The environmental impact of large appliances may be clear to identify, but what about those of small appliances? Running on electricity these small appliances can accumulate to have a significant impact on a person or companies carbon footprint. As a result finding less energy demanding, or, more efficient small appliances is just as important as for large appliances. One such small appliance is the humble clock! An environmentally friendly alternative exists in the water powered digital clock! ESW have a great range from a trendy water powered can clock to a more traditional analogue clock

The water powered digital clock works on the principle of electron transfer between a positive (cathode) and negative (anode) immersed in water [4]. Simplified a piece of slow dissolving zinc and electrons extracted from water complete an electrical circuit providing energy to power the clock. The total life expectancy of the clock can vary and depends on how long the zinc takes to entirely dissolve [1, 3]. The clocks do require maintenance as the water does diminish. How often the clocks require a water top up can vary widely between brands of clocks; anywhere from a few weeks to a year. Some clocks also require the addition of lemon juice in the water to increase energy production [3].

The primary environmental advantage of these clocks is they are devoid of batteries and do not require a mains supply, running entirely off the power produced by water!  The components of the clock are also ‘environmentally friendly’ improving recyclability. A variety of digital water clocks exist offering a variety of functions. As well as displaying the time some also act as an alarm, thermometer, timer and flower vase [3]! The clocks also come in a variety of designs, some reusing bottles to house the clock [5].

The general consensus from reviews is that the clock provides basic functions well (e.g. time) but more complex tasks (e.g. alarm) are compromised [6]. Without a back light these clocks are best suited to places used primarily during the day such as offices [5]. However these clocks do have a place in someone’s home or office; they are cheap to purchase, practically run for free and have great novelty value!

[1] Wikipedia: http://en.wikipedia.org/wiki/Water_powered_clock, (2009)

[2] Energy Harvesting Journal: http://www.energyharvestingjournal.com/articles/water-powered-clocks-00002245.asp?sessionid=1, (2010)

[3] Tip and Trick: http://www.tipandtrick.net/2009/save-the-environment-with-water-powered-clock/, (2009)

[4] How stuff works: http://science.howstuffworks.com/earth/green-technology/sustainable/home/water-powered-clock.htm/printable, (2009)

[5] Water Powered Clock: http://www.waterpoweredclocks.com/, (2010)

[6] Gadget Speak: http://www.gadgetspeak.com/gadget/article.rhtm/755/475846/Gizoo_Water_Powered_Clock.html, (2007)