PVI 3600 Outdoor 16A limited with 4.5 kWp panels

[DomB]

This touches on the debate about exactly which figure the Feed In Tariff calculations are based upon (sorry!):

If we install a "Power One Aurora PVI 3.6 Outdoors 16A limited" inverter with 18 No. 250W (4.5kWp) Yingli Solar panels the Aurora configuration tool tells us the inverter is optimally configured with a "possibility of output power limiting".

Given the Sun won't be pushing out 1000 W/m.sq. very often I'm thinking we could end up with a system which is optimally configured voltage-wise yet still pushes out a max of 16A. The rest of the time the customer will be doing very well from a 4.5kWp system.

I know from this forum that companies are installing >4kWp of panels but calc'ing the Declared Net Capacity on the MCS certifcate in a different way than what the certificate's "Help" file tells us to and declaring them as 4kW.

Has anyone had such a system, i.e. one which has >4kWp of panels but with a 4kW MCS certificate, passed OK by an MCS renewal audit?

I'd very much like to install this 18 x 250W system but need to keep the customer on or under the 4kWp tariff.

Thanks!

 

[ktech]

We have installed system with a net capacity exceeding 4kw on a 16A clamped inverter and declared as 4kW. I see nothing wrong with this and have an email from the energy saving trust saying this is ok. However I wouldn't offer these up for audit visits as i can only imagine the conversation with the auditor. No two auditers can agree on various aspects of installations as it is. I still do not see that we have done anything wrong. In addition we would be quite happy to install 11.5kW or 12kW and appropriately delcare as 10kW.
An example is my own installation of 5.4kW declared as 4kw. It has 4kw on a west roof and 1.4 on an east roof. Only during the summer months has this got the potential for exceeding 4kw generation. And during these potential times I have seen the SMA 4000TL max out at 4kW. Therefore this system will not produce greater than 4kw at anytime and is quite acceptable for the <=4kW tariff. The advantage is that during lesser generation times of the year I will be generating more than a 4kW system.