Wattnet: matching electricity consumption with low-carbon, low-water footprint energy supply

TL;DR

Wattnet tackles the mismatch between where electricity is produced and where it is consumed by applying a high-resolution flow-tracing framework to Europe. It jointly quantifies CF and WF using operational and life-cycle factors, accounting for cross-border energy transfers and temporal dynamics. The study shows that ignoring electricity flows and timing can misestimate footprints and reveals trade-offs where low-carbon mixes (e.g., reservoir hydropower) may elevate water use. The tool provides consumption-based environmental insights for workload scheduling, data-center operations, and policy, enabling more transparent and footprint-aware energy decisions across regions.

Abstract

The environmental impact of electricity consumption is commonly assessed through its carbon footprint (CF), while water-related impacts are often overlooked despite the strong interdependence between energy and water systems. This is particularly relevant for electricity-intensive activities such as data center (DC) operations, where both carbon emissions and water use occur largely off-site through electricity consumption. In this work, we present Wattnet, an open-source tool that jointly assesses the CF and water footprint (WF) of electricity consumption across Europe with high temporal resolution. Wattnet implements an electricity flow-tracing methodology that accounts for local generation mixes, as well as for cross-border electricity imports and exports at a 15-minute resolution. Operational and life-cycle impact factors are used to quantify and compare local (generation-based) and global (consumption-based) footprints for multiple European regions during 2024. The results demonstrate that neglecting electricity flows and temporal variability can lead to significant misestimations of both CF and WF, particularly in countries with high levels of electricity trade or hydropower dependence. Furthermore, the joint analysis reveals trade-offs between decarbonisation and water use, highlighting the prominent role of reservoir-based hydropower in increasing WF even in low-carbon systems. Wattnet facilitates informed decision-making for workload scheduling and energy-aware operation of DCs, while also enhancing transparency regarding the environmental impacts of electricity consumption for end users and policymakers.

Figures (6)

• Figure 1: Wattnet spatial zoning and links between zones.
• Figure 2: 12-hours averaged local and global operational CF (CO2 mass per ) calculated with high temporal resolution data (15-minute) (black) and calculated with monthly averaged data (red) for three countries: France (upper plot), Slovakia (intermediate plot), and Germany (lower plot).
• Figure 3: Upper plot: Daily average energy exchanges (MW) between Portugal and Spain along the year. Lower plot: Daily average energy generation (MW) by technology and local and global CF in Portugal (CO2 mass per ).
• Figure 4: Comparison of the energy generation mix and carbon footprint of Portugal and Spain, highlighting the energy exchanges between the two countries. The chart illustrates each country's energy source composition and its environmental impact, along with the interconnected energy flow that influences their shared carbon footprint.
• Figure 5: 12-hours averaged local and global WF (/) calculated with high temporal resolution data (15-minute) (black) and calculated with monthly averaged data (red) for three countries or zones: Germany (upper plot), Sweden1 (intermediate plot), and Croatia (lower plot).