Reduced energy consumption hasn’t helped too much!
Given that reducing household electricity consumption from our supplier wasn’t helping to reduce our costs, because the suppliers were simply increasing costs to more than balance our reduced consumption.
Next move was to look for an alternative electricity supplier.
Comparison between grid suppliers soon indicated that they were all much the same – even the same marketing tactics that involve initial ‘discounts’ that mask the true ongoing cost – ‘discounts’ that silently evaporate after a couple of billing cycles.
Installing solar panels
As a result of this review we decided to become our own electricity supplier by covering our roof in PV panels.
In the summer of 2015 we installed a 4.2 kwh solar PV system, which was the maximum we could accommodate on our available roof space. Half our panels face east, the remainder of our panels face west. The panels produce over 20 kwh per day in summer.
In addition to installing panels on our roof, we moved to a new grid supplier (Powershop).
In the 2016 Spring billing period (Sept – Nov) our household:
- consumed, from the grid: 1729 kwh of electricity – DOWN from 4439 kwh in 2009.
- consumed electricity, from the grid, at the rate of: 19 kwh per day – DOWN from 48 kwh per day from the grid in 2009;
- paid for the supply of grid electricity: $380.00 – DOWN from $791.00 in 2009;
- paid for the supply of grid electricity: 22c per kwh – UP from 12c per kwh in 2007;
- paid on average: $4.50 per day for electricity – DOWN from $8.60 per day in 2009.
(This figure includes ‘feed in’ credit of around $0.36 per day for electricity produced by our PV panels that is excess to our needs.)
The per unit cost of our grid-supplied energy is still increasing, but our reduction in grid usage has now outpaced those increasing costs.
The dollars – is it worth it?
Our roof panels cost $6000 to supply and install (including a government subsidy). If we were paying 22c per kwh for electricity at our 2009 rate of grid consumption (48 kwh per day), we would be paying $3854.00 pa for electricity. Our PV panels produce the majority of our daytime power. For the remainder we are currently paying $1526.00 pa for grid electricity, saving $2328.00 pa. At this rate the PV panels will have paid for themselves in under 3 years.
The next step
Of course, this isn’t the end of our quest to totally disengage from energy supply companies.
Graphs from our recently-installed smart meter indicate that the majority of our electricity consumption occurs, unsurprisingly, when our side of the planet is facing away from the sun.
We are keenly watching the declining costs of storage batteries. A Tesla Powerwall battery, which is able to store 14 kwh power costs $8000 plus installation. To completely cover our current consumption we will need two Powerwall batteries – costing around $18,000 installed.
We are busy saving our dollars. I expect that it may be about two years before our savings timeline intersects with reducing battery costs. Once the cost of two installed batteries is down under $10,000, we will be calling Tesla. (Assuming that we have enough excess solar power to charge the batteries.)
As more and more of us say farewell to the grid, or reduce our dependence on it, electricity suppliers will have to increase their per-unit costs to those who remain connected, to protect their income stream. In our own household example above, the unit cost of grid-supplied electricity increased from $0.12 per kwh in 2007 to $0.22 per kwh in 2016. An 84% increase in per unit cost in just 9 years.
In another 5 years it will be a lonely argument for our elected representatives, as they try to muster support for the continued use of fossil fuels by those last few poor souls who cannot afford to leave the grid.
Here are some graphs summarising our electricity usage pre-solar (before Spring 2016) and post-solar (from Spring 2016)…