Greenhouse year round grow possibility in Oregon

Didn't see much on RIU when I did a search, but watched a video from Colorado about greenhouse growing is the direction growing is going to go. I've been a medical grower (outdoor only) for the past 10 years and will transition to recreational grower January 2016. I' looking into semi-gable greenhouses at least 30x48. I have electricity, water, natural gas all nearby on my land.
Are there any experienced growers who have grown in a greenhouse in winter months? I like the idea of using available sunlight and suplimenting with lights.

Sounds cool. Wonder how much it would cost to heat it. Glass greenhouse?

What you SHOULD do is build a pit greenhouse. Once you get like 3-4 ft below ground level, temperatures stay fairly consistant around 50-60 degrees. Add in high humidity, and all the warmth from the sun, it should keep your greenhouse perfect temps year round.

I know a few vegetable growers in Colorado that are using this special greenhouse film called solawrap? They said they were logging temps of 100+ degrees in 50 degree weather this week. I am looking at transitioning into greenhouse growing myself..