The fuel can change. The process doesn’t have to.

RDF and other alternative fuels vary widely in quality. Moisture, calorific value and chlorine content shift from load to load, causing temperature swings, inefficient combustion and product inconsistency. These fluctuations increase operator workload and make reliable process control difficult.

An unstable flame puts stress on the entire system. Frequent fluctuations cause ring formation, where deposits build up to drive wear on kiln linings and increase the risk of unplanned shutdowns. Every temperature spike or fuel-related variance increases the cost of maintenance and threatens overall uptime.

Although RDF typically costs less than coal, its inconsistent quality can destabilize combustion, which leads to higher emissions and reduced efficiency. That instability means increased reliance on fossil fuel backups, higher carbon certificate costs, and mounting pressure on margins. Inconsistent combustion also limits your Thermal Substitution Rate (TSR), which is the share of energy supplied by alternative fuels. This makes it difficult to raise RDF use toward 100% or more without impacting performance. Without combustion stability, the financial and environmental gains from RDF simply evaporate.

Suppliers don’t always provide RDF that matches specifications. And without real-time measurement on delivery, plants have no way to verify quality or push back when loads fall short. Poor visibility at the door leads to greater instability inside the kiln.