Voltages and Profits

I have just run some tests to basically repeat an experiment that I did several years ago, with a different set of appliance and loads, to demonstrate how the power companies can sell you more power at higher voltages.

Here are the results:
Phantom Menace: every watt is a dollar a year
Appliances: Voltage vs. Power Consumption wattage @226 volts wattage @240 volts (%increase) wattage @254 volts (%increase)
IBM clone 486 & VGA monitor (in operation) 125 watts 125 watts (+0%)125 watts (+0%)
Samsung SF-505 Thermal Paper Fax Machine 12.0 watts 12.5(+4%)13.5 (+12%)
20 watt Compact fluoro Philips PL-20 20.0 watts 21.4 (+7%)22.5 (+12.5%)
Macintosh Color Classic (Standby mode) 14.6 watts 15.0(+3%)16.5(+13%)
Hoover Turbopower Model U2664 240v 50Hz 470W 331 watts 346(+4.6%)391(+18%)
Osram 60 watt incandescent light globe 57.7 watts 64.3 (+11.4%)69.2 (+19.9%)
JVC VCR model HR-D320EA (standby mode) 10.9 watts 11.6 (+6%)13.5 (+24%)
Rinnai Energysaver 302 space heater (standby mode) 6 watts 6.4 (+6%)7.5 (+25%)
"15 watt" !! fluoro desk lamp 21.4 watts 24.4 (+14%)27.8 (+30%)
Power Total (excluding vacuum cleaner) 267.6 watts 280.6 (+4.9%)295.5 (+10.4%)
Annual Cost @ 11.43 cents/kWh $267.60 $280.60 (+4.9%)$295.50 (+10.4%)

Note that EVEN WITH a considerable proportion of the total load being a "controlled" load such as the computer and monitor with sophisticated switch mode operation, the inescapable fact is that power company energy sales and profits will be increased at the higher voltage.

The Effect of Supply Voltage on Street Lighting
Test Date: Friday 13th August 1999
The Two Common Types: Sodium and Mercury Discharge Lamps
Lighting Voltage vs. Power Consumption wattage @228 volts wattage @242 volts (%increase) wattage @254 volts (%increase)
Sodium Lamp/Iron Ballast+PF (GEC HPS/U 22 SOLARCOLOUR 400W) 390 watts 464 (+19%)529 (+35.6%)
Aust. Total Sodium* (MWh) 657,000 781,000891,000
Mercury Vapour Lamp (Osram 400W HQL(MBF-U) /Iron ballast+PF 385 watts 433 (+12%)479 (+24%)
Aust. Total Mercury* (MWh) 657,000 739,000817,000
Annual greenhouse emission (tonnes) @300MW/12hrs/night* 1,314,000 1,520,000 (+16%)1,708,000 (+30%)

* assuming 150 MW (@ 230V) of sodium and 150 MW (@230V) of mercury lamps, 12 hours a night

These lamps, typical as they are of most Australian street lighting, indicate that we could save up to 400,000 tonnes CO2 by turning down the voltage at night. No wonder we have so much light pollution in our cities and towns: the poor old street lights are being force-fed with unnecessary power. If you care about the Great Barrier Reef and the environment generally, please contact your member of Federal parliament and demand they force power distribution companies to turn the voltage down. All that extra electricity is adding greatly to greenhouse gas emissions.

The test equipment consisted of a conventional spinning-disc watthour meter being supplied with three selectable AC voltages (unmodified mains, mains plus 6% and mains minus 6% - a trick done very simply with only two autotransformers: essentially equivalent to a Variac with only three output voltage settings). Power consumption was calculated by allowing the load to stabilise, checking the input voltage with a digital voltmeter, and using a stopwatch to accurately determine the rate of spin of the watthour meter. The watthour meter was calibrated against a similar unit on the Voltscommissar's front porch (property of Australian Gas & Light Pty Ltd.) - their rate of spin with a 1000 watt impedance test load was accurate to better than 0.5 per cent.

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Michael Gunter mickgg@suburbia.com.au