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Energy Supply and Demand

Energy Supply and Demand

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: helps keep heat from escaping and excess heat from coming in. It is efficient for maintaining an ideal space temperature in winter and summer.

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.

  • Exterior design: aero- and hydrodynamics are essential in reducing vehicle drag and enhancing speed. Trains worldwide already use a system of magnets to produce a levitating effect and reduce drag. Green roofs and walls can be used for buildings to minimise heat losses through the ceiling and walls.

  • Orientation and positioning: in the northern hemisphere, passive solar gains can be achieved by positioning a building's windows towards the south and ensuring that the north walls are well-insulated and have triple-glazing.

  • 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:

  • Hydropower: approx. 4200 TWh

  • Wind: approx. 1800 TWh

  • Solar: 1000 TWh

  • Other renewables combined: 763 TWh7

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:

FactorsDetails
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

  1. EIA, Electricity explained, 2022
  2. BBC, Redditch Crematorium begins to heat town pool, 2013
  3. OECD, Energy: The Next Fifty Years, 1999
  4. World Nuclear Association, World Uranium Mining Production, 2022
  5. Statista, Primary energy consumption worldwide in 2021, by country, in exajoules, 2021
  6. Felix Richter, China Is the World's Manufacturing Superpower, 2021.
  7. Hannah Ritchie et al., Breakdown of renewables in the energy mix, 2022
  8. Mengpin Ge et al., 4 Charts Explain Greenhouse Gas Emissions by Countries and Sectors, 2020
  9. United Nations, Renewable energy – powering a safer future, 2022.

Frequently Asked Questions about Energy Supply and Demand

The supply of energy is determined by natural and human-related factors: weather, human activity/working patterns, grid capacity, geopolitical situation, etc.

Energy demand is important because it establishes what our society needs most to function and flourish. 

The demand for energy is changing because of the stress put on natural resources and the stage of environmental degradation. It is also changing due to our technological advancements, but also due to social, economic, political, etc. situations.

The factors affecting energy demand and supply are technological, socio-economico-geo-political, historical, environmental, etc.

The way energy consumption affects economic development is through diversifying jobs, reducing the dependence on one single class of fuel (fossil), preventing climate change and thus preventing the need to invest in climate adaptation strategies, etc.

Final Energy Supply and Demand Quiz

Question

How does a passive solar home work?

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Answer

A passive solar home collects solar energy shining through south-facing windows and retains it in materials that store heat.

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Question

Objects with a small surface area to volume ratio lose heat more rapidly than those with a larger ratio.

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Answer

False

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Question

Define thermal mass.

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Answer

Thermal mass is the ability of a material to absorb, store, and release heat.

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Define thermal lag.

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Answer

Thermal lag is the rate at which a material releases stored heat.

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Define embodied energy.

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Answer

Embodied energy is the sum of all the energy needed to produce any goods or services.

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Question

Name three building materials with a low embodied energy.

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Answer

Rammed earth walls, limecrete, and straw have a low embodied energy.

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Question

Bermed buildings are built partially underground.

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Answer

True

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Question

Define thermal conductivity.

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Answer

The thermal conductivity of a material is a measure of its ability to conduct (transmit) heat.

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How do double-glazed windows work?

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Answer

Double-glazed windows consist of two glass panes separated by a gas cavity.

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What is low-emissivity glass?

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Answer

Low-emissivity glass has a thin, transparent coating that reflects heat.

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Where are insulation materials placed?

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Answer

Insulation materials are typically placed within floors, walls, and roofs.

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What is the most common insulating material?

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Answer

Glasswool

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Question

This passive solar home design uses a Trombe wall.

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Answer

Indirect gain

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Give some examples of construction materials with a high thermal mass.

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Answer

Concrete, bricks, and stone have a high thermal mass.

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What is limecrete made from?

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Answer

Limecrete is made from natural hydraulic lime and a lightweight aggregate.

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What percentage of carbon emissions come from buildings?

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Answer

39%

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Define energy demand management.

