---
title: "RDF / SRF / TDF"
description: "RDF, SRF and TDF are the three dominant waste-derived alternative fuels used in cement kilns, waste-to-energy plants and industrial boilers."
canonical_url: "https://sylio.co/glossary/rdf-srf-tdf"
last_updated: "2026-06-28T02:29:27.449Z"
---

**RDF**, **SRF** and **TDF** are the three dominant waste-derived [alternative fuels](/glossary/alternative-fuel) used in cement kilns, [waste-to-energy](/glossary/waste-to-energy) plants and industrial boilers.

<table>
<thead>
  <tr>
    <th>
      Fuel
    </th>
    
    <th>
      Source
    </th>
    
    <th>
      Specification
    </th>
    
    <th>
      Calorific value
    </th>
  </tr>
</thead>

<tbody>
  <tr>
    <td>
      <strong>
        RDF
      </strong>
      
       (Refuse-Derived Fuel)
    </td>
    
    <td>
      Municipal solid waste, lightly processed
    </td>
    
    <td>
      Loose, no formal CEN/TS specification
    </td>
    
    <td>
      12–18 MJ/kg
    </td>
  </tr>
  
  <tr>
    <td>
      <strong>
        SRF
      </strong>
      
       (Solid Recovered Fuel)
    </td>
    
    <td>
      MSW + commercial waste, processed to CEN/TS 15359 spec
    </td>
    
    <td>
      Defined particle size, ash content, calorific value, Cl, Hg
    </td>
    
    <td>
      15–20 MJ/kg
    </td>
  </tr>
  
  <tr>
    <td>
      <strong>
        TDF
      </strong>
      
       (Tyre-Derived Fuel)
    </td>
    
    <td>
      End-of-life tyres, shredded
    </td>
    
    <td>
      Shred-size grade or whole-tyre
    </td>
    
    <td>
      28–35 MJ/kg
    </td>
  </tr>
</tbody>
</table>

## Trade-offs

- **RDF**: cheap, high availability, variable composition; high chlorine swings
- **SRF**: more consistent and predictable than RDF; commands premium gate fees
- **TDF**: very high calorific value, supplies iron and sulphur to clinker chemistry; rubber-handling logistics

## Fouling implications

All three add chlorine, sulphur and alkali metals beyond what fossil coal contributes. The chloride loading from chlorinated plastics in RDF / SRF is the dominant driver of [chloride-bypass](/glossary/chloride-bypass) sizing. TDF adds zinc and iron oxides that can affect clinker chemistry.

## Related terms

- [Alternative fuel (AFR)](/glossary/alternative-fuel)
- [Thermal substitution rate (TSR)](/glossary/thermal-substitution-rate)
- [Waste-to-energy](/glossary/waste-to-energy)