Offpeak electricity could save 20%
IF the use of heat pumps, electric hotwater cylinders and fridges was spread more evenly through the day, New Zealand’s total electricity demand could be reduced up to 20% during winter, a University of Otago study has found.
Department of physics academic Michael Jack coauthored a report with Otago Centre for Sustainability director Janet Stephenson, and University of Southampton academic Ben Anderson, a visiting Marie Curie Research Fellow at Otago, and the report’s findings were released yesterday.
Hotwater cylinders, heat pumps, and refrigerators constituted 50% of the total residential electricity consumption in New Zealand, the study revealed.
In a statement, the researchers said they focused on the three appliances because they used a lot of energy and their energy demand could in principle be shifted out of peak demand periods, 6am to 10am and 5pm to 9pm.
At these times generation, transmission and distribution infrastructure ran close to or even at full capacity, especially in winter.
New Zealand faced a projected 150%to200 % increase in electricity demand, so the challenge of implementing a 100% renewable electricity system was a significant one, Dr Jack said — particularly in dry years when hydro power would not be enough.
‘‘If we can reduce peak consumption by shifting use out of peaks we will be taking a big step towards achieving our future targets without burdening households and the country with extra costs, and without increasing carbon emissions,’’ Dr Jack said.
Dr Anderson said if the shift was wellmanaged, the energy services provided by the appliances would remain the same.
‘‘Water will stay hot in the cylinder for people’s morning showers, living spaces could be prewarmed before 6am via smart thermostats, and fridges could remain cold despite being switched off for a short time during peak.
‘‘The combined result of these interventions across millions of New Zealand households could be substantial,’’ Dr Anderson said.
The report, ‘‘Estimating the Technical Potential of Residential Demand Response in New Zealand: A Summary of Results’’, has been prepared by the Green Grid Project, funded by the Ministry of Business, Innovation and Employment.