# Solar Energy Cell Efficiency - Renewable Energy

## What is Cell Efficiency in Solar Energy?

The ration between the power input and the power output is defined as efficiency. The ration of the power output in terms of solar energy electricity on the cell is efficiency related to photovoltaic.

Output power, pm = Voltage (v) * current (I) in the circuit (max value).

Input power Pi = Incident energy G (Wm-2) * Surface area of cell, A (m2).

The calculation of efficiency is as follows -

$$\eta\:=\:\frac{P_{m}}{G\: \times\:A_{c}}$$

Here, Pm should be the maximum power of the circuit. Voltage is used across open circuit (Voc) and current is used across the short circuit (Isc) for deriving Pm.

$$P_{max}\:=\:V_{OC}I_{SC}FF$$

The measurements need to be always measured under the following conditions - 25°C, Air mass of 1.5gm-3, incident energy, G of 1000Wm-2, which are considered as the standard conditions.

The output of the photovoltaic cell are affected by some of the factors such as -

• The wavelength of the incident light
• Recombination of electrons and holes
• Electrical resistance
• Temperature
• Fill factor
• Reflection factor of the material

Hence, the cells with the greater fill maximises the power. For many reasons, the output is determined by the positioning of the solar cell. The level of reflection upon the cell is determined by the angle and the amount of sunshine absorbed from 9 am to 3 pm determined by positioning. Avoid shadowing on the cells to obtain maximum efficiency.