Trade publications are a good source for experts. You can search them in Lexis and Factiva. Here’s Berkeley City College’s guide to understanding scholarly journal or trade publication articles
Remember, you want to challenge your assumptions by using diverse sources, however, here are some searches you can do in Nexis and Factiva to find out who has said what before on a topic. Just change the keywords to fit your topic:
Nexis Search:
alternative w/2 energ! w/10 (expert or authority or professor or fellow) w/30 (said or says)
Factiva Search:
alternative near2 energ* near10 (expert or authority or professor or fellow) near30 (said or says)