Why EPEX optimisation affects peak shaving behavior
When a dynamic (EPEX-based) energy contract is active, Alice optimizes battery charging and discharging based on hourly market prices. This means the battery may charge from the grid during low-price periods and discharge during high-price periods — behavior that keeps grid consumption at or near your contracted capacity limit (GTV) rather than actively reducing peaks.
If your goal is to maximize self-consumption of PV energy and minimize grid peaks regardless of market price fluctuations, you need to remove this market-driven incentive. The two approaches below let you do that.
Approach 1 — Use a fixed-price energy contract
Replacing the dynamic contract with a fixed-price contract removes the financial incentive for Alice to charge from the grid at low-price moments. Without that incentive, the battery will prioritize PV energy — both for direct consumption and for storage via the BESS — over grid energy.
The key rule Alice applies is straightforward: if the fixed grid price is higher than the configured battery surcharge, Alice will always prefer PV power over grid power. This maximizes self-consumption and prevents unnecessary grid charging.
To set this up:
Create a new fixed-price energy contract with your preferred import and export prices. See the Energy Contracts article for step-by-step instructions on creating a contract.
Assign the fixed-price contract to your simulation in the simulation settings.
Make sure the fixed grid import price is set higher than your battery surcharge to ensure Alice consistently prefers PV over grid power.
Approach 2 — Set a safety margin on the main connection
The main connection (hoofdaansluiting) includes a safety margin setting. When a safety margin is configured, Alice actively works to keep power consumption within that margin below the GTV — your contracted capacity limit.
For example: if your GTV is 160 kW and you set a safety margin of 20 kW, Alice will aim to keep peak consumption at or below 140 kW.
This lets you achieve lower actual power peaks without needing to reduce the GTV itself. Because the right margin will vary depending on your site's load profile and PV generation patterns, it is worth experimenting with different values to find the setting that works best for your specific case.
To configure the safety margin, go to the main connection settings in your site configuration. See the Main Connection Settings article for details on where to find this setting and how to adjust it.
Combining both approaches
In some cases, using either method on its own may not be enough to reach the simulation outcome you need. Combining a fixed-price contract with a safety margin gives Alice two complementary constraints to work with: no incentive to charge from the grid, and an explicit ceiling on peak consumption below the GTV.
This combined setup is particularly relevant when:
You are demonstrating peak reduction as part of a subsidy program, such as Flex E, where a measurable and consistent reduction in peak demand needs to be visible in simulation results
Your site has irregular or high base loads that make it difficult to achieve the desired peak reduction through fixed pricing alone
You want to present conservative, worst-case simulation outcomes for reporting or approval purposes