In recent years, the urgent need to address climate change and protect our planet’s natural resources has become increasingly apparent. Our water environment faces multiple challenges including deterioration from pollution, intensifying flood events, prolonged periods of drought, in addition to the pressures of a growing population placing increased demands on ageing infrastructure.
As their operational impacts extend from ‘source-to-sea’ effectively, water utilities play a crucial role in addressing these interconnected challenges given their capacity to influence emissions reductions across the managed water cycle. Achieving net zero across the water cycle will require the challenge to be viewed through a holistic, catchment-wide lens to adopt a “systems-thinking” approach to solution development.
To achieve net zero (most UK and Ireland utilities have set targets between 2030 to 2040), reducing emissions alone will not be enough and utilities must adopt a two-pronged approach: reducing carbon emissions (sources) and embracing nature-based solutions (sinks). A balance must be achieved between these strategies, which offers broader benefits for the environment and delivers the systemic change needed across the water industry.
Reducing carbon emissions in water services
Water utilities are significant contributors to carbon emissions due to the energy-intensive nature of water and wastewater treatment with a particular operational ‘hotspot’ associated with emissions related to electricity use (water services consumed 19 per cent of public sector electricity consumption in 2020)1. Utilities proactively reduce their energy-related emissions, by improving energy efficiency, optimising operational processes, and using renewable energy sources. A further source of operational emissions which represent a priority for water utilities are the greenhouse gases methane and nitrous oxide, which are produced as a result of the treatment of wastewater and sludge. While these are more challenging to quantify, efforts are underway across the industry to baseline emissions from all key sources (including process and energy sources), thereby determining the utilities carbon footprint, a position from which effective reduction trajectories can be planned.
Beyond their operational emissions, utilities are beginning to focus on the whole-life-cycle carbon of all infrastructure projects and programmes of work, considering the embodied carbon of assets in addition to the operational emissions. Effective reductions will require emissions from all sources across the entire life cycles of projects to be considered, including the embodied carbon (which is mainly emitted during the production/construction of buildings/infrastructure). Quantifying embodied carbon during the early work stages of projects, and applying a carbon reduction hierarchical approach2, helps water utility decision-makers to prioritise solutions which can avoid carbon emissions in the first place, switch to low carbon alternatives where feasible or, adopt solutions that improve the use of resources by embracing circular economy principles. By abandoning the unsustainable linear model, water utilities can potentially reduce whole-life-cycle carbon, e.g., by reusing treated water or recovering energy (operational phase) and, in the construction phase, by reducing the consumption of raw materials or by reusing excavated material as fill.
Nature-based solutions delivered by water utilities
Reducing the release of emissions, however, represents only one side of the net zero equation. Residual emissions, those that cannot be avoided, will remain. Nature-based solutions offer a complementary approach to emissions reduction, by leveraging the sequestering power of nature. By adopting the right measures in the right place, utilities can implement nature-based solutions, providing assets with less embodied carbon (by avoiding/reducing use of concrete and steel), less operational emissions (natural systems require less energy and emit less greenhouse gases), and with the potential to sequester carbon using natural vegetation to perform treatment functions.
Green (nature-based) infrastructure incorporates natural elements into the urban water cycle, which can help to manage stormwater runoff. By implementing solutions such as bio-swales and permeable pavements, stormwater flows can be retained, alleviating the inundation of existing conveyance systems, and potentially reducing the need to provide additional infrastructure and the associated carbon.
Nature-based alternatives to traditional treatment infrastructure e.g., integrated constructed wetlands and sludge-drying reedbeds, still require “construction”, but provide co-benefits using natural materials and the enhancement of biodiversity through the creation of artificial habitats which sequester carbon. While the provision of green alternatives to traditional solutions is a step in the right direction, nature-based solutions must be delivered rapidly and at scale to address multiple challenges effectively.
Co-benefits of catchment level nature-based solutions
Starting at source, healthy catchments will play a critical role in creating future resilience, adding socio-economic value, connecting the landscape, and supporting sustainable development. At Jacobs we recognise the central role collaborative stakeholder engagements play in the delivery of game-changing solutions for emissions reductions, water catchment approaches and nature-based solutions at scale. In association with a large collaboration of partner organisations, funding has recently been secured to support a national five-year programme of work aimed at mainstreaming water catchment and nature-based solutions in the UK3.
Down at catchment level, while degraded wetland habitats are documented to emit greenhouse gases4, carbon can be sequestered through wetland restoration initiatives which also provide natural storage reservoirs for storm water, whilst preserving biodiversity and increasing adaptive resilience. Holistically, protection and restoration of these habitats can provide co-benefits to water utilities by improving source water quality, resulting in less chemicals and energy use for subsequent treatment, regulating flows within catchments, alleviating pressure on already-constrained downstream infrastructure, and potentially avoiding future asset generation and energy demand.
Working together to balance the net zero equation
For water utilities striving to achieve net zero, the finite amount of land owned by the utility to deliver appropriate sinks represents a key challenge – notwithstanding the challenges faced to achieve nature balanced outcomes in urban areas. Demands to offset emissions will require ‘outside-the-fence’ collaborations to deliver decarbonised, nature positive solutions, and the establishment of new and innovative partnerships are central to success. Engagement with local ecosystem stakeholders, including landowners, regulators, policy makers and local communities, will be essential to understanding the competing land-use need and the common environmental objectives required to deliver sustainable solutions.
Appreciating the integrated nature of the need to decarbonise and tackle nature loss, a new level of ambition and opportunity for the water sector is emerging. Water utilities are in a unique position to demonstrate leadership to both encourage and enable collaborations across ecosystems and the supply chain, to scale effective solutions to balance the net zero equation.
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