The main thing to remember with a blog is that its job is to firstly bring relevant traffic from Google and secondly to convert that traffic to the next stage of your funnel, whether that's a purchase, catalogue download, or email address capture.
I've done SEO for many businesses whose blog posts are all about the industry award they won or the latest job they completed - sadly, nobody cares about that! And because nobody is searching for that information, posts like that never bring traffic to your site from Google!
With that in mind, only write posts that answer typical questions that your customers are likely to ask. In your industry they might be asking 'how much does it cost to install solar panels', 'what is the payback period for solar panels', etc.
Some of these are very competitive questions which makes it hard for a new website to rank highly in Google for them, however there will be less competitive questions related to your industry that are easier to rank for. Target these early to start generating a flow of traffic to your site.
As an example, I did a quick bit of research and found that 'how much do solar panels cost' is much more competitive than 'how do I pigeon proof my solar panels'. If mine were a new/young website, I'd be targeting questions like the pigeon-proofing one.
Whatever you target, always write helpful, comprehensive posts answering these questions and make sure to include a call to action (CTA) to have the reader move along your sales funnel, otherwise there was no point to writing the post to begin with.
Just know that blog posting is highly effective at bringing relevant traffic to your business website but it takes time and effort to get going and it only works if you give the information your audience is searching for.
Best wishes!