In the UK, I believe we’ve done a good job of making everyone much more aware of their impact on the environment. Yet green IT is still a relatively nebulous term and its definition rather unclear and the subject of much debate. Or perhaps it’s just that we all have a slightly different perspective on which elements are important to us across what really is a very broad scope?
Did you know?
Since February 2003 the Waste Electrical and Electronic Equipment (WEEE) Directive became a requirement across the European Community. The directive imposes the responsibility of the disposal of such equipment on the originating manufacturer. The UK didn’t enshrine the directive into law until 2007.
For household equipment that means you can request that the manufacturer disposes of the equipment they made free of charge to you and they must then either dispose of it in an ecologically friendly manner or reuse, refurbish or recycle it.
In the UK some retailers offer a one-for-one in-store take-back facility, others will direct you to distributor take-back schemes or local designated collection facilities. None of these will cost you anything as a consumer.
For business users the system is a little more complicated and it’s in flux, so best to check out the Environment Agency’s latest guidance as you may find your business is required to follow the WEEE directive when disposing of electronic equipment.
This all helps to reduce the two million tonnes of electronic waste we produce in the UK alone each year.
From dust to dust
Let’s first look at the lifecycle of a piece of computer hardware and see if we can establish how much embodied energy it has attributed to it just by bringing it into existence and then delivered to us for use. This will let us try and answer the big green question: ‘Should I sweat my IT assets or dispose of them when a newer, more energy efficient model arrives?’
If we ignore for a moment the type of device, this is already a really complex question to answer. Then, if you bring the device type into the equation, you realise it becomes not just device-specific but use-case-specific too.
There are many organisations working on trying to calculate energy (or in some cases carbon) footprints for electronic devices and, in some cases, specifically computing devices. The WattzOn Embodied Energy database claims that a generic laptop has an embodied energy of 1.2Giga Joules or 336kWh, which includes the energy of making the raw materials, the manufacture of the laptop itself, the transportation and the eventual disposal.
Now let’s say that your old laptop is used on its power supply all the time and it’s switched on for eight hours a day, 240 days a year at your desk. Let’s assume an average steady state power consumption of 40W including the power supply losses.
Let’s also ignore, for now, the fact that the office it’s in is heated during the winter and cooled during the summer and there are a thousand other laptops all placing additional 40kW of load on the building’s environmental control systems.
So, running the maths we find that the laptop will use 320Watt hours per day, or 77kWh per year of grid electricity. As a side note, at 10p per kWh the laptop will have consumed just under £8 of electricity during the year, so we are not going to make a business case on energy saving and don’t even think about replacing it with a thin client under an energy opex business case.
New vs Old
In many organisations there is a discussion about whether it is greener to replace old computers with newer ones because the manufacturer says the new ones use less power, the counter argument being ‘just think of all the embodied energy and toxic disposal’.
Ignoring for a moment the issue of whether your laptop will be able to run the software being shipped in five year’s time at any useful speed, let’s look at the energy consumption case.
We need to think of the embodied energy in the laptop in the same way our finance folks think of its purchase cost. The embodied energy is capital cost and we need to amortise that over the life of the laptop. When we spread that out over three years’ of use, eight hours a day, 240 days a year, we find that the equivalent consumption rate is 58 Watts for the hours the laptop is turned on.
Looking at the power draw we can’t just compare the 58 Watts amortised embodied energy with the 40 Watts of grid electricity, because it takes roughly three times as much source energy (fuel at the power station) to deliver that 40 Watts, meaning 120 Watts of energy consumption whenever the laptop is on (are you thinking of those people who claim incandescent bulbs are efficient because their waste energy comes out as heat?).
So, if we compare our old laptop with a shiny new one and want to try and make an environmental case, what we need to do is figure out how much less power the new laptop needs to draw and how long we will have to keep it for to amortise the embodied energy before we break even against keeping our old laptop. If we consider a laptop using 20 Watts, this will use 60 Watts of energy at the power station; if we keep it for three years then the amortising embodied energy is 58 Watts and we are saving an entire 2 Watts.
For more information
www.dcsg.bcs.org
