In a recent column about wood-fired cooling I celebrated combined heat and power as the combination that makes burning wood a viable option for society.

There’s an interesting example coming to the North Country, but unfortunately they’re using natural gas to generate electricity and heat, rather than wood pellets. At least it’s CHP.

The project, called North Country Growers, plans 20 acres of indoor greenhouses to grow leafy greens and some vegetables, employing some 80 people. New Hampshire Business Review story is here:

Rainwater and snowmelt will be collected from the greenhouse roof and used for irrigation, while thermal energy produced during power production can be stored in thermal storage tanks and utilized other times of day. Because growing variables (light, temperature and irrigation) can be closely controlled, a head of lettuce produced in the Berlin greenhouses can be grown in around 17 days — much less than as many as 42 days grown outdoors.

New Hampshire has one (that I know of) large hydroponic automated greenhouse for leafy greens, now owned by Brightfarms. It was formerly owned by a startup with the awkward name Lef, pronounced “leaf” with a bar over the “e” to show that it’s a long e although few typesetting systems can print that.

Large greenhouses seem a viable business despite higher costs for electricity compared to outdoor farming; they save it on water, labor and pesticides. The same can’t be said for vertical farms – basically multi-story greenhouses – which got a lot of attention because they’re cool but seem to have hit a wall. Their electricity costs are much higher because they can’t use much, if any, sunlight.

So far, indoor greenhouses like Brightfarms have been limited to a few high-markup items like specialty greens. They have shown no ability to do anything about global hunger by growing high-calorie crops. However, if extreme weather keeps making traditional farming harder with droughts and floods, they may prove more valuable.

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