The quarter started with the rainiest April and May in a while, and production numbers were lower than in March. April and May had 20-25% less sun than average. But June was pretty spectacular and compensated a little bit for the earlier losses (of opportunity) this quarter.

• My system capacity is 3.75 kW DC, 3.18 kW AC
• Azimuth is 345 degrees, almost due South with a minor Eastern bias
• The system is in downtown Toronto, on a flat roof, with a 22.5 degree tilt (half the system is at 15 degrees, half the system is at 30)

To throw a few quick facts out:

• 603 kWh production in June
• $483.60 in the “brightest” month of the year
• 1,481 kWh generated this quarter
• panels kick in before 6 AM and keep working past 9 PM
• on hot days, especially when there is no wind, it is fairly obvious that output is not staying at the peak for as long as it does during colder days (May)
• noticing slightly higher resistance loss on the wire between inverters and the meter – it is now slightly above 2%, whereas earlier in the year it was closer to 1%

Electricity production per day

Average production per panel

Electricity production curve - perfectly sunny day

You can see real-time production numbers from my system here.

Overall the system produced 2,341 kWh in the first two quarters. Extrapolation is not a fair evaluation and is not indicative of future performance, but if the trends remain what they are:

• $1,877.48 net income YTD
• Hoping for $3,754.96 in calendar 2011
• $75,099.28 over the life of microFIT contract (not factoring in gradual performance loss)
• 7 years and 3 months to break even
• 13.9% annualized return on investment (excluding gradual performance loss, inflation, and before taxes)
• 8.9% annualized gain (principal investment return not treated as income)

So far, the system is performing slightly above expectations, despite a lousy stretch of rains in April/May.

• Enphase inverters outperformed RetScreen by 3% in both April and May
  • When I say outperformed, I mean that relatively
  • In April solar insolation was 28.6% LESS than the average value used by RetScreen
  • In April my system produced 25.5% LESS than RetScreen modeled
  • Conclusion: my system performed better than RetScreen’s prediction by 3.1%, weather taken into account
  • In May solar insolation was 20.2% LESS than RetScreen’s value
  • In May my system produced 15% LESS than RetScreen modeled
  • Conclusion: my system performed better than RetScreen’s prediction by 5.2%, weather taken into account
  • Compared to NRCAN data, my production numbers blew past NRCAN, beating it by 25% in April and 15% in May – why, I am not sure. I find NRCAN’s performance data to be uber-conservative, to a point that they allow 20% or so in system losses (unrealistic, given my observations)

Since U of T has not published weather data for June yet, I’ll post a few more charts in the next post, a few days later.

Maxed out solar panel system