Building for low emissions

This Issue This is a part of the Climate change feature

By - , Build 156

Despite best intentions, New Zealand’s greenhouse gas emissions are projected to increase dramatically over the next two decades. Can the building industry do better?

The sustainable Christchurch civic building.
The sustainable Christchurch civic building.

AS NEW ZEALANDERS , we pride ourselves on our clean, green lifestyles, yet on a per capita basis, our greenhouse gas emissions are well above the global average. In 2014, as a country, we released more than 80 m/t of carbon-dioxide-equivalent greenhouse gases into the atmosphere.

Building emissions are significant

Building and building use-related activity contributed a significant proportion of this figure. The role of commercial and residential buildings in greenhouse gas emissions is mainly as a consumer of fossil fuels. This leads to both direct emissions, such as burning of natural gas, and indirect emissions, such as electricity generation from natural gas.

In 2010, buildings accounted for:

  • 32% of total final energy use
  • 20% of energy-related greenhouse gas emissions – mostly fossil fuels consumed for heating, cooling and electricity
  • approximately 33% of black carbon emissions due to inefficient combustion
  • a small amount of man-made fluorinated gases, such as hydrofluorocarbons.

New Zealand’s targets

The Paris Climate Agreement, adopted by 195 countries including New Zealand in 2015, has the goal that the world will limit the increase in global temperature to below 2°C above preindustrial levels. It will also actively attempt to limit the increase to below 1.5°C. In line with the agreement, New Zealand aims to reduce emissions to 30% below 2005 levels by 2030.

Scientists and economists believe it is a reasonable target, one the country can affordably achieve without relying on reductions overseas and buying our way out with carbon credits. But it’s not something that can be put off until tomorrow – reducing emissions requires immediate action. The good news is that, like every part of the economy, the building industry has many opportunities to limit climate change by reducing greenhouse gas emissions.

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Report identifies mitigation options

A new report, Transition to a low-carbon economy for New Zealand, released in April 2016 by the Royal Society’s Climate Change Mitigation Panel, attempts to assess our emission mitigation and sequestration options. It offers clear direction to reduce the impacts of climate change and is intended as an easy-to-read guide to help New Zealand individuals, businesses and organisations understand how they can contribute.

The report identifies several reduction opportunities for the building sector, but they mainly focus on the three areas of:

  • improving energy performance
  • greater energy efficiency
  • adopting renewable energy systems.

Improving energy performance

New residential and commercial buildings are already subject to thermal performance requirements in clause H1 Energy efficiency of the New Zealand Building Code. However, the report says the requirements are weak and provide no more than a minimum baseline. New building developers and owners are encouraged to strive for improved thermal and energy performance through, for example, higher R-value glazing and insulation. The report recommends making the current minimum energy efficiency requirements of the Building Code more stringent.

The longevity of the building stock means that many of the buildings that will exist in New Zealand in 2050 have already been built. Therefore, improving the energy performance of the existing building stock by retrofitting is an important action.

Increasing energy efficiency

Because buildings are one of the largest users of energy, increasing energy efficiency when they are designed and built yields a greater emissions reduction over the life of the building. The report also suggests the use of timber construction materials to store carbon over the medium to long term.

For new builds, the report recommends rating tools, such as Green Star and NABERSNZ, to drive greater greenhouse gas emission reductions. However, because these tools are only available for a limited range of building types, the ability to improve the energy efficiency performance of many buildings is partly constrained by their original design.

For the appliances themselves, in the same way that minimum energy performance standards helped remove energy inefficient appliances from the market, the report suggests greater use of consumer labels, such as EnergyStar. These can be used to encourage manufacturers to design, import and supply more efficient appliances for residential use.

Using renewable energy systems

To reduce the direct and indirect reliance that buildings have on fossil fuels, it is proposed that renewable heat and electricity systems integrated into the building fabric could provide energy services instead. New buildings could be designed to have a low energy demand, meaning the total energy requirement for heating, cooling and appliances could be met autonomously.

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Education and training also needed

The report also notes that technology, by itself, is not a solution. It says that education and training for those designing, manufacturing, installing and using buildings are also key to reducing greenhouse gas emissions. However, there is limited up-to-date knowledge about how energy is used in buildings, and this needs to be addressed for the building sector to play a greater role in climate change mitigation.

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Gauging local action

Many local authorities, including Auckland, Wellington, Christchurch and several smaller regions, have plans in place to deal with climate change. Many of these loosely align with the recommendations in Transition to a low-carbon economy for New Zealand.

Auckland

Low Carbon Auckland, for example, is Auckland Council’s 30-year strategy to reduce the region’s greenhouse gas emissions by 40% by the year 2040. The strategy indicates that approximately 51% of these emissions savings will come from transforming Auckland’s built environment. It’s an ambitious goal, but in the last year, the council made noteworthy progress, including:

  • insulating almost 75,000 homes with the Warm Up New Zealand and Retrofit Your Home programmes
  • implementing the NABERSNZ energy performance rating scheme
  • trialling a building warrant of fitness scheme for rental properties.

According to the Carbon Disclosure Project, Auckland’s emissions rose 0.9% between 2009 and 2013, while its population grew by 5%. Per capita, this represents a reduction in greenhouse gas emissions of 0.3 t/person. It’s a small reduction, but a reduction none the less.

Wellington

Further south, Wellington City Council’s Climate Change Action Plan aims for similar levels of greenhouse gas emissions, with a reduction of 30% by 2020 and 80% by 2050. To help achieve this, the council is focusing on three key areas in the building space:

  • Emissions from energy used in residential buildings.
  • Emissions from energy used in commercial and industrial buildings.
  • Local large-scale and small-scale energy generation.

One initiative, the Smart Buildings Challenge, aims to lower energy consumption in commercial buildings and increase sustainability performance with year-on-year performance improvements. Although voluntary, building owners and managers who join the initiative commit to achieving after 1 year:

  • a minimum 10% reduction in energy use (electricity and gas)
  • NABERSNZ certification.

Christchurch

A larger proportion of Christchurch’s greenhouse gas emissions come from agricultural sources, so Christchurch City Council’s Climate Smart Strategy 2010–2025 sets its sights slightly lower than Auckland and Wellington. It has a 20% reduction target by 2020 and a 50% reduction by 2050. Nevertheless, energy use in homes and buildings and transport fuels make up 85% of Christchurch’s total emissions.

The rebuild presents an opportunity for Christchurch to reinvent itself as a more sustainable city, including reduced emissions. It’s a vision reflected in the strategy, which aims to:

  • improve public health, wellbeing and cost savings through better building location, design, operation and greater consideration of future needs and natural hazards
  • reduce energy, water, waste and carbon footprints through more efficient and better building design, performance and material choices
  • improve access to up-to-date and independent advice about building design, construction and renovation.

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Action needed now

Whether these measures are enough to combat climate change remains to be seen, but the Royal Society makes one thing abundantly clear – inaction is not an option. Climate change is happening, and we must act now if we want to protect our environment, economy and way of life.

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For more

The Royal Society’s report is available for download from www.royalsociety.org.nz/expert-advice/.

Download the PDF

More articles about these topics

Articles are correct at the time of publication but may have since become outdated.

The sustainable Christchurch civic building.
The sustainable Christchurch civic building.

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