DC module + String inverter system

I am pleased to see at last, a glimmer of recognition by some design engineers that the "cost of labour" must feature as a critically important component in the overall engineering design of energy technology products and integrated systems.

In fact, no design worth its salt in the modern era should move from the drawing board to production unless this point has been rigorously and impartially examined first [outside of the engineering division] and signed off on.

Your AC module would come a very distant second to a DC module and string inverter design under a rigorous "cost of labour" examination. The AC module system would also fail the "hardware component cost" design shoot out. Finally the MTBF of the AC system verses the DC system and string inverter wouldn't even be close.

Commercial viability evaluation is often overlooked when there seems to be plenty of cash floating around [through R & D subsidies; end user rebates, and FIT's] which is the history of the PV industry up to now.

As these subsidies evaporate though, design engineers must assume more responsibility to commercial viability which will shift the focus [including R & D] to labour saving products and system designs.

About the risk of system failure due to a string inverter malfunction. It can easily and cost effectively be dealt with. Our own string inverters incorporate double redundancy technology within the one unit [effectively a hot spare auxiliary on standby] and we are about to do our first triple redundancy unit [aircraft employ triple redundancy technology].

Coupled with remote monitoring and control, the DC module + string inverter system can be highly reliable with guaranteed continuity of supply and provide for machine initiated planned maintenance management communications in event of component failure.

Importantly it can be cost effective with particular design emphasis on "cost of labour". The AC modules will have trouble gaining traction as the PV economics landscape changes.