Software Tools Supporting Village Power System Design

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Software Tools Supporting Village Power System
Design
Jean Ku APEC Village Power Workshop November 9,
2004
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Why do we need new models?

• Traditional Rural Electrification
• Grid extensions, micro-hydro or diesels
• New and Renewable Alternatives
• Small-scale individual DC systems
• Solar Lanterns, Solar or Wind Home Systems
• Hybrid Power AC Systems
• Wind, PV, Biomass, Gensets, Batteries
• Mini-grids, Micro-enterprise Zones, Battery
  Recharging Stations

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The Role of Models

• Objective and subjective criteria
• Computers analyze objective criteria
• People analyze subjective criteria
• Offers simplicity and transparency
• Its easier to weigh the quality of service
  issues when you have comparable cost estimates
  for each alternative

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The Modeling Process

• What is the most economical way to meet a
  communitys power needs?

Data Inputs Local energy resources Community
loads Basic component costs General maintenance
costs
Modeling Tools Distribution system configuration
(on- vs. off-grid) ViPOR
Results Basic system design Installation and OM
costs Base line cost of alternatives Yearly power
production Fuel consumption
Modeling Tools Power System Design HOMER, Hybrid2
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NRELs Suite of Models

• ViPOR An optimization model that determines the
  best mix of centralized and isolated power
  generation for a particular village.
• HOMER An optimization model that determines the
  least-cost system configuration.
• Hybrid2 A simulation model to determine the cost
  and performance of a wide variety of power
  systems given the load and available resources.

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Village Power Optimization Model for Renewables
An optimization model to design village
electrification systems, ViPOR will

• Optimize the mix of centralized and isolated
  generation
• Select between grid extension and stand-alone
  systems for centralized power
• Select the optimal placement of the centralized
  power system(s)
• Determine the optimal placement of transformers
• Design the optimal MV and LV distribution grid

ViPORs optimization procedure considers costs
and revenues.
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ViPOR Inputs

• Location energy requirements for expected loads
• Potential locations of centralized power
  system(s)
• Wire and transformer costs
• Power generation costs for isolated and
  centralized power systems (can be calculated by
  HOMER)
• Expected revenues from each load (on-grid and
  off-grid)
• Terrain description (spatial map)
• Maximum low voltage line length

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ViPOR Sample village

• Water is shown in blue, forest green, grass
  white, and trail gray.
• Green dots are houses, brown are stores, orange
  is church.
• Yellow triangles are high-wind sites, orange is
  low-wind site.

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ViPOR Solution for sample village

• ViPOR has chosen a high-wind site to power the
  centralized system
• Houses not on the grid are to be given PV home
  systems
• Red lines are MV wires, blue are LV wires
• Red dots are transformers

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ViPOR Numeric Output
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ViPOR Numeric Output
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ViPOR Future enhancements

• Explicit calculation of voltage drops
• Calculation of power losses in distribution
  system
• Multiple transformer sizes
• Multiple wire sizes
• Tighter integration with GIS and HOMER

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What is HOMER?

• A tool for comparing and evaluating micropower
  technology options for a wide range of
  applications
• Village power systems
• Stand-alone applications
• Grid-connected systems
• Conventional technologies
• New technologies

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(No Transcript)
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What does HOMER do?

• HOMER finds the combination of components that
  can serve a load at the lowest life-cycle cost
• Shows how this result can vary given different
  assumptions

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Technologies HOMER Can Model

• Single technology systems and multiple-technology
  (hybrid) systems
• Compare multiple combinations of different
  technologies

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Generators

• Fossil fuels
• Biofuels
• Cofired
• Cogeneration
• Up to three generators

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Grid Extension

• Compare to stand-alone system
• Breakeven grid extension distance

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Grid-connected Systems

• Rate schedule
• Net metering
• Demand charges

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Renewable Technologies

• Solar PV
• Wind
• Biomass and biofuels
• Hydro

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Emerging Technologies

• Fuel cells
• Microturbines
• Small modular biomass

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Questions HOMER can Answer

• Should I buy a wind turbine, PV array, or both?
• Will my design meet growing demand?
• How big should my battery bank be?
• What if the fuel price changes?
• How should I operate my system?
• And many others

