Passive income:))

The Solar Investor system enables property owners to offer reduced energy bills to their tenants.
Can I offer my tenants reduced water bills? How about internet and phone? Adult entertainment services?

What's in it for me? A quick look at their website says nothing.
Yearly returns do not make sense to me. The smaller the system the more power you will offset and the less you will export so therefore figures to me should go something like this:
2kW - $550
3kW - $760
4kW - $850
5kW - $900

Not much difference I know but to me the figures are out therefore discredits all they say.
I was looking at this too on another site
I think this site explains it a bit better.
From the above site...
The Owner provides power to the property through a combination of solar and grid supply.

The Tenants pay for all power used as they would normally do.

The Owner benefits by being paid the market rate for the solar electricity their tenants use. Everything leftover is then purchased from the owner by the grid; it?s a win-win solution.
I see how it can benefit the LL, but can't see how it provides any benefit to the tenant. If I was a potential tenant I think I'd just tell you shove it.

If I understand it correctly the power bill is in the LLs name. That provides additional risk that if the tenant skips without paying for their power the LL is on the hook to the power company, not the tenant.
From what I have read between the 2 sites, you can offer the tenant a discounted rate for their electricity so that might appeal to some. Perhaps you could tie the discount to paying on time as some suppliers already do.
I would like more information as to some of the issues you have raised Ed and might get someone out for a chat to nut out the nitty-gritty.
tenants dont pay extra for having solar, unless their power bill was astronimical for whatever reason

any extra rent would offset their bill anyway
I wouldn't do it cause if something goes wrong it is just another thing you will need to fix and not supplying electricity will be a huge pain in the *** for a LL if it wasn't working.