[Thilak29]

Originally Posted by docsr

1. Are the various components listed standard
2. Is the costing reasonable
3. How do I decide between the 3Kw and 5Kw
4. Is there a facility to add batteries to this rig at a later date
5. Any infö about the company Wenergie
6. Anything else I should consider

I own a Kona Electric that is currently being charged via a dedicated electricity meter, different than the domestic house one. Can I charge the car via the solar panels?
.

Seems pricey for poly setup, also in this arrangement seems like the entire responsibility remains with the 'empanelled vendor' and you don't have a say in choosing the components?
Decide between 3kW/5kW by looking at your monthly power consumption history over 12/18 months.
You can add batteries part of the inverter at home but on-grid won't become an off-grid one without significant revamp.
Does Kona need 3 phase setup ? If yes, make sure your grid-connected solar too is on same if you wish to use power from there.

Originally Posted by Sankar

If you are not getting subsidy there is no reason to use poly panels, these only reason to use poly panels is that mono panels do not qualify for govt subsidy.

As part of my RTI discussions, I am told when solar is subsidised the purchase tariff also goes down significantly. Poly is age-old tech so I felt it's worth going for mono with a slight premium.

[SKC-auto]

Originally Posted by docsr

Thanks for the very informative writeup.
I had applied to BESCOM for it's solar panel promotion (Sourya Gruha Yojana)

The pricing seems on the higher side if they are already subsidized.

The panels usually produce 4 units in a day, if you are using 3kw system you get 12 units, if you are using 5kw system you get 20units of energy. Take your monthly bills and see if your monthly usage is less than 12*30=360 units then go for 3kw system, if your usage is around 20*30=600 units then go for 5kw system.

[Sankar]

Originally Posted by docsr

I own a Kona Electric that is currently being charged via a dedicated electricity meter, different than the domestic house one. Can I charge the car via the solar panels?

This is not EV meter specific but unless there is a better solution this can be a workaround and is legal. Details given below is from KSEB but similar should be available from BESCOM as well. In solar application form there is a provision that allows the solarunits produced at an ongrid solarplant at one location to be used elsewhere. There are a few caveats and they are as below:

1) Both connection agreements should be under the same name. I.e., connection which has the ongrid solar plant and the other sada metered connection elsewhere.

2) Min 500 solarunits per month should be available for export. Ie., during daytime solarplant will be powering your home and at 6pm solar production ends (ongrid inverter is programmed to work between 6am and 6pm but production ends earlier if there is no sun) and from 6pm to 6am grid power will be used. If solarexport (after local consumption) during daytime is higher than consumption from grid during night there will be a +ve balance (surplus) in the netmeter. This means no need to pay for electricity anymore. But if consumption from grid is higher than local production balance is -ve in the netmeter and payment should be made for excess units consumed, there is no surplus. So if there is minimum 500 solarunits surplus each month one qualifies for the solarunits produced to be used elsewhere.

3) About 5% from soalrexport will be deducted as transmission loss and for other expenses. Meaning if one exports 500 solarunits per month from the residential solarplant they can only claim 475 units deduction from your other connection's monthly bill.

4) This should be mentioned while making the aplication for ongrid solar plants.

Originally Posted by docsr

Thanks for the very informative writeup.
I had applied to BESCOM for it's solar panel promotion (Sourya Gruha Yojana). The wheels turned sloooowwly! After the initial verification, the local AE came to do a site inspection and took measurements.

Follow up with BESCOM to find out if your site qualifies for subsidized grid installation. They will only approve if there is enough sun available without shade throughout the day and if there is ease of maintenance and accessibility for electric company personnel.

Again after a long gap, today, I received an email with a formal quotation under this scheme. I have attached the quote. This seems to be from a company called Wenergie.

Attachment 2133441

If your site qualifies for subsidised installation from BESCOM you are free to choose from their list of approved vendors, there will be many apart from this particular one.

If your site do not qualify for subidised installation you are literally free to choose from any qualified ongrid solar plant installer. Choose one who gives the best deal, has a few years experience in this field and who can liaise with bescom for approvals et al.

The quote you have got, like I mentioned earlier is on the higher side. Go for mono solar panels. Go for 5KW solar plant if finances allow. Is your home supply 3 phase or 1 phase? If its 3 phase you can use a 3 phase or 1 phase solar inverter. Single phase inverters can only go upto 5kw. If your residential supply is 3 phase you can choose to go with either 1 phase inverter or a 3 phase inverter (more expensive) if you plan to put more panels on the roof and take it beyond 5kw.

Originally Posted by Thilak29

As part of my RTI discussions, I am told when solar is subsidised the purchase tariff also goes down significantly. Poly is age-old tech so I felt it's worth going for mono with a slight premium.

Yes, its better to use mono panels and the premium is justified.

[docsr]

Thank you all for the very valuable and practical advice.

I spoke to the vendor today.

1.The quotation given is the unsubsidised rates.

2.I believe BESCOM has not come up with the subsidy they are going to provide. There is not even a probable time line as to when this will happen. So either I wait till the BESCOM clarifies matters (may be several months) or go ahead now with no subsidy (with an expectation that the purchase agreement with BESCOM will hold and that they may or may not offer any subsidy on the installation)

3. The same vendor has mono panels ( the panel cost will go up by about 10-12%.

4. I have asked for a site visit a more detailed costing.

Will keep updating as I go through this process.

Regards.

[Sankar]

Originally Posted by bejoy

My uncle who retired from KSEB have the 3KW on-grid setup at his home in Kerala and and here are some titbits from him:

• The on-grid setup will be allowed by first come first serve policy only. This is because KSEB maintains a percentage of power generation by homes for each end transformer. i.e. if the last transformer is 100KW, only 13.5kW return generation is allowed. He got it right in time as a nearby school had already put up a 10KW setup.