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Inputs

• Component cost and performance data
• Resource availability
• Loads

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Simulation - Optimization - Sensitivity Analysis

• Simulation
• Estimate the cost and determine the feasibility
  of a system design over the 8760 hours in a year
• Optimization
• Simulate each system configuration and display
  list of systems sorted by net present cost (NPC)
• Sensitivity Analysis
• Perform an optimization for each sensitivity
  variable

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Sensitivity Analysis

• Important information is very uncertain
• Loads
• Even if you have data loads will change with
  system
• Resources
• Data for a different place, natural variability
• Costs
• Fuel prices, OM costs
• Policy and market analyses requires input ranges
  not point estimates

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Simulation Results

• Cost and performance of a particular system
  configuration

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Optimization Results

• Ranked list of system configurations

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Sensitivity Results

• Graphs and tables

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The Hybrid2 Simulation Software

• A tool designed to accurately predict the long
  term performance of a wide variety of power

systems made up of conventional fuel generators,
wind generators, photovoltaics and energy storage
through batteries
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Hybrid2 Data Requirements

• Loads
• Primary time series or daily load profile,
  including deferrable and optional loads
• Site/Resource parameters
• Wind speed and incident solar time series
• Ambient temperature time series or nominal value
• Elevation, site position and wind turbulence
  parameters
• Power System
• Configuration and components
• Component performance parameters (Library)
• Dispatch Strategy (Library)

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Hybrid2 Analysis Procedures
Site/Resource parameters Wind and solar time
series Ambient temperature data Elevation, site
position and wind turbulence parameters
Loads Primary time series or daily load profile

• Power System
• Configuration and components
• Component performance parameters (Library)
• Dispatch Strategy (Library)

Performance Results System design
Economic Results Capital cost OM cost
Detailed Modeling
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Hybrid2 Software Features

• Probabilistic/time series model Accounts for the
  fluctuations of the wind and load during each
  time step
• Very diverse system architecture
• AC, DC and combined systems can be modeled
• System can include multiple wind turbines,
  multiple diesels, batteries, PV and 4 different
  types of power converters
• Detailed economic analysis
• On line library of manufactures equipment
• Detailed dispatching options 17 different
  control parameters
• Hybrid systems glossary of commonly used terms
• Energy audit/estimation tool
• Resource data gap filler

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Hybrid2 Power System Design

• The power system is designed to meet the required
  loads using the resources available. This
  requires a fair amount of hybrid system and
  design experience.

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Hybrid2 Results Interface

• Simulation results displayed in a graphical
  format as well as a summary file which includes
  power flows from each component, loads, and
  system losses.

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HOMER and Hybrid2

• Design philosophy Simplicity vs. flexibility
• Use Optimization vs. performance predictions
• System configuration
• HOMER output, Hybrid2 input
• Main differences
• Hybrid2 HOMER
• - Intra-hour variability - Easy initial use
• Bus voltages - Dispatch optimization
• Dispatch flexibility - All DG technologies
• - Engineering tool - Options analysis

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These are only models!

• ViPOR, HOMER, and Hybrid2 do not provide "the
  right answer" to questions. It does help you
  consider important factors, and evaluate and
  compare options.

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Model Availability

• ViPOR Available from www.nrel.gov/vipor.
• HOMER Available from www.nrel.gov/homer.
  Inquiries, email peter_lilienthal_at_nrel.gov.
• Hybrid2 Send e-mail to Hybrid2_at_nrel.gov.
  Provided with software, manuals and user support.
• These models were developed with funding from the
  US Department of Energy and the National
  Renewable Energy Laboratory