1. The Energy-Water Nexus Bringing Together Different Perspectives Water Climate change is a key driver of water systems. Current focus is water sufficiency and climate change adaptation. Energy dimension provides new insights into mitigation potential in the water sector. Energy Energy systems drive climate change Current focus is energy sufficiency and climate change mitigation. Water dimension provides new insights into how climate adaptation will affect energy systems. 1 Charles Heaps, Ph.D. Director, US Center of SEI charlie.heaps@sei-us.org

2. A Few Nexus Issues Hydropower Cooling Water for Thermal Power Systems Energy for Desalination Water and Land-use for Biofuels Energy for Agricultural Pumping Energy and Water for Sewage Systems Integrating Mitigation and Adaptation 2

3. Models to Support Nexus Policy Rather than create new tools unfamiliar to both energy and water professionals, link existing tools that are already widely used and credible in both fields. Provide insights to both groups as a way of starting dialogue between energy and water professionals. Over last two years, SEI has been developing such a system based on its existing modeling tools: LEAP (energy) and WEAP (water). Tightly coupled system where LEAP and WEAP run together and are dynamically linked: each tool can request data or results from the other. Common assumptions on scenarios, seasonal/time of day information, geographic boundaries Flexible enough to model a wide variety of energy-water issues. Transparent & easy to use for a wide target audience, but powerful enough to provide genuine insights. 3

4. Long range Energy Alternatives Planning System www.energycommunity.org Integrated energy planning and GHG mitigation assessment. Local, national, regional and global applicability. Energy, emissions and cost-benefit assessment. Fast, transparent, powerful data management, reporting & scenario building tools. Choice of methods: simulation/optimization & engineering/econometrics. Widely applied (1000s of users in 195 countries). Used by governments, NGOs, utilities, universities, consulting companies. Recent applications: 2012: Energy for All: 20 region global energy study for Rio+20 2010: Modeling to support the Massachusetts Clean Energy & Climate Plan 2009: Europes Share of the Climate Challenge

5. Water Evaluation And Planning System www.weap21.org Integrated watershed hydrology and water planning model GIS-based, graphical drag & drop interface Physical simulation of water demands and supplies Additional simulation modeling: user-created variables, modeling equations and links to spreadsheets, scripts & other models Scenario management capabilities Groundwater, water quality, reservoir, hydropower and financial modules

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7. Results Displayed on the Map 7

8. Linking Water and Energy Issues 8 Limited hydropower & cooling water, increased energy requirements for pumping. Increased energy requirements for desalination. Water requirements for hydropower & thermal cooling Water conservation Hydropower & fossil generation Wind & solar, less water- intensive cooling Insufficient water for hydro and cooling, even with increased groundwater pumping. Still insufficient water--further enhance supply with desalination. Electricity demand Energy efficiency Fuel Use GHGs Local air pollution Costs Energy Demand Water Demand Water Supply Energy Supply Hydropower energy & cooling water requirements Reduced water demands Groundwater depletion Water quality Unmet ecological flows Costs

9. Status 9 Beta version being tested: full release summer 2012 www.weap21.org www.energycommunity.org Charles Heaps, Ph.D. Director, US Center of SEI charlie.heaps@sei-us.org