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Dunedin energy study shows worrying trends

Monday 9 November 2020 4:37pm

More diesel use; less renewable energy; less energy efficiency; more carbon emissions – a new report from the University of Otago’s Centre for Sustainability identifies many worrying energy use trends in Dunedin.

The Dunedin City Council-funded Dunedin Energy Study report analysed the city’s energy consumption in the year to 30 June 2019.

Janet Stephenson 2020 image
Associate Professor Janet Stephenson.

Centre Director Associate Professor Janet Stephenson says that despite some bright spots, such as more solar generation and electric vehicle registrations, the latest research identified some worrying energy use trends.

“The city’s energy use is tracking mostly in the wrong direction – diesel consumption and carbon emissions are up, while renewable energy use and energy efficiency is down,” she says.

Report co-author and Otago PhD candidate Felix Cook says data on all the electricity and fuel use – including coal, wood, LPG, diesel and petrol – showed Dunedin used 13.7 Petajoules of energy for 2018/19, up 2.3 per cent on the previous year.

Cook says that in comparison to 2015/16, when the annual study began, energy use has become less efficient: energy consumption per capita has increased an average of 3.25 per cent per year, and energy consumption per unit of GDP has increased nearly 2 per cent per year.

Over this period, the proportion of use of non-renewable fuels in Dunedin’s energy supply has increased from 63 per cent to 67 per cent. Diesel use is the biggest factor behind this, increasing 12 per cent between 2017/18 and 2018/19 alone. LPG use has also doubled since 2015/16.

Felix Cook 2020 image
Mr Felix Cook.

“It is hardly surprising that energy-related carbon emissions have increased at an average rate of nearly 4 per cent per year,” Cook says.

Trends identified over successive studies show the city is mostly “heading in the opposite direction to the City Council’s goals”, says Stephenson.
Dunedin Mayor Aaron Hawkins believes the results highlight the need for urgent, community-wide action to reduce the city’s carbon footprint.

“The Energy Study again highlights the scale of the mountain we face to achieve the city’s goal of being net zero carbon by 2030.

“Our upcoming 10-year plan is an opportunity to carefully consider which initiatives we might need to progress or speed up to have a significant impact on reducing emissions.
Clearly, reducing transport emissions needs to be a key point of focus, but there’s also a role for the DCC to better understand the specific drivers of these increased transport emissions.

“It is also clear that the Council won’t be able to achieve the net carbon zero goal on its own. It is critical that the city’s major employers, institutions and stakeholders work together on this most urgent issue,” Mayor Hawkins says.

Mayor Aaron Hawkins 2020 image
Mayor Aaron Hawkins.

The report does contain some bright spots. Stephenson highlights an upward trend for solar generation, with photovoltaic units increasing by 17 per cent (to 384 installations) over 2018/19. Electric vehicle registrations have also steadily increased every year since 2015, to a total of 799 by the end of the 2019 calendar year. While locally sourced biomass (mainly firewood and woodchips) are also consistently used to produce energy.

Encouragingly, coal use has been trending down since the first Energy Study, and decreased by 21 per cent on the previous year. This large drop may be due to the closure of the Cadbury factory and the conversion of one of the four coal fired boilers at the Dunedin Energy Centre to biomass.

The researchers make several suggestions for addressing these trends.

“Knowing where we’re off track is the first step, as is being aware that every energy-related decision we make – as families, businesses or organisations – is either going to reinforce those depressing trends or help to turn them around.”

“Transport is clearly a big issue, so we need to continue to improve public and active transport infrastructure and its use by the public and businesses. If new vehicles are essential, put electric bikes or electric vehicles at the top of the list, not a SUV,” Stephenson says.

Supporting households to improve insulation and adopt clean heating, which would have health benefits and reduce emissions, and shifting businesses and institutions away from coal and diesel use, would both be positive steps, as would making better use of Dunedin’s forest resources for biomass.

“Ultimately, it’s about keeping our eyes on the goal of a low-carbon future, and making every decision count. If we are to play our part in avoiding dangerous climate change, we don’t have long. We have less than 10 years to make a serious dent in our energy-related carbon emissions,” Stephenson says.

Dunedin Energy Chart image (2)
Energy consumption profile for Dunedin City for the 2019 financial year.

For more information on the Dunedin Energy Study 2018/17

For more information, contact:

Associate Professor Janet Stephenson
Centre for Sustainability
University of Otago
Email janet.stephenson@otago.ac.nz

Sam Stevens
Communications Adviser
Division of Humanities
University of Otago
Tel +64 3 479 8143
Mob +64 21 279 8143
Email sam.stevens@otago.ac.nz