The Alternative Energy Thread - Generators, Solar, UPS, Wind

[mrdeejay]

Are you sure about this that a 10 KW hybrid inverter can support a load of 13 KW, also why can't the on-grid inverter do this.

It can't. 10KW is the max output of a 10KW inverter, however, they usually support slightly higher PV Input e.g. a 10KW inverter might allow you to connect upto 15KW solar array. Best to check specs

[mrdeejay]

How does that work.

Let's say you are producing 7KW of solar power during the day. Your house load is only 1KW. You use the 1KW from solar and export remaining 6KW.

But if you turn on your AC which is not connected to the inverter, it won't take solar power but power from the grid. Now how will the meter decide to import or export the power because the AC needs grid power but you also need to feed the solar power back to grid.

Electricity meter only monitors flow of current. When you're exporting there is Net negative flow, which is recorded. E.g. if you're inverter is generating 6KWh excess, but you're running an AC consuming 2 KWh, then meter will record 4KWh (units) of energy exported.

I've noticed on our bill, when I know 600+ units were generated using solar, the bill will only show around 300-400 meaning the rest of exported units were simultaneously consumed by ACs etc connected with grid supply.

[pwuser150013678596]

@talhawaleed Yar i cant thank you enough for the knowledge imparted.

So the thing is, i am removing my current meter for 2 kanal house that is on lesco owned transformer. I am getting a new transformer that will have only 1 meter for complete 2 kanal house.

Now their (Lesco) argument is.... 25KVA is the transformer output. 25 KVA X 0.8 (power factor) = 20KW. Just like in UPS, a 1 KVA ups gives 700-800 watts. they say 25KVA does not = 25KW. it equals 20KW.

They say total they can sanction if 100% efficiency is expected would be 20KW but officially and in reality SDO said they can approve max load of 16KW for a 25KVA transformer.

Anyhow. i checked through NEPRA website, the people who got net metering approved, and the maximum residential setup i saw for 100-200 licenses in all of lahore was 25 KW generation maximum.

I did not see a single setup over 25KW in lahore for residential use. There were 100 KW setups but those were commercial meters, educational institutes, hospitals etc. their reference numbers start with 24 .

So after checking net metered license bills on LESCO website, i saw that there was only one house who managed to get a 18KW load printed on his bill. This guy had a 25KVA transformer and managed to have LESCO approve 18KW but his generation was 25KW on nepra license. A woman had 16KW load printed and her generation was 24.90 KW on nepra license.

honestly bro i saw around 200 bills from 2020, 2019 of all net metered customers through NEPRA and LESCO website and none of the houses had a load of more than 16KW printed except that one house with 18. And when i checked their solar generation on the license, it was always (1.5 X the load) printed on bill. so you were dead sure right.

Now regarding transformer, what do you suggest,go for 25KVA or 50KVA ?

Do you think i should ask him to print at least 18KW by showing that other guys bill and then add the additional panels after approval? or do you think i should do 50KVA transformer, coz the difference in price is 50k but procedure is bit lengthy.

thanks a ton man.

[mrdeejay]

Do you think i should ask him to print at least 18KW by showing that other guys bill and then add the additional panels after approval? or do you think i should do 50KVA transformer, coz the difference in price is 50k but procedure is bit lengthy.

I would strongly advise to play it safe when dealing with this much energy. There are a lot of calculations that go into stuff like this and we're not qualified electrical engineers to work these things out. You may be able to run the setup for a years without an issue but things could go wrong anytime and the result could be really bad i.e. all electronics destroyed in your home etc.

Hopefully, you won't forget to upgrade all the main wiring and main breakers in your house to handle this much current as well.

Why not follow the KISS principle? just stick with 15KW system, you'll be we'll within the transformer load range, lesco process will be simplier and you'd still generate huge amount of units annually that you won't have to worry about paying bills.

[pwuser150013678596]

@mrdeejay I am already using 3100-3300 units max in summers so i think my house current wiring can handle the current? what did you mean by upgrading the wiring?

I don't even know why they use sanctioned load, my home is using load of 3100-3300 units on a 600 watt sanctioned load right now. For the last 20 years my home was under 600 watt load and taking in load way greater than 600 watt. The only reason i can think of is so I am forced to buy my own transformer due to high billing under 0.6KW slab tariff . Well it took 20 years for them to convince me on buying my own transformer. lol

[mrdeejay]

Sanctioned load is probably used for planning purposes i.e. how to size transformer for the street etc.

Lets say you go with 18KW system and your generating 15KW on a pleasant sunny March afternoon. You probably won't be running ACs in march, so almost all of the electricity will be sent to lesco. That means the main wire needs to be able to handle 68 Amps, I'm not sure how the 3Phase will play into this, weather it means each Live Wire is carrying 22 Amps of current. This you need to discuss with lesco or a really qualified electrician.

This is different than consuming 3000 units because units are consumed over 30-day period. Even if you're running 3 1.5 Ton ACs at the same time, it still only 5KW of consumption at any given point, but run for hours at a time, it will add upto lots of units, while load is still around 5KW. See my point?

