Ask a Renewable Energy Expert

Over the years I've heard many a reference to "energy payback," meaning that the embodied energy of a solar panel, or other renewable energy system, will pay for itself. The concept is simple. For example, with a pv panel there is embodied energy that goes into making the panel. Because the panel produces energy that initial output effectively "pays" for the amount of energy it took to make it, thus canceling the energy debt. 

Once that's achieved then the energy the panel produces is net positive. 

I've never read an article about energy payback, let alone seen any studies about it. Any leads appreciated. 

Dan Antonioli
going-green.co

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Dan Antonioli
Owner
Going Green
Dryden NY
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Hi,

Energy payback time for solar PV systems is dropping as more efficient cell manufacturing processes are developed. 

For rooftop PV systems, in 2004 an NREL document stated an energy payback time of less than 4 years for multi-crystalline based systems and 3 years for thin-film based systems. (https://www.nrel.gov/docs/fy04osti/35489.pdf) 

A more recent 2022 report by Fraunhofer found roughly 1year energy payback time for mono-crystalline systems. From the report, the number varies from 0.44 years (India) to 1.42 years (Canada) depending on the location as shown on the map. (https://www.ise.fraunhofer.de/content/dam/ise/de/documents/publications/studies/Photovoltaics-Report.pdf) 

There are several studies estimating the energy payback for renewable energy systems. If the search is focused on solar cell-level energy payback maybe you will get more results and more accurate numbers. At the system level, it is harder to estimate the energy cost of various components each with a complex supply chain structure. 

Best regards




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Elias OUEDRAOGO
Business Developer
Future Energy Company
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Thanks Elias. I've downloaded the Fraunhoufer article and am reading through it carefully. 

I'm on a mission to get as much clarity on this issues as I can. "Energy payback" is a phrase I've heard many times and of late find both intriguing and troubling, mostly because the metrics are not defined and many of the details are simply not included. For example, if you have a system with a large lithium battery and don't factor in the negative mining practices for lithium (as well as the social impact) then it's hardly a "payback." Same goes with EVs...which are often touted as "clean emission vehicles." 

To be continued. 
Dan

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Dan Antonioli
Owner
Going Green
Dryden NY
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Original Message:
Sent: 01-08-2023 07:56 AM
From: Elias OUEDRAOGO
Subject: Energy Payback Metrics

Hi,

Energy payback time for solar PV systems is dropping as more efficient cell manufacturing processes are developed. 

For rooftop PV systems, in 2004 an NREL document stated an energy payback time of less than 4 years for multi-crystalline based systems and 3 years for thin-film based systems. (https://www.nrel.gov/docs/fy04osti/35489.pdf) 

A more recent 2022 report by Fraunhofer found roughly 1year energy payback time for mono-crystalline systems. From the report, the number varies from 0.44 years (India) to 1.42 years (Canada) depending on the location as shown on the map. (https://www.ise.fraunhofer.de/content/dam/ise/de/documents/publications/studies/Photovoltaics-Report.pdf) 

There are several studies estimating the energy payback for renewable energy systems. If the search is focused on solar cell-level energy payback maybe you will get more results and more accurate numbers. At the system level, it is harder to estimate the energy cost of various components each with a complex supply chain structure. 

Best regards




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Elias OUEDRAOGO
Business Developer
Future Energy Company
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