BentleyJ
Solar Wizard
I got curious today as to how much solar electricity our panels have actually produced, at what cost, compared to the production guarantees and projections on the Solar City lease. Not sure if this will be interesting to any one, it is little different than the typical cost benefit analysis as this is looking back vs. looking forward trying to predict future price trends and what the pay back period will be. Our Solar City 11 panel, 2.82kW DC string system was turned on in April of 2011. Then March through November 2016 I added a total of 11 more panels with Enphase M250 microinverters, approx 3kW. So 5.8kW total. Here are the numbers.
We are in the 12th year of a 20 year lease that has an escalating payment plan of approx. 3% per year. So far the system has produced(according to the Fronius Inverter) 55,334kWh with total payments of $9,298 made so far. This works out to 16.9 cents per kWh on average. However, because the lease payments started out lower and production was slightly higher, the first year our solar electricity cost was only 13.5 cents and has now increased to 19.5 cents. While during that same time SCE rates were approx. 16 cents per kWh in 2011 and now have increased to 28 cents. Electric utility rates are clearly increasing at a higher rate than previously projected making the cost of electricity from legacy solar systems even more attractive. As the lease payment continues higher each year for the next 8 years the total paid will be just over $19,000 and the guaranteed solar production totals up to 85,333kWh. This is about 22.2 cents per kWh but so far the system is ahead of the guaranteed minimum production by 2,500kWh. If this trend continues the realized solar production cost will actually end up at about 20 cents per kWh average over the 20 years. In retrospect, the escalating payment plan was nothing short of genius because it ensured that the customer would always be paying less than utility rates for their solar electricity. With no down payment, the system started saving money the first month and every month thereafter.
Bottom line: Installing solar in 2011 even when panel prices were much higher and considering the extra system cost of interest attached to the lease, it was absolutely worth it and has saved real dollars.
The Enphase System has produced 27,700kWh and was a DIY install paid for up front in cash, $5,213.23. Avg. cost per kWh as of today (4 years in operation) is 18.8 cents but will continue to decrease as the kWh add up but the investment is fixed. Rough estimate indicates that about 30% of the cost has been recovered already and as rates continue to go up I expect another 50% pay back over the next 4 year period. So I would have to say this was well worth it also.
Two other positive factors that I cannot put a dollar value on because the data is lacking: 1) Due to having the solar system supply a substantial portion of the electrical demand during summer air conditioning months, utility usage was kept well within the lower Tier 1 pricing structure. 2) Having the Calif. NEM 1.0 agreement in place has so far prevented the utility from forcing Time of Use metering at this location. ToU rates between 4 to 9 pm can be over 50 cents per kWh.
Lastly, In 2018 a DIY whole house back up inverter & batteries (AC Coupled) was installed at a cost of approx. $11,000. While it is capable of providing peak load shaving for ToU rates, this feature is not currently needed. As such this item can only be considered a convenience and there is no pay back to justify the expense. Not to mention I really wanted to do the DIY project. I believe this belongs in the same category as ordering your new truck with ALL the options when the standard model would have been fine.
We are in the 12th year of a 20 year lease that has an escalating payment plan of approx. 3% per year. So far the system has produced(according to the Fronius Inverter) 55,334kWh with total payments of $9,298 made so far. This works out to 16.9 cents per kWh on average. However, because the lease payments started out lower and production was slightly higher, the first year our solar electricity cost was only 13.5 cents and has now increased to 19.5 cents. While during that same time SCE rates were approx. 16 cents per kWh in 2011 and now have increased to 28 cents. Electric utility rates are clearly increasing at a higher rate than previously projected making the cost of electricity from legacy solar systems even more attractive. As the lease payment continues higher each year for the next 8 years the total paid will be just over $19,000 and the guaranteed solar production totals up to 85,333kWh. This is about 22.2 cents per kWh but so far the system is ahead of the guaranteed minimum production by 2,500kWh. If this trend continues the realized solar production cost will actually end up at about 20 cents per kWh average over the 20 years. In retrospect, the escalating payment plan was nothing short of genius because it ensured that the customer would always be paying less than utility rates for their solar electricity. With no down payment, the system started saving money the first month and every month thereafter.
Bottom line: Installing solar in 2011 even when panel prices were much higher and considering the extra system cost of interest attached to the lease, it was absolutely worth it and has saved real dollars.
The Enphase System has produced 27,700kWh and was a DIY install paid for up front in cash, $5,213.23. Avg. cost per kWh as of today (4 years in operation) is 18.8 cents but will continue to decrease as the kWh add up but the investment is fixed. Rough estimate indicates that about 30% of the cost has been recovered already and as rates continue to go up I expect another 50% pay back over the next 4 year period. So I would have to say this was well worth it also.
Two other positive factors that I cannot put a dollar value on because the data is lacking: 1) Due to having the solar system supply a substantial portion of the electrical demand during summer air conditioning months, utility usage was kept well within the lower Tier 1 pricing structure. 2) Having the Calif. NEM 1.0 agreement in place has so far prevented the utility from forcing Time of Use metering at this location. ToU rates between 4 to 9 pm can be over 50 cents per kWh.
Lastly, In 2018 a DIY whole house back up inverter & batteries (AC Coupled) was installed at a cost of approx. $11,000. While it is capable of providing peak load shaving for ToU rates, this feature is not currently needed. As such this item can only be considered a convenience and there is no pay back to justify the expense. Not to mention I really wanted to do the DIY project. I believe this belongs in the same category as ordering your new truck with ALL the options when the standard model would have been fine.
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stripped everything off and sold all the parts, netted positive just on the materials, not including 6 years of free energy
