The environmental impact of computers

• Energy consumption is measured in watts and kilowatts.
• One kilowatt is 1000 watts.
• All computers use some electrical energy while they are switched on, regardless of whether they are being used or not (think about your smartphone, for example)
• Generating energy for computers and their attached devices has an impact on the environment
• Servers need to run 100% of the time, for example a web server.

• A computer system may use very little electrical energy due to huge increases in both performance per watt (for example, Apple's M1 and M2 chips are very high-performance but also very low-power consumption chips)
• But there are energy uses involved in computer systems besides the general energy consumption of them when they are being used

• A MacBook Pro with an M1 chip uses around about 30 watts of energy and a maximal energy consumption of just 50 watts of energy.
• A typical desktop with a high-end (AMD Ryzen 2700X) will operate at around about 150 watts of energy with a maximal energy consumption of 600 watts of energy.

• Add in a high-end graphics card and several disk drives and the power consumption can get much higher than that, sometimes into the kilowatts

• Computer manufacture requires a lot of energy too
• Computers are also manufactured with some harmful materials including:
  • Lead (Pb)
  • Lithium-ion (Li-ion)
  • Arsenic (As)

The carbon footprint of a device is something that both manufacturers of devices and the consumer need to think about.

The carbon footprint of a computer is not just limited to their purchase and energy use but also due to things like the the manufacturing footprint and the shipping footprint

• The carbon footprint of a device or appliance is the amount of greenhouse gases (CO2, NOX, CO) that is produced by using a device.

• We can, of course, do things to save energy.
• For individuals, this could be:
  • Switching off computers and devices when they are not being used instead of leaving them on stand by
  • Using the energy savings settings on the computer or device where possible.

• For National 5, you need to know about:
  • controlling settings on monitors
  • power down settings
  • leaving computers on standby/hibernation

• The monitor or display of a computer system can also be switched off to conserve power.
• As well as this, most monitors offer power saving modes (some monitors feature things like USB ports which can also be switched off in an eco mode). Some power saving modes will reduce the brightness, since the brighter the display the more energy it will consume and they may also automatically switch the monitor off after a few seconds of inactivity.

• Power down settings allow certain devices to switch off after a prolonged period of time
• A computer itself can go to sleep mode automatically after time
• Hard drives and solid-state drives can automatically power down when not needed (a hard drive consumes around 25-35 watts of energy so powering them down saves a considerable amount of energy)
• Allow the CPU to enter a lower performance state (aka a P-state) such as P0 (the lowest P-state). Intel and AMD CPUs support this through their own technologies.

• Power down settings also allows the user to set up a way of shutting down the entire computer automatically at specific times.
• I use this kind of thing to wake my home server at 6.30am and switch it off at 23.30pm since it is not needed between these times.

• Standby and hibernate are options available on most computers to put it into a lower power mode and reduce power consumption.
• In standby the computer stores the data the user was working on in the RAM and keeps the RAM powered.
• In hibernate (also known as a sleep or deep-sleep mode), the computer stores the data stored in the RAM on the hard drive or solid state drive and completely powers down. Compared with standby, hibernate is slow to resume and start.

• You will probably have heard of the ENERGY STAR certification.
• The ENERGY STAR certifications are used to certify certain computers and devices as meeting certain energy requirements, much like fridges and cookers with their A* to G- ratings.
• Computers with the the ENERGY STAR certification need to have good efficiency levels.

• If you've ever looked up or bought a power supply unit (PSU) for building a computer, you might also have seen the following badge.
• The 80 Plus Gold standard is for PSUs which are higher than 80% efficient (that means that more than 80% of the energy that comes into the power supply is turned into useful computer energy, not heat or sound)