Roof-top Solar Power

 

Roof-top Solar Power

(4 min read)

Why this Blog?

To persuade at least some readers to be producers of solar power.

Solar Power generation at home

This piece is especially for home-owners with a roof-top space of 300 sqft or more, and a willingness to invest about 3 lacs.

India’s non-fossil power

India’s non-fossil power generation capacity touched 174.53 GWs at end of 2022 with a share of 42.57% in Total Power generation capacity of 410 GW. Solar Power generation capacity was 63.3 GW, a share of 15.44% in the total, and 36.27% share of non-fossil power.

Solar Energy Potential

India has a Solar Energy Potential (SEP) of 748.98 GWs, which is 182.68% of the country’s present total power generation capacity of 410 GW.

Rajasthan, J&K, Maharashtra, MP, AP, and Gujarat have the highest SEP, as per the National Institute of Solar Energy. But other States and UTs also have significant potential.

My Solar Power Plant: Smart Investment in Green Energy

I installed a 5 KWp roof-top solar power unit on 01/11/21 at a net cost of 2.71 lacs after government subsidy of about 0.5 lac. Recently, I took stock of the performance of the unit, and the return on my investment.

While I share the details below, I may mention right away that

• ·       It feels good to be a producer of green energy, responsible for deforestation reduction by about 400 trees, and CO2 reduction by more than 2600 kgs!
• ·       Return on Investment (ROI) in rooftop solar project is far more attractive than a bank FD.

Net Export

Since Nov 2021 to Jan 2023, I generated more power than I consumed, and made a Net Export of 2161 units to the MPCZ (DISCOM for Bhopal) grid, thus making my modest contribution to the country’s mission to generate more green energy.

Highlights:

1.       Tata Solar Roof-top Unit- 5 KWp

2.       My net investment, after subsidy- 2.71 lacs (Solar panels-2.5 lac, Structure & erection-0.21 lac)

3.       Total Generation: 01/11/2021 to 15/12/2022 - 6495.8 units. Much less than the average generation of 4 units per kw (20 units per day, 7300 units a year. For 13 months, it should be 7900 units!) assured by Tata Solar. My unit was out of order for 3 weeks. Inverter blown, which was replaced free of cost by Tata Solar. But the generation loss was mine.

4.       Net Export- Units (up to Jan 2023)

4.1.   Export: 6412 (Total Generation – Self-consumption)

4.2.   Import: 4251

4.3.   Net Export- 2161 (my contribution to the power grid)

5.       Expenditure (INR) on Elec Bills

5.1.   Before solar power project: Jan-Dec 2021- 49108

5.2.   After solar power project: Jan-Dec 2022 -6194 (87.31% reduction in bill payment vis-à-vis previous year)

5.3.   Saving: 42914 (5.1-5.2)

6.       Return on Investment: 15.84% (42914/271000*100), Tax-free. In fact, if upfront subsidy of 50000 is reckoned, the RoI is 34.29% (50000 + 42914= 92914/271000*100).

7.       Yearly Return on FD (If solar plant cost were invested in FD):

7.1.   Gross- 6.5%

7.2.   Post-tax – 4.55% (way lower than 15.84%)

7.3.   Since Core Inflation is > 5%, Return on FD is Negative! RBI forecast for FY 24 is 5.3% inflation.

8.       Warranty: Solar Power Plant has 5 years Warranty against any manufacturing defect, and Solar photovoltaic modules carry a performance warranty against excess of 20% degradation in 25 years. The Company has assured me that the unit has a life of 25 years, but I guess I may not be around to verify the claim. Further, the technology for harvesting solar energy is bound to change and be more efficient in the coming years, rendering my unit sub-optimal or obsolete. But I’m happy if my total investment is repaid through savings in electricity bill over a period of 5 to 6 years.

9.       Insurance: For unforeseen damages, if any, to the solar power unit, I bought a general insurance cover for an annual premium of 427.

10.   Environmental Benefits (as per ShinePhone App of the Inverter Supplier Co)

10.1.                     CO2 Reduction/Coal saved – 2597.9 kgs

10.2.                     Deforestation reduced – 357 trees

11.   Though I am a net exporter to the grid, owing to Discom policy (fixed charges/billing on basis of month-wise consumption, and settlement of my export to grid once a year in April), I had to pay a modest billed amount during the year. Also, Discom pays me @2.00 per unit I exported, but charges me @8.0 for units imported by me. Despite these policy parameters, which I understand are specific to M.P. (a few other states have a more liberal policy to support private investment in solar power generation), I am happy to note that my electricity expenditure has reduced by more than 87%, and my return on investment is significantly higher than post-tax return on FD.

12.   Annual Tariff Hikes: Electricity Regulatory Authority issues enhanced tariff rates every year after considering the petitions by the DISCOMs and other stakeholders, and factoring in all cost variables of power production, purchase, and distribution. Since the tariff would increase year on year, the savings accruing to me from electricity bill payment would also increase.

Solar irradiance and other variables

Performance of solar unit is dependent on several variables of which solar irradiance at your location is the most important.  If your roof-top solar unit receives 10 hours or more of direct sunshine, the production will be optimum. Spraying water at least once a week to remove the layer of dust and bird droppings from the solar panel will improve performance.

Your power consumption pattern also has a direct bearing on your bill, if higher at night when you import from the grid, you pay more; so use washing machines, water pumps, geysers, etc. during peak solar power generation hours.

DBT

GoI now provides DBT (Direct Benefit Transfer) for payment of subsidy to the beneficiary’s bank account.

Current Cost

At present, a 3 KWp unit costs 2.25 lacs after subsidy of 43000, and a 5 KWp unit costs 3.25 lacs after a subsidy of 58000. Cost of tubular strucutre and erection may be about 20000 for 3 KWp and 30000 for 5 KWp. It is best to check with various dealers/Companies to ascertain actual cost of installation.

Is your roof-top rendered unusable?

No. I have installed the solar panels at a height of 8ft to 6 ft with a slant to enable me to walk under it, get my vitamin D from the sun in the morning and the afternoon, and also grow pots of flowers and vegetables under it.

Reducing Carbon Footprint

We, the homo sapiens (wise man, how very ironical!) have ravaged the earth by mindless consumption. The consequences of our greed and exploitation are staring us in the face. Now is the time for everyone to act. Each person can reduce carbon footprint by sensible and sustainable consumption. 

Those who can, may also produce green energy.

Conclusion

If you have a roof-top space of 300 sft or more, have put your long-term savings in a bank FD, and do not know of an investment that would give you more than 15 per cent yearly return, you may consider this eco-friendly investment.

***

Acknowledgement

For reading the draft of this blog and offering many valuable comments and suggestions, I am thankful to my friends and colleagues, and especially to - Subhash Khuntia, Upendra Tripathy, Dinesh Goel, Pradeep Pujari, Dev Raj Birdi, SPS Parihar, and Manu Srivastava.

***

Note: 

• Author's profile may be seen at http://amazon.com/author/pkdash
• Books by this author are available on Amazon.in, Kindle eBook, Flipkart, and Notion Press, Chennai.

***