Can I claim Solar panel installation ?

I had solar panels installed it started in Nov 2018 & the panel installation ended in Dec. 2018. I had no upfront costs...They finally turned the solar panels on in March 2019.. can i claim this on my 2018 taxes ? Or do i need to wait till next year? I've looked online and it tells me 30% cost which I already know I need a more detailed answer to my question about.