Commissioner’s Solar Report More than Hot Air

Published: Sat 11 Aug 2012 04:34 PM
11th August 2012
Commissioner’s Solar Report More than Hot Air
The Commissioner for the Environment, Dr Jan Wright’s new controversial report into Solar Water Heating has generated a fair bit of heat since its release.
Dr Wright’s report asserts that Solar Water Heating does little to reduce CO2 emissions at times of peak wintertime electricity , when electricity demand is at its highest, and therefore may not be the environmental panacea that some of it supporters claim.
This core assertion of the report has provoked a number of negative responses – all at a time when local councils such as the Auckland Super City ramping up their support for solar water heating. A number of smaller councils are also looking at promoting Solar Water Heating.
So its not surprising to see opposition to the Commissioners findings and recommendations. Even Meridian Energy, our largest generator of renewable electricity weighed in this week saying that the commissioners report “wrongly concludes that this [the ability of solar water heating to operate at peak load times] is critically important”.
However none of the responses have actually refuted the truth of the report’s core assertion, ie that peak CO2 emissions occur at those wintertime peaks and Solar Water Heating is virtually useless at reducing them. After all, our Maori forebears named our great land “Aotearoa” or “The Land of the Long White Cloud” for good reason.
If Solar Water Heating wont help reduce fossil fuel emissions at peak load times, are there any alternatives that will?
Near the end of the report the reader finds some alternatives. Using night rate tariffs can help. Wetbacks can help where practical.
Using heat pump water heaters to heat water also will help. Section 7.2 of the report says “ In marked contrast with solar water heaters, heat pump water heaters save most electricity when it is most valuable from both an environmental and economic perspective. And since their performance is not dependent on weather, they reliably lower the winter peak.”
There is a range of heat pump water heaters available on the New Zealand Market. These heat pump water heaters produce between two to four times as much heat as electricity consumed. Consumer has estimated that if 1 million households were to retrofit a recommended model of heat pump water heater, it could save 320,000 tonnes of CO2 per year and the electricity use of 225,000 homes. Even more could be saved if heat pump water heaters were used in conjunction with night rate tariffs. If this not-so-bold plan were implemented it would go a long way to making the coal-fired Huntly Power Station obsolete.
Not to mention the tax-free savings at a household level that are currently estimated at $756 per annum for an average family. That’s money that financially strapped families could use right now.
In light of Dr Wright’s findings - that we need to find green ways that reduce peak electricity demand - using heat pump technology to heat hot water makes even greater sense. After all its harnessing an energy source that’s available 24/7 and 365 days of the year.
That’s certainly not a load of hot air.

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