1© 2016 Electric Power Research Institute, Inc. All rights reserved.

Overview of Techno-Economic Assessment

Simulation & Analysis tools for Microgrids

2© 2016 Electric Power Research Institute, Inc. All rights reserved.

What is Feasibility (Techno-Economic) Assessment?

Evaluate use cases for Microgrid & DERsMicrogrid designDER sizing & Optimal dispatchFirst-order analysis of Costs & Benefits Identify challenges that need to be addressed in detailed design and

demonstration/implementation phases

3© 2016 Electric Power Research Institute, Inc. All rights reserved.

Study Process

4© 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/benefitsMicrogrid design

Policy

Costs/benefit

s

Technical

specs.

5© 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

6© 2016 Electric Power Research Institute, Inc. All rights reserved.

Modeling ProcessOverview

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

ObjectivesMinimize Cost

Minimize Emissions

% Renewable Penetration

… Outage Duration

ConstraintsCost/Emissions Cap

Zero Net Energy

Specify DER types/size/models

Optimization/Search Engine

7© 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)

8© 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

9© 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

10© 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

11© 2016 Electric Power Research Institute, Inc. All rights reserved.

EPRI Feasibility Projects

12© 2016 Electric Power Research Institute, Inc. All rights reserved.

Feasibility AssessmentChallenges

Outage Design Criteria Value of Resiliency/Reliability

Cost/Benefit Perspective?

Existing vs NewSite Data Availability Data Granularity

Deterministic vs Stochastic

Model

Power Flow?Thermal Flow?

Study Detail vs

Time Spent

13© 2016 Electric Power Research Institute, Inc. All rights reserved.

Together…Shaping the Future of Electricity