How to select the best solar panel based on degradation rates: continued

Tuesday, May 31, 2022
Training
by
Veli Markovic

Your project

We're continuing on our panel spreadsheet series of presentations this week we're looking at a range of panels and comparing apples with apples.

  • We were looking at a 400 kilowatt system
  • We selected a panel with a particular degradation profile 
  • And looked at the 25-year accumulated savings

Some assumptions are:

  • 25 cents per kilowatt hour cost of electricity 
  • With a three percent increase in electricity pricing 
  • and the maintenance cost increasing every year

In this presentation we'll be looking at the following: we're going to compare accumulated savings between a number of panels and we're going to do this using a data table from the what-if analysis function in excel and we're going to examine some other metrics that will allow you to make the best decision in regards to what is the best panel for your needs.

By looking at a range of panel options out there the installer designer can compare overall production data savings for a 20 to 25 year period and look at the dollar savings per watt installed and the total cost of the solar panel component of the project so obviously there's a relationship between all these factors and you've got to have the ability to compare apples with apples is good thing!

Now we have do the following:

  • Set up a table that compares the outputs of all the panels under consideration
  • Then look at the total savings for each panel
  • Look at various ratios that will help with the decision making process in regards to best panel

25 year production numbers

So we have a table here of various panels ranging from REA  to ACme and we have year 2021, 22,  23,  24,  and year 25 and the accumulated total kilowatt hours produced.

The difference between the largest production number and the smallest is 568 050 kilowatt hours.

25 year savings

You can see here and the difference between the larger saving number and the smallest is a figure of $87,064

20 - 25 best total savings

We can see that there are three panels that are at the top of the list in regards to total savings:

  • And the also happen to be  the most expensive per watt
  • But the best 25 year savings per watt value at $4.78

Price for the panels alone are:

  • $212,000 for SunP
  • $232,000 for LONGO and
  • $232,000 for Trima

This is the question

The best total savings come from the panels with the highest dollar watt price so overall project price is higher assuming other material installation costs are the same regardless of panel price

Also, as mentioned,  the difference between the best and worst savings over a 25-year period is $87,064 so what do you do?

20 - 25 year Best savings panel price ratio

We can see that there are three panels that are at the top of the list in regards to savings panel price ratio:

  • And the also happen to be the cheapest per watt
  • And vary in regards to 25 year savings per watt

Price for the panels alone are:

  • $176,000 for Solarus
  • $184,000 for ACMe and
  • $188,000 for Soluna

What metric?

For example let's say we:

  • Select the ACMe panel 
  • Which has the second best savings panel price ratio compared to the Solarus but 
  • Total 25 year savings of $1,893,187 compared to $1,825,891
  • A difference of $62,296 
  • BUT the cost to you for the panels alone is $8000 more!!

You can only decide if you have the data

A commercial solar proposition is presented as a financial option for the target business. As a designer and installer you must have all the pertinent data at your disposal so correct decisions can be made.

When there is a range of panels on offer with different degradation rates, prices what metric do you choose but to be able to ask this question you need the data.

Good luck on your next commercial solar project.

If you’d like to see more of what Greenwood Solutions get up to in the real world of renewable energy, solar, battery storage and grid protection check out our industry and commercial pages:

https://www.greenwoodsolutions.com.au/industry 

https://www.greenwoodsolutions.com.au/commercial

https://www.greenwoodsolutions.com.au/news

https://www.greenwoodsolutions.com.au/commercial/customer-stories

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About the author

Veli Markovic

CEC Designer
Veli has nearly two decades of experience in the renewable industry. He is passionate about providing people with valuable education and is highly regarded throughout the industry as an educator and operator.
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