Waste to Energy or Waste of Energy?
The proposed Waimate rubbish incinerator’s $350 million price tag is said to produce 20- 30MW of electricity.
By 2020, New Zealand had a electricity generating capacity of 9758MW. In this context, the Waimate incinerator’s anticipated addition of 20-30MW of electricity would constitute a mere 0.3% of this figure.
Municipal solid waste incineration produces between 700g – 1.2kg of CO2 emissions per 1kg of waste.
The Waimate plant will incinerate 365,000 tonnes annually, releasing up to 438,000 kg of CO2 annually.
WIND ENERGY versus WASTE TO ENERGY
The Waipipi wind farm in South Taranaki, with a similar investment of $325 million, boasts an electricity capacity of 133 MW, a significant 5–7 times the energy output of the proposed Waimate incinerator. This stark contrast in efficiency should raise concerns about the viability of the Waimate proposal.
For the Waimate incinerator to match the electricity output of the Waipipi wind farm, it would need to incinerate approximately 1.8–2.5 million tonnes of waste, resulting in up to 3 million tonnes of equivalent CO2 emissions. This starkly contrasts with the zero CO2 output of the wind farm, highlighting the significant disparity in energy generation potential.
SOLAR ENERGY versus WASTE TO ENERGY
Lodestone Energy has invested $300 million to build five solar farms across the North Island of New Zealand. The first is the Kaitaia Lodestone Two solar farm, which will have an electricity capacity of 39 MW. The total $300 million investment spread across the five farms will have an annual output of 320 GWH and make up almost 1% of New Zealand’s electricity generation.
In contrast, the Waimate incinerator’s $350 million investment will produce around 0.3% of New Zealand’s overall generation.
Compared with the Waimate plant’s footprint of 15 hectares, the Kaitaia solar farm’s footprint is 20.5 hectares but is also used for sheep farming. Once built, the five solar farms will produce zero emissions.
Waste to Energy versus Coal and Gas fired electricity
The UK Environment Agency asked companies to start including CO2 information based on continuous monitoring in their annual performance reports. OpenDemocracy and the UK Without Incineration Network (UKWIN) have analyzed this data and found that the average UK incinerator produces more than twice as much CO2 per unit of electricity as gas-fired power plants, and some have a higher carbon intensity than coal plants.
The proposed Waimate plant’s annual incineration of 365,000 tonnes of waste will result in a substantial environmental cost. This process is estimated to produce a staggering 438,000 kg of CO2 annually, equivalent to an extra 100,000 cars on the road.
23% versus 100% renewables
SIRRL claims energy generated by its proposed incinerator as renewable energy. However, most of the electricity generated by the incinerator will come from burning non-renewable materials, including fossil fuel-derived plastics. If recyclables and compostable green waste were removed from the content SIRRL intends to burn, the percentage of renewable material left would be around 23%. This figure, already low, is set to drop even further with future innovations in sorting and recycling practices.
When we compare the incinerator’s 23% renewable material with wind, solar, and hydro energy, which are 100% renewable, the disparity is stark.
Given that New Zealand’s overall electricity generation is currently around 87% renewable, with aspirations for 100%, a shift towards waste-to-energy incineration could be a step in the wrong direction. It could not only threaten these aspirations but also put our future export markets at risk, given the global trend towards products made from sustainable and renewable sources.
Incineration returns only a fraction of energy
Plastics are derived from fossil fuel-based chemicals like natural gas or petroleum, which require energy for production.
The energy input during primary plastic production can be recovered from waste plastic via recycling. Recycling of waste plastics allows the reuse of this energy and reduces the consumption of virgin raw materials.
Studies have shown that the energy input of producing virgin polyethylene and polypropylene polymers and processing them into plastic packaging reaches 109.2–115.2 MJ/kg.
Also, factor in the energy required to transport these products to the market and the consumer.
Incinerating these plastics to produce electricity releases up to 46 MJ/kg. That’s less than half the energy input required to produce them in the first place. Then, subtract any energy needed to transport waste to the site and dispose of residue ash and any energy and resources required in the incineration process, including pollution control mitigation.
As you can see, incineration returns only a fraction of the energy input used to produce these plastics and also creates further problems by releasing harmful toxins and by-products.