Net zero by the numbers – understanding emissions

Getting to grips with the numbers to get the most from technology

Recent research has shown that utilities have ambitious plans to decarbonize, with 75% of utilities intending to achieve greenhouse gas (GHG) reduction goals by 2040. But taking practical steps to reach these targets demands an in-depth understanding of the numbers. Alexis de Kerchove, Senior Director of Client Sustainability at Xylem, discusses the figures behind each emissions scope and how utilities can begin to measure these.

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Reducing greenhouse gas emissions presents a rare opportunity to rethink what is possible through technology and data-driven decision-making. As outlined in Xylem’s paper Net Zero – The Race We All Win, fresh approaches and affordable technologies can kick-start network optimization, enabling utilities to decarbonize and serve their communities more effectively.

An in-depth understanding of emissions is essential to cut emissions to as close to zero as possible. But mapping a carbon footprint is a significant task.

Recent research by Parravicini et al. showed that wastewater management by European utilities was leading to emissions of up to 35 million tons of CO2e/year (CO2e accounts for carbon dioxide and other gases such as methane (CH4) and nitrous oxide (N2O)). Around 14 million tons of this CO2e are due to the embedded carbon in infrastructure.

The numbers by scope

Understanding where and how a utility can cut emissions should start with a review of different emissions scopes across their business.

Scope 1 (direct emissions) and Scope 2 (indirect emissions) are the operational emissions that utilities can directly control. Scope 3 (external emissions) arise from a utility’s activities across its value chain, such as emissions generated by suppliers and customers.

Around 25% of water utility emissions will fall in Scope 1, 25% in Scope 2, and 50% in Scope 3, according to Parravicini et al. and Xylem estimates*. These estimates are indicative, rather than something that can be used as a scientific reference. The breakdown by scope can vary significantly depending on a utility’s processes, size, and geography.

Scope 1 (direct) are direct greenhouse emissions (GHG) from sources controlled or owned by an organization. For example, fuel combustion from diesel backup generators. According to Xylem estimates, Scope 1 emissions account for 25% of water utility emissions.

The majority of these come from fugitive – or unintentional - process emissions from biological treatment processes for wastewater and sludge, particularly N2O and CH4. Utilities can mitigate these through real-time optimization of biological processes and the detection of gas leaks. Fugitive emissions of methane and carbon dioxide can also occur during drinking water treatment from the pH adjustment of groundwater.

Scope 2 (indirect) accounts for GHG emissions associated with the purchase of electricity, steam, heat, or cooling. While these emissions happen elsewhere, they are included in an organization’s GHG inventory because they are a result of the organization’s energy use. For utilities, this accounts for around 25% of emissions. At utilities that only treat and distribute drinking water, Scope 2 emissions are usually the most significant source of emissions.

Purchasing renewable energy is a common approach to addressing Scope 2 emissions. However, according to the IEA, 80% of global electricity generation still depends on fossil fuel and nuclear power sources. Simply put, there is not enough renewable energy for all industries to eliminate their Scope 2 emissions.

Reducing energy use is a more sustainable approach. This can be achieved by targeted upgrades of assets and process controls. Investment in onsite energy generation with hydropower, biogas production, and heat recovery can also mitigate fossil fuel dependency.

The most complex to measure and mitigate, Scope 3 (external) emissions come from activities not in a utility’s direct control but triggered by its suppliers and customers. It is estimated that half of utility emissions fall within Scope 3. These emissions come from three main sources: embedded carbon in civil infrastructure built by a utility, manufacturing of chemicals purchased by a utility, and third-party management and disposal of sludge from a utility.

The availability and accuracy of data from a utility’s value chain is critical to measure these emissions. Utilities can mitigate these emissions and optimize operations by improving asset management and operations, and by prioritizing suppliers with a strong sustainability record.

Getting to grips with the numbers

To begin to tackle emissions, utilities can break down the approach into three stages: plan, develop, and manage.

At the planning stage, utilities focus on assigning the right resources, teams, and budgets to understand how emissions are recorded and categorized, and how to get to grips with them. Many have signed up to guiding principles such as Science Based Targets.

Collecting data on emissions is fundamental as utilities define their emissions baseline – also known as a carbon inventory.

This involves careful examination of core data sources, starting with electricity, natural gas, and fuel purchase invoices, and moving on to energy generation and process emissions data. A robust profile can be rounded out by sourcing information from suppliers and customers, which are becoming increasingly used to emission information requests as standard.

Water utilities have a unique challenge to calculate accurate measurements for process emissions – particularly methane and nitrous oxide. They may have to use approximate figures to calculate some of the emissions from the biology of wastewater treatment. This will likely be a temporary step as measurement devices for nitrous oxide and methane improve.

What gets measured gets managed. Accurate information from internal and external sources is vital as utilities set a reduction target and begin to plan the practicalities of cutting emissions. This information can help with more than lower emissions, it can enable utilities to cut energy use and reduce water losses – dramatically lowering costs.

Getting to grips with the numbers and defining strong targets is not easy. We have heard from utilities that have found sourcing accurate data and maintaining data integrity to be challenging. However, the right expertise and digital platforms can support utilities in categorizing and tracking emissions.

From measurement to momentum

The technology exists today to transform water management and rapidly decarbonize the water sector.

Breaking down the numbers can equip utilities with the information needed to deploy technology and resources where they will have the most impact.

Take Muncie Wastewater Treatment Plant, Indiana, US, as an example. By upgrading to a digitally enabled system, the utility significantly reduced its Scope 2 emissions by reducing the energy used in aeration. The utility became both greener and more cost-efficient, spending thousands less on energy each month.

Utilities need to invest in new infrastructure to build capabilities and resilience to a changing environment. These capital investments inevitably involve carbon emissions, putting the onus on utilities to consider all available technologies and find the solution that leads to the lowest capital and operational emissions. A mindset shift to look first at local rehabilitation and optimization before building anything new will help reduce the sector’s emissions.

Running the race together

Utilities are not racing to net zero alone. This is a three-legged effort with suppliers, technology providers, and utilities partnering to make progress.

We are all connected in this quest. A water utility’s Scope 2 emissions (owned emissions) are essentially a technology provider’s Scope 3 emissions (emissions an organization indirectly affects) from the energy utilized to run equipment. An equipment provider’s Scope 1 and 2 emissions are related to a utility’s Scope 3 emissions.

Focusing on customers as fundamental partners in solving water challenges is central to Xylem’s sustainability strategy. By working together to deploy innovative technologies, utilities can significantly reduce their environmental impact, as well as mitigate water scarcity, reduce water loss, and optimize systems to improve affordability.

It all begins with understanding the numbers as a first step toward GHG reduction and building a more resilient and sustainable world.

*Estimates are indicative and should not be used for scientific reference. The breakdown of scopes can vary significantly depending on a utility’s processes, size, and geography.