There is clearly a case for both. Wave energy is by far the...

There is clearly a case for both. Wave energy is by far the better long term solution as IMHO, like solar, once the technology is proved (and CWE are very close on that score), we will see a mass customisation and implementation model quickly emerge. We were early adopters of solar on our home 10 years ago and the cost today is about 20% of what we paid.... but we secured a 66c buy back for 25 years.

Notwithstanding the above re solar and the point you make about battery technology becoming a reality, maybe you should take a close look at Orocobre (ORE). ORE is in the final stages of ramping up their Lithium plant in Argentina. This is the largest new Lithium plant in the world in the last 20 years. Take a look at their recent quarterly report.

ORE's order book is full for the next 12 months even before they are at nameplate production. this together with the Lithium growing at 10% compound for the next 5 years makes this a sound medium term investment.

I have held both for over 5 years and I have a substantial holding in both.

Having said all that, do your own research.