# Using energy: food, materials, mobility and buildings: Where final energy goes Source page: https://www.materialinsights.org/learn/energy/using-energy/p1/ [Understanding Energy](https://www.materialinsights.org/learn/energy/) / [Module 11: Using energy: food, materials, mobility and buildings](https://www.materialinsights.org/learn/energy/using-energy/) Part 1 of 5 ## Where final energy goes Energy statistics usually start at the mine, the well and the dam. This part starts at the other end: the factories, vehicles and homes where energy is finally used. Looking at use first explains why some sectors are easy to clean up and others are stubborn, and why the same exajoule can be worth very different amounts depending on what it does. ### 1.1 Final energy is split roughly into thirds: industry, transport and buildings Energy accountants follow three stages. Primary energy is what is taken from nature: coal, crude oil, natural gas, uranium, the flow of rivers and wind, sunlight on panels. The Energy Institute put the world total at about 592 exajoules (EJ) in 2024. Final energy is what is delivered to users after power stations, refineries and pipelines have taken their cut: electricity at the socket, petrol at the pump, gas at the boiler, coal at the steel mill. Useful energy is what the user's own machine turns into heat, motion or light. The biggest single gap is between primary and final energy, because most of the world's electricity is still made by burning fuel in plants that waste more than half of it as heat. So final consumption is only about 70% of primary supply. The United Nations energy statistics put world final consumption at about 419 EJ in 2023, not counting the fuel loaded onto ships and aircraft on international routes. Industry took about 134 EJ, transport about 101 EJ, and a group the statisticians call 'other' (homes, offices, shops, public buildings, farms and fishing) about 139 EJ. A further 45 EJ was oil, gas and coal used not as fuel but as raw material for plastics, fertilisers and solvents. Those proportions shift only slowly, and the rough picture is easy to hold in the head: a little over two-fifths for industry once feedstocks are included, about a third for buildings and other users, and about a quarter for transport, rising a little if international shipping and aviation are added. India's split leans more towards industry and towards traditional biomass in homes, while rich countries spend a larger share on cars and space heating. The value of this framing for an investor is that each third has its own physics, its own capital stock and its own rate of turnover. Cars are replaced every 12 to 20 years, boilers every 15 to 25, blast furnaces and cement kilns every 40 or more. That turnover sets the speed limit for change. Data World total final consumption by sector, 2023 | Sector | EJ | Share of total | |---|---|---| | Industry (fuel and electricity) | 134 | 32% | | Transport (excluding international bunkers) | 101 | 24% | | Other: homes, services, farming, fishing | 139 | 33% | | Non-energy use (feedstocks) | 45 | 11% | | Total final consumption | 419 | 100% | Shares rounded (calculated). Fuel for international shipping and aviation is counted separately and not included. Buildings make up the great majority of 'other'. Industry plus feedstocks is a little over two-fifths of final use. Source: United Nations Statistics Division, Energy Statistics Yearbook 2023, Table 3: Total final consumption and its components (2023 data), https://unstats.un.org/unsd/energystats/pubs/yearbook/2023/t03.pdf (world 2023: total final consumption 418,723 PJ; industry 134,055; transport 100,542; other 139,235; non-energy use 44,891; international bunkers not included) In the data #### Three numbers to remember Primary energy in 2024: about 592 EJ. Final energy: roughly 70% of that, about 419 EJ in 2023 before international shipping and aviation fuel. Useful energy at the point of service: perhaps 30% of primary energy, once engine, boiler and lamp losses are counted. The second and third gaps are where efficiency and electrification do their work. Any claim about saving energy should say which of the three stages it is measured at, because a saving at the point of use is multiplied back up the chain. - [United Nations Statistics Division, Energy Statistics Yearbook 2023, Table 3: Total final consumption and its components (2023 data)](https://unstats.un.org/unsd/energystats/pubs/yearbook/2023/t03.pdf (world 2023: total final consumption 418,723 PJ; industry 134,055; transport 100,542; other 139,235; non-energy use 