The GoodWe SEMS Portal provides extensive energy and system data. Terms like yield, self-consumption or energy independence seem clear at first, but often lead to misunderstandings in practice. This article explains the key metrics in the SEMS Portal and puts them into context.
An overview of the monitoring system can be found in GoodWe SEMS Portal: Features, Login & Data Overview.
What Data Does the GoodWe SEMS Portal Show?
Depending on system configuration and installed measurement hardware, the following values may be displayed:
- PV yield
- current power
- electricity consumption
- self-consumption ratio
- grid consumption
- feed-in
- battery state of charge
- system status
Not every system automatically shows all values. Scope and accuracy depend on inverter type, meters and storage system.
Yield in the SEMS Portal
Yield describes the energy generated by the photovoltaic system. It is measured in kilowatt-hours and is typically shown as:
- daily yield
- monthly yield
- yearly yield
- total yield
Yield only indicates how much electricity was produced, not how it was used.
Power vs Yield: Important Difference
A common misunderstanding is confusing power with yield.
- Power (kW) is the current electricity production.
- Yield (kWh) is the amount of energy generated over time.
Fluctuating power values are normal and depend on weather, time of day and consumption.
Understanding Consumption and Self-Consumption
Consumption describes the total electricity demand of a household or business.
Self-consumption is the portion of generated solar energy that is used directly or later taken from the battery.
A high yield does not automatically mean high self-consumption, as part of the energy may be fed into the grid.
Grid Consumption and Feed-in
Grid Consumption
Grid consumption refers to electricity drawn from the public grid when the PV system does not produce enough or the battery is empty.
Feed-in
Feed-in is the portion of solar energy that is not used on-site and is exported to the grid.
In simplified terms:
PV yield = self-consumption + feed-in
Small deviations due to measurement differences are possible.
Battery Values in the GoodWe SEMS Portal
For systems with battery storage, the SEMS Portal provides additional data:
- battery state of charge in percent
- charging power
- discharging power
The battery increases self-consumption by storing excess solar energy.
Why Do Values Fluctuate During the Day?
Fluctuations are technically normal and caused by:
- changing solar irradiation
- varying household consumption
- internal energy management strategies
- battery charging and discharging cycles
Individual data points should not be evaluated in isolation.
Energy Independence and Self-Consumption Rate
The SEMS Portal often displays metrics such as:
- energy independence rate
- self-consumption ratio
These values are useful for trend analysis but should not be evaluated based on a single day.
Data Delay in the SEMS Portal
Data in the SEMS Portal is updated with a delay.
This means:
- no guaranteed real-time data
- updates typically occur within minutes
- daily values are only complete at the end of the day
For accurate analysis, completed time periods should be used.
Common Misunderstandings About SEMS Portal Data
- High yield does not mean high energy independence
- Low feed-in is not an error
- Differences between app and web portal are normal
- Short-term fluctuations are system-related
Data should always be evaluated in context.
When is SEMS Portal Data Sufficient and When Not?
Sufficient for:
- single systems
- private use
- general overview of energy flows
- optimizing self-consumption
Limited for:
- multiple locations
- cross-manufacturer analysis
- precise billing
- external reporting
Frequently Asked Questions about GoodWe SEMS Data (FAQ)
Why do yield and consumption not match?
Yield refers to produced energy, while consumption refers to used electricity. Part of the generated energy is either fed into the grid or stored.
Why does my electricity meter show different values?
Grid operator meters are legally calibrated. The SEMS Portal uses internal measurements that may differ in timing or method.
Why don’t I see consumption data in the portal?
Without proper measurement hardware, consumption cannot be accurately displayed.
Is the data real-time?
No. Data is updated with a delay and is intended for analysis, not second-by-second monitoring.