Our local electricians aren't that smart, so I just wanted to point out one more variable so you don't end up with melting wires or a house fire.

[mrdeejay]

Personally, I still don't get the whole transformer required for 2-kanal house logic. We've lived in 2 kanal houses in the past, never had to get a transformer. Even now there are many 2 kanal houses being built all over DHA & Lahore, never heard of anyone getting a transformer installed.

My friend's 2-kanal house is in Valencia he didn't get any transformer installed - to be fair, Valencia has their own electricity system. Still, there is no need for a transformer unless you're really running high loads.

At our current 1 kanal house, our sanctioned load is 12KW, for a 2 kanal house typically there is a lot of empty space for garden area, the house is not much bigger than a 1-kanal house, maybe 2 rooms extra (so 2 ACs extra), that still doesn't explain why you need to get a separate transformer.

[pwuser150013678596]

Let me explain.

In DHA you cannot get lesco connection for a new 2 kanal house if you dont buy your own transformer. I had 2 houses built next to me in the last 2 years and they both had to buy their own 25KVA transformer.

My house was completed in 1997, at that time there was no such policy. So we got the lesco connection in 1997. But what we didn't realize from 1997 to 2020 is that our sanctioned load was 0.6KW which meant we were paying every slab peak hour. There was no off peak or peak units on our bill because we were charged maximum. I accidentally noticed this when I saw someone's bill being 60k and they used 100 more units than me. My bill for same amount was 85k. thats where i got to know something was wrong and also because my bill did not mention off peak or peak units.

Now regarding societies that own their transformers, you don't have to deal with lesco. the society has its own rules and they have bought those transformers and are running a contract with lesco. Bahria town makes its own electricity so no lesco there.

Now in DHA Lahore, they sent us a survey as they wanted to do lesco electricity underground for phase 1 2 and 3. They said if 70% residents said they wanted underground then they would proceed. But majority residents said NO to underground. Thats because DHA was going to charge each house and people did not want to pay for what they already had. So when I spoke to lesco about transformer they asked me to check with DHA because if DHA was to proceed with underground wiring then my transformer would go to waste and that i would have to deal with DHA once they installed their own transformers.

Basically had DHA gone ahead with it, then DHA would charge and provide meters. They would basically buy all the equipment from lesco and make their own policies to charge residents, what kind of meters to give, how many meters to give.

Right now, for any new 2 kanal house you need to buy a transformer, this is SOP policy. It is probably because they think that 2 kanal houses are built by rich people so they should not burden the grid line and can purchase a 150,000 transformer. 1 kanal and less do not need transformer for load sanctioning or additional meter. I don't know if they need it for higher load for net metering. Regarding why you did not have to purchase transformer for 2 kanal house is because it was either old house (and had lesco connection from before) or had bought its own transformer but the owner forgot that he paid 150k to the contractor for requisitioning transformer for lesco connection. Most 2 kanal houses even have load adjusted on lesco owned transformers, but thats because they realized long ago and did it before this new policy existed.

[pwuser150013678596]

Any reviews on solar panel companies?

How is canadian solar 440 W mono perc?
Canadian Solar has also launched 590W hiku6 mono panels on July 1 2020

Most quotations i got from big companies are quoting me canadian solar panels. Some say Longi is best?

[centos]

It can't. 10KW is the max output of a 10KW inverter, however, they usually support slightly higher PV Input e.g. a 10KW inverter might allow you to connect upto 15KW solar array. Best to check specs

Thank you. So if I want to put the whole house in front of inverter I need bigger inverter to make sure it never trips, doesn't matter I install half the amount of panels.

But if I use a 20KW inverter and only install 10KW panels, how would Lesco rate it? as 10 KW setup or 20 KW setup.

Electricity meter only monitors flow of current. When you're exporting there is Net negative flow, which is recorded. E.g. if you're inverter is generating 6KWh excess, but you're running an AC consuming 2 KWh, then meter will record 4KWh (units) of energy exported.

I've noticed on our bill, when I know 600+ units were generated using solar, the bill will only show around 300-400 meaning the rest of exported units were simultaneously consumed by ACs etc connected with grid supply.

So one phase is importing and the other is exporting, right. We can't have electrons running in both directions like a 2 way road. Electricity flows one way.

[centos]

Both Canadian solar mono perc and Longi mono perc are are good panels and both brands are considered as tier 1.

[pwuser150013678596]

NEPRA and LESCO will consider your panel wattage as your system size.

So if you have a 30KW inverter, but installed 20 KW panels, your system size will be 20KW on license.

On your license the model and capacity of your inverter will be printed along with your panel wattage (generation) .. and the allowed generation will be mentioned equal to the panel wattage that you have installed and shown.

[centos]

Thanks

Any idea how high can we install the panels in DHA Lahore

[pwuser150013678596]

You have to call building control in DHA office Phase 6.

