RegGuheert
Well-known member
I finally managed to extract 5-minute production data from Enlighten for my solar array and convert it into one-hour data for the same hours that I retrieved from the power company. With this data, it is easy to calculate what my production, consumption and net consumption would be with various amounts of solar in place. I can also then calculate the impact of batteries on those results.
For this post, I will show the impact of simply adding photovoltaics with no batteries.
Assumptions:
- Net metering is NOT available (although with smaller arrays, most energy is self-consumed)
- Cost for photovoltaics is US$2.00/kWp(DC)
- Photovoltaics last 25 years
- Cost per kWh will be for all photovoltaics added to the system (similar to what I did with the batteries)
There are a couple of interesting conclusions to be made from this result:
- Even without net metering, the first few kW of photovoltaics still make sense because nearly all of the production is directly self-consumed.
- OTOH, without net metering, the marginal costs of adding photovoltaics get very high very fast. The reason is that the production has little overlap with the consumption after a certain point. For instance, when I add that 13th kWp(DC) to my system to go from net consumer to net producer, I only reduce my actual consumption by 205 kWh/year! That means that spending $2000 dollars on PV without net metering would cost me US$0.39/kWh! If I had instead spent that $2000 to purchase two Enphase AC Batteries, I would save 708 kWh/year, or 3.5X as much! And even though the life of the AC Batteries is likely shorter, the per-unit cost of the batteries would be lower at US$0.28/kWh. (And I'm not convinced that the AC Batteries will not last as long, but I have no data on their calendar life.)
In other words, at higher levels of production, net metering reduces the costs of photovoltaics to the point that they are more attractive than modern batteries, even though at some points batteries become both cheaper and better for the power grid (at least here).
For this post, I will show the impact of simply adding photovoltaics with no batteries.
Assumptions:
- Net metering is NOT available (although with smaller arrays, most energy is self-consumed)
- Cost for photovoltaics is US$2.00/kWp(DC)
- Photovoltaics last 25 years
- Cost per kWh will be for all photovoltaics added to the system (similar to what I did with the batteries)
Code:
-------------------------------------------------------------------------------------------
| Total | Storage | Storage | Energy | Energy | Energy | Net Energy | Cost per |
| Solar | Capacity | Power | Produced | Consumed | "Rescued" | Consumed | kWh |
| kWp(DC) | kWh | kW | kWh | kWh | kWh | kWh | US$/kWh |
|---------|----------|---------|-----------|----------|-----------|------------|----------|
| 0 | 0 | 0 | 0 | 18,072 | 112 | 18,072 | 0.000 |
| 1 | 0 | 0 | 17 | 16,654 | 1418 | 16,654 | 0.056 |
| 2 | 0 | 0 | 132 | 15,353 | 2718 | 15,212 | 0.059 |
| 3 | 0 | 0 | 524 | 14,319 | 3753 | 14,319 | 0.064 |
| 4 | 0 | 0 | 1127 | 13,497 | 4575 | 12,360 | 0.070 |
| 5 | 0 | 0 | 1858 | 12,803 | 5269 | 10,935 | 0.076 |
| 6 | 0 | 0 | 2674 | 12,193 | 5878 | 9510 | 0.082 |
| 7 | 0 | 0 | 3576 | 11,670 | 6402 | 8085 | 0.087 |
| 8 | 0 | 0 | 4561 | 11,230 | 6842 | 6659 | 0.094 |
| 9 | 0 | 0 | 5614 | 10,857 | 7215 | 5234 | 0.100 |
| 10 | 0 | 0 | 6723 | 10,541 | 7531 | 3808 | 0.106 |
| 11 | 0 | 0 | 7882 | 10,275 | 7797 | 2383 | 0.113 |
| 12 | 0 | 0 | 9076 | 10,043 | 8029 | 957 | 0.120 |
| 13 | 0 | 0 | 10,297 | 9838 | 8234 | -468 | 0.126 |
| 14 | 0 | 0 | 11,554 | 9670 | 8403 | -1894 | 0.133 |
| 15 | 0 | 0 | 12,827 | 9517 | 8555 | -3319 | 0.140 |
| 16 | 0 | 0 | 14,114 | 9379 | 8693 | -4744 | 0.147 |
| 17 | 0 | 0 | 15,417 | 9257 | 8815 | -6170 | 0.154 |
| 18 | 0 | 0 | 16,731 | 9145 | 8927 | -7595 | 0.161 |
| 19 | 0 | 0 | 18,053 | 9042 | 9030 | -9021 | 0.168 |
| 20 | 0 | 0 | 19,381 | 8945 | 9127 | -10,446 | 0.175 |
-------------------------------------------------------------------------------------------- Even without net metering, the first few kW of photovoltaics still make sense because nearly all of the production is directly self-consumed.
- OTOH, without net metering, the marginal costs of adding photovoltaics get very high very fast. The reason is that the production has little overlap with the consumption after a certain point. For instance, when I add that 13th kWp(DC) to my system to go from net consumer to net producer, I only reduce my actual consumption by 205 kWh/year! That means that spending $2000 dollars on PV without net metering would cost me US$0.39/kWh! If I had instead spent that $2000 to purchase two Enphase AC Batteries, I would save 708 kWh/year, or 3.5X as much! And even though the life of the AC Batteries is likely shorter, the per-unit cost of the batteries would be lower at US$0.28/kWh. (And I'm not convinced that the AC Batteries will not last as long, but I have no data on their calendar life.)
In other words, at higher levels of production, net metering reduces the costs of photovoltaics to the point that they are more attractive than modern batteries, even though at some points batteries become both cheaper and better for the power grid (at least here).
Perhaps it was wishful thinking!
