Manufacturing Technology

A digital device starts life as materials dug out of the ground. Raw materials are the basic substances taken from the Earth before anything is manufactured, and many of them are obtained by mining — digging open pits or tunnelling underground to reach rock that holds useful minerals and metals.

Damage caused by mining

Mining harms the environment in two main ways. Land contamination happens when the chemicals used to separate metal from rock, and the metals themselves, soak into soil and wash into streams and groundwater, so land can be too toxic to grow crops and the pollution spreads downstream. Erosion happens because digging removes the soil and the plants whose roots held it in place, so rain washes loose soil and rock away and slopes can collapse.

Finite and non-renewable

Metals and minerals formed over millions of years in the Earth's crust, so there is only a fixed amount. That makes them non-renewable and finite: once accessible supplies are dug up and built into devices, they cannot be replaced, and getting the next batch out becomes harder and more expensive. Non-renewable is not the same as non-recyclable — the copper in an old pair of headphones can be recovered and used again, which stretches supplies, but the deposits on Earth are still limited.

Plastics

Not every part of a device comes from a mine. The shell of a games controller and the insulation around a charging cable are plastics, made from crude oil — another non-renewable resource. Plastic that is not recycled is usually buried in landfill or burned. Buried plastic takes hundreds of years to break down and crumbles into tiny pieces that spread through soil and water, while burning it releases harmful gases. Recycling plastic parts means less new oil is extracted and less waste is left behind.

Both making a digital device and moving it to the shop use energy. Factories need electricity to run machines that mould cases, solder components and assemble devices. Transport needs fuel to move parts between factories and to carry finished devices by lorry, ship or plane.

Much of this energy comes from non-renewable sources, such as coal, oil and natural gas, which are also called fossil fuels. They took millions of years to form and are used up far faster than they are replaced, so they will eventually run out.

Burning fossil fuels releases carbon dioxide. Carbon dioxide is a greenhouse gas, so adding more of it to the atmosphere increases the environmental impact of a device. That impact happens before you switch the device on, because it is built into the manufacturing and transport stages.

Worked example

A pair of wireless earbuds is assembled in a factory where the moulding and soldering machines run on electricity generated by burning fossil fuels. The tiny chips inside are made in another country and flown in, and the finished earbuds then cross the sea on a cargo ship. The power station, the plane and the ship all released carbon dioxide before anyone listened to music on the earbuds.

So a device's energy use is not only about charging it. The fuel and electricity needed to make it and move it often come from non-renewable sources, which increases its overall effect on the environment.

Water is a renewable resource: rain refills rivers, lakes and reservoirs through the water cycle, so the supply keeps being replaced. Even so, making digital devices can use large amounts of it. A factory that moulds the plastic cases for headphones, for example, uses water to cool the moulding machines and to wash leftover plastic and oil out of the moulds between production runs.

That water is usually drawn from a river, a reservoir or a borehole underground. A factory that takes a lot can leave less for the town around it: families in their homes, a local leisure centre with its pool, a nearby bakery, and farms that irrigate their crops. The river suffers too, because very low water levels can harm the fish, insects and plants that live in it. Water is renewable overall, but the amount available in one place at one time is limited, so heavy use can lead to water scarcity.

Before a factory can use it, water usually has to be collected, treated and delivered. Pumps lift it, filters and chemical treatment take out grit and impurities, and pipes carry it to the factory gates. Every one of those steps needs energy, and most of that energy comes from power stations that burn fossil fuels.

Burning those fuels releases carbon dioxide, a greenhouse gas. Extra carbon dioxide in the atmosphere traps more heat and adds to global warming. Water use in manufacturing is therefore linked both to local water shortages and to climate change.

Manufacturing digital devices often uses water to wash equipment, cool machinery, dissolve chemicals or carry materials. Once it has been used, that water may hold substances that were not in it before. Waste water from manufacturing is water that leaves a process after being used, and it can be contaminated.

What contamination means

Contaminated means the water contains harmful substances. These might be acids or alkalis from cleaning, oils from machines, solvents, detergents or tiny metal particles. Water can be contaminated even when it looks clear. For example, a factory making tablet screens washes glass panels with water; the waste water carries fine glass dust and polishing chemicals. If it flows into a stream, the chemicals can harm fish, and the glass dust settles in the mud.

Pollution when it is released uncleaned

If contaminated waste water is released without being cleaned, it can pollute rivers, seas and land. In a river, chemicals can poison fish and the insects they feed on, and suspended particles can block light so water plants struggle to grow. In the sea, pollution can spread along the coast and harm shellfish and other creatures. On land, contaminated water can soak into soil, damage crops and collect in puddles or muddy ground where animals drink.

Harm to people and wildlife

People can be harmed if they swallow contaminated water by accident, or if spray from waste water gets into their eyes or a cut. Wildlife can be harmed directly, for example birds feeding in polluted mud may take in toxic substances, or indirectly as poisons build up through a food chain. Factories can reduce this by cleaning waste water before release: letting solids settle, filtering particles, neutralising acids and alkalis, or treating it with chemicals. Releasing it uncleaned into the environment can cause this pollution.

Energy consumption during use is the electrical energy a digital device takes from its power supply while it is working or charging. A smartwatch on your wrist, the tablets in a classroom trolley and a handheld games console all need a steady supply of electricity to run their processors, screens and wireless connections.

Where that electricity comes from

Electricity reaches your socket through the mains, but it has to be generated first. A common method is to burn fossil fuels such as coal, oil and gas in a power station: the heat boils water into steam, the steam spins turbines, and the turbines drive generators. Burning the fuel releases carbon dioxide, a greenhouse gas that traps heat in the atmosphere and contributes to global warming and climate change.

