Note: Peak Demand Shaving is part of a staggered rollout, so not every account has it yet. If you haven't seen it in your account so far, it should appear within the next few days.
Peak demand shaving (included for Pro and Enterprise users) is a battery dispatch strategy in which a battery energy storage system discharges stored energy during periods of high electrical demand at a facility, thereby reducing the peak power (measured in kW) drawn from the grid. Because many commercial and industrial electricity tariffs include demand charges based on a customer's highest recorded power draw within a billing period (often measured over 15-, 30-, or 60-minute intervals), lowering this peak kW value directly reduces the demand charge portion of the utility bill.
Peak Demand Shaving Simulations
To model Peak Demand Shaving in HelioScope, on the Storage tab, enter your battery specs
On the right-hand side, you can toggle the Storage Simulation on and off
Peak Shaving Configuration
Specify peak targets: By default, HelioScope auto-generates peak shaving targets from the uploaded consumption file.
Users can override this by enabling Specify Peak Targets and manually set a kW target to shave for each month (all 12 months are required).
Support grid charging the battery: When on, this allows grid power to charge the battery. Before selecting, verify if this is supported by the utility.
Consumption: You can upload a consumption file (recommended 15 min interval data upload for accuracy). Or you can enter monthly consumption values (For US-based projects, the default consumption data is sourced from NREL. Typical data is used from a nearby location and a residential base building type, pro-rated to 1,500 kWh monthly. Edit this or upload your own for more accurate storage simulation results)
Utility Rate: Select the utility rate that will be used for the storage simulation. For accurate simulation results, verify the rate includes all relevant charges, including energy and demand.
Running the simulation: Once a utility rate and consumption file are set, users can calculate peak shaving.
Peak Shaving Calculations
Once calculated, financial results populate automatically in the metrics bar at the top of the screen.
Under Peak Shaving Calculations, you will see the original peak, the new shaved peak after storage, and the annualized savings.
Scenario comparison: You can toggle settings like grid-charging the battery on/off, or compare system-generated vs. custom peak targets, by copying designs and rerunning simulations — then compare outcomes via reports/proposals/financials.
One-click simulate: After initial setup, hitting the "Simulate" button (on the design or reports page) reruns production, peak shaving, and financial calculations together — no need to jump back into the storage tab separately.
Iteration: Design changes (e.g., swapping inverters, removing modules) invalidate the prior peak shaving results, but re-simulating recalculates everything in one step. HelioScope's unlimited designs per project let users build and compare multiple storage configurations for client options.
HelioScope's Peak Demand Shaving Algorithm
HelioScope's Peak Demand Shaving algorithm is based on the automated dispatch controller model developed by NREL for the System Advisor Model (SAM). The model computes a target grid power level based on load and PV production, then dispatches the battery to charge from excess PV or the grid and discharge during peak periods — flattening demand and reducing demand charges, while respecting battery state-of-charge and monthly peak constraints. For full details on the underlying algorithm, see the NREL report here: https://docs.nlr.gov/docs/fy18osti/68614.pdf.