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Clean Heat impact on household electricity usage 'neutral'

Thursday 3 December 2009, 3:04PM

By Orion New Zealand Limited

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CHRISTCHURCH

Contrary to predictions, Environment Canterbury’s Clean Heat project, which has seen thousands of Christchurch homeowners install electric heat pumps, has not increased overall household electricity consumption in Christchurch.

A joint study by Environment Canterbury, Meridian Energy and electricity network company Orion of 3,500 homes has revealed an overall zero per cent net impact on electricity usage, a year after installation of an approved appliance.

In addition, homes that removed an open fire actually saw a 2% decrease in their electricity usage when they installed a heat pump.

“The results confirm the Clean Heat project has had very limited impact on electricity usage overall, despite around 9,300 homes in total shifting from a wood/coal based form of heating to heat pumps. The results are what we expected given our own observations in the last few years of mild growth in total electricity usage across our network,” says Orion chief executive Roger Sutton.

“It is a fantastic result, particularly given the explosion in heat pump usage in recent years. We believe the low impact of the Clean Heat project is due to the improvement in home insulation and a large number of homes which previously had inefficient open fires or woodburners no longer having to also operate, say, an old electric bar heater to stay warm.”

Prior to the study there were predictions the Clean Heat project would increase overall household electricity usage, which meant Orion would need to spend money increasing capacity in its urban network areas. “We are now saving this cost, which would have fallen on all local electricity consumers, and achieving cleaner air which is a great result for Christchurch,” says Mr Sutton.

The Clean Heat project was initiated in 2003 in an effort to clean up Christchurch’s air. To date it has subsidised the replacement of open fires and polluting wood burners with over 15,500 clean air approved heating appliances, mostly heat pumps. A subsidy is also provided to bring home floor and ceiling insulation up to a certain level. The subsidies are provided with funding from Environment Canterbury and the Energy Efficiency and Conservation Authority (EECA).

While the study shows installing a heat pump typically increases a household’s electricity usage by two percent, this was balanced by homes that reduced electricity consumption by converting to newer, more efficient solid fuel appliances, pellet fires or gas. The net impact was zero percent.

Environment Canterbury’s director of operations, Ken Lawn, says Environment Canterbury was also very interested in the results.

“It is pleasing to see the study demonstrates that the Clean Heat project is not adding significantly to the total use of electricity and that Christchurch people are benefiting from cleaner air and better insulated homes."

In addition to the 15,500 homes that have participated in the Clean Heat project, in recent years many more homes have changed their form of heating to more efficient appliances such as heat pumps. However many of these homes will not have installed insulation, so are likely to have higher electricity usage than homes with insulation.

A copy of the study is available on the Orion website www.oriongroup.co.nz.