WATER NEW ZEALAND UPFRONT
Opportunities and risks at the heart of the water-carbon nexus By Lesley Smith, Water New Zealand principal data scientist Water New Zealand has warned of the risk of overlooking the important role of water in the country’s efforts to reduce carbon emissions. In the words of the Australian Prime Minister’s science advisors, “Energy, water and carbon form the cradle of life itself, and sustain us at every level from the cells of our bodies to ecosystems and economies. Together, energy, water and carbon provide the foundation for the evolutionary emergence of new forms from old ones, not only in living organisms but also in human societies and cultures.” In a submission to He Pou a Rangi, the New Zealand Climate Commission, Water New Zealand pointed out the many opportunities for the water sector to assist in national efforts to decarbonise. These include the bioenergy potential of our wastewater (see the March/April 2021 edition of Water for a comprehensive overview), the energy efficiency opportunities that exist within our assets, and the carbon savings that could be realised through seizing the many opportunities that exist to reduce water use. The submission on the commission’s first draft package of advice to the government on how to reach net-zero carbon by 2050, feeds into the final report to be presented to the government at the end of May. The submission points out the perils of neglecting the relationships between water and carbon. As we develop our water supplies to respond to the dual pressures of population growth and climate change, there is a significant risk of locking in high carbon pathways. Desalinated water supplies, as well as recycled wastewater, have significantly higher energy intensity than our traditional supply sources.
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Conversely, the availability of water is a neccesary prerequistisite for a number of energy generation options. Furthermore, the development of water infrastructure itself is carbon intensive. A recent assessment by Watercare found that the embodied carbon in their capital works programme, exceeded their operational emissions. Unlocking water sensitive design opportunities have the potential to mitigate against high carbon pathways, as well as facilitating greener, more climate friendly cities in the future. These are important issues that require attention to realise the vision of a thriving, climate-resilient and low-emissions future. In 2018, gross greenhouse gas emissions in New Zealand were about 45.5 Mt CO2-e of long-lived gases, and 1.34 Mt CH4 (biogenic methane). He Pou a Rangi’s analysis shows if policy stayed as it is now, we would fall short of achieving the 2050 net zero long-lived gas target by 6.3 Mt CO2-e. Biogenic methane would reduce 12 percent below 2017 levels and fall short of the current target of 24-47 percent. Their advice provides detailed analysis and emissions budgets that outline various changes that could enable us to reach the targets. The draft consultation piece is still available online. To read it, go to bit.ly/3tLQ3sI. Water New Zealand’s submission is available at www.waternnz.org.nz. Those interested in the role the water sector has to play in this transition can join the Water New Zealand Climate Special Interest Group for its inagraual carbon symposium. This hybrid in-person, online event will be happening in regional centres throughout the country on June 23. Visit the Water New Zealand website for more details and to register.
