August consumption and hot weather

The article entitled, ‘Hydro bills feeling the heat’ (Toronto Sun, 6 September 2011), inspired me to look at my own consumption through August.  Courtesy of my local utility’s webportal (Waterloo North Hydro), I was able to download what I concluded were ‘hourly-DST’ data.  Here, I give some results, and make some comparisons.

Below, in the table, are some core results.

time period	consumption (kWh)	percentage of total consumption	commodity cost ($)	percentage of total commodity cost
on-peak	210.03	18.5	22.47	27.1
mid-peak	199.47	17.6	17.75	21.4
off-peak	723.74	63.9	42.70	51.5
total	1,133.24	100	82.92	100

So, though we were often ‘at home’ during this period, our use ended up being very close to the standard 18/18/64 division that the Ontario Energy Board cites as ‘usual’ with regard to distribution of electricity across the three time periods.

Indeed, when I compare our ‘commodity costs’ to what they would have been if we were not on time-of-use rates (but were on the traditional, ‘two-tier system’), I find it striking – and I report it in the table below – that the difference is one cent.

consumption bracket	consumption (kWh)	commodity cost ($)
below threshold (6.8 cents per kWh)	600	40.80
above threshold (7.9 cents per kWh)	533.24	42.13
total	1,133.24	82.93

Our consumption was high in August – indeed, a little bit higher than usual.  (For some historical data, see an earlier blog posting.)

In any case, I was interested to see how consumption correlated with temperature.  To explore this, I retrieved temperature data from the University of Waterloo weather station, and compared them with my hourly consumption data in three ways:  plotting daily average temperature versus daily consumption; plotting daily maximum temperature versus daily consumption; and plotting hourly temperature versus hourly consumption.  Results are below.

Average daily temperature versus daily electricity consumption,

single home in Waterloo, ON,

August 2011

Maximum daily temp. versus daily electricity consumption,

single home in Waterloo, ON,

August 2011

Hourly temperature versus hourly electricity consumption,

single home in Waterloo, ON,

August 2011

Though the visual suggests that the relationship is not completely ‘direct’ (that is, higher temperature, higher consumption), but the trend is there.  Indeed, in these three graphs, there are positive correlations, with values of 0.277, 0.120 and 0.378, respectively.  Hot weather, not surprisingly, leads to greater consumption.