So every unit of electricity your device uses usually means a little more fuel burned and a little more carbon dioxide released. Where electricity is generated from wind, solar or hydro power instead, the same device causes far fewer emissions, which is why how the energy is generated matters as well as how much is used.

Why the amount of energy matters

The more power a device draws and the longer it is left running, the more electricity has to be generated. If that electricity comes from fossil fuels, more fuel is burned and more carbon dioxide is released. Devices left on standby still draw a small current, so a device that looks switched off can keep adding to emissions hour after hour.

Worked example: a school leaves a trolley of 30 tablets charging overnight when only 5 are needed the next morning. The other 25 are charged for nothing. Each tablet uses only a small amount of electricity, but across a school year and across thousands of schools that wasted electricity has to be generated, so extra fossil fuel is burned and extra carbon dioxide enters the atmosphere.

An energy rating is a label on a product that shows how energy-efficient it is. It lets consumers compare models that do the same job, so they can choose the one that uses less electrical energy.

Two devices can look almost the same but use different amounts of energy. The rating shows this in a standard way, so the comparison is fair: it is usually a class from A (most efficient) to G (least efficient), and the label also gives an energy figure for a set amount of use. A better rating means the device uses less energy to do the same task.

For example, imagine two 27-inch monitors used for the same number of hours each day:

Monitor P uses less energy for every 1000 hours of use, so across its useful life it uses less electrical energy than Monitor Q. Choosing the model with the better rating therefore reduces the energy used while you own and use the device.

The rating only covers energy used while the device is running, not the energy and materials used to make it or to dispose of it, so it is one part of judging how environmentally friendly a device is.

Every device left running draws electrical energy, and much of that energy is generated by burning fossil fuels, which releases carbon dioxide. Using less energy while you own a device therefore lowers its environmental impact.

What a user can do on a phone or tablet

The choices you make while using a device change how much energy it needs:

• Turn off wireless connections you are not using. The aerials keep searching for a signal even when nothing is being sent, and that searching costs energy, so switching them off or using flight mode stops it.
• Close apps you have finished with. A game or a video editor left open in the background keeps the processor busy, so closing it lets the device rest and the battery last longer.
• Reduce how often apps check for messages. An app set to check every minute wakes the device constantly; checking every half an hour lets it stay idle.
• Install updates. Updates often include better power management, so the same jobs are done with less energy.
• Switch on power-saving mode. It dims the screen, restricts background activity and slows the processor, so each charge lasts longer.

For example, a student heading off on a two-day residential trip with no charger keeps the phone alive by using flight mode between tasks, closing the video editor left running and turning on power-saving mode after lunch. The phone lasts the trip and the charger stays in the bag.

What an organisation can do

A school, health centre or warehouse office may run hundreds of machines, so a small saving on each one adds up.

• Set computers to sleep when idle. A power setting that suspends a computer after ten minutes without a keystroke stops it drawing full power while nobody is working, and it wakes again the moment it is needed.
• Put displays on standby after inactivity. A monitor or projector left glowing across a lunch break still draws power and heats the room, so a setting that switches it to standby after a few idle minutes saves energy.
• Stop storage devices running when idle. A hard disk that keeps spinning when nothing is being read or written wastes energy, so letting it slow to a stop until the next file is opened saves power.

The replacement cycle is the time between buying a device and buying the device that replaces it. If you get a tablet in 2024 and its replacement in 2028, the replacement cycle is four years. It is not the same as how long the device lasts: it is the gap between the two purchases.

Why devices get replaced

Components can stop working: a charging port may wear out or a battery may stop holding charge, and a repair may cost more than the device is worth. Newer software may also need more advanced hardware, so an older processor struggles with a demanding program and you replace the machine to keep up.

Short and long cycles

A shorter cycle means factories make more devices and more old ones are discarded. That increases demand for raw materials such as metals in circuit boards and glass in screens. It also means more factory energy and water, more chemicals, more delivery journeys, and more e-waste going to landfill or unsafe processing, which can cause pollution. A longer cycle reduces these demands because fewer devices are built and fewer are thrown away.

For example, a small bakery replaces its till tablets every three years instead of every six. Over twelve years it buys four sets rather than two, so twice as many tablets are manufactured and discarded. That means more metal and glass taken from the ground, more energy and water used in factories, and more e-waste to dispose of. A longer cycle therefore usually lowers environmental impact.

Planned obsolescence is when a manufacturer designs a product to fail after a set period, so that you replace it sooner than you otherwise would. Manufacturers do this because every early replacement means another sale. The failure might be built into a component, or a worn-out part such as a battery might be sealed in so that it cannot be replaced. It is not only about software becoming out of date: physical parts can be designed to fail.

For example, imagine a home printer fitted with a built-in page counter. Once it has printed a fixed number of pages it stops working and shows an error message, even though the rollers and print head are still in good condition. The counter cannot be reset, so the owner throws the printer away and buys a new one rather than paying for a repair. The short life was not an accident; it was planned into the design.

Why it matters

Planned obsolescence shortens the replacement cycle, which is the time between buying a device and buying its replacement. A shorter cycle means more products are bought over the same number of years. Each extra product must be manufactured, which uses raw materials, energy and water, and each old product must be disposed of, adding to e-waste and landfill. The overall environmental impact therefore rises.

A longer replacement cycle usually has the opposite effect: fewer devices are made and thrown away, so fewer resources are used and less waste is created.