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KenB
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« on: August 23, 2007, 11:54:46 AM » |
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List,
The modern home is an energy efficiency disaster. Instead of reducing electricity consumption, the UK has seen a steady rise in the last 20 years, and much of this can be attributed to modern electronics for home entertainment, communications and of course personal computers.
Manufacturers of electronic goods are partly to blame, some home entertainment equipment uses almost as much power in standby mode as when active, I have a mini-Hi-Fi with radio and CD player that uses 7W when turned off.
The modern home is littered with cheap electronic goods, all of which are permanently powered. It is these devices which present parasitic power consumption, and can amount to 20% unnecessary electricity consumption. By identifying these devices and taking steps to disconnect them when not in use, can lead to major savings in electricity consumption.
No modern home can function without electricity, and although often stated as being the purest form of energy, electricity has a pretty dirty track record. For every unit of electricity consumed in the home, almost 4 units of fossil fuels are consumed at British power stations. This leads to carbon dioxide emissions and other pollutants, and the other 3 units of energy end up as heat and are dissipated to the atmosphere.
Whilst combined heat and power schemes have been possible for nearly 100 years, right since the start of the electricity generation industry, they were often dismissed on the grounds of adding unnecessary extra complication. The Central Electricity Generating Board, which controlled the electricity industry right up until privatisation in the early 1990s, went out of its way to ensure that CHP schemes were NOT built. As a result we have a legacy of very wasteful power stations.
With this in mind, it makes sense to reduce electricity consumption in the home, as it has a large effect on reducing the fossil fuel consumption and carbon dioxide emissions from UK power stations. Some will argue that they only use "Green Power" but currently renewables only make up a very small percentage of UK power generation - about 5%. This means that only 1 in 20 households can actually be using renewable power at any one time.
A few have chosen their own route, and generate their own renewable power by wind generation, solar pV or micro hydro. Other emerging technologies will make it possible to run combined heat and power systems on biomass and renewable biofuels. For all these home-generation schemes, it is essential that energy is not wasted unnecessarily - all the more reason for reducing your electricity consumption. When you don't have much in the first place, you don't really want to waste it.
In my opinion, there are few appliances that should remain permanently connected to the power supply. Fridges and freezers are the obvious first choice. The inconvenience and expense caused if a freezer loses its power for anything more than a few hours is considerable. This said, it might be possible to get better efficiency from a freezer, by turning it off for a few hours, and using the thermal capacity of the frozen food to maintain the cold temperatures. When it does come on, the compressor runs for longer, and does not go through several inefficient start-stop cycles. This technique is entirely conceptual at the moment, and should be undertaken at your own risk, however, it might be possible to power a freezer down for 6 - 8 hours per night on a timeswitch.
Defrosting the freezer every 3 months can also make a big difference. After the defrost, I saved 0.75kWh per day. It also a good chance to either consume or compost all those things lurking on the bottom shelf.
Whilst in the kitchen, some consideration can be given to the high wattage devices, like kettle, dish-washer and washing machine and tumble dryer.
I use the kettle on an almost hourly basis during the working day. By filling to just enough for 1 mug of coffee, and turning it off as soon as it boils - not waiting for the auto switchoff, I reduce the boil time by some 30 seconds. Over the course of the year, this can save up to 40kWh of electricity.
The dishwasher, used on average just less than once per day is plumbed into the hot water supply. This reduces the amount of need for the heating element and saves power. It is generally run on a low wash temperature.
The washing machine is used perhaps twice a week, and a low temperature program selected whenever possible. There are only 2 of us in the house normally, and I wait for sunny or breezy weather before running the machine. This avoids having to run a tumble dryer. I realise that a household of 2 has a much reduced clothes washing requirement than say a family with 2 kids, but a little clever timing of the wash day activities to match favourable weather, can lower the electricity bill considerably.
The next appliances that seem to be wasteful are those that maintain a clock display. Cookers, microwave ovens, breadmakers and video recorders. Many of these are left on overnight, or when not in use, solely because of the inconvenience of re-setting the clock.
Very few people actually use the timer functions that these devices offer.
Here are some examples
Microwave clock 4W
VCR Clock 8W
TV standby 9W
Telephone with LCD 2W
Just by turning these devices off or unplugging from the wall could save 184 kWh per year - about £18 worth.
In the last 5 or 6 years, Broadband and the rise of PCs at home has led to a large increase in power consumption.
An older desktop machine can use the same amount of power as a 100W light bulb. Kids often have these machines in their rooms, and they get left on, unattended for hours, not to mention those who work in offices where desktop computers are often left on 24/7 . A single home PC could easily be consuming 400kWh per year, whilst not actually being used. The same can be said for printers, speakers, games consoles, broadband routers and monitors all left in standby.
I have an inkjet printer that consumes 20W just waiting to be used, and my wireless router uses 8W, all those hours I am not using it.
These items can be collected together onto the one4-way mains distribution block, and turned completely off when not being used. Most computer stores sell an adaptor block that turns off all the peripherals when the main PC is turned off. These are also used for the TV hi-fi stack, allowing all the set top boxes, satellite decoders, DVD players to be turned right off when the TV is turned off.
Of course a modern laptop with a PCD screen will use significantly less power than an older desktop PC with a CRT monitor.
Living and working at home out of a "home-office" allows you some freedom to dictate your own hours and your own energy consumption. I devised a scheme where I could keep my office activities down to within a 200 to 300W power allocation - which I notionally called "The 200W Office". This allows anyone working form home to keep their office powered up and productive for perhaps 10 hours per day, on a power budget considerably less than the average commercial office.
Working from home enables you to minimise your power consumption - after all, you are probably paying for it. And it reduces the mileage and fuel consumption by not having to commute each day. You become your own boss and IT and energy manager rolled into one. I have a staff of one, a black moggy called Monty, and he manages to find the warmest place in the house - normally the place where the hot pipes leave the airing cupboard.
I began positive steps to reduce my electricity consumption in September of 2005, at a time when I was using 3700 kWh per year. In the two years since, consumption has now been lowered to just 2500 kWh per year - a saving of nearly 33%.
How further can we take this process, without affecting normal household operations or resulting in disharmony?
Well the TV and video stack are still consuming 1kWh per day, partly because my wife listens to the radio on Freeview through the telly, rather than the radio. This consumes an unnecessary 65W. She also is very forgetful/ignorant of not turning the TV stack off, last thing at night.
I would be interested to hear from others that have adopted similar techniques for lowering their consumption.
Ken
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