Overview |  |  |  |

| This topic describes SAM 3.0 and has not been revised for SAM 2009 Beta. You may find useful information, especially if you are new to SAM, but some of the information may be inconsistent with the new version.

The Solar Advisor Model provides a consistent framework for analyzing and comparing power system costs and performance across the range of solar technologies and markets, from photovoltaic systems for residential and commercial markets to concentrating solar power and large photovoltaic systems for utility markets.

Solar Advisor is based on an hourly simulation engine that interacts with performance, cost, and finance models to calculate energy output, energy costs, and cash flows. The software can also account for the effect of incentives on cash flows. Solar Advisor's spreadsheet interface allows for exchanging data with external models developed in Microsoft® Excel. Most of Solar Advisor's inputs can be used as parametric variables for sensitivity studies to investigate impacts of variations in performance, cost, and financial parameters on model results.

Solar Advisor models system performance using the TRNSYS software developed at the University of Wisconsin combined with customized components. TRNSYS is a validated, time-series simulation program that can simulate the performance of photovoltaic, concentrating solar power, water heating systems, and other renewable energy systems using hourly resource data. TRNSYS is integrated into Solar Advisor so there is no need to install TRNSYS software or be familiar with its use to run Solar Advisor.

The Department of Energy's Solar Energy Technologies Program (SETP) initially developed Solar Advisor for analysis to support the implementation of the SETP Systems Driven Approach. The model also has applications for the solar industry for planning research and development programs, and developing project cost and performance estimates. Solar Advisor is being used as part of the Solar America Initiative application and monitoring process.

The current version of the Solar Advisor Model models photovoltaic and concentrating solar power technologies for electric applications in several markets. Solar Advisor also includes a simple model of fuel-based electric generation that can be used to model baseline systems for comparison with the solar technologies. The current version of the Solar Advisor Model does not model solar heating and lighting technologies.

Photovoltaic Systems

Photovoltaic systems in Solar Advisor can be based on flat-plate system or concentrating photovoltaic modules. Solar Advisor offers several options for modeling flat-plate modules, and one option for concentrating photovoltaic modules.

Table 1. Current status of photovoltaic modeling

Technology | Module | Inverter | Storage | Balance of System
Flat-plate photovoltaic |
• | Single-point efficiency
• | Sandia PV Array Performance Model
• | CEC Performance Model
• | Single-point efficiency
• | Sandia Performance Model for Grid-Connected PV Inverters
• | Under development
• | Under development
Concentrating photovoltaic |
• | Single-point efficiency
• | Single-point efficiency
• | Sandia Performance Model for Grid-Connected PV Inverters
• | Under development
• | Under development

The single-point efficiency models are simple representations of system components based on a size value in rated watts or kilowatts and an efficiency value. The flat-plate PV single-point efficiency model also includes a simple representation of module temperature effects. The Sandia and CEC models model commercially available PV modules and inverters using a set of parameters developed by Sandia National Laboratories and the California Energy Commission (CEC), respectively. System components that are in development are not available in the current version of Solar Advisor.

Concentrating Solar Power Systems

Solar Advisor models parabolic trough and dish-Stirling concentrating solar power systems. The trough model is based on NREL's Excelergy model. The dish-Stirling model is based on research at the University of Wisconsin.

Table 2. Current status of Concentrating Solar Power modeling

Technology | Solar Field | Collector and Receiver | Power Block | Storage | Parasitics
Parabolic trough |
• | Layout as multiple of design point or specified area
• | List of heat transfer fluid options
• | Library of collector types
• | Library of receiver types and condition
• | Library of power cycle types
• | Storage capacity defined in number of hours at full load
• | Thermocline
• | Two-tank storage
• | Library of parameter sets for parasitic losses
Dish-stirling |
• | Field area defined by number of collectors and separation
• | Mirror area reflectivity parameters
• | Conduction, convection, and radiation parameters
• | Stirling engine part-to-full load efficiency curve
• | Engine operating parameters
• | None
• | Pump and fan motor loss parameters
Power tower |
• | Heliostat positions defined either in radial zones or individual x-y coordinates
• | Solar field optimization wizard
• | Molten-salt external Receiver
• | Eight options for heat transfer fluid flow through the receiver
• | Rankine steam cycle
• | Polynomial regression model using design electric output, cycle efficiency, inlet and outlet temperatures, and mass flow rate
• | Storage capacity defined in number of hours at full load
• | Two-tank storage
• | Library of parameter sets for parasitic losses

Generic (Fuel-based) Systems

The generic model is a simple, linear, efficiency-based representation of the performance of a fuel-based electricity generator coupled to Solar Advisor's cost model.

Table 3. Current status of Generic fuel-based electric generation modeling

Technology | Configuration
Generic |
• | First year annual output calculated as a function of nameplate capacity, heat rate, capacity factor and other performance factors.