Hi. The easiest way for this is to use the power of "Social Media Marketing". To achieve your target reach:
1. Identify the business groups in solar industry, your target countries, stereotypes etc.
2. create some ad sets and campaigns (yes everything can be regarded as an advertisement) and follow their leads to see how effective is your ad in that group.
3. if the conversion rate is good and the performance of the leads are positive, continue publishing the ad sets and you will get more people showing interest in your website.

if you need their feedbacks and assessment, you can still use the social media. Before starting social media marketing targeting the public, find solar-industry related business people / influencers and send some quick surveys to them (please keep in mind that time is very important for everybody, so you should be convincing them in some way, the common method for this is to provide them some promotional giveaways or industry-related information).

Last but not the least, Facebook and Linkedin seems to be the most powerful media for your targets. Consider having some marketing budget and premium accounts, or hiring some professionals who have already this kind of database.

Thanks.

veyis