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Case study - Optimization in the Energy Consulting Industry
PSRI (Power Systems Research Inc.) has been
providing consulting services in Latin and North America and
Asia since 1987. They specialize in computational models for
production simulation, tools for risk management and integrated
optimization of assets, and financial-economic evaluation
of projects, with special emphasis on hydrothermal systems.
For the development of its new computational tools, PSRI uses
Dash Optimization's XpressMP.
Solutions:
Optgen, one of PSRI's latest computational
tools is an expansion-planning tool for energy systems. Optgen
minimizes the investment cost for the construction of hydro
generators, thermal generators, and interconnection links
between regions. The model that PSRI has created minimizes
the sum of the generation and transmission reinforcement`s
investment cost, the plants' operation cost, and the penalties
for energy not supplied. There are many constraints in this
problem including obligatory project constraints, optional
project constraints, mutually exclusive project constraints,
associated project constraints, minimum installed capacity
constraints, water balance constraints, load supply constraints,
environmental constraints, operating limits, minimum generation
constraints for individual generators, and fuel consumption
constraints. This optimization problem is a multi-period problem
with 1,000 binary variables, 110,000 continuous variables
and 20,000 constraints handled by a decomposition technique.
Other recent tools that PSRI has developed using
Xpress-MP are Optnet and Optfolio. Optnet is a transmission
network expansion tool with problem sizes characteristically
around 5,000 constraints and 3,000 variables (of which around
300 are integer binary variables). This problem together with
an upper bound of 1% provided by GRASP metaheuristic took
1 hour and 50 minutes (20 minutes were spent in the metaheuristic
phase) for XpressMP to solve. Optfolio is a decision support
tool used for energy portfolio management. Problem sizes in
Optfolio typically have 15,000 rows and columns and 100 binary
variables.
More Specifics and Benefits:
PSRI is currently using Xpress-MP modeling
component libraries that are linked to their applications
using Watcom C routines. PSRI attests "The Xpress environment
provides a straightforward way to define optimization problems
using the modeler language. Addition and modification of constraints
and variables are very easy to implement. The data input of
the model is also simple because of the coma-separated format
for ASCII files."
About PSRI:
PSRI has offices in Brazil and the US, which
house their technical staff that is supported by a large number
of independent consultants. PSRI's clients come from over 20 different
countries and include energy investors, utilities, oil/gas companies,
multilateral institutions, regulators, power exchanges, and ISOs,
and consultants/research centers.
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