Following from an earlier post on Green ICT, and again in light of Earth Day this weekend, this post suggests some ways in which greenhouse gas emissions from computers can be reduced.

Reducing greenhouse gas emissions will increasingly become the responsibility of all global citizens. In the Caribbean, most countries have not yet implemented comprehensive “green”-oriented programmes. As discussed in an earlier post, Making the world a greener place: Decreasing ICT’s carbon footprint, managing our electricity consumption can reduce the carbon footprint from PC use. Five options are outlined below.

1. Turn off PCs when not in use. Although this recommendation might seem obvious, a desktop computer with a CRT monitor can consume the same amount of electricity as 3 or 4 bright (non-energy saving) lights on full time. If both the monitor and CPU are left on for 8 hours (the average workday), five days a week, in a month up to 58 kWh could be used. Further, if they are left on all day, everyday, and are not configured to go into sleep/standby mode or to switch the monitor off when not in active use, electricity consumption can jump to as much as 245 kWh per month.
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Equipment (Operating duration) 1 day/ kWh 31 days/kWh
Desktop PC with 17” CRT monitor (8 hours) 1.2 – 2.6 36 – 82
Desktop PC with 17” CRT monitor (24 hours) 3.5 – 7.9 108 – 246
Desktop PC with 17” LCD monitor (8 hours) 0.7 – 2.3 20 – 70
Desktop PC with 17” LCD monitor (24 hours) 2.0 – 6.7 61 – 209
Desktop PC with 20 – 24” LCD monitor 0.7 – 2.6 21 – 80
Desktop PC with 20 – 24” LCD monitor 2.0 – 7.7 62 – 240
Laptop (8 hours) 0.1 – 0.4 3.7 – 11
Laptop (24 hours) 0.4 – 1.0 11 – 33

Table 1: Approximate daily and monthly electricity consumption for select computer systems (Source: Saving Electricity)

2. Manage your PC power plan. Most PCs have power management features that allow users to configure electricity consumption by device.  Typically, users are allowed to choose settings for when the equipment is fully operational and actively being used, and for inactive periods. Depending on the manufacturer, a range of options are given, such as:

  • power saving options when the PC is in active mode
  • turning off the monitor after a specified period of inactivity
  • turning off the CPU after a specified period of inactivity
  • activating sleep/standby mode after a specified period inactivity.

3. Limit the use of screensavers. Although screensavers are a way to personalise your PC, when they are triggered, they can keep the both the computer and monitor active. No power savings are realised. However, some might contend that having a screensaver shields the images on their computer screens from prying eyes. If this is a concern, the power saving settings of the PC should also be activated to eventually switch off the monitor (at the very least) if the PC remains idle for an extended period of time.

4. Monitor consumption. There are a few software applications that claim to monitor and manage the power consumption of PCs, with the aim of realising significantly lower electricity bills. Most are targeted at enterprise network environments, such as GreenTrac, Joulex and NightWatchman, but a few such as Granola are designed for the individual PC.

There is also Welectricity. Welectricity a social network that provides a free online service that helps its members track and reduce their electricity consumption at home. Welectricity was developed in St. Vincent and the Grenadines, in the Caribbean, and is currently being used in 78 countries around the world.

5. Use greener equipment/devices. As reflected in the above Table, there is direct relationship between the equipment used and power consumed. For example laptops are considerably more efficient than desktop computer systems. However, laptops tend to be more expensive than desktops and generally, they need to be replaced more often than desktops, which can be more easily upgraded or have parts replaced. Further, greater care and consideration is needed when selecting laptops, as the environmental impact of their manufacture and disposal should be factored in. For guidance on the most environmentally friendly laptops, see the Guide to Greener Electronics.

Additionally, it is increasingly possible to purchase more energy efficient computing equipment. The most widely recognised standard is Energy Star, which is an international standard used for energy-efficient consumer products. There is usually no appreciable difference in price for Energy Star-compliant products when compared with other non-compliant devices. It is therefore strongly recommended that energy efficient options be considered.

How do you plan to reduce your computing carbon footprint? Are there any tips you would like to share?

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