Wednesday, September 3, 2008

environmentally unfriendly LCDs

Computers involve environmentally toxic manufacturing processes. These machines and their trim are nasty! The lifetime of a computer (for somebody who works in computer science) is limited to a few years at most. One can try to stretch this out, perhaps to five years, by carefully selecting new models and soldiering through operating system and software upgrades stoically. So far this Powerbook G4 has served me well for 4 years (OK, I needed to replace a dud hard drive).

My recent street rambles have occurred during our suburb's hard rubbish collection. The number of CRT monitors and TVs piled on people's nature strips is astonishing. The LCD revolution is here with its promise of clearer pictures, less energy consumption and flat, elegant displays. But, is there a cost? LCD monitors consume less power during their use and so the naive assumption people make is that CRTs should be replaced with this new technology to "green up an office".

Unfortunately, such replacement is not necessarily a good thing. The paper, Life-cycle environmental impacts of CRT and LCD desktop monitors (by Socolof, M.L.; Overly, J.G.; Kincaid, L.E.; Dhingra, R.; Singh, D.; Hart, K.M. in Proceedings of the 2001 IEEE International Symposium on Electronics and the Environment, 2001, pp. 119 - 127) compared LCD and CRT environmental impacts. It assumed in its survey that the monitors were replaced after the same period and for technological upgrade, rather than because the device had failed. The analysis, taking into account potential sources of error in the data, investigated 16 components of the impact of the production, use and decommissioning of these monitors: non-renewable resource use; renewable resource use; energy use; global warming; ozone depletion; air acidification; photochemical smog; air particulate matter; aesthetics (odor); water eutrophication; water quality: biological oxygen demand; water quality: total suspended solids; hazardous waste: landfill space use; solid waste: landfill space use; radioactive waste: landfill space use; radioactivity.

Energy cost and global warming contribution were given special attention in the paper. The CRT requires a lot of manufacturing energy, in particular for glass. This is the most significant factor, and exceeds by far the amount of energy that these monitors consume in use. CRTs consume more energy in production and during their life cycle than LCDs. LCDs do not consume as much energy in production, nor do they consume as much electricity during use. (Although interestingly enough, they are nastier in production than CRTs in almost all other ways - a point for another day!)

Global warming contributions of the monitors is however the reverse of what one might expect from considering energy consumption. The main global warming contribution of CRTs comes from electricity consumption during their use. During their manufacture, various forms of energy production are employed and these do not all uniformly contribute to global warming. LCDs, as noted above, consume less energy to manufacture and use than CRTs, but in the manufacturing process sulfur hexafluoride (SF6) is employed and this swings the pendulum against the LCD when considering global warming contributions:

"According to the Intergovernmental Panel on Climate Change, SF6 is the most potent greenhouse gas that it has evaluated, with a global warming potential of 22,200 times that of CO2 over a 100 year period" (Science Daily)

Oh dear, we are not saving the planet by throwing out energy hungry CRTs. Instead we are worsening the situation by increasing the manufacture of LCDs and tossing out CRTs that may have had a good few years left in them, their manufacture being the dominant component of their energy cost, even if not their contribution to global warming.

So what should we do? My suggestion is to keep CRTs until they are worn out and use 100% renewable, green energy to avoid the CRTs making any further contribution to global warming. Simple!

Of course since LCD monitors certainly consume less energy in use than the CRTs and energy consumption is measurable by business on an energy supplier's bill, changing to LCD is an easy way to make documented claims about "being green". I suspect this naive approach will be more likely to occur. Anyway, LCDs are much slicker technology and take up less desk space so that we can reduce office sizes and save on rent, heating and air-conditioning bills :-)

Face it. Computers and electronics are environmentally toxic. Use them for as long as you can and on green power. Resist the urge to upgrade.

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