.
Fuel shortages can occur due to intermittence, and careful management is important.
Techniques such as peak shaving are achieved through efficient storage technologies like pumped-storage hydropower.
Fuel mixes ensure socio-economic stability, and renewables allow moving away from the dependence on one single class of fuel (fossil).
As the population increases, so does the energy demand and the environmental footprint of our energy-intensive activities.
References
- EIA, Electricity explained, 2022
- BBC, Redditch Crematorium begins to heat town pool, 2013
- OECD, Energy: The Next Fifty Years, 1999
- World Nuclear Association, World Uranium Mining Production, 2022
- Statista, Primary energy consumption worldwide in 2021, by country, in exajoules, 2021
- Felix Richter, China Is the World's Manufacturing Superpower, 2021.
- Hannah Ritchie et al., Breakdown of renewables in the energy mix, 2022
- Mengpin Ge et al., 4 Charts Explain Greenhouse Gas Emissions by Countries and Sectors, 2020
- United Nations, Renewable energy – powering a safer future, 2022.
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