I suppose anyone who has some knowledge re electricity knows what they're trying to say here, and for anyone who doesn't it won't make much difference, but reading a sentence like this still hurts me a little.
MW (megawatts) are a measure of power, not energy. This means the "per year" part is meaningless. Also for what it's worth, 300MW for 300k homes is 1kW/home, which is a pretty old rule of thumb for average household power use. I believe the current average in Canada (and the US) is considerably higher But that's also just the average; the peak is much higher. 300MW is the peak output for the plant, so the true number of homes it could power is lower regardless, absent storage.
None of that to say the prospect isn't exciting! And I suppose the source here is the weather network, so perhaps they're a bit outside their area of expertise.