> For the complete documentation index, see [llms.txt](https://docs.alphaess.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.alphaess.com/alphaess-app/function-module/power.md).
# Energy Data
### What is the difference between kW and kWh
These are two units that are easy to confuse, but have different meanings:
* kW - Power: indicates the rate at which electricity flows at a certain moment, that is, how fast a device is currently producing, consuming, charging, or discharging. The value changes in real time with the system state and is used to describe the "current state".
* kWh - Energy: indicates the electricity accumulated or consumed over a period of time. Running at a Power of 1 kW for 1 hour equals 1 kWh, and is used to describe the "cumulative total".
In short, kW reflects instantaneous Power, while kWh reflects accumulated Energy. Therefore, the real-time data in the home energy flow diagram on the homepage is shown in kW, while historical Energy statistics and electricity billing are shown in kWh.
### Real-time Power Overview
The homepage shows your household's current energy status. In the household energy flow diagram, you can see:
* **PV generation Power (kW):**Current solar generation status
* **Battery status:**Shows the battery's charge/discharge Power (kW), current Energy (SoC, %) and operating status (Charge, discharge, or standby)
* **Household load Power (kW):**The electricity your household is currently consuming
* **Grid Power (kW):**Shows whether electricity is currently being drawn from the grid or fed back into the grid
* **EV Charge point Power (kW):**Displayed only when the system is connected to a Charge point
The direction of energy flow shows where energy goes between devices, helping you quickly understand the current energy usage pattern.
### Historical Energy data
In **Energy** page, you can review your household's generation and energy usage over different time scales. You can view:
* PV Generation
* Battery charge/discharge Energy
* Household Energy usage
* Grid import and export Energy
These data help you understand your household's energy usage habits, as well as the system's performance over different periods.
### How to read Energy charts
Energy charts are used to show trends in energy changes, rather than instantaneous values.
* During the day, solar energy is usually the main source of power
* At night, the system relies more on the battery or the grid
Click the **stacked display** button at the bottom of the chart, and the Energy chart will use different colors to distinguish the sources and destinations of energy, helping you intuitively understand the household's energy composition during each period. For example: on rainy days, household electricity use comes more from the battery or the grid; on sunny days, it is usually mainly solar energy.
### Renewable energy achievement
**Renewable energy achievement** Shows how much of your household energy use truly comes from solar and the battery. The system calculates, based on the household's total Energy consumption within the selected time range, the proportion supplied by renewable Energy, and presents it intuitively. As this proportion continues to increase, your household will:
* Reduce dependence on the grid
* Lower electricity costs
* Move closer to a sustainable lifestyle
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Renewable energy achievement is affected by seasons and weather. When there is less sunlight in winter, the value is usually lower than in summer. If the value remains low for a long time, it usually means solar supply is insufficient, and you may consider increasing the installed PV capacity or optimizing the system configuration.
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