Basic Solar Energy Engineer Interview Questions and Answers (Q&A)

Basic Solar Energy Engineer Interview Questions and Answers

Are you passionate about renewable energy and interested in pursuing a career in the field of Solar energy plant? Congratulations! To help you with that, we’ve collected a list of Basic Solar Energy Engineer Interview Questions and Answers (Q&A). Solar energy plant is a rapidly growing field that plays a crucial role in combating climate change. Before you step into your solar energy engineer interview, it’s essential to be well-prepared for the questions that may ask by interviewer. Please go through and review it before your Interview.

Basic Solar Energy Engineer Interview Questions and Answers (Q&A)

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1. What is solar energy, and how does it work?

Answer: Solar energy is the energy which harness from sunrays in terms of Photon energy and converted into electricity by using PV Cell (Photovoltaic cell). Photovoltaic cells absorb sunlight and release electrons which generating direct current (DC) electricity. This DC electricity is then converted into alternating current (AC) electricity using inverters for household or industrial use.

2. What are the Types of Solar Panel?

Answer: The Solar panel divided into 4 categories. The solar panels are determined by the type of solar cells present in it. Each cell has a unique characteristic and has a different appearance. 

1. Monocrystalline solar panels

2. Polycrystalline solar panels

3. Thin-film solar panels

4. Passivated Emitter and Rear Contact cells (PERC) solar panels

3. What are the key components of a solar PV system?

Answer: The main components of a solar PV system include:

  1. Solar Panel (PV Panels)
  2. MMS (Module Mounting Structures)
  3. SCB (String Combiner Box)/SMB/AJB
  4. Inverters
  5. Transformers
  6. HT Panels or Switch Gears
  7. Battery Bank
  8. Electrical Cables
  9. WMS (Weather Monitoring System)
  10. SCADA
  11. Battery Charger
  12. LDB (Lighting Distribution Box)
  13. ACDB (AC Distribution Box)

4. What are the Different Parts of Module Mounting Structure (MMS).

Answer: The Module mounting structure (MMS) is used for mounting PV panels or Solar panel. Parts or components as follows.

  1. Cloumn Post
  2. Rafter
  3. Bracing
  4. Purlin
  5. Cleat
  6. Mounting Clamp
  7. Nut-Bolts

5. What is Solar Structure or Table?

Answer: Solar Structure or Table means a group of PV panels mounted in MMS either in Portrait or Landscape mode as per required angle for optimum harnessing solar energy.

6. What is the meaning of String in Solar Plant.

Answer: A string in solar plant means combination of Two tables or Structures by using Y-Connector or T-Connector. It connected parallelly with two Tables which used for increasing current capacity.

7. What is the meaning of PV ROW or Array?

Answer: A PV Row or Array means a number of PV table or structure placed in a line with some calculated gap.

8. How PV panels are connected electrically in a Table or structure?

Answer: Series connection is used for connecting required number of PV panels in a Table by MC4 Connector. With series connection all PV panels voltage added but current remain constant.

9. How PV panels are connected electrically in a String?

Answer: Parallel connection used for connecting two PV table or structure by Y-Connector or T-Connector. With Parallel connection both tables current increased by keeping voltage constant.

10. Can you name some PV panels or Solar Module Make?

Answer: There are different types of PV panels company available. Here are some names for reference i.e., Vikram Solar, Trina Solar, ZNShine, Telsun, Emmvee Solar, Waree, Tata Power, Loom Solar, BYD etc.

11. What are some Major Advantages of Solar energy?

Answer: Here Some Major advantages of Solar energy offers are as follows.

  1. No harmful emissions
  2. Renewable Energy Source
  3. Saves Environment
  4. One-time investment
  5. Reduced electricity bills

12. What are the Different Kinds of Solar PV systems?

Answer: There are three main types of solar PV systems.

  1. Grid-connected systems: These systems are connected to the utility grid and allow excess electricity to be fed back into the grid. They are commonly used for residential and commercial applications.
  2. Off-grid systems: These systems operate independently of the utility grid and use battery storage to store excess electricity. They are suitable for remote areas with limited or no access to the grid.
  3. Hybrid systems: These systems combine both grid-connected and off-grid features, utilizing battery storage and a backup generator to provide power during grid outages.

13. What is STC means in PV Panel?

Answer: STC means Standard Test Condition on which Solar modules give full rated power. Standard condition test in Lab under criteria of Irradiance is 1000W/M2, Temperature is 25oC, Air mass (AM) of 1.5.

14. How to Calculate Solar Panel Efficiency?

Answer: The equation below can be used to calculate the approximate efficiency of a solar panel, as a percentage:

For Example: If power module is 300W or 0.3kW, it is 1.64m long and 0.99m wide. The efficiency is: 18.1%

15. What is Fill Factor in Solar Energy?

Answer: The fill factor, very commonly abbreviated as FF in solar energy technology is a measure of how closely a solar cell acts as an ideal source.

The following formula is used to calculate the Fill Factor. FF=P/(VI)


FF is the Fill Factor ( )
P is the maximum power from the solar sell (W)
V is the open circuit voltage (volts)
I is the short-circuit current (amps)

16. What are the different types of problems affecting Solar Panels?

Answer: Here are the most common problems affecting solar panels:

  1. Micro-cracks
  2. Delamination and internal corrosion
  3. Hot spots
  4. PID effect
  5. Snail trails
  6. Back sheet chalking

17. How do Solar Panel Works?

Answer: Solar panels are made out of photovoltaic cells that convert the sun’s energy into electricity.