44,891; international bunkers not included)) · web - Energy Institute, Statistical Review of World Energy 2025 (2024 data) [web ↗](https://www.energyinst.org/statistical-review) · web ### 1.2 We buy energy for heat, motion, light and information, and each service has its own carrier Nobody wants energy for its own sake. People want a warm room, a moving lorry, a lit page, a cold medicine fridge, a hot furnace, a running server. These services fall into a few families, and each family has historically been tied to particular fuels. Heat is the largest. Industry needs heat at very different temperatures: under 100 degrees Celsius for washing, drying and pasteurising, a few hundred degrees for chemical reactions and steam, and well over 1,000 degrees for steel, glass and cement. Homes need low-temperature heat for rooms, water and cooking. Most of this heat still comes from burning natural gas, coal, oil products and, in poorer homes, wood, dung and crop residues. Motion is the second family. Engines turn fuel into rotation in cars, lorries, ships, aircraft, tractors and pumps. Electric motors turn electricity into rotation in factories, fans, compressors and trains. Smil stresses that motors are among the most efficient converters humans have built, often above 95% for large units, while combustion engines in cars rarely beat 30% in real driving. Light, information and electronics form a third family that runs almost entirely on electricity. It is small in energy terms but grows fast, as data centres and air conditioning show. Finally there are feedstocks: hydrocarbons whose atoms end up inside a product, such as the hydrogen in ammonia or the carbon in polyethylene. Here energy and material are hard to separate. This breakdown matters because the hardest parts of decarbonisation are high-temperature heat, long-distance motion with heavy loads, and feedstocks. Low-temperature heat, short-distance motion and all electrical services have mature electric options already. Value chain What final energy is used for - **Final energy use** - **Heat** - **High-temperature industrial heat: steel, cement, glass** - **Medium-temperature process steam: chemicals, food, paper** - **Low-temperature heat: rooms, hot water, cooking** - **Motion** - **Combustion engines: cars, lorries, ships, aircraft** - **Electric motors: industry, pumps, fans, trains, EVs** - **Electrical services** - **Lighting and displays** - **Cooling and refrigeration** - **Computing and data centres** - **Feedstocks** - **Hydrogen for ammonia and refining** - **Carbon for plastics and chemicals** - **Coke as a reducing agent for iron** Source: Smil, Energy: A Beginner's Guide (2006), via Smil Mastery Course, M1 'Conservation and efficiency' Common misreading #### Electricity is not most of energy use Electricity dominates news coverage, but it is only about a fifth of the world's final energy, roughly 20% according to the IEA's World Energy Outlook 2025. The other four-fifths is delivered as fuels: oil products for vehicles, gas and coal for heat, biomass for cooking. Cleaning up the power sector is necessary but covers only part of the job. The rest needs electrification of end uses, or clean fuels where electricity cannot reach. - Smil, Energy: A Beginner's Guide (2006) · via Smil Mastery Course, M1 'Conservation and efficiency' - [IEA, World Energy Outlook 2025, International Energy Agency, 2025](https://www.iea.org/reports/world-energy-outlook-2025 (electricity's share of final consumption and its rise)) · web - [IEA, World Energy Outlook 2025, International Energy Agency, 2025, as reported by POWER magazine](https://www.powermag.com/the-age-of-electricity-and-5-other-forces-reshaping-the-global-energy-outlook/ (electricity 'roughly 20% of global final energy use')) · web ### 1.3 Electrification shrinks the useful-energy gap, which is why demand forecasts look odd If you compare a petrol car with a battery car doing the same trip, the petrol car might burn fuel containing about 2 megajoules per kilometre, while the electric car draws roughly 0.6 megajoules of electricity from the socket. The difference is not magic. The petrol engine turns most of its fuel into heat in the radiator and exhaust. The electric motor wastes very little, and regenerative braking recovers some energy that brakes would otherwise burn off. The same is true of heat pumps against gas boilers. A good boiler turns about 90% of the gas into useful heat. A heat pump moves heat from outside air or the ground, delivering three or four units of heat for each unit of electricity. Smil's general point about converters