SolarPlus has specific tools for modelling Off-grid systems (aka SAPS), namely
Off-grid systems follow the same system design approach as grid-connect, with some minor changes.
Generator Run time and fuel cost calculations
On the Energy page, under Energy Costs, select ‘Off-grid’.
You will then be prompted to choose between:
Compare with 100% Generator. Choose this option if the client is currently running a generator to supply their loads.
Compare with Grid Connection. Choose this option if the client currently has no power and is comparing the cost of connecting to the grid against an off-grid solar and battery system.
Generator Running Cost
Tariff Name: Enter a unique name for this generator run cost profile, such as “Staunch 10kVA”
Generator kVA Output. This is the nameplate kVA rating.
Genset Fuel Consumption (litre/hr): You have the option to add this value if you know it from past consumption or generator specs. A typical value for a 10kVA Genset is 1.7L/hr.
Genset efficiency: The default efficiency of the generator is 30% and can be adjusted.
Genset Power Conversion (kW/litre): The default of 10.607kW/L suits most situations, but can be altered.
Diesel Cost ($/litre)
Genset Maintenance Cost: This is the cost of maintaining the Genset as a percentage of the running costs. This can be hard to quantify but can be considerable, so is worth including in the energy cost. This value is set at 25% by default.
Generator Load factor: This is a percentage of the nameplate capacity load. This is used for the indicator of generator suitable size in relation to the consumption. Ie if max. demand is 74kVA, and there is a 100kVA genset with a load factor of 75% then this will be deemed suitable. This is not used to indicate the generator power provided to the inverter/charger, which is set at 75%.
Genset kWh cost – This field considers all the variable parameters above to calculate the kWh cost.
Off-grid Load Profile Builder
To set the consumption profile for an off-grid job, you have 3 options:
use a Typical Profile and modify if as required,
upload .csv meter data, or
specify the specific appliances and run times using the Off-grid load profile builder.
From the Energy Page, click ‘Off-grid load profile builder' at the bottom right.
Give your profile a name
Optionally, set the Time Ranges to customise the chunks of the day you wish to organise your loads. Do not edit time periods after building your loads as this will reset the load table and clear data.
For each load, you can choose to include it in the yearly profile and/or include it in the calculation of surge rating demand. Check 'Only used with excess solar/genset' to omit this load from the yearly load profile.
Add each of your loads with quantities, power ratings and duty cycle. Then set the number of hours within each period this load is typically used. Note that load times are randomised within each time range. eg. 2 x 500kW loads that are on 3 hours out of a 9-hour time range, will be switched on and off in different hours for a more realistic load profile. (Load pattern is currently one day repeated across each season.
You can configure options for continuous load demand and surge load demand on the right side of the table.
Use the help in the heading to see the definition of each item.
When you have your loads entered and the calculated averages per season look reasonable, click 'Build Profile'.
You can now Save your data and this will populate your quote yearly consumption profile.
Return to the Energy Page.
Form for customer input
Use this spreadsheet for customers to fill in as required.
Notes for V1 of Load Profile Builder:
SolarPlus does not currently check the load continuously and surge demand against the ratings of your selected inverter/charger. Please check this yourself for now.
Please disregard the graphs generated on the Energy Page in V4 - they cannot accurately reflect seasonal variations in load.
To include in the handover manual,
in your web browser menu, select File > Print
set Zoom to 30%, and orientation to landscape
save as PDF
upload PDF on Commissioning Page
DC-Coupled MPPT charge controllers
DC-coupled charge controllers are managed in SolarPlus in the same way as PV Inverters and can be selected under the Inverter section on the left-hand side.
Off-grid System Performance Modelling
The Design Review page is similar to grid-connect systems, with the addition of a generator supply in place of the grid.
Consumption vs Production by Month
SolarPlus calculates the generator run times (green dotted line) for each month along with the comparison of Energy consumption, Solar production and Genset supply figures(dark blue bars) for individual months.
Please note that due to limitations with typical year meteorological data, generator run-time and battery hours of autonomy calculations do not account for the absolute worst case scenarios of long rain events during La Nina years, so we encourage designers to use common sense when sizing off-grid power systems to take this into account. See more here:
Daily Performance
To check that you’ve sized the system well, the most useful view on this chart is the Weekly View, which shows a series of 7 days. Select the month which has the worst sunshine, and check each week of that month to ensure that the battery charge and discharge, and generator runtimes are as you would like them to be.
You can simplify the graph by de-selecting unwanted parameters, and just showing specific ones, such as Genset Supply and Battery Charge.
Off-grid proposal template
When your design and quote are finalised, be sure to select the Off-grid proposal template to send to your customer. This can be customised to suit your specific needs.
Off-grid SLDs and System Handover Manuals
On the System Designer page, on the right under Grid Configuration, select Off-grid. This will ensure that the correct handover manual template and SLD structure is used.