Beat the High Cost of Natural Gas by Heating Greenhouses With Biomass - Greenhouse Grower

2021-12-23 06:54:53 By : Ms. owen owen

Biomass boilers are emerging as an ideal solution for providing reliable, efficient, and cost-effective heating of commercial greenhouses producing leafy green vegetables and fruits.

They’re a proven alternative to boilers fueled by natural gas, the cost of which had been predictably low for a decade but is now extremely volatile. In 2020, natural gas prices averaged $2.03 per million British thermal units (MMBtu); natural gas futures surged to $5.72 per MMBtu in November. That’s the highest they’ve been since 2009. It’s also a warning signal that the potential price at the burner tip will be pushed well past the $6 per MMBtu threshold commercial greenhouse operators typically set.

That’s not good news for commercial operators. They’ve depended on natural gas to achieve their financial performance plans as well as optimize plant growth and crop yield by maintaining ideal greenhouse temperatures and providing a source of CO2 (carbon dioxide). Meanwhile, biomass feedstock prices remain steady and supplies plentiful, making the operating costs of biomass boilers more predictable for commercial greenhouse operators.

Where natural gas prices go next year and beyond is anyone’s guess, but they’re not expected to drop back down to the pricing levels experienced in recent years. Production and investment in new gas wells have been constricted during the pandemic and will take time to recover. At the same time, demand for residential heating is growing rapidly, with significant amounts of the available natural gas inventory being liquified and exported.

Adding to the challenge is a lack of natural gas infrastructure in cold-climate regions (especially in the Northeast and Midwest) where commercial growers want to house or place their facilities. Of the five U.S. states that consume the most natural gas, only Pennsylvania is in a cold, northern climatic location.

Contrast what’s happening with the escalating price of natural gas to biomass fuel, whose average price per ton actually decreased slightly, even as consumption increased nearly 40% from January through July this year.

Wood and other biomass feedstock also are widely available in all regions and will continue to grow as demand develops. As a result, commercial greenhouse operators who choose biomass boilers instead of natural gas boilers can mitigate significant business risks while also ensuring that their vegetable and fruit plants receive the right amounts of heat and CO2.

Natural gas has long been the preferred fuel choice for commercial greenhouse boilers — and it’s not just because of its historically low price.

Natural gas burns efficiently; 90% or more of its available energy is converted to warm vegetables and fruits. In addition, CO2 produced as a combustion by-product can be captured from flue gases and redirected to feed the plants. Plants then combine carbon dioxide with water and light through photosynthesis to make carbohydrates that nourish their growth.

Another benefit: once installed, natural gas boiler systems do not require additional labor and logistics to operate. And they’re typically less expensive to buy and commission; biomass boilers can cost as much as six times more, than natural gas-fired equipment, based on internal research at Prospiant.

However, the uncertainty caused by higher natural gas costs and price volatility is jeopardizing commercial growers’ operating budgets. And operators new to the industry, along with established commercial growers looking to expand their multi-state operations, are discovering that their preferred locations for greenhouses do not have natural gas pipelines nearby.

For these reasons and more, biomass boilers are increasingly specified in commercial greenhouse applications.

Today’s advanced biomass boiler technology burns feedstock ranging from wood pellets, chips, or split logs and other agricultural and organic waste material. Feedstock also can include construction waste or demolition debris. Regardless of the source, combustion of biomass efficiently warms vegetables and fruits in a commercial greenhouse; as much as 85% of the available energy in wood pellets, for example, is converted to usable heat.

Biomass is also a carbon-neutral, renewable resource. Commercial greenhouse operators can achieve their sustainability goals because the burning of wood pellets and other feedstock releases the same amount of CO2 as was absorbed by trees or other biomass plants during their growth cycles. Combustion of wood pellets and chips reduces greenhouse gas emissions that contribute to climate change from 65 to 100% compared to other fuels. And utilizing construction waste and demolition debris maximizes resources while also preserving landfill space.

Biomass systems are designed to run continuously (whereas natural gas boilers fire up and cycle off on demand). Properly sized heat and CO2 storage and a reliable fuel supply chain are paramount. One Prospiant customer operates six 800 horsepower biomass boilers at his commercial greenhouse. Fueling these boilers consumes 14 semi tractor-trailer loads of wood every day. Dedicated employees maintain adequate fuel levels in the infeed system and also operate systems for ash removal and emission control.

To recover the CO2 released by burning biomass, absorption technology from the petrochemical industry is applied to recover 100% of the CO2 plus latent heat from exhaust gases. Since biomass boilers operate continuously, they can be appropriately sized to heat the greenhouse space during the day when less heat is needed for the vegetables and fruits. At the same time, the boilers can heat water that’s stored in vertical tanks to 95°F. At night, the hot water is released from the storage tanks and circulated throughout the greenhouse to keep the plants at their optimal temperature.

The price of natural gas had been low for so long that commercial greenhouse operators considered it a fixed cost. But that’s no longer the case. It’s become a moving target that’s only expected to increase.

The only question is how high natural gas prices will go in 2022 and beyond due to reduced supply in the short term and ever-increasing demand from commercial, power generation, and residential consumers worldwide. These unstable market conditions increase financial and other business risks for commercial greenhouse operators.

To better manage fuel costs and provide an efficient, carbon-neutral heating option, commercial greenhouse operators should consider biomass boiler systems.

In many locations that lack a natural gas infrastructure, they are the best heating alternative for commercial producers of vegetables and fruits. Compared to natural gas, the cost of wood and other biomass is stable and supply is available and abundant in all regions. That’s how biomass technology provides significant benefits to businesses which need boilers ranging in size from 60 to 65 horsepower per acre to heat commercial greenhouses.

Modern biomass boiler systems can be automated and operate reliably, efficiently, and safely. The upfront investment in a biomass system is higher than a conventional natural gas boiler. However, eliminating fuel cost volatility can enable commercial greenhouse operators to offset the initial costs and realize a return on their investment in three to five years.

Selecting the right heating solution is critical to your success if:

Ensure that your crops thrive by providing the right amounts of heat and CO2 and the right times by partnering with controlled environment agriculture technology experts. You can leverage their deep soil-to-market experience. You’ll recognize them because the right partner for your commercial greenhouse will have succeeded at every aspect — design, installation, integration, operations, maintenance, and expansion — over and over again.

Henry Froese is Principal, Produce Business Development at Prospiant. See all author stories here.

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