Recent debate over Blackle and other dark-screen search engines are just the tip of the iceberg when it comes to potential savings.

In some ways, we’ve been quite surprised that the idea of a black-screen search engine has become one of THE ways the eco-friendly technology bloggers have been using to promote a more sustainable use of energy.

Our own tests on LCD and CRT monitors show that not only are power savings from this idea marginal at best, the very idea of a black-screen search engine could actually cause you to use MORE energy rather than less.

Unfortunately, much of the debate about power savings lurches from the sublime to the ridiculous and not enough of it is based of fact or a technological basis. So you end up with ideas such as a black-screen search engine for saving the planet.

Saving 750-megawatt-hours sounds like a huge amount of energy but in reality, it is the ultimate example of a grain of sand compared to a beach when you compare it to worldwide power consumption.

According to the US Energy Information Administration, the world consumed 15.441billion megawatt-hours in 2004, the latest currently available figures.

That’s 15,441 million megawatt-hours. You divide 750 by 15,441million and you get a proportion so small you need a scientific calculator to count the number of zeros after the decimal point.

But that doesn’t mean there aren’t some serious power savings to be made. There are – but you need to understand how computers use electricity, when they use it and where you can save it.

We carried out power consumption testing for a major feature story in the June 2007 edition of Australian PC User magazine and have been studying the details of our tests ever since.

Here are five tested ways you can help save some serious amounts of electricity.

1. Turn off your PC after work

Many business PCs are left on overnight with either just the desktop or possibly a screensaver running. There is a misnomer here – screensavers are not “green” savers. Screensavers are designed to save your monitor’s screen from burn-in but they do not use any less energy than your normal work load.

We’ve carried out power consumption tests and found the average business PC consumes an average of just over 100-watts. Add to that a typical 19-inch LCD screen and you increase that by another 40-watts.

If you choose a conservative time frame of 12 hours that a PC is left on and not being used, even if you just powered down your PC into standby mode, you can cut the power consumption down from 140-watts combined to around 8W.

That alone would save 1584 watt-hours every day. Over the course of a 365-day year, that’s 578.1kilowatt-hours per year for one PC.

It would take only 1297 business computers to be switched off of a night instead of left of 24/7 to make a saving of 750megawatt-hours per year.

Forget about search engines, there are some incredibly huge amounts of energy that can be saved if every business PC was switched off at night.

2. Drop the screen brightness

Our recent contribution to the Google vs Blackle power saving debate has given us plenty of room for investigation and while much of that debate has centred around the questionable possibility of saving power using a black screen, there’s a much simpler way of saving considerably more power.

And that’s dropping the brightness of your computer screen.

We carried out some basic tests with a few monitors and found, particularly with LCD screens, that the power consumption can be as much as halved by simply dropping the brightness. For example, an LG L192WS 19-inch LCD monitor consumes 32.4W with the brightness at 100% and just 15.1W with the brightness at 0%. Now unlike CRT monitors, the brightness range of an LCD monitor is nowhere near as great and at 0%, the L192WS is still easily pumping out enough light to see the screen.

Make sure you get this – this is a significant development. Dropping the power consumption by more than half is something you cannot achieve by changing your search engine but you can definitely achieve by dropping the screen brightness.

By pushing the contrast to 70%, we were able to drop the power consumption a little further to just 14.7W – a saving of 17.7W - so there are some serious power savings to be made here.

If your LCD monitor was adjusted to save a conservative 10W, over a 12-hour usage day, you’d be saving 43 kilo-watt-hours per year. Multiply that by just the 75million LCD monitors that were shipped in 2005, and you’re talking about 3.285 million mega-watt-hours of power saved.

3. Switch of your ADSL modem at night

The average ADSL modem/router consumes an average of approximately 8.5W on our recent testing but unlike most other electronic devices, ADSL modems are permanently on and have no standby mode, so it’s pulling that 8.5W of energy even when you’re not using it.

According to the DSL Forum, 185million users worldwide were connected to DSL modems as of the end of 2006. If every user switched off their ADSL modem at night for the average eight hours they’re asleep, each modem would save 24.82 kilowatt-hours of energy per year. Multiply that by the 185million ADSL modem users and you’ve got a possible energy saving here of 4.591million megawatt-hours of electricity each year.

Now we’re starting to talk about some serious power savings and all you’re doing is switching off your gear at night when you’re not using it.

4. Switch everything off at the wall

Even if you turn your computer off at the end of the day, chances are it’s not really off and still consuming power. Standby power is quickly becoming the real curse of modern technology.

Take a standard business PC, a LCD or CRT monitor, a printer and you’ve got a power consumption of approximately 9W, broken down to 7W for the PC power supply, 1W for the monitor in sleep mode and the same again for the printer.

Again, even if we just take the 75million people who bought an LCD monitor from Example 2, you’re talking about another huge amount of power being saved.

Each PC/monitor/printer combo switched off at the wall would save for the conservative eights hours a night they’re not used would save 26.28 kilo-watt-hours per year. Multiply that by the 75million and you get 1.971million mega-watt-hours of electricity saved.

5. Set your desktop PC power management

While it’s common knowledge that notebook computers have built-in power management, it’s the same for desktop computers too.

Every computer running Microsoft’s Windows Vista has a minimum of three power settings – high-performance, balanced and power saver. Now most business PCs don’t need to have their processors running at full tilt all day, particularly for we call the WISE (Word processing, Internet, Spreadsheets and Email) applications.

It would certainly make sense here to switch Vista into the PowerSaver mode. You can do this yourself by selecting the Start Orb in Windows Vista, the choosing Control Panel, the System and Maintenance, clicking on Power Options and finally choosing PowerSaver from the three options.

More investigation needs to be done to work out how much power can be saved by using PowerSaver instead of Balanced over the course of a day but if it were able to only drop power consumption by 10% or 10watts, you’d be looking at similar power savings as dropping the LCD screen brightness for every Windows Vista PC. And according to Microsoft’s own figures, they sold 60million copies of Windows Vista in the first six months of its release. If you take a conservative figure that 40million of those were actually installed, you’d still be looking at some serious power savings.

Per PC over an eight-hour day, you’d save 80watt-hours or 29.2kilowatt-hours per year. Multiply that by 40million Windows Vista computers and you’ve got a power saving of 1.168million megawatt-hours per year.

On balance, we’ve found over 10million megawatt-hours of energy savings that could be made by just the last four of these tips and by only a fraction of the number of worldwide computer users.

Given that worldwide energy consumption in 2004 was 15,441million megawatt-hours, 10million megawatt-hours is still a tiny drop in the bucket but it will have a far more significant effect than mulling over which search engine you use.

Darren Yates is a B.Sc. (electronics) graduate of Macquarie University, Sydney, Australia and a contributing editor to Australian PC User magazine.