Burgess BioPower, a wood-burning electricity plant in the North County city of Berlin, has gotten a $500,000 state grant to heat a greenhouse for vegetables with its waste heat. From a press release:
The recovered energy will be used to heat a state-of-the-art, $25 million hydroponic greenhouse, growing baby leafy greens, to be located on the plant’s property in Berlin. This marks an important milestone as Burgess BioPower looks to complete a co-location agreement with a third-party company, which would build and operate the greenhouse.
The recovery system will repurpose heated water that’s created by Burgess’s cooling water circuit as it lowers the temperature of steam from the power-generating turbine. This energy is currently rejected to the atmosphere by the facility’s cooling tower. The warm water will be piped to the proposed greenhouse to heat the facility, allowing it to grow produce year-round, whatever the weather may be outside. The proposed greenhouse project will grow baby leafy greens, such as spinach, arugula and kale
Heating greenhouses with excess heat from power production sounds like an obvious move but it’s more complicated than it seems, judging from research into the topic.
The money for the grant comes from the Public Utilities Commission’s Renewable Energy Fund, which is funded by fines paid by power plants that can’t meet the state’s requirements for renewable energy production.
Burgess BioPower uses a closed pulp mill that was converted to electricity production. Its design burning wood chips to boil water for steam to power a generator produces a lot of waste heat. NHPR reports that another idea is to use it to melt snow off the sidewalk.
Burgess is one of a half-dozen large (well, large-ish) wood-fired power plants in the state. Most of them are involved in a long and complicated fight over whether they should be subsidized. Burgess has a separate power-purchase deal with Eversource that has generated its own debate.
The problem is that burning wood merely to produce electricity is not very efficient. It tends to be expensive and the environmental benefits are somewhat questionable. Producing both heat and electricity from the same wood-burning unit – known as cogeneration – makes a lot more sense, which is why Burgess is trying to re-engineer itself to do some of that.