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Answer

Energy demand management is the modification of energy demand through financial incentives and behavioural changes.

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Question

Load shifting decreases total energy consumption, while peak shaving stays the same.

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Answer

False

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Question

What is an occupancy sensor?

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Answer

An occupancy sensor is an electronic device used to detect the presence of a person, and automatically control lights, temperature, or ventilation systems.

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What is the most common insulation material?

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Answer

The most common insulating material is glasswool.

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How does solar ventilation work?

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Answer

Solar ventilation uses a solar-powered fan to ventilate and dehumidify rooms.

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What are heat exchangers used for?

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Answer

Heat exchangers are used to transfer thermal energy from one medium to another.

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Which heat exchanger is used in cars?

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Answer

Air-cooled

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Question

How much more efficient are LEDs than traditional incandescent bulbs?

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Answer

75%

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Question

Define white goods.

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Answer

White goods are large home appliances, such as refrigerators, ovens, dishwashers, and tumble driers.

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Which types of occupancy sensors use the Doppler effect?

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Answer

Ultrasonic Sensors

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Name some benefits of ventilation.

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Answer

Ventilation promotes respiratory health, improves cell function, and positively impacts mood and concentration.

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What does CFL stand for?

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Answer

CFL stands for compact fluorescent lamps.

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What does LED stand for?

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LED stands for light-emitting diode.

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How much money did the average UK household spend on gas and electricity in 2021?

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Answer

£1339

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What does an energy storage system do?

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Answer

An energy storage system allows the capture of heat or electricity when it is readily available, storing it for later use.

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Why will energy storage technologies benefit renewable energy systems?

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Answer

Energy storage technologies will limit wasted energy, maximise efficiency, and make the systems more practical.

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Define chemical energy.

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Answer

Chemical energy is the energy stored in the bonds of chemical compounds.

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What is an electrolyte?

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Answer

An electrolyte is a medium containing dissolved ions, allowing electrical conduction.

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What is the symbol equation for the reaction that takes place in a hydrogen fuel cell?

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Answer

2H2 + O2 → 2H2O

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Question

What are lithium-ion batteries, and how efficient are they?

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Answer

Lithium-ion batteries are rechargeable batteries that use lithium ions to store energy. They have a 99% efficiency.

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How do pumped storage hydropower plants work?

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Answer

Pumped storage hydropower plants pump water uphill into a reservoir. When the demand for energy is high, the water in the reservoir is released through turbines.

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Define peak shaving.

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Answer

Peak shaving is a strategy to level out peaks in energy consumption by relying on alternative sources of power, such as batteries or PSH systems

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How do compressed air storage systems work?

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Answer

 A gas is compressed and stored under pressure. When electricity demand is high, the gas is heated in an expansion turbine, driving an electrical generator.

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Why does a flywheel float on magnetic bearings?

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Answer

The flywheel floats to minimise air resistance and energy loss.

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Question

What are vehicle-to-grid systems?

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Answer

Vehicle-to-grid systems are bidirectional charging technologies that allow car batteries to give back to the power grid. 

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Question

What are power-to-gas systems?

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Answer

Power-to-gas systems convert renewable energy into hydrogen gas.

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Question

What is stored thermal energy used for?

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Answer

Stored thermal energy is used for heating and cooling, and power generation.

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Question

What is the hydrogen economy?

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Answer

The hydrogen economy is a strategy to decarbonise economic sectors that are difficult to electrify. 

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Question

What is a carbon-free source of hydrogen?

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Answer

Electrolysis of seawater

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Question

A steady supply of coal helped...

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Answer

kick-start the industrial revolution of the 17th century

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Question

Because energy fluctuates during the day, power stations can...

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Answer

adjust their power output

Show question

Question

Which country has a higher solar irradiance index?

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Answer

Australia

Show question

Question

Kazakhstan is the world's biggest primary supplier of...

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Answer

uranium ore

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Question

Which industry sector is more energy-intensive?

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Answer

Mineral processing

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