(304c) A Multi-Objective Energy-Water Nexus Planning Model: A Case Study of the Power Systems in Texas Edwards Aquifer

Increasing power demands and water scarcity as well as
environmental concerns give rise for the need of a planning strategy for power
generating systems that takes into consideration the nexus between energy and
water [1]. Power systems planning problems are complex and comprise of
decisions related to:  (i) the ability to add additional power plants with
different types of cooling and power generating technologies, (ii) the ability
to convert the cooling and or power generating technologies of existing power
plants, (iii) uncertainties, and (iv) environmental
and social impacts [2]. Given that the type of power generating and cooling
technology of a power plant directly affects its water usage, the optimization of
a power system is a multi-objective problem [3]. Therefore, a systematic
methodology based on the Energy-Water Nexus (EW-N) is necessary for modeling
and solving the optimization problem on power systems planning [4].

In this work, we develop a novel superstructure for planning
strategies of power generating systems based on EW-N connections. The EW-N
problem is formulated as a two-stage stochastic multi-objective mixed integer
linear program [5]; with “here-and-now” decision variables such as additional
power plants with specific power generation and cooling technologies and
“wait-and-see” decision variables comprising of and not limited to the capacity
and water utilization of power plants. The model determines the optimal
conversion and expansion policies for the current infrastructure, based upon
uncertain future water availability and power demands. The model is implemented
into a case study regarding EW-N in the Edward Aquifer, aiming to provide
policy makers with a systematic tool to analyze various scenarios and
technology options. Moreover, the model is also flexible in that it can also be
integrated into the Edwards Aquifer Groundwater and River System Simulation
Model (EDSIMR) [6, 7], which is a regional model for the comprehensive
decision-making and resources allocation regarding Food-Energy-Water Nexus in
the Edwards Aquifer.

References:

[1]
Diangelakis, N. A., & Pistikopoulos,
E. N. (2017). A multi-scale energy systems engineering approach to residential
combined heat and power systems. Computers & Chemical Engineering, 102,
128-138.

[2]
Koltsaklis, N. E., Dagoumas,
A. S., Kopanos, G. M., Pistikopoulos,
E. N., & Georgiadis, M. C. (2014). A spatial
multi-period long-term energy planning model: a case study of the Greek power
system. Applied Energy, 115, 456-482.

[3] Mohtar, R. H., & Daher, B. (2016). Water-energy-food nexus framework for
facilitating multi-stakeholder dialogue. Water
International, 41(5), 655-661.

[4] Garcia, D. J., & You, F. (2016). The
water-energy-food nexus and process systems engineering: a new focus. Computers & Chemical Engineering, 91, 49-67.

[5]
Birge, J. R., & Louveaux,
F. (2011). Introduction to stochastic programming. Springer Science &
Business Media.

[6]
Gillig, D., McCarl, B. A.,
& Boadu, F. (2001). An economic, hydrologic, and
environmental assessment of water management alternative plans for the south
central Texas region. Journal of Agricultural and Applied Economics, 33(1),
59-78.

[7]
McCarl, B. A., Dillon, C. R., Keplinger,
K. O., & Williams, R. L. (1999). Limiting pumping from the Edwards Aquifer:
an economic investigation of proposals, water markets, and spring flow
guarantees. Water Resources Research, 35(4), 1257-1268.