Rooftop solar PV in India – Gujarat and Kerala show the way

With the power tariff hikes and the rise in power cuts in most states, rooftop solar PV is increasingly being viewed as a solution to these problems. As we mentioned in an article last week, there is a growing optimism that rooftop solar PV has a huge potential and with proper policy and regulatory support, rooftop solar PV will take off in a very big way. Two states, Gujarat and Kerala, are implementing rooftop policies which are capable of unlocking the potential and mainstreaming rooftop solar PV.
The fascinating aspect of the rooftop PV policies is how different they are. While the Kerala policy is only for off-grid systems, the Gujarat rooftop model is grid connected. Let us examine some of the differences.
It is too early to say which model is better. But what these two states have shown is that rooftop can be mainstreamed with some imagination and will power from the administration. Will other states follow? We will know soon..

4 thoughts on “Rooftop solar PV in India – Gujarat and Kerala show the way”

  1. Mr. Madhavan,
    Thanks for your expert opinion and a good presentation on comparison of policies of two states.Could you through some light on the constraints of Roof Top systems to connect with grid especially in Discoms point of view and Consumer’s point of view.
    Can you suggest, some ways, to restructure the solar policies of state governments ( which are extending some incentives to the solar developers to attract investment and those incentives are making the developers to ineligible for REC mechanism), even if the incentives offered are enjoed by the developer still they should fit into the REC mechanism as per the existing REC regulations of central as well as State.

  2. Hello Nagesh,
    There are innumerable technical issues/constraints involved in grid connected solar PV rooftop, a list highlighting a few are given below.
    1. Grid Synchronization – the inverter will automatically sync its voltage and frequency as per the grid requirements. In India, the grid is never stable, so will can exp lots of sync issues.
    2. Over voltage condition – Grid inverter has to isolate from the grid automatically during this condition
    3. Low voltage below the preset value – inverter has to automatically switch off/disconnect within few milliseconds.
    4. There could always be possibility of something being wrong with the inverter and it continues to put electricity to the grid in the event of grid failure. “Grid failure” detection is very important with inverter.
    5. Injection of DC power into the grid – Isolation of DC is very important. If the inverters are transformerless there is a possibility of DC injection into the AC side. To avoid this external insolation transformers must be installed on the AC side.
    6. THD – Total Harmonic Distortion level should be kept below a certain value (Voltage-THD should be less than 5% as per CEA regulations). These harmonics are caused by non-linear load and proper measures must be taken by the DISCOM by installing harmonic measurement meters and harmonic filters to maintain it below the regulation level.
    7. Voltage level of primary side of distribution transformer (step down transformer)- usually 11KV in TN. So there is a requirement for additional transformer which has to collect all the big rooftop outputs (usually >100kWp) together and step us to the 11kV level (So, lots of infrastructure changes will be required – who will take up this cost? DISCOM or rooftop owners?).
    Giridaran Srinivasan

  3. Hi – This comparison was made in 2012. Now 2 years down the line what is the situation of the 10 MW in kerala and 5 MW in Gandhinagar?

  4. Looking back, as a proud customer of the 10000 Rooftop solar plant project, I can summarize as below.(as on 02 June 2014)
    1) Minister talked about 4-5-6-7 units per day.
    2) The booklet supplied along with the eqpt. says about 2.5 to 3 units per day
    3) Reality seen now a days is only 2 units.
    4) ANERT of Kerala has almost absolved itself of the responsibility after collecting Rs.500/- per connection.
    5) The installing agency will ask you to wait for next day for increase in sunshine.
    6) If summer is like this, then monsoon and winter is left to anyone’s imagination.
    7) I am the owner of a costly inverter running on God’s grace (solar power) in God’s own Country.

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