The R1 Energy Efficiency Formula

The Waste Framework Directive (WFD) has contained a hierarchy of waste management methods since the 1st of April 1993. In the revised WFD (Directive 2008/98/EC) the hierarchy prioritises waste prevention followed by preparing for reuse, recycling, recovery and finally, least favourably, disposal.

The Waste Framework Directive (WFD) Article 3 makes the following definitions:

  • 'recovery' means any operation the principal result of which is waste serving a useful purpose by replacing other materials which would otherwise have been used to fulfil a particular function, or waste being prepared to fulfil that function, in the plant or in the wider economy. Annex II sets out a non-exhaustive list of recovery operations; [Article 3(15)]
  • 'disposal' means any operation which is not recovery even where the operation has as a secondary consequence the reclamation of substances or energy. Annex I sets out a non-exhaustive list of disposal operations; [Article 3(19)]

Despite the lists of recovery and disposal operation provided in the Annexes of the WFD, the classification of a recovery operation or a disposal operation becomes uncertain when considering waste incineration. A Municipal Solid Waste Incinerator (MSWI) could be classified as either a recovery operation (R1 - Use principally as a fuel or other means to generate energy) or a disposal operation (D10 - Incineration on land). As waste policy has evolved and become increasingly focused on moving waste 'up the hierarchy', national targets for recycling and recovery reflect this shift in emphasis. The distinction between 'recovery' and 'disposal' has become progressively more relevant, both commercially and economically.

In 2003, the European Court of Justice made two judgements[1] that established principles to differentiate between R1 operations and D10 operations. To be classed as an R1 operation the process must meet the following criteria:

  • The combustion of waste must generate more energy than the consumption of energy by the process itself;
  • The greater part of the waste must be consumed during the operation;
  • The greater amount of the energy generated must be recovered and used (either as heat or electricity);
  • The waste must replace the use of a source of primary energy

These judgements superseded the previous standards used by Member States (such as calorific value of waste, quantity of harmful substances and energy efficiency of the process) without addressing the specifics of classifying a plant so still did not ensure a consistent application of the WFD across Europe.

The Revised WFD now specifies that incineration facilities dedicated to the processing of municipal solid waste can be classified as R1 only where their energy efficiency is equal to or above:

  • 0.60 - for installations in operation and permitted in accordance with applicable Community legislation before 1st January 2009
  • 0.65 - for installations permitted after 31st December 2008

The Formula

The formula used to calculate this value of energy efficiency, "the R1 Energy Efficiency Formula" is:
The R1 Energy Efficiency Formula

It should be noted that the R1 formula does not calculate a conventional efficiency but the efficiency at which the produced energy is utilised.


Even when the formula is used there is still considerable scope for variation in its use. Comprehensive guidance has been produced by the European Commission to ensure a consistent interpretation and a harmonised application of the R1 formula across the EU which specifies:

  • Definitions of the energy terms Ef, Ew and Ei
  • The system boundaries
  • Qualification in on an annual basis and verified with plant data ('annual average')
  • R1 status must be tested after 'major' plant modification or after a maximum of 10 years
  • R1 value is to be calculated using plant design data for new plants
  • R1 value must be verified in using plant performance tests for new plants

The guidance was issued by the European Commission's DG Environment on 1st July 2011, and is available at: EC R1 Energy Efficiency Formula Guidance

The Scope of the Formula

Annex II of the WFD restricts the scope of the formula to "incineration facilities dedicated to the processing of Municipal Solid Waste" so it does not apply to plants that are dedicated to incineration or co-incineration of hazardous waste, hospital waste, sewage sludge or industrial waste.

It is also crucial that the formula is applied to the correct parts of the EfW process and that the 'system boundaries' are set correctly. The system boundaries that are used will have considerable implications on the energy streams that are calculated as Ef, Ew and Ei in the efficiency calculation. Therefore, the 'system boundaries' are clearly defined in the guidance as the 'functional incineration unit' not the installation according to the IPPC permit. The functional incineration unit is set as the incineration oven(s), the boiler(s), and the incineration flue gas cleaning system and, often, energy transformation and recovery equipment such as heat exchangers feeding a district heating or cooling network and/or turbine generator.

Issues with the R1 Formula

  1. Climate - the use of heat instead of electricity significantly increases the R1 value achieved. The ability for an installation to use the heat produced is very much dependent on climate. For example, heating degree day (HDD) values- a quantitative indices that reflects the demand for energy to heat homes and businesses - vary hugely across Europe, with Portugal having 1007.58 while Finland has 4871.03. [2]
  2. Location - An installation located in a rural area is unlikely to find efficient use for its produced heat. However, industrialised areas are unvaryingly heat consumers, so plants located in urban or industrialised areas have a far higher probability of finding a heat client and improving their R1 rating.
  3. Size - Larger plants are often more efficient due to economies of scale.


  1. Energy from Waste (EfW) plants being classified as recovery rather than disposal.
  2. The R1 formula will facilitate Energy from Waste moving up the waste hierarchy.


CEWEP (Confederation of European Waste-to-Energy Plants) produced a report[3]estimating the number of Energy-from-Waste plants that would currently achieve 'R1' status based on operation years 2007-2010. The results are summarised in Table 1:

Table 1 - CEWEP Report - R1 Achievement

No. of EfW plants in Europe (EU27+CH+NO) in 2009


No. of EfW plants participating in CEWEP study


Number of EfW plants achieving efficiency 0.60


Percentage of European EfW plants that would currently achieve R1 status




[1] ECJ 13 February 2003 (Commission v Luxembourg, C-228/00), European Court reports 2003, page I-1439; ECJ 13 February 2003 (Commission v Germany, C-458/00), European Court reports 2003, page I-1553.
[2] Cooling and heating degree days by country - annual data – Eurostat.
[3] CEWEP Energy Report III (Status 2007-2010) Results of Specific Data for Energy, R1 Plant Efficiency Factor and NCV of 314 European Waste-to-Energy (WtE) Plants, December 2012.