ON-Grid system general advice

[Arnby]

Hello all,

First of all thanks for the help as I am new to this.
I am currently looking into doing my first investment and as we have a small piece of land we would like to do a test on it with solar.
The piece of land is around 75m by 5m. The 5m width can be increased if needed to. FYI it is a dirt land.
We would like to produce as much as possible to sell directly to the grid or maybe with a battery in between.
Meaning I don't use any of the electricity myself and will all be sold consider it a second source of income.
The battery of course depends on the budget and if it is worth it. Again these wouldn't be for personal use only to sell to the grid at a later time when the price is higher.

Personally I was thinking of placing one row on the ground with 3 panels on top of each other.
Or would you say it would be better to go with 2 rows of each 2 panels on top of each other?
Are there other things I would need to know as we are currently talking about a minimum of 225 panels?
For example concerning inverters, connection to the grid, panels, system to place on the ground...

Any help or tips would be highly appreciated!
I already looked things up online but you go from one thing to another.
Haven't really found like a step to step guide like hey this is what you need to take into consideration this is how you buy it and what you pay attention to and this is how you build it.

Anyway thank you everyone!

 

[BentleyJ]

First, you need to identify goals as far as what percentage of your usage do you wish to supplement with solar or perhaps eventually go off-grid totally? How important is it to have battery back up because this will increase the budget quite a bit.

How much utility electricity do you use now on a daily and monthly basis. Are the high usage months during the winter when days are shorter? Peak demand? How many kW do you use in the worst case scenario when everything you normally use is ON all at the same time. This all factors in when sizing the system then choosing equipment.

 

[Arnby]

First, you need to identify goals as far as what percentage of your usage do you wish to supplement with solar or perhaps eventually go off-grid totally? How important is it to have battery back up because this will increase the budget quite a bit.

How much utility electricity do you use now on a daily and monthly basis. Are the high usage months during the winter when days are shorter? Peak demand? How many kW do you use in the worst case scenario when everything you normally use is ON all at the same time. This all factors in when sizing the system then choosing equipment.

Hello,

Thank you for your feedback! For clarification I don't use any of the energy myself. It's only purpose is to sell to the grid.

 

[BentleyJ]

Apologies, totally misread and misunderstood your post. It really depends on what the sell back rates are and if there is any Time Of Use periods where they would pay higher rates for power. I'm curious if what you propose is even allowed. It would make you a net generator and competitor to the utility company. In the US this can be done but the permitting is quite a bit more involved than a installing a small residential or commercial system that reduces your utility usage but doesn't exceed it.

As to your question specifically. The math would be fairly simple.

Scenario 1: Lets say you pick a number like 20kW as the size of the proposed array and add the constraint that it will be Grid-Tie only, no batteries. This is the least expensive option. Solar Panels, Ground Mounting Hardware, Microinverters or DC String Inverter, Wiring & Acc. & Labor. Using something like this: https://pvwatts.nrel.gov/pvwatts.php you model the 20kW array and find the optimum Azimuth and Tilt. The calculator will estimate the Annual production (broken down by Month) in kWhours. I did a quickie test run for your location and got 18,666kWh for a year.
Take that value times how much they pay for electricity. Say 10 cents/kWh so your annual income is $1,866 (Euros are about par with the Dollar now)
If the system cost $25,000 to install then the pay back period is 14 years and after that it starts producing income. Of course, there is probably some "economy of scale" to be had if the system was larger, 100kW but then again is that allowed?

Scenario 2: The utility pays more for power during peak usage periods which may be from 4 pm to 8pm weekdays like here in CA. If they pay 20 cents per kWh then you would want to maximize production during that time period by adjusting the Azimuth of the system and/or adding batteries that would allow the system to keep producing even as the sun goes down. In this case the added cost of the batteries and different type of inverter have to be added to total installation cost and then divided by the higher income expected to see if this reduces the payback period and increases future income by enough to justify batteries.