[RE-wrenches] Large Off Grid Inverter?

[Ray]

Greetings Fellow Wrenches;

We are consulting on a power system for a large off grid facility that 
is currently operating on a 1500 kW gen set.  The loads are enormous for 
normal off grid: in the neighborhood of 600 amps continuous at 480 v 3 
phase.  Surges are close to 2000 amps, but we are working on control 
programming to bring that number down substantially.  That is due 
primarily to a 250 Hp motor start. (that's not a typo!). EPA and local 
regulations are dictating that the current generator be retired in the 
near future.  Grid power is a possibility, but we need to offer a viable 
off grid option as well.

My question to the group: does anyone have real off grid experience with 
large format battery based inverters?   I've heard of some micro-grid 
systems running in Haiti on Princeton Power inverters, and Dynapower has 
a 250 kW inverter that has a "grid forming" mode.  As we all know, it is 
easier to make claims in spec sheets than to deliver hard motor starting 
power in a remote location.  We need proven products, with a track 
record of reliability.

We are considering SMA type systems that use AC coupled PV to offset 
fuel consumption of a generator, but those seem dependent on the 
generator to maintain the stability of the micro grid during hard 
starting loads. Ideally we would want to reduce the generator run time 
to under 200 hrs/ yr and reduce its size to 500 kW.  We have excellent 
solar resources year round, and the possibility of  limiting operations 
during cloudy weather to meet these goals.

Thanks,

Ray Walters

Remote Solar