Multiple Systems

A multiple systems analysis allows you to model a power system as a combination of subsystems. This makes it possible to model a photovoltaic system consisting of separate subsystems with arrays oriented in different directions, or a CSP trough system consisting of two separate subsystems with different characteristics. Each subsystem is a complete electricity generating system, which means that for a CSP system for example, each subsystem would include a solar field, storage system, and power generating unit.

Solar Advisor applies a single set of financing, tax credit and payment incentives to a combined system, but applies separate performance and climate specifications to each subsystem.

The results such as levelized cost of energy and annual electric output displayed in graphs and tables on the Results page are for the combined system rather than for the individual subsystems.

For an example of a Solar Advisor file with multiple systems, open the sample template Combined Multiple PV Systems: On the File menu, click Open Sample Template and select the template from the list.

To display the multiple system simulation setup options:

1.	On the Main window, click Configure Simulations to view the Configure Simulation page.

2.	On the Configure Simulations page, click Multiple Systems to display the multiple system analysis setup options.

SS_ConfigureSimulations-MultipleSystemsClick

Contents

►	Page Reference describes the multiple system analysis setup options.

►	Setting up a Multiple System Analysis describes the steps for combining subsystems into a combined system.

Page Reference

The multiple system setup options allow you to choose which cases in the project file to combine into a system, and display the capacity and cost values for the combined system.

Select Additional Performance Outputs

List of available cases	The list of available cases shows the cases in the project file that you can combine into a single system. You must create a case for each subsystem to be combined into a single system. Solar Advisor includes only checked cases in the combined system. The list of cases corresponds to the case tabs in the project file.
Enable this simulation	This box must be checked for the system to be modeled as a combined system.

Aggregate System Variables

The aggregate system variables display values for the combined system that Solar Advisor calculates by adding values from the individual subsystems.

Variable	Description	Units
Combined Nameplate Capacity	The sum of the subsystem nameplate capacities displayed on the System Summary page for each subsystem. For photovoltaic systems, the nameplate capacity is equivalent to the total array capacity in DC kW. For CSP systems, it is the nominal capacity of the power cycle in kW of electricity.	kW
Combined Heat Rate	This applies only to generic fossil systems and is the sum of each subsystem's heat rate from the Fossil Plant page.	MMBtu/MWh
Total Direct Cost	The sum of the total direct cost values displayed on each subsystem's costs page.	$
Total Installed Cost	The sum of the total installed cost values displayed on each subsystem's costs page.	$
Total Direct Sales Tax	The sum of the total sales tax values displayed on each subsystem's costs page.	$
O&M Annual Cost	The sum of the fixed annual operation and maintenance costs displayed on each subsystem's costs page.	$/yr
O&M Annual Capacity Cost	The sum of the fixed annual operation and maintenance costs displayed on each subsystem's costs page.	$/kW-yr
O&M Variable by Production	The sum of the fixed annual operation and maintenance costs displayed on each subsystem's costs page.	$/MWh

Setting up a Multiple System Analysis

Setting up a multiple system analysis involves creating a case for each subsystem to be combined, and then selecting the cases to be included in the multiple system analysis.

After setting up the analysis, click the Run All Simulations button, or click Run All Simulations on the Case menu to simulated the combined system..

To set up a multiple system analysis:

1.	Create a case for each subsystem to be included in the combined system.

2.	Display the case that you want to be the primary system.

Solar Advisor will apply the input variables on the Utility Rate, Financing, Tax Credit Incentives, and Payment Incentives pages from the primary system to the combined system. It will ignore input values on those pages from the subsystems.

3.	Display the multiple system analysis setup options as described above.

4.	Under Select Additional Performance Outputs, check each case to include in the combined system, including the current (primary) case indicated by "This case is required" in parentheses next to the case name.

Solar Advisor displays the combined system nameplate capacity and costs under Aggregate System Variables.

Check Enable this simulation to include the multiple system analysis in simulation runs. You can save the parametric simulation setup options and exclude the analysis from simulations by clearing the checkbox. Clearing the checkbox allows you to shorten simulation run times without losing the setup configuration.