Integrated water-energy-emissions analysis: Applying LEAP and WEAP together in California

The document argues that climate, water, and energy are intricately linked, requiring integrated modeling tools to understand cross-sectoral tradeoffs. To address this, the Stockholm Environment Institute (SEI) linked its WEAP and LEAP systems. A California case study shows that meeting 5% of Southern California's urban water demand via desalination by 2049 could reduce water imports by 300 million cubic meters per year in normal years, but would increase the water sector's electricity use by approximately 3 TWh and GHG emissions by 1.4 million tonnes of CO2e per year.

• Climate, water, and energy are interdependent, meaning policy decisions in one sector can impact the others. This 'nexus' requires integrated analysis tools to understand interactions and tradeoffs for optimal policy outcomes.
• SEI has integrated two existing decision support systems—the Water Evaluation and Planning (WEAP) system and the Long-range Energy Alternatives Planning (LEAP) system—to allow users to model evolving conditions and cross-sectoral impacts in both water and energy systems.
• In California, the water sector accounts for 19% of the state's electricity consumption. The State Water Project (SWP) is the largest single power consumer in the state, utilizing 3% of total electricity to pump approximately 4 billion m3 of water annually.
• California's Global Warming Solutions Act (AB32) targets reducing GHG emissions to 1990 levels (427 million tonnes of CO2e) by 2020. Electricity generation represents about 24% of total emissions, with 13% from in-state production and 11% from imports.
• A case study on Southern California desalination (meeting roughly 5% of current urban water demand) indicates that while it could reduce water imports by about 300 million cubic meters per year in normal years, it would increase water-sector electricity use by nearly 3 TWh and GHG emissions by 1.4 million tonnes of CO2e per year by 2049.
• The integrated WEAP-LEAP model reveals that the benefits of desalination for reducing water imports vary significantly between dry and wet years due to climate-linked local supply variability, and that after 2030, the region may still need to import large volumes of water despite desalination.

APA

Stockholm Environment Institute (2012). Integrated water-energy-emissions analysis: Applying LEAP and WEAP together in California. https://www.sei.org/mediamanager/documents/Publications/SEI-PolicyBrief-IntegratedWaterEnergyEmissionsAnalysis-2012.pdf

Chicago

Stockholm Environment Institute. Integrated water-energy-emissions analysis: Applying LEAP and WEAP together in California. 2012. https://www.sei.org/mediamanager/documents/Publications/SEI-PolicyBrief-IntegratedWaterEnergyEmissionsAnalysis-2012.pdf.

Wikipedia

{{cite report |author=Stockholm Environment Institute |title=Integrated water-energy-emissions analysis: Applying LEAP and WEAP together in California |date=2012 |url=https://www.sei.org/mediamanager/documents/Publications/SEI-PolicyBrief-IntegratedWaterEnergyEmissionsAnalysis-2012.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{stockholmenvironmentinstitute2012integrated, author = {{Stockholm Environment Institute}}, title = {{Integrated water-energy-emissions analysis: Applying LEAP and WEAP together in California}}, institution = {Stockholm Environment Institute}, year = {2012}, url = {https://www.sei.org/mediamanager/documents/Publications/SEI-PolicyBrief-IntegratedWaterEnergyEmissionsAnalysis-2012.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }