How much tilt should photovoltaic panels have to be to be effective

To optimize performance, tilt your panels at an angle that is 10-15 degrees less than your latitude. For example, if you live at a latitude of 40 degrees, set your panels at about 25-30 degrees. [pdf]

Solar engine power generation calculation

The annual power generation can be calculated using the formula: Annual Power Generation = Solar Radiation at Specific Angle × Module Installation Capacity × Comprehensive Efficiency Coefficient [pdf]