Last year I wrote about how the Howard government’s 2004 Solar Cities initiative was, unlike many other Energy White Paper initiatives, actually showing some promising results. Now one of those ‘Solar Cities’ – Central Victoria – has delivered its final evaluation report with some useful insights into how household electricity demand is falling.
The Central Victorian Solar City encompassed a range of regional towns and surrounding farming areas from Swan Hill along the Murray at the north; to Ararat, Ballarat and Bendigo.
One of the main reasons for undertaking the Solar Cities was to test and learn various approaches for reducing energy and greenhouse gas emissions. By themselves the Solar Cities were too small to make any major difference to Australia’s greenhouse gas emissions.
One of the good things about the Central Victorian Solar City was that they put a bit of effort into establishing a control group of households for whom they did not attempt to assist in reducing their energy consumption. This gives a good insight into what was happening with overall electricity demand in the Central Victorian Solar City Region as well as the extent to which the Solar City interventions made any real difference.
The chart below, which is our chart of the week, illustrates that reductions in electricity demand were universal across not just those involved in the Solar City, but also the control group.
Average daily electricity consumption for control and intervention households (kWh)
What’s really interesting is that reductions in the control group were actually very large, average electricity consumption reduced from 16kWh per day to a touch above 13kWh. Across an entire year this works out to a reduction of around 1000kWh, similar to the reductions experienced in Energex’s South-East Queensland region.
This is a very big reduction – equivalent in scale to removing a refrigerator and air conditioner from every home. Some level of care is required however, because this data has not been analysed to adjust for any possible weather effects.
Yet even though the control group had quite significant reductions in consumption, the households targeted by the Solar City achieved a further 13 per cent reduction in consumption compared to similar households within the control group.
The data suggest they were able to pull out electricity consumption equivalent to another refrigerator through a combination of measures including home energy assessments, promoting solar hot water and solar PV, use of in-home displays and housing retrofits.
The chart below illustrates the extent of reductions in electricity consumption by intervention type. The gross effect indicated in yellow is the actual impact on households’ electricity consumption before and after they implemented the intervention. The net effect is an adjustment factor to assess the role of the Solar City in driving these reductions.
This is to account for the fact that many of the those in the control group were also installing solar PV and solar hot water and installing insulation etc. even though they hadn’t been targeted by the Solar City group.
Changes in household electricity consumption by intervention type