Evaluating options for Balancing the Water-Electricity Nexus in California: Part 1 – Securing Water Availability

Abstract

• Part I presents a spatially and temporally resolved model of California's surface reservoirs.• Part II presents GHG emissions and grid renewable penetration for water availability options.• In particular, the energy signature of water supply infrastructure is delineated.• Different pathways for securing California's water supply are developed quantitatively.• Under baseline conditions, portfolios capable of securing surface reservoir levels emerge.• Under climate change conditions, the water supply must be carefully selected to allay emissions. A study was conducted to compare the technical potential and effectiveness of different water supply options for securing water availability in a large-scale, interconnected water supply system under historical and climatechange augmented inflow and demand conditions. Part 2 of the study focused on determining the greenhouse gas and renewable energy utilization impacts of different pathways to stabilize major surface reservoir levels. Using a detailed electric grid model and taking into account impacts on the operation of the water supply infrastructure, the greenhouse gas emissions and effect on overall grid renewable penetration level was calculated for each water supply option portfolio that successfully secured water availability from Part 1. The effects on the energy signature of water supply infrastructure were found to be just as important as that of the fundamental processes for each option. Under historical (baseline) conditions, many option portfolios were capable of securing surface reservoir levels with a net neutral or negative effect on emissions and a benefit for renewable energy utilization. Under climate change augmented conditions, however, careful selection of the water supply option portfolio was required to prevent imposing major emissions increases for the system. Overall, this analysis provided quantitative insight into the tradeoffs associated with choosing different pathways for securing California's water supply. a b s t r a c t a r t i c l e i n f o

Global warming and changes in risk of concurrent climate extremes: Insights from the 2014 California drought

“…Using data from the 2014 California drought, we show that a univariate return period analysis based on precipitation, commonly used in hydrology, substantially underestimates the occurrence probability of the 2014 California drought because of ignoring the effects of temperature. This is even more important for regions like California where a drying trend has been observed [Damberg and AghaKouchak, 2014], and a warmer and drier climate is expected in future [Seager et al, 2007;Cayan et al, 2008Cayan et al, , 2010 with potential impacts on the ecosystem, water availability, energy production, and agriculture industry [Connell-Buck et al, 2011;Zhu et al, 2005;Tanaka et al, 2006;Lund et al, 2003;Madani and Lund, 2010;Tarroja et al, 2014aTarroja et al, , 2014b. Historically, California has faced summer fraught with difficult decisions as demands from farms that help feed the nation clash with the water needs of city residents.…”

Groundwater and surface water connectivity within the recharge area of Guarani aquifer system during El Niño 2014–2016

“…aquifer recharge, d-excess, groundwater-surface water connectivity, Guarani aquifer system, lcexcess, stable isotopes 1 | INTRODUCTION Decrease in water availability in many parts of the world (Chenini, 2010;Li, Guo, Liu, & Chen, 2010;López-Moreno et al, 2014;Olmstead, 2014;Pingale, Jat, & Khare, 2014;Bucak et al, 2017;Tarroja et al, 2014), either due to a decrease in water storage or quality, have increased the international awareness for water security and sustainability under a changing climate (Foster & MacDonald, 2014). In this context, the spatial-temporal changes in water circulation and distribution under climate variability is challenging in water resources management.…”

Compounding Impacts of Human-Induced Water Stress and Climate Change on Water Availability

“…The PCR-GLOBWB model is forced with daily CMIP5 precipitation and temperature simulations after bias adjustment 65 to generate inflow to the reservoirs (see Figure S2) and reservoir storage (Figure S3) based on the projected demand (Table S2). A reservoir model is then nested with the hydrologic model and used to estimate the water storage 42, 44, 66, 67 . The storage, S (L 3 ) of the reservoir is computed using a simple water balance equationwhere t (T) denotes time, Q in (L 3 T −1 ) and Q out (L 3 T −1 ) are the reservoir inflow and outflow volume rate, respectively, Q add (L 3 T −1 ) defines the additional release from the reservoir for flood control and reservoir management, and Q evap (L 3 T −1 ) signifies evaporation.…”

“…As a result, different regions will see different water availability changes depending on their local infrastructure and capacity to cope with variability or adapt to change. Omitting surface water reservoirs from large-scale water cycle models introduces a large source of uncertainty in current assessments of the global water cycle and hinders evaluation of climate change and variability on hydropower energy production 42 . Continental-scale closure errors of the water budget range from 13% (Europe) to 21% (Australia) 43 , which can be attributed to input data uncertainty, modeling assumptions and anthropogenic influences on water distribution.…”