Cutting back on wasted electricity is the cleanest power source of all – as our household shows
Monday 24 August 2015
A few years ago, I couldn’t read an energy bill beyond the charge levied. I couldn’t tell you how energy was measured, or ultimately how its use related to making my life better or worse, let alone how it affected broader society and the planet.
I resolved to change this. I studied energy and sustainability at university, and have gone on to teach there. Throughout this time my wife and I have made many changes to how we use energy at home. Yet when we decided to take a closer look into our electricity bill, we were surprised by what we found.
There are three of us in our household now, since our son was born last year. Notwithstanding that, our metered electricity use continued to go down, coming in a little under what it was the same time the previous year.
According to our bill for the spring quarter of 2014, we used 3.79 kilowatt hours (kWh) per day, down from 3.95 kWh per day the previous year, despite the extra person in the house. (Granted, he’s a small person, but any parent can tell you how much small people add to the general load of your life, including energy use.)
We don’t feel particularly heroic about this, but when our bill also informed us that the average use for a household of three people in our region of inner Melbourne is 14 kWh a day in summer and 17.1 kWh a day in winter, it got me thinking. Even for households of two, the respective daily averages are 11.6 kWh and 14.8 kWh, and for one person, 9.2 kWh and 12.4 kWh. These are massive amounts of energy to be getting through every day.
Importantly, none of these figures counts how much energy is used from other sources such as gas, or electricity generated by solar panels. In our case, we don’t have gas, but we do have solar panels. So how much electricity did we use from the panels in this period? This is a harder question to answer than you might think.
Our bill tells us that we exported 5 kWh per day to the grid, but it tells us nothing about how much electricity from the panels we actually used. The retailer doesn’t receive that data – apparently, nobody does. This makes it hard to know how much energy we use in total, both as a household and by extension as a society.
That’s a sizeable blind spot for such an important issue. It’s as if solar-powered electricity is somehow regarded as “free” – a fraught idea to say the least. While sourcing electricity from our solar panels is (a lot) better than coal, it’s still an industrial technology.
In the absence of this information I turned to daily monitoring of our inverter, which shows how much electricity is generated by the panels each day. Subtracting what was sent to the grid, it seems that we used a daily average of about 1 kWh of electricity from our panels. Added to the 3.79 kWh on our bill, our household’s actual electricity use during the period in question was about 4.8 kWh per day, or 1.6 kWh per person – a fraction of the average for people in our neighbourhood.
Comparing per capita energy use is relevant because if living alone makes us more intensive energy users, then one of the most effective things we can do is share a place. This is all the more relevant when we take into account the embodied energy of each building, to say nothing of the related energy costs of urban sprawl, extended service provision, car dependence and so on.
But to get back to comparing apples with apples, the average three-person household used around three times the electricity we used (and probably more, given that we are including what we used from our panels, and comparing our household figures for spring with the wider average for summer, when our energy use tends to be substantially less). This raises a promising prospect.
How to get ‘free’ electricity by not using it
Consider this. Our household used around 9.2 kWh per day less than the average household in our area. Over the quarterly billing cycle, that adds up to 837 kWh, far eclipsing the 455 kWh we exported to the grid from our solar panels. In effect, it can be said that we “sourced” that 837 kWh for other (or future) uses, not by selling electricity to the grid, but by conserving it.
In industrialised societies like ours, where we tend to use far more energy than we actually need, this is a significant and genuinely clean energy source that is begging to be tapped. It is hidden, not in the bedrock of the earth, but in the bedrock of our minds, habits and expectations.
“Conservation mining”, as the late sustainability professor Frank Fisher called it, is “mining” energy by conservation. Here’s a sense of how we’ve gone about it.
We’re in a rental townhouse not particularly designed with low energy use in mind, but the owners were happy to invest in a few relatively low-cost, “low-tech” changes, such as draught-proofing, insulation, thick window blinds, and solar hot water.
Beyond that, most of the changes have been to how we live. We use heaters specific to the rooms we’re in, and only when the temperature dips below 16C. If that seems low, it is interesting how we do adjust, particularly with more appropriate clothing (like Ugg boots and thermals in winter), moving our bodies more, and of course huddling together.
Cooling is a bit easier at our place, as there is a lot of tiled surface. We use the thick blinds and airflow judiciously at different times to regulate the temperature on hot days, and have a small fan the size of your hand for personal use if we happen to get successive hot days.
There are other things that play their part, like washing clothes in cold water and washing them less (though still enough). Another tip is to fill a thermos each time the kettle is used. These are strategies that require no more than an initial change of habit.
All this has certainly lightened the load on the family budget, and therefore the time we need to spend working for money (with its additional energy use). In an era where we need to reduce our energy use substantially in industrialised societies, it’s empowering to know that a better and more sustainable life isn’t so much found in new technology, as in our own hands. That’s something our young son may come to be very thankful for.