applies: the history of energy is as much about better machines as about more fuel. This has a strange effect on statistics. When a country electrifies its cars and heating, its final energy use can fall even while the services it delivers grow. Electricity's share of final energy, about a fifth today, is rising in all IEA scenarios, because nearly every growth market for energy (EVs, air conditioning, data centres, industrial heat pumps) runs on electricity. For an investor this means two things. First, demand forecasts in exajoules can mislead. A falling total may hide strong growth in services. Second, the useful-energy view helps rank technologies. A unit of clean electricity used in a heat pump or a motor displaces two to four units of fossil fuel, while the same unit used for resistance heating displaces barely one. Process flowchart Fuel to wheels: petrol car versus electric car Inputs **Petrol**about 200 MJ per 100 km **Electricity at the socket**about 60 MJ per 100 km Process steps 1 **Petrol engine** chemical energy to motion, about 20 to 30% in real driving; the rest leaves as heat 2 **Charger and battery** about 90% round trip 3 **Electric motor and inverter** about 90% or more, plus energy regained when braking Outputs **Motion at the wheels**roughly 40 to 55 MJ per 100 km in both cases Rounded illustrative figures for a mid-sized car; the useful work at the wheels is similar, the input is not. Source: Smil, Energy: A Beginner's Guide (2006), via Smil Mastery Course, M1 'Conservation and efficiency' Worked example #### Same trip, three ways A 100 km drive in a mid-sized car. Petrol: about 6 to 7 litres, roughly 200 MJ of fuel. Battery electric: about 16 to 18 kWh, roughly 60 MJ at the socket. If that electricity came from a coal plant at 38% efficiency, through a grid that delivers 93%, the coal burned would be about 165 to 185 MJ (calculated), still less than the petrol. On a clean grid, the primary energy drops further. - Smil, Energy: A Beginner's Guide (2006) · via Smil Mastery Course, M1 'Conservation and efficiency' - [IEA, World Energy Outlook 2025, International Energy Agency, 2025](https://www.iea.org/reports/world-energy-outlook-2025 (electricity's share of final consumption and its rise)) · web ### See it in the table [H₂O Water](https://www.materialinsights.org/commodities/water/)[Oil Crude oil](https://www.materialinsights.org/energy/crude_oil/)[Gas Natural gas](https://www.materialinsights.org/energy/natural_gas/)[U Uranium](https://www.materialinsights.org/energy/uranium/)[St Steel](https://www.materialinsights.org/commodities/steel/)[Cem Cement](https://www.materialinsights.org/commodities/cement/)[H2 Hydrogen](https://www.materialinsights.org/chemicals/hydrogen/)[NH3 Ammonia](https://www.materialinsights.org/chemicals/ammonia/)[DC Data centres](https://www.materialinsights.org/energy/e_data_centres/) ### Check your understanding Roughly what share of world primary energy reaches users as final energy? Power plants and refineries take a large cut, mostly as waste heat from thermal generation. Final energy is about 70% of primary supply. The 30% figure is closer to useful energy after end-use machines. Why can a country's final energy use fall while its energy services grow? Electrification swaps lossy converters for efficient ones. A battery car needs about a third of the final energy of a petrol car for the same trip, and a heat pump gives three to four units of heat per unit of electricity. Which of these is the hardest family of energy use to electrify today? In feedstocks the molecules themselves end up in the product, so electricity cannot simply replace them. Lighting, mild-climate heating and urban driving all have mature electric options. [← Module contents](https://www.materialinsights.org/learn/energy/using-energy/)[Mark read · Part 2: Food: nitrogen, ammonia and fossil-fuelled farms →](https://www.materialinsights.org/learn/energy/using-energy/p2/) ## Other sections - [Module overview](https://www.materialinsights.org/learn/energy/using-energy/index.md) - [Food: nitrogen, ammonia and fossil-fuelled farms](https://www.materialinsights.org/learn/energy/using-energy/p2/index.md) - [Materials: steel, cement, plastics and aluminium](https://www.materialinsights.org/learn/energy/using-energy/p3/index.md) - [Moving people and goods](https://www.materialinsights.org/learn/energy/using-energy/p4/index.md) - [Buildings and appliances](https://www.materialinsights.org/learn/energy/using-energy/p5/index.md) - [Key terms, quiz and sources](https://www.materialinsights.org/learn/energy/using-energy/review/index.md)