Personal computers are ubiquitous in our everyday life. We all rely on them and, in fact, it would have been impossible for me to write this without one. It is one of the great success stories of our time.
Most people are aware of Moore’s Law – that computing power doubles roughly every 18 months. What most people don’t know is that the electrical efficiency – the number of computations that can be completed per kilowatt-hour of electricity used – also doubles every 18 months. This is great news in a world where carbon emissions need to be reduced and energy costs are rising.
However, while electrical efficiency and computing power seem to be rising at a constant rate, the growth in the sales of PCs is accelerating.
The number of computer units shipped has increased from 135 million in 2000 to 355 million in 2011. This is predicted to rise to over 700 million by 2016 (including tablets) – fantastic growth rate by any measure. In the last decade sales doubled. In the next five years they are predicted to double again. Is this growth rate sustainable?
Trucost calculated the financial costs for the environmental impacts of a desktop and a laptop. It is worth noting that we used industry average data and that, of course, there is significant variation among products. We analyzed the stages of the product lifecycle – from raw material processing and manufacturing through to transportation, use by the customer and endisposal or recycling. The carbon emissions, water, and waste flows were calculated for generic products in each category. Note that for the use phase we did not include the emissions arising from the Internet (data centers), only the electricity consumed by each device. Trucost then calculated the “natural capital” cost of each of these environmental impacts. For carbon we used the social cost. For water, a local issue, we correlated the volume of water required to produce the raw materials with local scarcity by gathering data on the location of production and pricing water accordingly.
Our analysis indicates that, on average, if nature charged for its services, the “true cost” of a desktop computer would be around 6 percent higher than the retail price, while the laptop would be 14 percent more expensive.
Carbon emissions create most of the cost but there are significant differences between the desktop and the laptop. The largest proportion of the desktop’s impact comes from its electricity consumption. Laptops consume significantly less energy during the use phase, which is the reason why they perform better overall, though they are marginally more water intensive than desktops.
