Is panel level optimisation worth it?

[Lowlight]

Because of extensive unavoidable shading at the site, I am looking for ways to get the best possible panel performance. It would be an 8 x 400W panel array on the roof of a cabin to be built in the sunniest spot. Shade will still recede in the morning and lengthen in the afternoon for much of the year.

Theory suggests that shading pulls the whole system down. But it some tests show that shade doesn't have a big effect. So I am confused. Is adding electronics at the panel level a good idea in this case?

Microinverters or DC optimisers seem to get around the apparent shade problem, but they introduce other failure risks. As it would be an off-grid system, DC optimisers seem to make more sense. It is also suggested that shingled panels are more shade tolerant. What do you think?

[J.P.M.]

Is this still for your site that faces 35 deg. south in New Zealand ?

[Lowlight]

Yes, the site is on a steep south-facing slope and is about 35% south. Lots of big trees up the northern slope on the right too. The picture was taken at about 2pm in late spring. The digger bucket is in the sunniest spot.

992 solar site.jpg

[J.P.M.]

Yes, the site is on a steep south-facing slope and is about 35% south. Lots of big trees up the northern slope on the right too. The picture was taken at about 2pm in late spring. The digger bucket is in the sunniest spot.

992 solar site.jpg

Nice Wellies.

Correction: given that you're in New Zealand, make that nice Gummies.

[bcroe]

Shade is devastating to solar output, electronics cannot find energy that
is not there. Things like optimizers are intended to compensate for spot
variations in panel energy, but can do nothing for an entire system shaded.

To optimize energy collection, you might try to determine the positional
range of direct sun available to you, including elevation angle. Then plan
an array optimized for that. Any energy collected at shaded times will be
a much smaller bonus, but will not be so dependent on the orientation
since it is dispersed light.

If you could put up several times as many panels, you might collect energy
at least a decent fraction of the peak times, but probably for more hours.
That is done here with panels not optimized for peak times, but instead
turned so as not to overload the equipment at peak times. Bruce Roe

[solarix]

SMA says their string inverter shade optimization software is as good as hardware optimizers.
See this link for the white paper:sma-america.com/shadefix/whitepaper-download.html

SDU (Southern Denmark University) Associate Professor Wulf-Toke Franke noted traditional module-based optimizers only achieved higher power output under heavily shaded conditions. He also said that error susceptibility increased in PV systems with module optimizers. More components in the system necessitated additional connections, increasing the risk of system failures and fires. On the whole, the study (The Impact of Optimizers for PV Modules) contradicts general statements about additional energy generation through the use of optimizers. In fact, Franke found very few scenarios where the use of optimizers improved system performance.

[Mike90250]

In some cases, Rapid Shutdown of the High voltages on the roof are dictated by code. First, only microinverters accomplished that, then optimizers came along. Both add complexity to the system, and the more complex, the less reliable the system becomes.

[heimdm]

SMA says their string inverter shade optimization software is as good as hardware optimizers.
See this link for the white paper:sma-america.com/shadefix/whitepaper-download.html

SDU (Southern Denmark University) Associate Professor Wulf-Toke Franke noted traditional module-based optimizers only achieved higher power output under heavily shaded conditions. He also said that error susceptibility increased in PV systems with module optimizers. More components in the system necessitated additional connections, increasing the risk of system failures and fires. On the whole, the study (The Impact of Optimizers for PV Modules) contradicts general statements about additional energy generation through the use of optimizers. In fact, Franke found very few scenarios where the use of optimizers improved system performance.

... any Sony told us that Software emmulation on Playstation 3 was just as good as hardware. I don't know about SMA's stuff, but generally hardware outperforms software. Software is usually "good enough." On the optimizers, one of the biggest reasons for going that route is boosting the voltage to 400v to reduce yours amps/wire cost.