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Insulation can dramatically reduce emissions, but there are emissions costs as well. Wei-Hang Chua

Pink batts: not a scandal, but not as good as claimed

The words “pink batts scheme” are rarely heard without “debacle”. But a recent Insulation Council of Australia report by Energy Efficient Strategies (EES) has described the government’s home insulation program as an environmental success. Unfortunately, the report doesn’t take account of all emissions associated with insulation.

The nationwide insulation scheme was abandoned quickly following the death of four workers, house fires, and many maintenance interventions. But the Insulation Council of Australia suggests that finishing the job and insulating the remaining houses across Australia would yield significant monetary savings. It would also reduce energy consumption and greenhouse gas emissions.

By 2020, the report claims that insulating Australia’s houses would save at least 38 petajoules of energy (equivalent to lighting all Australian households for one and a half years) and avoid 14 Mt of CO2-e greenhouse gas emissions.

However, these estimated energy and greenhouse gas emissions savings do not take into account the full environmental implications associated with installing insulation.

Most energy efficiency studies focus solely on the operational aspect of buildings, such as the energy it takes to heat and cool them. However, various studies have proven that the energy and emissions required to manufacture building products, such as insulation, can be just as significant. When they’re calculated using a comprehensive assessment technique, which includes all of the energy expended across the entire supply chain, the so-called “embodied” energy and emissions of a building can be equivalent to 50 years worth of a building’s operational energy requirement.

The energy and emissions embodied in the manufacture of insulation is completely ignored in the recent report by Energy Efficient Strategies.

To address this omission, we have conducted a life cycle energy and emissions analysis based on the data used by Energy Efficient Strategies. We complemented this with embodied energy and emissions figures for the manufacture of insulation.

As shown in Figure 1, our findings suggest that even by 2020 the net energy savings of all insulation scenarios (excluding duct insulation for lack of data) considered in the original report are still negative. This is because the initial energy required to produce the insulation batts is still greater than the accumulated energy savings for heating and cooling (until up to 2023 for the floor insulation scenario).

Figure 1: Energy savings.

Similarly, in 2020 the net greenhouse gas emissions abatement is totally negligible because the insulation is just starting to pay back its embodied emissions (see Figure 2).

However, once all houses are insulated and embodied energy and emissions have been paid back by operational savings, the insulation saves increasing amounts of energy and prevents the emission of millions of tonnes of greenhouse gases into the future (assuming continued optimal performance of the insulation batts).

Figure 2: Greenhouse gas abatement.

In 2030, the total energy saved is estimated (conservatively) at 314 PJ and the total emissions avoided are 22 Mt of CO2-e.

This shows that in the long term, insulation will not only pay back its embodied energy requirements and emissions but will also result in significant energy savings and greenhouse gas emissions reductions while being cost effective.

We agree with the main findings of the Energy Efficient Strategies report, that insulating buildings can result in a significant reduction in energy demand and emissions. But a more holistic view indicates that the possible savings are likely to be less and take considerably longer to achieve.

In addition, it is also important to consider other aspects in the assessment of the benefits of insulating our buildings, such as the release of pollutants, production of waste and depletion of resources associated with manufacturing insulation products.

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