OVERKILL
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This topic has been touched on a pile of times in numerous threads but we haven't really had a formal discussion about the phenomena.
We are I believe, all aware that solar cells produce less and less over time. The amount of degradation however, does it vary between brands? Do all of the high quality cells degrade at the same rate? Do newer cells degrade less than older technology cells?
Our local solar farm is 10MW and 200 acres and is cited by our PUC as producing 14,300MWh of electricity a year. This facility had 1/3rd of its panels replaced recently because they were underperforming significantly. However, there's no mention of the incremental decline in performance of these panels as the facility ages.
Cue example B:
The Webberville 35MW solar farm in Texas
Originally Posted By: Wikipedia
The 35 MW Webberville Solar Farm, located in Webberville, Texas, is a photovoltaic array in Texas. It is made up of 127,728 Trina Solar solar panels[1] mounted on single-axis trackers, covers an area of 380 acres (150 ha), and was built at a cost of $250 million.[2] It is expected to generate 61 GWh in the first year of operation,[3] and 1.4 billion kWh over its 25 year life. Operation began on December 20, 2011, while ribbon cutting by Austin's mayor, Lee Leffingwell, was held on January 6, 2012.[4] The project was constructed by RES Americas, who will operate the plant for five years. SunEdison in 2012 sold the plant to MetLife and Longsol Holdings, but will operate the plant for 20 years upon the expiration of the responsibilities of RES Americas.
Actual generation output of the facility has been as follows:
With the first year actually besting the target of 61GWh, but there has been a steady decline in output since that first year, with 2016's output putting us at 44GWh. Now, how much of this is due to weather and exposure and how much of it is due to the degradation of the panels? I don't know. December of 2012 seems to stand out as an anomaly at 7GWh with subsequent Decembers hovering around 3GWh. Averaged over the 5 years of operation however, the general trend is a reduction in output of 5GWh a year. It will be interesting to see, going forward, if that trend is maintained. This makes the claimed output of the facility over its lifetime questionable.
To expand further: the claimed 25 year output is 1,400GWh. Based on 61GWh a year, we end up with 1,525GWh, so obviously there is some degradation factored into that number, as the average based on the aforementioned figure is 56GWh a year. However, looking at the trend in our table above, that number appears to be highly optimistic. Our average presently is already
Now, using our above provided figures, if the facility produces 1.4 billion kWh in 25 years, and had a installation cost of 250 million, this requires $0.178/kWh for 25 years to break even. So it would be interesting to see what kind of rate they are being paid for their generation. This is actually more than the break-even cost on my local example, which is paid a handsome $0.42/kWh.
This also, I believe, demonstrates that solar panel pricing still has a significant way to go in terms of unit cost, not even factoring in the degradation over time, and further still if we do.
If the above is typical, then this also touches on the issue of output for a given capacity of solar generation going the opposite direction of demand. While demand, particularly with the electrification of the transportation industry should be trending upward, actual output of these installs will be going the other way. This is not the case with other modes of generation.
We are I believe, all aware that solar cells produce less and less over time. The amount of degradation however, does it vary between brands? Do all of the high quality cells degrade at the same rate? Do newer cells degrade less than older technology cells?
Our local solar farm is 10MW and 200 acres and is cited by our PUC as producing 14,300MWh of electricity a year. This facility had 1/3rd of its panels replaced recently because they were underperforming significantly. However, there's no mention of the incremental decline in performance of these panels as the facility ages.
Cue example B:
The Webberville 35MW solar farm in Texas
Originally Posted By: Wikipedia
The 35 MW Webberville Solar Farm, located in Webberville, Texas, is a photovoltaic array in Texas. It is made up of 127,728 Trina Solar solar panels[1] mounted on single-axis trackers, covers an area of 380 acres (150 ha), and was built at a cost of $250 million.[2] It is expected to generate 61 GWh in the first year of operation,[3] and 1.4 billion kWh over its 25 year life. Operation began on December 20, 2011, while ribbon cutting by Austin's mayor, Lee Leffingwell, was held on January 6, 2012.[4] The project was constructed by RES Americas, who will operate the plant for five years. SunEdison in 2012 sold the plant to MetLife and Longsol Holdings, but will operate the plant for 20 years upon the expiration of the responsibilities of RES Americas.
Actual generation output of the facility has been as follows:
With the first year actually besting the target of 61GWh, but there has been a steady decline in output since that first year, with 2016's output putting us at 44GWh. Now, how much of this is due to weather and exposure and how much of it is due to the degradation of the panels? I don't know. December of 2012 seems to stand out as an anomaly at 7GWh with subsequent Decembers hovering around 3GWh. Averaged over the 5 years of operation however, the general trend is a reduction in output of 5GWh a year. It will be interesting to see, going forward, if that trend is maintained. This makes the claimed output of the facility over its lifetime questionable.
To expand further: the claimed 25 year output is 1,400GWh. Based on 61GWh a year, we end up with 1,525GWh, so obviously there is some degradation factored into that number, as the average based on the aforementioned figure is 56GWh a year. However, looking at the trend in our table above, that number appears to be highly optimistic. Our average presently is already
Now, using our above provided figures, if the facility produces 1.4 billion kWh in 25 years, and had a installation cost of 250 million, this requires $0.178/kWh for 25 years to break even. So it would be interesting to see what kind of rate they are being paid for their generation. This is actually more than the break-even cost on my local example, which is paid a handsome $0.42/kWh.
This also, I believe, demonstrates that solar panel pricing still has a significant way to go in terms of unit cost, not even factoring in the degradation over time, and further still if we do.
If the above is typical, then this also touches on the issue of output for a given capacity of solar generation going the opposite direction of demand. While demand, particularly with the electrification of the transportation industry should be trending upward, actual output of these installs will be going the other way. This is not the case with other modes of generation.