Totally agree Sam. You have to do some serious calculations to determine what the payback may be and if you are happy with that. Adding solar will also add value to your home, so if it's a case of spending the kids inheritance vs not ticking of bucket list items, it may be worth it. There are a set of folks who will do this for other reasons too (like reducing your reliance on fossil fuel), but that is another story.Making the decision to have PV panels installed is not easy. Figures will vary but as one example a 4Kw system will be about £6k to install. The estimated savings each year where I live is about £500 so that's going to take 12 years before I would break even.
Now its a sad fact of life and not a pleasant thought but when you get to be over 70 years old your not sure how long you've got left. Average life expectancy for men is about 79 years and women 83. So just as your about to start seeing the benefit you might just shuffle off this mortal coil. (I'm hopeful I'll have longer because my father was just 7 days short of his 100th birthday)
Of course as fuel prices rise then the payback period would be shorter provided other things don't detract from that such as reductions in the Smart Export Guarantee, increased maintenance costs, replacement cost in case ,of failures
Currently you can easily get savings rates of 4.75% which on the £6k out lay you would have paid will yield £285 per year and you still have your capital to play with if you need it.
Maybe it would be better to use the money if you have it and your at that certain age to tick of the items on your bucket list.
The Ripple thing is something that you can leave to the beneficiaries of your will. My parents bought into the scheme at the age of 78. Of course they hope to see the payback of their investment, but are actually more motivate by the fact they are helping to fund and build a wind farm that will offset all of their electricity use.