On Tuesday, May 16, 2017 at 5:22:41 PM UTC-4, mike wrote:


You don't have a commercial installation.
You have a bunch of auction acquired stuff cobbled
together to make something that works for you.
Nothing wrong with a hobby project; I do it all the time.
But that's not something you can do with a commercial
installation. For general use, you'll find your customers
more demanding.

You've described a situation where you have grid tie.
You have decided that you can tolerate a 30-second loss of power
when the grid is down.
You replaced battery storage with diesel LOCAL storage and a generator
to convert it to electrical energy.
You have not described what happens when the generator is running
and the cloud has passed, or the load dropped below what solar can
supply, or what happens when a new cloud arrives.

Take a look at the curve he
https://www.wholesalesolar.com/solar...nel-efficiency

When solar becomes insufficient, the operating point is past the knee
of the curve. Small changes in load current can change the voltage
dramatically.
If the refrigerator starts, the current surge can drop the voltage
below your threshold and shut down your system. That lets the panel
voltage rise above the threshold. What do you do?
With the grid down and insolation low, you will see a lot of those
cycles. They can happen way short of 30 seconds apart. They'll
probably happen every time you turn on the electric stove
or air conditioner when insolation is low.
Do you start the generator? Do you let the fridge try to restart
every few seconds?

Engineering is a process of defining a problem and providing a ROBUST
solution that meets the needs of your entire customer base.
Sure, you can restrict your customer base to those who want a generator
in their back yard and tolerate limit-cycle oscillations in their
utility supply. A commercial supplier cannot do that.

Even residential customers can't. So far, Diesel hasn't provided us
with examples from all the solar installers that offer a residential
grid-tied system that also supplies power to the house when the grid
is down, without a battery bank. If this was possible, practical, it
would be a powerful selling point. But it isn't, with the cloud
problem, the rainy day problem, etc, being the major, insurmountable
problem. Like you say, customers aren't going to tolerate brown outs,
total outages, from passing clouds. And during a power outage, when
do you need power the most? Typically at night, when the sun isn't
shining. That's why you don't see installs that offer power without
the grid or batteries.