We discussed the Google AdWords policy on a max URL character space of 35 in the past. They recently started enforcing this rule back in June of this year.
A new Google Groups thread has an issue where on advertiser needs to have a display URL that is longer than 35 characters. So what can he/she do? AdWordsPro Sarah says that you can submit an exception.
In short, make your display URL 35 characters, and ask for an exception to allow the display URL not match your real URL. Sarah explained:
We can grant exceptions for URLs that are over the 35 character limit. I suggest you modify your URL to something like GreenSolar-Wind-Hydrogen-Energy.com and then, when you submit the ad, ask for an exception request (see links below). If you explain that your URL is over the 35 character limit, our policy team can help manually approve your ad to run.
Forum discussion at Google Groups.