Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.
Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.
It is absolutely necessary to have some form of energy storage.
You said exactly the same thing I did, a MPPT controller stores energy in capacitors. ....
You said exactly the same thing I did, a MPPT controller stores energy in capacitors. Some have discussed using diversion outputs with a solid state switch. That is better than just not using available energy, but it is not efficient without capacitors to store the energy. The PV hot water systems I build are much like the Sunflux. I like how they say up to 96% efficient. Only the Shadow knows. If you find someone more creative than me, let me know.
I can see solar PV hot water not providing enough hot water but electric resistance water heating is as simple and trouble free as it gets. The problem is when people forget that it is truly an opportunity load and don't plan for back-up heating. Running out of hot water mid-shower is likely to make you think "This doesn't work" but it should never be expected to work as the base load for heating water.
Expecting solar by any method to supply all hot water isn't very cost effective. Sure, there are some places where a barrel painted black on the roof will work. That will not be an option for most people. Supplemental PV heating is a very exciting idea. I bought 520W of panels for $240. That is something that can be done any day by anyone. That few of panels can easily find a place on any home and running a wire is nothing. Putting that power into a water heater is far more cost effective than a heat pump. As supplemental, 100% of the potential power will go into heating.