Purchase considerations

[loraine1971]

I'm new to solar and am looking to have a grid tied system. My electric provider has a Monopoly in this area and they're the only provider I can use. Every stage of the solar project has to be pre-approved and signed off on by them before allowing me to hook my system into their Network. Everything has to be done by licensed installers and even the blueprints have to be presented to them by an engineering firm for approval before any work begins. That being said I got an estimate from a solar company which was $27,000 for 17 panels that will provide at minimum 75% of my current electrical usage 6.08 kilowatts During peak times with optimum weather it's been estimated to exceed that. Now I'm a newbie at all this stuff but I've done a little research and 27,000 seems really high for labor and panels and installation. I know it's going to be a bit on the pricey side because of all the permits and approvals involved in my area but I wanted to get y'all's thoughts on this and we greatly appreciate any insights or concerns that might be apparent to some of you seasoned solar veterans. Thank you for your time and patience.

 

[kommando]

I analysed my location and its potential and worked out with the max panels plus a battery I can go off grid 8 out of 12 months. You should be able to do better if you have space for the panels, where I am in Winter I only get 10% of the summer output. When I go back on the grid I only connect the amount of PV my local electricity supplier will take and so did it all DIY as it was under the permission threshold for UK of 3.68kw.

So if you have the space for the panels and do not have to pay for special installers and just use qualified electricians and no fees for signing off could you go off grid. As long as you disconnect all the PV, batteries you could still use the grid as a backup when there is a string of cloudy days..

 

[loraine1971]

I just spoke with the solar company and he said that if I went with a split level system I could have them install 10 panels now bringing the cost down to $18,000. I'm thinking that I could get up there and DIY the remaining panels myself after all of the electric companies approvals and hopefully no one would be the wiser. He also told me there would be a discount for cash purchases which is what I'm trying to do because I avoid debt like a disease.

 

[Hedges]

GT PV hardware costs $1/W
Turnkey installed, $3/W

Based on Insolation calculator, you may get 6 hours effective sun in summer, 2 hours in winter. So a 5kW system could make 30 kWh and 10 kWh respectively.

Battery systems cost more, but in some cases a hybrid inverter can be included for above prices. Then just cost of battery itself. UL listed ESS may be required.

Is this going to be net metering, where you backfeed the grid and get a credit?
Another alternative, "zero export", might keep the utility out of your shorts. Permission to operate is still likely required, if the inverter synchronizes with grid and blends power with it.

A UPS type system which uses transfer switch to disconnect from grid when operating off PV/batteries ought to be doable without utility involvement. Include a battery charger e.g. Chargeverter for on-line UPS operation, keeping batteries charged and perhaps never having to switch.

 

[hsync33]

They claiming it would cover 75% of your usage sounds on the high side, unless they have some sort of yearly netmetering? I would check how they came to that conclusion before signing anything and get it on writing for future reference.

We're pretty diligent on our consumption. On April we exported 377KW and imported 160KW from the grid. The array produced 632KW. Its sized 7KW with a 3.6KW inverter, East/West facing. So as you see we only managed to use about 1/3 of the array capacity, with the rest being night usage, which includes mild heating this time of the year, mostly through the day and couple hours after sunset.
We have all all electric house, from water heating through cooking and climate control.

What I think would be a rational decision for you to consider is a zero export inverter, with or without battery storage. Those, only inject enough to cover your usage without any export. Any excess is stored on the batteries if available. Since you're not exporting you should not need permissions from the utility and in case you go with battery storage you can ofset any excess production during the night.

You tipically loose the ability to sell the surplus to the grid. But the price per MW here is just under £60, so I would be lucky to recoup £100 a year from that. I immagine the same is true in other parts of the world.

Same for battery storage.
For a 7KW system you're probably looking at a 10KW battery, but really run the numbers based on battery cost and install price. Assuming 20c/KW, a 5KW pack discharged 2KW every day would save you $730 over the course of 5 years, assuming the utility buys none of your unused energy back. For 10KW maybe you can tripple that, but those prices are a far cry from what you're paying upfront for the battery in the first place, unless there is a big spike in energy prices, you can keep the system running for many years past the warranty finishing or your electricity is significantly more expensive that the numbers I run above.

With the solar panels alone, maybe you can halve your electricity bill if you're diligent using loads during the day and waiting for good weather to run heavy loads such as laundry, etc.

Shop arround how much it would cost you to run maybe 5KW of panels with a zero export and see if that makes any sense versus what you are being quoted now. The installer should be able to advise about any required permissions.