Photovoltaic cells are sandwiched between layers of semi-conducting materials such as silicon. Each layer has different electronic properties that energize when hit by photons from sunlight, creating an electric field. This is known as the photoelectric effect – and this creates the current needed to produce electricity.

18. What is Photovoltaic Effect?

Answer: The photovoltaic effect is a process that generates voltage or electric current in a photovoltaic cell when it is exposed to sunlight. It is this effect that makes solar panels useful, as it is how the cells within the panel convert sunlight to electrical energy.

19. What is the Use of String Combiner Box (SCB-SMB) in Solar energy?

Answer: String Combiner and Monitoring Boxes (SCB-SMB) are used as combiners” that collate multiple strings of solar PV modules to give a single main output to inverters. It is used as wire reduction, otherwise it will be difficult to trace any string fault from bunch of Cables.

20. Why lightning arrester (LA) is used in PV Field?

Answer: It used to protect electrical equipment’s like PV modules, Inverters, SCB etc. from Lightning strike. LA is used as protection which ground high surge which coming from lightning.

21. How to calculate performance ratio (PR) of solar power plant?

Answer: The performance ratio (PR) is stated as percent and describes the relationship between the actual and theoretical energy outputs of the PV plant. The performance ratio (PR) is stated as percent.

Performance Ratio (PR) of a plant for a period of time ═ Daily Energy Produced (kWh) / (Irradiance Actual (kWh/m2) x Plant Capacity (KWh) *100

23. How to calculate Capacity Utilization Factor (CUF) of Solar plant?

Answer: Capacity Utilization Factor (CUF) =Energy measured (kWh) / (365*24*installed capacity of the plant) x 100.

24. Which Instrument is used for measurement of solar Irradiance?

Answer: A pyranometer is an instrument used to measure the amount of solar radiation (power) the sun produces in a specific location.

25. What is WMS system in Solar Plant?

Answer: Weather Monitoring Station (WMS) is one of the most crucial instruments installed in Solar PV Power plants. A weather monitoring station can be immensely helpful in monitoring the efficiency and performance of any solar power plant. In WMS system following parameters are monitored.

  1. Irradiance or Radiation
  2. Module Temperature
  3. Ambient Temperature
  4. Rain
  5. Wind Speed
  6. Wind Direction
  7. Humidity
  8. Pressure
  9. Wind Gust

26. What are the factors that affect solar Power Generation?

Answer: There are several factors which can affect solar power generation. Here as follows.

  1. Soiling
  2. Shadow
  3. Bird dropping
  4. Hot Spot
  5. Mismatch
  6. PID
  7. Diode Failure In PV Module
  8. Cell Hot spot
  9. Plant Availability & Grid Availability
  10. Inverter Efficiency
  11. PV Panel Degradation
  12. Temperature

27. How to Improve Performance Ratio (PR) of Solar Plant?

Answer: Performance ration Directly depends on Energy Produced and Indirectly depends on Irradiance. If we improved our generation then Performance Ration will also improve. Several factor which affects Generation in Solar power Plant.

  1. Soiling (Need to periodically clean Solar PV module to reduce Soiling Loss)
  2. Shadow (Vegetation management, Bird dropping or any other which directly affecting solar generation)
  3. Plant Availability (Keep Plant availability 100% by Minimizing downtime or try to rectify any fault on Priority Basis)
  4. Grid Availability (Try to keep Grid Availability 100% by Through checking of Transmission line)
  5. PV Panel Degradation (Test PV panel as YOY PV panel degraded 0.7 % but there are several factors due to which degradation of Solar panel is more. Test By Taking Thermography, IV Curve, EL test, Flash Test of PV module etc)
  6. Inverter Efficiency (Check Inverter Efficiency and do proper Maintenance of Inverter to Improve its performance i.e. Do Frequent Filter cleaning, Check Temperature, Check Settings etc.)
  7. Proper Maintenance of Equipment (Do Maintenance as per OEM Guideline)
  8. Spare Management (Proper spare management can reduce your plant downtime)

28. What is the Standard operating Procedures (SOP) for Solar Panel cleaning?


  • During Wet cleaning, quality of water is crucial when cleaning solar modules. Hard water may cause defects on module as in long time frame you will observe water scaling due to deposition of high mineral content on glass surface. It will decrease module efficiency. So, it required to test your water frequently from Trusted LAB. If Hardness found more, then you can opt for RO system for Module washing. High mineral content water is not recommendable.
  • For Good Wet cleaning, you need to have good quality wiper or brush. Always use water & Sponge cloth for Cleaning. A mild, non-abrasive cleaning agent can be used to remove stubborn dirt. Do not use abrasive sponges or aggressive tools that could scratch the module surface.

Also read: Solar Panel Cleaning Standard Operating Procedure (SOP)-Engineers Guide

29. How to decide Module cleaning Schedule?

Answer: The cleaning schedule can vary based on the site location, weather conditions, and the level of soiling. Develop a cleaning schedule based on the site-specific needs and environmental factors. If the soiling on module is more than you required to do more cleaning as compared to low soiling area.

30. What is the suitable time for Solar Panel cleaning?

Answer: The recommended time for cleaning modules is during low light conditions when production is lowest. However, when sun shines during the day, the panels also get heated up and cleaning solar panels with cold water in evening may result in thermal shock for panel which can permanently damage them which also called thermal damage. Hence, the best time to clean Solar Panels is early mornings, when the plant is not in operation, risk of electrical shock hazard is minimum and also temperature of solar panels is not high.


These are some basic Interview Questions that you should prepare before technical round interview. Please go through and Type on comment section if any doubts you have.

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