Zero Waste Week - Powering off to Save the Environment

Zero Waste Week is a UK initiative aimed at raising awareness of the environmental impacts of waste. It has run every September since 2008, with this year’s Zero Waste Week happening from the 2nd-6th September.

With a few weeks to go until Zero Waste Week, I started wondering what I could do this year to reduce my environmental impact. Over the course of the year I had implemented soft plastic recycling at home, as well as diverting food organics from landfill by building a worm farm. What more could be done?

A Powerful Idea

I came across a report by the Natural Resources Defense Council (NRDC) on power wastage caused by electrical equipment on standby. The report, from 2015, stated that standby power cost consumers US$19 billion annually, equivalent to the output of 50 large power stations and accounting for 23 percent of annual electricity consumption for the average home in the US.

Here was something I could definitely improve on - at home we have plenty of devices on standby, some of which are rarely, if ever, used.

Measuring Energy Usage

Many Australian homes are fitted with smart meters, which record usage remotely and send the data back to suppliers and network providers. Individuals can then access their information online to see how much electricity they are using.

I pulled my data for the past 2 years (it handily comes as a CSV file) and dumped it in to Excel, from where I did some analysis. Using the data, I averaged the energy usage every 30 minutes over a period of 6 weeks.

Average energy usage over 6 weeks, measured at 30 minute intervals

This enabled me to see what the energy usage is at night when everyone is sleeping - effectively the standby energy usage in the house, when most devices are off - which turned out to be about 0.12 kWh.

Next, I looked at what constituted the 0.12 kWh. This was harder to do because although most devices provide volt and amps allowing the power when the device is operating to be worked out, they do not provide the standby power consumption.

Choice provides some guidance on minimum and maximum power consumption, but I opted to buy an energy cost meter from Bunnings, allowing me to put the below table together.

The totals pretty much equated to the 0.12 kWh night time energy usage, so I had accounted for everything, at least. But how could this usage be reduced?

Reducing the Impact

The things that stood out in the table were:

• The subwoofer, which consumed 3.9W on standby, even though it is rarely used. It could be turned off completely and turned on when watching TV.
• The Mac, which consumed 30.5W and the PC (a media server), which consumed 21.4W when not in use (sleep mode). Better power saving settings could reduce the consumption on these.
• The NAS, which consumed 28.8W. Spinning down disks when not in use may reduce this and prolong the life of the disks.
• Many devices consumed considerable power 8-10W) when on standby. Typically these were older or larger devices like the water heating. Newer, more efficient devices like the washing machine, printer and dishwasher all consumed far less on standby, but also automatically switched off after a period of inactivity.
• One of the phone chargers was constantly plugged in and charging a music player, even though the player was not being used. That charger could be unplugged and only plugged in again if the music player was in use.

Turning off devices when on holiday, even for a weekend away, would have a big impact on energy usage and consequently on electricity bills.

For the rest of the time when we are home, I looked to reduce consumption by turning off the subwoofer, turning on some better power management on the Mac, the PC and the NAS, and unplugging a few devices which were not in use.

I monitored usage over the next month and see what difference these changes made.

The Results

At the end of the month I was able to pull the latest energy usage data from my provider and plug it into my Excel spreadsheet to compare usage before making changes, to usage after powering off/implementing better power management, to usage while we were on holiday and most devices were powered off completely.

Average power usage before changes, after changes, and during holidays

The results were better than I expected. As visible in the graph above for the night-time usage period, there was an 6-22% improvement from pre-changes (the red line) to post-changes (the green line). There was a further 5-18% improvement on that again at night-time while the house was empty during our holidays (the blue line).

The post-changes (green line) lower usage trend also continued over the course of the day too, meaning that the energy saving measures had a lasting impact on energy consumption in general.

All that from powering off a few devices and implementing better power management on some computers!

It also showed that turning off devices while on holiday can help to reduce energy consumption and save money on energy bills. Something I’ll definitely be doing for future holidays.

I’m looking forward to my next electricity bill to see how much my energy saving measures translated into a saving in dollars on my bill.