If last transformer is 100KW and max return feed is 13.5KW then its just 13.5% of transformer capacity. Isn't that too low?

In a recent KSEB solar plant feasibility report I saw the return feed allowed is 75% of the transformer capacity.

[bejoy]

Originally Posted by Sankar

If last transformer is 100KW and max return feed is 13.5KW then its just 13.5% of transformer capacity. Isn't that too low?

In a recent KSEB solar plant feasibility report I saw the return feed allowed is 75% of the transformer capacity.

More than the technical capability, it has to do with the throttling capability of the power generation. There is periodic power purchase trade that happens between the power producing companies and the national grid. This is based on the demand at any point of time and the rate for the power purchased varies based on this. What I understand is that it the rates are negotiated multiple times a day. If a producing board has less demand and there are no takers for excess supply, there is a chance for the generators becoming unstable. So throttling of the production is necessary. For KSEB, majority of production is via Hydro electric, and it has control over all the generators. But the solar electricity generated by households cannot be controlled. So they keep a margin of what power generation that can be controlled.

[Sankar]

Originally Posted by bejoy

But the solar electricity generated by households cannot be controlled. So they keep a margin of what power generation that can be controlled.

I would like to know whether this margin is different under various transformers? The report I saw reads; transformer capacity in kVA = 500, 75% of capacity in KW =337, capacity of plants connected till now in KW = 51.5, remaining capacity than can be connected in KW = 285.5. But the return feed of transformer your uncle have the plant connected is 13.5% (13.5KW of total 100KW).

[rdst_1]

Any reason for spending so much on micro-inverters. Even if they are more efdicient, they are very costly compared to what you called string inverters. If I read your post correctly, you paid around 15k for each which would make your inverter cost alone at 1.5L for the 10 panels.
When I was doing my research, I was very impressed by the range from Flin which are basically rebranded Voltronics inverters and they even have a suitable 'Hybrid' option which allows you to use the batteries in case of the power cut , for an on-grid inverter. Someone who is also a fellow solar enthusiast has been using one of the Flin offerings for a couple of years now and very happy with the inverter.

[bejoy]

Originally Posted by Sankar

I would like to know whether this margin is different under various transformers? The report I saw reads; transformer capacity in kVA = 500, 75% of capacity in KW =337, capacity of plants connected till now in KW = 51.5, remaining capacity than can be connected in KW = 285.5. But the return feed of transformer your uncle have the plant connected is 13.5% (13.5KW of total 100KW).

I checked with him again, and he confirms it is 15%. I was wrong when I said 100kW transformer, it should be 100kV and with a 0.9 power factor, it should be 90kW, so 13.5kW is 15% capacity. Please PM me the report if you can, and I can get it checked with my uncle.

[Sankar]

Originally Posted by bejoy

I checked with him again, and he confirms it is 15%. I was wrong when I said 100kW transformer, it should be 100kV and with a 0.9 power factor, it should be 90kW, so 13.5kW is 15% capacity. Please PM me the report if you can, and I can get it checked with my uncle.

They are keeping PF 0.9 for KVA to KW conversion, same here. The report is below and is a fairly recent one.

[bejoy]

Originally Posted by Sankar

They are keeping PF 0.9 for KVA to KW conversion, same here. The report is below and is a fairly recent one.

Ok, I shared this with my uncle and he checked with some of his ex-colleagues. It is true that the return feed capacity is increased to 75% recently. Earlier upto 15% was fixed per transformer and the sanction was given to whom ever applied without the feasibility study. And, above 15% needed a feasibility study to be done for the sanction. Now, it seems they can sanction the application upto 75% without any feasibility study. The 15% cap was a hurdle for the on grid solar initiative as the slots gets filled up very fast especially in towns as there is lot of demand.

PS: The feasibility study involves monitoring of load on the transformer twice a day for a week and taking the average to compute the available capacity.

[Sankar]

Originally Posted by bejoy

Ok, I shared this with my uncle and he checked with some of his ex-colleagues. It is true that the return feed capacity is increased to 75% recently. Earlier upto 15% was fixed per transformer and the sanction was given to whom ever applied without the feasibility study. And, above 15% needed a feasibility study to be done for the sanction. Now, it seems they can sanction the application upto 75% without any feasibility study. The 15% cap was a hurdle for the on grid solar initiative as the slots gets filled up very fast especially in towns as there is lot of demand.

PS: The feasibility study involves monitoring of load on the transformer twice a day for a week and taking the average to compute the available capacity.

I asked about this to the solar installer and he said the same. Two years ago 15% was the norm and now its 75%. I am getting a plant done and work is progressing and I expect the plant to be on-grid by April end taking into account delays, if any, due to elections.

[docsr]

Thanks all for a very informative and detailed discussion on this topic. I have been exploring the roof top solar panel option in Bangalore. The quotation I got is attached here.



This is a poly panel and they are calculating a recuperation of cost over 5 years at my current usage.

Is this a reasonable? The company guys seem professional and communicative enough. I believe that BESCOM is now paying 3.99 per unit. The application was made under a subsidy scheme- though no details of subsidy has been announced by the government!

[snr]

Hey that's a nice set up! A friend of mine got it installed in his factory, but he complains that the electricity bill has actually shot up. So he's not sure if it's done correctly or not. Any good leads in HSR to come check the solar?

[kutts]

Very happy with the performance of the plant I installed 4 months back. Now paying 110/- per month as electricity bill, to cover the meter rent and basic charges. Earlier it used to be above 4000/- bimonthly. Statistics included for past 3 months. Plant capacity is 5kw. The <10kw generation per day on couple of days is due to KSEB power shutdown and wifi outage.