Decarbonising heat: How electric systems are transforming gypsum production

Gypsum production involves calcining raw material to remove moisture, followed by shaping and drying in massive systems that may require 15 – 40 MW of thermal energy. Electrifying this demand requires more than heater installation; it calls for thoughtful engineering of airflow, temperature control, thermal inertia, and electrical infrastructure.

The environmental impact is significant. A mid-sized plant producing 500 000 t of gypsum annually emits 75 000 – 125 000 t of CO2 when gas-fired; coal-fired systems can exceed 200 000 t. Gas systems emit 150 – 250 kg CO2/t and coal 250 – 400 kg CO₂/t. Even grid-powered electric systems (if non-renewable) add 50 – 100 kg CO2/t. Yet, plants using renewables can reach net-zero emissions, highlighting the critical role of electrification in sustainability efforts.

Practical solutions in thermal design

Electric duct heating systems are emerging as an effective solution, offering scalability and compatibility with existing infrastructure. Their rugged design reduces maintenance downtime, particularly vital in dusty gypsum environments. Systems with field-replaceable heater elements and durable housings further enhance reliability.

Power control is equally important. Closed-loop strategies using silicon-controlled rectifiers (SCRs) adjust power delivery in real time, optimising thermal performance and reducing electrical stress. Integrated sensors and control algorithms convert heating systems into data-rich intelligence platforms, enabling predictive maintenance. For example, a resistance drop might indicate upstream air pressure issues rather than heater failure – insight that supports system uptime.

Electric systems are inherently more reliable, especially for 24/7 operations typical in gypsum manufacturing. Unlike gas systems that need routine cleaning, electric heaters, when paired with proper power control, exhibit fewer failure modes.

Enhancing system longevity

Design choices like soft-start functionality and corrosion-resistant materials significantly affect performance. Soft starts limit thermal shock and mechanical stress at power-up, helping avoid localised overheating and fouling. In dusty environments, this is crucial, as particulates on hot surfaces can form carbonised deposits. Materials like high-grade stainless steel resist scaling and corrosion, preserving thermal efficiency and minimising unplanned downtime, critical in continuous production.

Although electric systems can involve higher initial capital costs, especially in retrofits, long-term savings often offset this. Gas systems operate at 30 – 50% efficiency, losing energy via flue gas and radiant heat. Electric alternatives can achieve 75 – 99% efficiency. Maintenance and personnel demands are lower, further reducing total cost of ownership.

Energy metrics underscore these advantages. Gas-fired plants consume 5 – 10 million Btu/t of board. Electrified systems use 100 – 200 kWh/t. Water consumption remains 100 – 300 l/t.

Some manufacturers are exploring hybrid systems, combining electric and gas heat for flexibility, e.g. using electric heat during off-peak hours or as a backup. While transitional, most who pursue electrification tend to fully integrate once feasibility is confirmed.

Policy and market influence

Electrification decisions are not purely technical. Policy, energy pricing, and carbon regulation heavily influence outcomes. In areas with low-cost renewables or strong carbon pricing, electrification becomes economically attractive. Elsewhere, subsidies and carbon credits may tip the scales. Manufacturers must weigh these external incentives against internal ESG targets and operational strategies.

The scale of potential impact is broad. With over 470 gypsum plants globally, only a few have electrified, but that is changing. By 2028, gradual adoption is expected to increase. As systems are validated at scale, standardised designs will enable faster replication across plants with similar layouts.

Thermal systems are increasingly being developed with repeatable configurations for ease of deployment. In gypsum production, drying temperatures generally range from 150 – 300°C, making standardised heater designs practical. Once adapted for voltage or airflow differences, a single platform can be implemented across multiple facilities.

Watlow’s role in accelerating electrification

Watlow supports this transition through integrated thermal systems combining specialised heaters, SCR-based control, and real-time sensing. These are designed for ease of retrofit, minimal maintenance in dusty environments, and compatibility with plant control networks. This level of integration simplifies commissioning, reduces vendor coordination, and enables performance guarantees.

Conclusion

Electrifying gypsum production is about more than emissions reduction, it marks a shift toward intelligent, reliable, and efficient thermal systems. Electric heat unlocks new levels of process visibility and control, previously unattainable with gas-fired systems.

This is a systems-level evolution, not just a technology swap. Success requires careful engineering, cross-functional collaboration, and a redefinition of thermal performance in a low-carbon future. The gypsum industry is poised for transformation, and the tools are ready. Now, it is about aligning strategy, economics, and execution to build cleaner, smarter plants.

Read the article online at: https://www.globalminingreview.com/mining/24062025/decarbonising-heat-how-electric-systems-are-transforming-gypsum-production/