Cost and Payback of Solar Roof Top PV power plants for Homes and Apartments in India

How does the cost and benefits of Solar Roof Top PV power plant work out for Home Owners, Apartments or other residential  electricity consumers in India ...

Solar roof top power plants  can be installed by different type of consumers in India  - Domestic consumers or home owners  ( including Apartment common areas ) , Commercial building consumers , Industrial or Factory consumers 

Lets us look at Home owners  or Apartment common areas  - Who are ideal candidates among home owners for Ongrid Solar roof top power plant in India ?

First - If your average monthly electricity consumption is at least 300 units ( kwhr ) or your monthly bill amount is over Rs 2500  - you can start with a 2.5 to 3 kw solar plant ( the consumption needs to be in one meter , not combined with different meters). You should also ensure that you can install the Solar Roof Top Power plant under Net Metering scheme by your ESCOM or Electricity Board , as this will be much more beneficial in savings compared to Gross metering scheme -where you may be saving much lesser than Net Metering.

Next- If you have shadow free area of at least 30 sq mtr on your terrace  ( 300 sq ft for 3 kw plant)  - or 10 Sq mtr for every kw of solar power plant planned  ( and ensure that installer's is the owner of the building and their name is on the monthly electricity bill ) Please keep in mind that the Solar PV panels needs to be cleaned periodically to get better performance and the expected output of eletrical units. 

Finally, Since the cost of the On grid solar power plant ( without battery storage)  in todays market would be from Rs.65,000 to 80,000 per kwp for such small plants of capacity 2.5 kw to 5 kwp - the consumer can recover the cost of installation of the plant in 6- 8 years. If your solar power plant capacity is higher than 5kwp then the payback may be quicker than the 6 years depending on your consumption and ESCOM tariff paid by you. 

Additionally - If you can avail subsidy for the solar power plant  - then the budget for the solar power plant may reduce by about Rs 9000 to 18,000 per kwp of plant capacity depending on the capacity of the solar plant, and with subsidy benefit the payback from the solar power plant can be achieved faster in 3-5 years. 

If you are going for Solar power primarily for cost savings and returns - then you should pay attention to the payback on your investment and life time returns from the investment in Solar power plant. It is recommended to install the right capacity of Solar roof top power plant matching with the units consumed by that home. If your solar power plant is sized to always generate more units than units consumed by your home -  the exported units may be paid at a rate of Rs 2.50 to 4.00 by the ESCOM ( Electricity board) - much lower than the savings of Rs. 6.00 to Rs 9.50 realized for your consumed units. So exported units beyond home consumption will offer slower savings and payback will be delayed by few years.

Since the life of Solar power plant is considered to be 25 years - after payback the remaining period of Solar power plant life would provide free power of the capacity of the plant to the home 

As a side note- If your area has reasonably continuous power supply ,  since on grid solar power plant without battery storage works only when ESCOM of Electricity board power is available. There are hybrid solar power plants for Ongrid  which can provide battery storage and backup -  but these are limited due to high cost and low availability of the approved Hybrid inverters for Ongrid power plants

If your electricity consumption is lower than 200 units - then the cost of the solar roof top power plant will be high compared to the savings from the electric units generated by the solar power plant, this is due to the high fixed cost of some of the electrical cables, meters, earthing cables and pits that are required as per the ESCOM or Electricity Board norms - even for a Solar roof top power plant of 1kwp 

To achieve the size of solar roof top power plant of say 3kw -  the solar panels can be selected from the suitable size - 9x 330 wp panels , or  6x 445 Wp  or 5 x 540wp. As per ESCOM or Electricity board norms the solar power plant capacity cannot exceed the sanctioned load of your home meter ,  if your home meter is 3 kW then you can install plant of 3000 Wp or lower , not even marginally higher than 3000 Wp. 

 Solar PV panels can be of basic  Polycrystalline type, or Mono crystalline type which gives about 10% more output , or half cut Mono crystalline panels which can be suitable if shadows in the early morning or late evening hours - reduce the output of solar plants.  The On grid  inverter for your Solar roof top power plant can be single phase or three phase based on your home meter type. The Solar PV panels, Solar inverters  and Bidirectional meters may need to be approved by the ESCOM or Electricity Board or BIS certified -based on the state norms.  

The first step in getting your Solar roof top power plant installed is to apply to your ESCOM or Electricity Board , get a feasibility approved and sign a Power Purchase Agreement signed with your ESCOM - which is usually for a duration of 25 years. Then you can proceed to get your Solar power plant installed on your roof, and once installed the commissioning of the solar Roof top power plant can be done after the approval of the ESCOM or Electricity Board.

 After the Solar power plant is commissioned the consumer will receive a detailed net metering bill from the ESCOM , instead of the previous simple monthly electricity bill,  showing the Solar power generated , the units consumed by the home and any exported units - along with the savings and any extra amount still payable to the ESCOM. 

Once the Solar power plant is commissioned the routine maintenance of Solar roof top power plant is limited to cleaning the Solar panels periodically to remove dust and stains. Minor faults in the inverter either get reset after power off /on and if inverter fault persists it may require visits by service technicians.

In our later blogs we will look at the cost and benefits of Solar Roof top PV power plants for Commercial and Industrial consumers in India.  If you have further questions on Solar Power - please check out our other blogs or podcasts, or drop a comment in this blog. You can also visit our website www.ecopowermitra.in or www.vineetitechnologies.in