Energy availability and price volatility are increasingly influencing greenhouse heating strategies, particularly in markets exposed to imported gas and disruptions associated with the conflict in the Middle East. For commercial growers, the risk is not limited to higher operating costs; interruptions to fuel supply can directly threaten crop continuity.

Adel Alekasir of Enorpa says the industry is moving toward a broader view of energy risk.

"Energy strategy has shifted from being purely an operational cost factor to a core risk-management requirement for project viability."

According to him, sudden gas shortages, LNG supply disruptions and fuel-price fluctuations can affect both project planning and day-to-day operation. Facilities dependent on a single energy source may therefore face difficult decisions when supply conditions change.

Multi-fuel operation
Enorpa's Multiful boiler is designed to operate with gas, solid fuel and biomass within a single boiler body. The ability to change the primary fuel provides an alternative to designing a greenhouse heating system around one commodity market.

"Fuel flexibility is becoming essential because it decouples crop security from the volatility of any single energy market." The system can use locally available biomass feedstocks, including agricultural residues and pellets, when gas becomes less economical or less readily available. Gas can remain an alternative when biomass supply or pricing is less favorable.

According to Adel, the mechanical conversion from natural-gas operation to solid biomass operation takes approximately three hours, following combustion-chamber cleaning. The process involves changing the boiler access and burner doors, mounting the burner, connecting fuel lines, sealing the solid-fuel flame throat, and commissioning the burner. A certified burner commissioning specialist is required.

Managing heating costs
The economic value of multiple fuels depends on local fuel prices, availability and logistics. Rather than remaining exposed to one tariff, growers can compare available fuels on their thermal cost. "Multiple fuel options grant growers purchasing power and operational hedging."

A biomass option can provide access to agricultural supply chains and locally sourced feedstocks such as wood chips, pellets or crop residues. "This can reduce exposure to short-term gas-price movements, although the economics depend on the characteristics and delivered cost of each fuel."

He notes that biomass can also provide a baseline heat source during periods when gas is expensive or supply is constrained.

"Biomass and solid fuels serve as a highly reliable, cost-effective primary or backup baseload heating source."

Filtration and emissions control
Solid-fuel operation introduces particulate emissions that must be managed both for regulatory reasons and to protect greenhouse performance. Multiful incorporates a multi-cyclone filtration system available in six-, nine-, and 12-channel configurations.

"The multi-cyclone system captures fine particles before exhaust leaves the stack, protecting the roof covering and maximizing sunlight entry."

The boiler's PLC can also integrate particulate-matter sensors, allowing real-time and historical PPM data to be recorded for environmental monitoring. "Where lower particulate limits apply, standardized connection points allow additional equipment, including bag filters or electrostatic precipitators, to be incorporated."

Integration and project design
"Multiful is intended for both new greenhouse developments and retrofit applications. It can connect to existing hot-water loops, heat exchangers and buffer tanks, while its three-level configuration uses vertical space for the ash and hydraulic systems, combustion grate and heat-transfer surfaces."

However, multi-fuel systems require more space than conventional gas boilers, including areas for fuel storage and ash handling. He also emphasizes the importance of system configuration.

"Installing parallel multi-fuel units provides built-in operational redundancy, lower shipping and installation friction, and better turndown efficiency during low-demand seasons."

For greenhouse operators facing uncertain fossil-fuel markets, the principal role of a multi-fuel boiler is therefore not simply fuel substitution. It is the ability to maintain heating continuity while adapting the energy mix to changing availability, cost and regulatory conditions.
 

Source: www.floraldaily.com