Report: where the system loses energy and money
The system
It is a rooftop, not a farm: 78.6 kWp of nameplate power on 9 inverters . The data covers 8 of them , or 69.9 kWp . Inverter inv7 is in the system description but has no measurements . Its production is not in the data, so its losses are not counted. The data runs from 2015-01-01 to 2015-12-31 . In that time the inverters produced 75.2 MWh . I price every loss at an assumed 450 zł/MWh . That is an assumption, not a market quote.
Headlines
- Real losses (the inverter outage and underperformance) are at least 5.05 MWh, or 2 272 zł. That is 6.3% of the energy the monitored inverters could have produced . It is a lower bound: the data of inverter inv4 ends on 2015-09-01 , while the outage was still on.
- Simulated curtailment adds 5.96 MWh, or 2 684 zł, in 78 orders . It is a simulation on real production. No operator issued these orders. This loss is not part of the real loss.
- In the simulation, the claims that have not lapsed are worth 3.35 MWh, or 1 509 zł , at the assumed price. Compensation may be lower than the value of the energy.
Inverter inv4 outage
Inverter inv4 stopped producing on 2015-04-22 . Its data ends on 2015-09-01 , while the outage was still on. So the outage lasted at least 132 days . The loss is at least 4.99 MWh and 2 246 zł . That is 99% of the real loss . We do not know how much energy the system lost after 2015-09-01 , because there is no data. An alarm for an inverter at zero while its neighbours run would catch such an outage within days.
Underperformance
The analysis found 21 windows in which an inverter gave clearly less than its neighbours . Together they cost 58.8 kWh and 26 zł . That is small. The largest window is inverter inv1 from 2015-03-07 and costs 7.6 kWh . The data does not say what caused it.
Curtailment (simulation)
The data holds no curtailment order. The simulation lays down 78 orders on real production. In June they cut 14.2% of the potential production . That is a published figure (Forum Energii, PSE redispatch, large-scale PV). For May, July and August the same share was assumed, and for April and September half of it, 7.1% . These are assumptions, not data. Orders fall first on weekends and holidays, in the midday hours.
A claim must be filed within 14 days of the start of the order, not of its end. The deadline applies only to installations in the auction support scheme (art. 93 para. 18 of the Polish Renewable Energy Sources Act).
Of 78 orders , 45 were filed , 32 lapsed after the deadline , and 1 is still open . The lapsed claims are worth 2.61 MWh and 1 174 zł and the filed ones 3.31 MWh and 1 489 zł . Deadlines count from the simulated report date, 2015-09-30 . The open order C-076 has 4 days left , until 2015-10-04 .
The claims that have not lapsed (filed and open) are worth 3.35 MWh, or 1 509 zł , at the assumed price of 450 zł/MWh . Compensation may be lower than the value of the energy at that price.
Most expensive months
Real losses only, without simulation: July 1.32 MWh and 596 zł , May 1.31 MWh and 591 zł , June 1.19 MWh and 537 zł .
Including simulated curtailment: July 2.59 MWh and 1 164 zł , May 2.58 MWh and 1 160 zł , June 2.34 MWh and 1 051 zł .
Per MWp
The figures of this system come first. To compare it with a system of another size, we divide the losses by the monitored capacity: 69.9 kWp . That is 8 of 9 inverters, assuming equal DC power per inverter. For each MWp, the real losses are 72.2 MWh and 32 503 zł , and simulated curtailment is 85.3 MWh and 38 387 zł . It is a linear estimate, not a forecast.
What to do
- Set an alarm for an inverter at zero while its neighbours run for more than an hour.
- Check whether inverter inv4 is still down. Its data ends on 2015-09-01 .
- Watch the deadline of 14 days from the start of an order . 32 orders lapsed .
- File the claim for the open order C-076 by 2015-10-04 .
- Read the per MWp figures as a linear estimate, not a forecast.
Limits
- The price of 450 zł/MWh is an assumption. Compensation from the operator may be lower than the value of the energy.
- Curtailment is simulated. The 14.2% share is for large-scale PV, and this system is a rooftop.
- The deadline of 14 days applies to installations in the auction scheme. We do not know whether this system belongs to it.
- The loss of inverter inv4 is a lower bound, because its data ends on 2015-09-01 .
- Inverter inv7 has no data , so its losses are not in this report.
- The data does not give the causes of the outage or of the underperformance.