Energy White Paper Perspectives on Water Supply Energy Use City of Santa Cruz & Soquel Creek Water District scwd2 Desalination Program Prepared by: April 2011 Table of Contents Table of Contents ....................................................................................................................... ii List of Tables ............................................................................................................................. iv List of Figures ............................................................................................................................ iv List of Appendices ..................................................................................................................... iv Section 1: Executive Summary and Background ......................................... 1 1.1 Executive Summary .............................................................................. 1 1.2 Background .......................................................................................... 2 1.3 Current Water Supply Portfolios ............................................................ 2 1.3.1 SCWD Water Supply Portfolio ................................................... 2 1.3.2 SqCWD Water Supply Portfolio ................................................. 3 Section 2: Energy and Our Current Water Supply ........................................ 4 2.1 What is Energy? ................................................................................... 4 2.2 Our Society is Fundamentally Reliant on Energy .................................. 5 2.3 Our Current Water Supplies Require Energy ........................................ 6 2.3.1 SCWD Water Supply Energy Requirements .............................. 6 2.3.2 SqCWD Water Supply Energy Requirements ............................ 7 2.4 Typical Residential Energy Use Including Water Supply ....................... 8 Section 3: Desalination Energy Requirements ........................................... 12 3.1 The Seawater Desalination Process ................................................... 12 3.1.1 Seawater Desalination Has Become More Energy Efficient ................................................................................... 13 3.2 Energy Use of Proposed Desalination Facility .................................... 14 Section 4: Putting Desalination Energy into Perspective .......................... 15 4.1 Desalination Energy Compared to Typical Santa Cruz Area Energy Uses ....................................................................................... 15 4.2 Water Supply Energy with Supplemental Desalination ........................ 16 4.2.1 SCWD Water Supply Energy with Supplemental Desalination ............................................................................ 16 4.2.2 SqCWD Water Supply Energy with Supplemental Desalination ............................................................................ 17 4.3 Desalination Energy Compared to Typical Household Energy Uses ................................................................................................... 17 ii Energy White Paper, Perspectives on Water Supply Energy Use Table of Contents (cont'd) Section 5: Energy Minimization and Greenhouse Gas Reduction Study .......................................................................................... 19 5.1 GHG Regulatory Guidelines ............................................................... 19 5.1.1 California Environmental Quality Act (CEQA) .......................... 19 5.1.2 California Global Warming Solutions Act (AB 32) .................... 20 5.1.3 California Coastal Commission and the California Coastal Act ............................................................................. 21 5.1.4 Monterey Bay National Marine Sanctuary ............................... 21 5.2 Projected scwd2 Indirect GHG Emissions ........................................... 21 5.3 Putting Desalination GHG Emissions into Perspective ....................... 22 5.4 Investigating Renewable Energy and GHG Reduction Options .......... 23 References ............................................................................................................................... 24 Energy White Paper, Perspectives on Water Supply Energy Use iii List of Tables Table 2-1 Estimated SCWD Residential Annual Energy Consumption by End Use ............ 9 Table 2-2 Estimated SqCWD Residential Annual Energy Consumption by End Use ......... 10 Table 3-1 Conceptual Range of Energy Requirements of the Project ................................ 14 List of Figures Figure 2-1 PG&E 2009 Power Mix ........................................................................................ 5 Figure 2-2 SCWD Graham Hill WTP ..................................................................................... 7 Figure 2-3 SqCWD Groundwater Pump ................................................................................ 8 Figure 2-4 Typical Santa Cruz Area Residential Energy Use Including Water Supply ........... 9 Figure 2-5 Estimated SCWD Residential Annual Energy Use ............................................. 10 Figure 2-6 Current SqCWD Residential Energy End Uses .................................................. 11 Figure 3-1 Desalination Plant in Pleasanton, CA ................................................................ 12 Figure 3-2 Typical Desalination Process ............................................................................. 13 Figure 3-3 Energy Consumption by the RO Desalination Process ...................................... 14 Figure 4-1 Desalination Energy Use Relative to Santa Cruz Area Demands ....................... 15 Figure 4-2 SCWD Residential Annual Energy Consumption with Supplemental Desalination Water Supply ..................................................................................................... 16 Figure 4-3 SqCWD Residential Annual Energy Consumption with Supplemental Desalination Water Supply ................................................................................. 17 Figure 4-4 scwd2 Household Desalination Water Supply Energy Equivalents ..................... 18 Figure 5-1 Categories of GHG Emissions ........................................................................... 20 List of Appendices Appendix A: Units, Conversion Factors, and Calculations...................................................... 26 iv Energy White Paper, Perspectives on Water Supply Energy Use Section 1: Executive Summary and Background 1.1 Executive Summary The City of Santa Cruz Water Department (SCWD) and Soquel Creek Water District (SqCWD), partnering together as scwd2, are evaluating seawater desalination as a supplemental source to their current water supply portfolios. The energy requirement of seawater desalination is among the key issues in the evaluation of the proposed scwd2 Regional Seawater Desalination Project (Project). scwd2 is committed to thoroughly studying the potential energy use of the scwd2 Regional Seawater Desalination Project (Project). A desalination facility uses electricity from the power grid, similar to a home or business. scwd2 is conducting the Energy Minimization and Greenhouse Gas Reduction Study to ensure that the most advanced and energy efficient technologies and approaches are identified and incorporated into the proposed Project and to inform the Project’s Environmental Impact Report (EIR). The study will also explore renewable energy options (such as photovoltaic solar systems, third party providers, etc.) to offset power requirements of the Project. This paper serves as a preface to the scwd2 Energy Minimization and Greenhouse Gas Reduction Study. This paper will describe the energy requirements of traditional water supplies with those of the Project (which includes the water treatment facility as well as the related intake, pump stations, etc.), and compare the respective energy uses to typical energy requirements for a household. This comparison will put the energy requirements for desalination into broader perspective. The proposed scwd2 Seawater Desalination Project, running at full capacity year-round would have a peak demand of 1.6 MW and require about 13,700 MWh of energy annually. In a typical, non-drought year, the facility is expected to run at half capacity and thereby require approximately 0.8 MW or about 6,800 MWh annually. This is a small to moderate amount of energy compared to other demands in our society. The desalination plant would use energy similar to a small manufacturing facility or mid-sized hospital. The energy required to produce water from traditional supplies (such as surface water and groundwater) for customers served by the City of Santa Cruz or Soquel Creek Water District is approximately 0.5 to 0.7 “…because desalinated water would be used percent of a household’s total energy only to supplement existing water supplies usage. While the process of desalination the energy required to deliver water would requires more energy than a typical become approximately 1 to 2.3 percent of the water supply, because desalinated water would be used only to supplement total energy used in a typical household.” existing water supplies, the energy required to deliver water would become approximately 1 to 2.3 percent of the total energy used in a typical household. Although the water supply energy could increase by 2 to 3 times with desalination, the energy use is still only a small percentage of the energy we use in our households every day. Energy