How do I enter peak demand from customer utility bills?

For tariffs that have demand charges, SolarNexus will estimate monthly peak demand based on usage. However, this estimate can often be far off from actual peak demand. If you know the actual monthly peak demand, you can enter the actual peak demand levels on the Energy Use screen and SolarNexus will use these values instead of estimates.

To enter the actual peak demand levels from customer bills, go to the Energy Use screen, expand the Tariff Rate Criteria section, and fill in the blanks for the monthly peak demand.

SolarNexus will estimate post-project peak demand based on modeled PV output. However, again, this can be far off from actual post-project peak demand. For example, if peak demand occurs during the evening, solar will have no impact on peak demand.

To enter an estimate for post-project peak demand levels, go to the Analysis screen, click to expand the Electric Tariff section of the Analysis Parameters, uncheck "Use Pre-Project Rate Criteria", enter your estimates for monthly post-project peak demand, and then click Analyze.

To review the numbers used in the SolarNexus bill calculation, go to the Utility Bills tab of the Analysis screen and click the + next to any month to see the billing details for that month. It will show you the energy usage and demand level for that month along with the $/kWh and $/kW rates and resulting charges. 

NOTE: SolarNexus currently only supports entering peak demand levels in kW. If the tariff calculates demand charges in terms of kVA, you need to convert kVA to kW. SolarNexus uses an assumed power factor of 0.9, so you can convert kVA to kW by multiplying the kVA by 0.9. For example, if the utility bill shows 48 kVA for January, you should enter 48 * 0.9 = 43.2 in the January Peak Demand field. 

The unit for the demand values currently always show as "kW" on the Utility Bills tab even when it is actually kVA. So when the tariff measure demand in kVA, if the demand charge for a month says e.g. 48 kW, that actually means 48 kVA.