Presentation from the EPRI-Sandia Symposium on Secure and Resilient Microgrids: Simulation & Analysis Tools for Microgrids, presented by Dean Went and Andre Cortes, EPRI, Baltimore, MD, August 29-31, 2016.

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© 2016 Electric Power Research Institute, Inc. All rights reserved.
Overview of Techno-Economic Assessment
Simulation & Analysis tools for
Microgrids

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© 2016 Electric Power Research Institute, Inc. All rights reserved.
What is Feasibility (Techno-Economic) Assessment?
 Evaluate use cases for Microgrid & DERs
 Microgrid design
 DER sizing & Optimal dispatch
 First-order analysis of Costs & Benefits
 Identify challenges that need to be addressed in detailed design
and demonstration/implementation phases

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© 2016 Electric Power Research Institute, Inc. All rights reserved.
Study Process

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© 2016 Electric Power Research Institute, Inc. All rights reserved.
Microgrid design
Three driving aspects of the design:
– Technical requirements
– Capital & Operating Costs
– Policy
Technical specifications affect costs/benefits
Microgrid design
Policy
Costs/benefits
Technical
specs.

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© 2016 Electric Power Research Institute, Inc. All rights reserved.
Microgrid design: Software tools
Software tools combine:
Optimization algorithms
Heuristics
Databases
Outcome: A “good” idea of the
microgrid design
UI
SOLVER
MODEL
DATABASE

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© 2016 Electric Power Research Institute, Inc. All rights reserved.
Modeling Process
Overview
Inputs
Electrical &
Thermal Loads
Electricity & Gas
tariff data
DER data
Site Weather
Data
Outputs
Optimal DER
Mix & Capacity
DER Dispatch
Quantitative
Cost/Benefit
F Investment &
Financing
Objectives
Minimize Cost
Minimize Emissions
% Renewable Penetration
… Outage Duration
Constraints
Cost/Emissions Cap
Zero Net Energy
Specify DER
types/size/models
Optimization/Search
Engine

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© 2016 Electric Power Research Institute, Inc. All rights reserved.
Limitations
Optimization is a powerful tool,
but not every problem can be
solved, due to:
– Non-convexity,
– Prohibitively large number of
variables
Methods include relaxations
(might neglect important
design specifications)

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© 2016 Electric Power Research Institute, Inc. All rights reserved.
Addressing limitations
Execute
optimization
approach
Test design
feasibility on a
more realistic
model
Final
economic
analysis/
decision
making
Use engineering
judgement,
heuristics, previous
experience
New constraints
If infeasible
If feasible
Design
parameters

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© 2016 Electric Power Research Institute, Inc. All rights reserved.
Examples of software tools
 DER-CAM
– MILP Bilevel optimization approach
– Deterministic
– Computationally intensive
– Optimizes both dispatch and sizing
– Different versions include:
 Uses only 3-day types
 Steady-State power flow approximations
 Emergency day-types
 HOMER
– Smart-search based approach
– Dispatch is carried out using simple but robust dispatch rules
– Sizing is performed through a smart search algorithm
– New versions allow user-defined dispatch rules

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© 2016 Electric Power Research Institute, Inc. All rights reserved.
Handling uncertainty
Some of the design parameters might be unknown
– Greenfield projects with unknown load
– Electricity rates to establish
– Project ownership
This sort of uncertainty can be handled using sensitivity
analysis
– Scenarios for different values of the uncertain parameters
The resulting information should help decision making

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© 2016 Electric Power Research Institute, Inc. All rights reserved.
EPRI Feasibility Projects

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© 2016 Electric Power Research Institute, Inc. All rights reserved.
Feasibility Assessment
Challenges
Outage Design Criteria
Value of
Resiliency/Reliability
Cost/Benefit
Perspective?
Existing vs New
Site
Data Availability Data Granularity
Deterministic
vs Stochastic
Model
Power Flow?
Thermal Flow?
Study Detail
vs
Time Spent

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© 2016 Electric Power Research Institute, Inc. All rights reserved.
Together…Shaping the Future of Electricity