I can't really answer your question why it's trading low. Maybe partly fear of rising interest rates. Maybe partly fear of "wind don't blow" like you mention. Many utilities and interest-sensitives seem to be down, including green ones. It might be mostly a general sector thing.
AQN is about 1.3% of my portfolio. It has disappointed so far. I've a small positive return but that may disappear tomorrow. I must confess I bought it on macro considerations and expert recommendations rather than my own careful financial analysis.
One "highlight" in their announcement struck me badly. They say "an opportunity to replace over 1 GW of rate based fossil fuel generation with renewable energy." Does that mean they bought a problem? Is it shareholder friendly to buy a bad thing and then spend money to fix it? Calling a problem an "opportunity" doesn't impress me. Sounds like hype.
Plus the new offering is 2.5% below the last close, which was relatively low in itself.
Right now I wish I didn't own it.