Im sure you cannot construct big structures on roof but can install angled 1 layers panels. Best person to guide will be building control DHA. Let me also know if you find out.

[centos]

Yar DHA ne to nak main dam kiya howa hai. They don't answer their phones, even if you manage to get connected the person responding is always some junior clerk type who has no idea. Twice I managed to talk to some one and explain them the issue, they redirect the call and then no one picks up.

Due to corona they don't let you in and you have to get an appointment for everything. Last time I checked they were giving 6 weeks time for the appointment.

Even when you go there with appointment they don't let you go beyond the parking lot. In the parking lot they have setup desks with junior staff who doesn't know any thing. I had to make many calls and wait for a month to get a simple routine work done.

[centos]

Height limit for the building is 35 ft from the middle of the street so in my case I have 8.5 ft to use. I plan to leave a clear space of at 6 feet below the panels that'd leave me 2.5 ft to angle the panels. Let's see how that goes.

Where do you plan to buy the equipment, is there a market in Lahore. Who are you going to use for installation and net metering.

[elxlr]

THe quotation part where 30 lacs+ is being asked. A friend of mine who live in lahore, he can get that to 20 lacs with same efficiency. And he can guide better. Its just he doesnt have an office or company.

I have read all the posts in this thread right now and will be discussing with him.
As you guys seem educated in this, you should get his opinion about how can he help reduce the quotation by helping u build his own or buy efficient but cheap panels.

Carry on, and good luck with your setup.

[pwuser150013678596]

I tried going to DHA office on thursday and they didn't let me in and said appointment leni paregi..but i called someone in DHA and they got me the info i needed.

Regarding roof top panel mounting, i haven't seen a single house in dha with those structure panels on roof. if they have panels on roof they are usually one panel angled or maximum 2 small ones. i could be wrong so its always better to ask DHA because they dont want structure pillars on roof. they could say its not safe bla bla so although they allow a maximum height, it doesnt mean you can put up high panel structures.

Regarding equipment, i have always wanted to source my own equipment so i can be sure of quality. Like i can check each panel for scratches or dents, but if you hire a turn key company, jo agaya woh apka, could be used, you never know and they usually ask you for 100% payment before delivery and installation of all equipment is made to your home.

I got quotations from Nizam energy, Sky electric and Hadron solar. I told these companies what i wanted i.e. huawei 36 kw inverter and mono perc panels. For sky electric i asked for 22 KW setup and for the other 2 i asked for 25KW panels.

1. Nizam energy is giving me 25 KW panel + Huawei 36 KW inverter plus installation and net metering etc for 21 lacs.

2.Hadron is doing it in 18 lacs Without net metering (They did not quote net metering and typed FOC) now foc could mean free of charge because in customer scope for net metering they have written i have to provide disconnect switch and earthing

3. Sky electric is doing 22 kw panel (I told them 22 kw) for 20.70 lacs which is expensive for 22 KW panel

i personally like Nizam energy, their proposal had the most details, with projected energy injected in grid, all charts, amount of generation in 25 years projected.

You can tell each company what product/inverter and what kind of panel you want, they will make you a proposal based on your required brands. so dont ever just go with what they assess.

I'm going to get my transformer issue resolved and then will wait a bit for Canadian Solar 590 Watt mono perc panel to reach pakistan (already released in canada).

Also you should go with a company that gives least quotation with good repo because net metering is not easy to do, earthing, grounding, disconnect switch etc requires professionals.

Also angle, and installation of panel is of supreme importance. if there is even a little bit of shadow on a Poly panel, it highly affects current generation. So engineers should properly identify angle, check for shadow on roof and then finalize. watch youtube video https://www.youtube.com/watch?v=UNPJapaZlCU&t=91s to see how shadow affects panel.

All three companies above are AEDB recognized.

[centos]

Regarding roof top panel mounting, i haven't seen a single house in dha with those structure panels on roof. if they have panels on roof they are usually one panel angled or maximum 2 small ones. i could be wrong so its always better to ask DHA because they dont want structure pillars on roof. they could say its not safe bla bla so although they allow a maximum height, it doesnt mean you can put up high panel structures.

You are right mostly people have bolted the frames on to their roofs but I have seen few high ceiling type structures so that's why I am planning to install them like that. One such example is near my house in phase 5 and other is in phase 7. I'll take pics and share here.

i personally like Nizam energy, their proposal had the most details, with projected energy injected in grid, all charts, amount of generation in 25 years projected.

Where are they located now days. They used to be on walton rd near defence mor. I thought they were out of business.

I'm going to get my transformer issue resolved and then will wait a bit for Canadian Solar 590 Watt mono perc panel to reach pakistan (already released in canada).

I am interested in PERC panels too but LeTID issue concerns me.

[centos]

Good news for new house builders of DHA Lahore. My architect shared this with me.

I am building 195 sqft access area and I would have paid about 5 lacs fine, now it's reduced to 2.5 lacs.

@pwuser150013678596 You can extend your first floor by 150 sqft without a fine if you have not done so already.