1. ECE/OPTI 4/514a NREL System Advisor Model Demonstration
Photonics Systems Laboratory
Department of Electrical and Computing Engineering
University of Arizona
ECE/OPTI 4/514a NREL System Advisor Model Demonstration
By: R.A. Juan M. Russo

2. What is SAM?
Financial calculator that takes into account the time value of money.
PV: Present value
Complicated legislation on incentives
Energy rates
Costs: (initial, ongoing, installation, BOS, etc.)
Engineering calculator for system performance
Database of equipment or simple models.
Weather/location (incl. shading, tracking, etc.)
Energy consumption of the customer

3. Time Value of Money
What would you prefer? $100 USD today or $100 USD in a year?
Having the money today is more valuable than in a year. I could invest it, use it for an asset that produces income, etc.
What would you prefer? $100 USD today or $110 USD in a year?
Now, waiting to get the money is worth $10 USD.
Is it worth it? Depends on the financial environment…

4. TVM and Solar Energy The system lifetime is long (20+ years)
System initial costs are high
System has ongoing costs throughout its lifetime
We need a metric that compares apples to apples:
Levelized Cost of Energy (or Electricity)

5. LCOE
In $/kWh is basically all the cost divided by all the energy the system will be able to produce.
Cost include initial, ongoing and financing costs.
LCOE treats energy as if it was money (so subject to TVM)
Will include incentives paid by Federal and State governments as well as utilities.
Nominal vs. Real: nominal takes into account inflation.

6. Costs Direct Costs: Indirect costs: O&M costs:
Inverter and modules (in $/WDC or $/Unit)
BOS: wiring, racking, etc. (in fixed $, per WDC or per area (m2)
Installation
Indirect costs:
Overhead type.
Permitting
Sales taxes
O&M costs:
$ Fixed, per kW installed, per MWh. All per year.
Maintenance costs

7. Performance (Energy Yield)
Choose location
Choose the PV module and Inverter
From model list or Enter your own parameters
Design your array:
Have SAM figure it out (tell SAM the desired array size) or Manually describe the array (Inverters, strings, modules/string, etc.)
Input system de-rates
Energy losses due to BOS components, soiling, etc.
Tracking or no tracking
Choose your model for incident radiation

8. Shading and Load Shading: Electric load:
If you know the shading of the site you can enter it here: in % shade vs hr of day or %shade at AZI and POLAR coordinates.
Electric load:
Customer provides a profile of the energy consumption of the household (i.e. from energy audit or recording device)
Helps determine real cash flow of the system.

9. Run your simulation
SAM will use TM2 weather data for the location entered and calculate performance for the first year.
Subsequent years are calculated based on first year and degradation rates, interest rates, escalation rates, etc.

10. Other features Parametric simulations
Sensitivity analysis (tornado graphs)
Optimization
Statistical analysis
Compare systems
Links to MS VB for Applications and MS Excel
Proprietary Scripting language

11. Other tools out there Specialized: Optical and general Eng. tools:
NREL SAM (U.S.) (free)
PVSyst from PVSyst SA (Switzerland) (800 CHF)
CAD interface for shading analysis
Optical and general Eng. tools:
Ray tracing software + MS Excel (may not take into account temperature)
MATLAB

12. Questions?