Core functionality and Use Cases
The scope of the project has been limited to three use cases that provide the most value for end consumers, manufacturers, and the energy system and that demonstrate the value of interoperability between HEMS and connected devices:
- Optimizing Self-Consumption: The HEMS maximizes the use of self-generated solar energy by intelligently distributing surplus power to batteries and/or EVs. This increases energy independence and reduces grid feed-in during local solar generation peaks.
- Dynamic Tariff Optimization: The HEMS responds to fluctuating electricity prices by shifting consumption to lower cost periods and storing energy (e.g. in a battery or hot water buffer). This reduces household energy costs and grid pressure during peak pricing periods.
- Limiting Peak Grid Demand: The DSO forecasts grid load and sends capacity profiles to the HEMS, which then limits import/export using local flexibility. This helps prevent congestion during high-demand periods, especially in winter.
Optimize the Use of Self-Generated Energy
The first use case focuses on maximizing the consumption of solar power that is generated within the household. When generation exceeds immediate household demand, the HEMS can distribute surplus energy intelligently by e.g. charging a home battery and/or EV, in order to increase self-consumption.
This not only improves the household’s energy efficiency and independence, but also optimizes electricity costs and reduces stress on the local grid, especially during periods of high solar generation.
In this scenario, the HEMS monitors local production and manages energy flows to optimize the use of self-generated power, based on local production data, local usage data, and/or smart grid meter data.
Dynamic Tariff Optimization
The second use case focuses on control that is based on dynamic electricity tariffs. The HEMS can optimize a household’s energy costs by, for instance, storing cheap power in a battery or as heat in a hot water buffer allowing the home to draw on its own reserves during expensive periods. The guiding principle is to avoid unnecessary consumption when prices are high and to exploit cheaper periods whenever they occur.
In this scenario, dynamic tariffs are provided via proprietary APIs (e.g. ENTSO-E) and communicated to the HEMS. Currently, there is no widely adopted open standard for accessing or processing dynamic tariff data. Based on feedback from the earlier RFI, market parties indicated that developing a new standard is not necessary at this stage, and proprietary solutions are currently considered sufficient.
Limiting Peak Grid Demand
The third use case focuses on limiting grid capacity. The Dutch power grid experiences constraints due to demand peaks, especially during winter. By forecasting grid load, the DSO can calculate a capacity profile that defines upper limits for both feed-in and usage. The HEMS, as the home’s central controller, receives these messages and uses the available device flexibility to always keep the household connection within specified limits at all times.
In this scenario, the capacity profile is sent either (a) from the grid operator to an aggregator, and then to the HEMS; or (b) directly from the grid operator to the HEMS. In both cases, the capacity profile is sent through an OpenADR open-source connector provided by ElaadNL.
