Energy boom and groundwater bust: Mexicos water-energy nexus with implications for the U.S. border region Presented at First Western Forum on Energy and Water Sustainability, Bren School of Environmental Science & Management, Univ. of California, Santa Barbara, 22 March 2007

Energy Boom and Groundwater Bust Mexicos Water-Energy Nexus with Implications for the U.S. Border Region Christopher Scott University of Arizona Dept. of Geography & Regional Development, and Udall Center for Studies in Public Policy

What Nexus? Resources – water and energy are coupled in fundamental ways Management – of water or energy in isolation likely has (unforeseen) consequences for the other resource Sustainability – policy tools for water, energy need to be mutually reinforcing

Water-Energy Coupling Groundwater Inter-basin transfers Municipal supply Wastewater, reuse reservoir storage evaporative demand energy for pumping lift, distribution treatment, distribution treatment, desalination Hydropower Thermo-power cooling

Resource Feedbacks Water use Energy demand Energy use Water demand

De-coupled Management… Water management options tend to externalize energy implications, e.g.: ~70 billion kWh/yr for U.S. water and wastewater projected to increase 20% in 15 years greater if desalination roadmap is followed water represents 1/3 of municipal energy budgets groundwater irrigation is a large % of total electricity demand, e.g., in Mexico 10% in Sonora state 17% in Chihuahua state 30% in Zacatecas state

… Needs to be [Re-] Coupled Energy management needs to internalize water implications: increased hydropower reliance entails sectoral water reallocation cooling water salt concentrations a major challenge (e.g., Phoenixs Palo Verde uses high TDS effluent)

Sustainability and Policy Behind groundwater boom-bust cycles (e.g., Mexico) are energy supply and pricing. Conversely: Energy supply and pricing offer tools for sustainable groundwater management

Global Groundwater Boom 26,000

… Leading to Groundwater Bust Number of Wells in Mexico GW Irrigation in India

ASCENCION BAJA BABICORA CASAS GRANDES F.M.-V. AHUMADA CHIH-SACRAMENTO MEOQUI-DELICIAS JIMENEZ-CAMARGO JUAREZ(Z. Urbana) PARRAL-V. DEL V. TAB.-ALDMA CUAUHTEMOC ACUIFEROS SOBREEXPLOTADOS ABATIMIENTO MEDIO EN m/año

1 VALLE DE JUAREZ 2 ASCENCION 3 CASAS GRANDES 4 F.M.-V. AHUMADA 5 BAJA BABICORA 6 CUAUHTEMOC 7 CHIHUAHUA-SACRAMENTO 8 TABALAOPA-ALDAMA 9 DELICIAS 10 JIMENEZ-CAMARGO 11 PARRAL-EL VERANO DISTRIBUCIÓN DE LOS ACUIFEROS SOBREEXPLOTADOS

Groundwater-Energy Supply Nexus Groundwater overdraft and multiple impacts are driven by electricity supply and pricing

Increasing Volume, Declining Share

High Energy % for GW Pumping

Ag. Groundwater Pumped, 2005 (derived from energy data; national total 17.6 km 3 /year)

Aquifer Overdraft

GW Sustainability Initiatives water rights, titling wells Registro Público de Derechos de Agua (REPDA) annual concessioned volume water meters, but monitoring or compliance inadequate Water resource (river basin) master plans bans on new wells in overdrafted aquifers recharge programs (controversial, runoff impacts) groundwater user committees

Ag. GW Share of Total Water Titled

GW Titled GW Pumped

2002 – Mexico seized the GW-energy nexus opportunity Rural Energy Law (Ley de Energía para el Campo) primarily to level the playing field for Mexican agriculture under NAFTA Power tariff structure modified with medium-term subsidy support Sliding-scale ag. power tariff with threshold fixed by energy equivalent of groundwater volume titled

2003 – lost the thread? … with lower night-time ag. tariff, but ineffective controls on volume or area irrigated 32% difference Example: Chihuahua tariffs US$ 1.00 = Mex$ 10.80

Growth, night ag. power consumption

Shift to Night-time Irrigation

Financially, A Losing Proposition?

… But Overall Profits High

GW-Based Intensive Ag. Production Exports to U.S., Canada, Pacific rim Expanding Mexican domestic market Costa de Hermosillo (Sonora) grapes Cuauhtemoc (Chihuahua) apples Low water productivity in basic grains (wheat, corn) competing with high productivity horticulture

High Per-User Volumes (Titled)

Mexicos Virtual Water Exports to the U.S. are Groundwater

Mexicos Virtual Water Imports are Rainwater (w supplemental irrigation) Corn… despite the ethanol-tortilla debacle Wheat Grain-fed beef Other animal products Deciduous fruit

Virtual Water Failure of the Virtual Water Argument: possible explanations using the case study of Mexico and NAFTA – manuscript by Jorge Ramirez-Vallejo and Peter Rogers

Conclusions Boom (partial collapse) of groundwater in northern Mexico fueled by electricity supply and pricing CNA (water) and CFE (electricity) at institutional loggerheads Energy supply management a promising tool for water demand management

Future Challenges Should Mexico seek to manage virtual exports of groundwater? How? Urban growth in (northern) Mexico will increasingly appropriate groundwater Water-energy nexus for desalination?

Thank you. Christopher Scott (520) Acknowledgements Comisión Nacional del Agua Comisión Federal de Electricidad Tushaar Shah, International Water Management Institute Ana María Caliz, Tendencias – Consultores en Economía Jorge Ramirez-Vallejo and Peter Rogers, Harvard University