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Energy from Waste Plants and Energy Efficiency

Energy from Waste Plants and Energy Efficiency. Keith Riley Managing Director Veolia Environmental Services. “the definition of a recovery operation is based on the criterion of use and hence of the objective of the operation.”. European Court of Justice - 2002. The European Commission.

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Energy from Waste Plants and Energy Efficiency

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  1. Energy from WastePlants and Energy Efficiency Keith Riley Managing Director Veolia Environmental Services

  2. “the definition of a recovery operation is based on the criterion of use and hence of the objective of the operation.” European Court of Justice - 2002

  3. The European Commission • Waste is recovered if: • Its combustion generates more energy than is consumed by the process itself; • Most of the waste is consumed during the operation; • Most the energy generated is recovered and used (either as heat or electricity); • The waste replaces the use of a source of primary energy. • .

  4. Three Possible Criteria Over the years three criteria had been considered by the Commission: The energy content of the processed waste, i.e. the calorific value - criticised because MSW has CV similar to some commonly used fuels; The ECJ case of principal objective - this is a subjective criterion and would require additional complex specifications; The energy efficiency of the plant.

  5. 2008/98/EC WASTE FRAMEWORK DIRECTIVE

  6. WASTE FRAMEWORK DIRECTIVE 2008/98/EC • Seeks to clarify the distinction between recovery and disposal; • Makes it clear that facilities whose principle purpose is the treatment of waste may be classified as recovery; • BUT…. • Facilities dedicated to processing of municipal solid waste have to meet specific requirements regarding energy efficiency listed in Annex II of the WFD in order to be classified as energy recovery facilities (as opposed to disposal).

  7. Where: Ep is annual energy produced as heat or electricity, calculated with energy in the form of electricity being multiplied by 2.6 and heat produced for commercial use multiplied by 1.1 (GJ/year) Ef is annual energy input to the system from fuels contributing to the production of steam (GJ/year) Ew is the annual energy contained in the treated waste calculated using the lower net calorific value of the waste (GJ/year) Ei means annual energy imported excluding Ew and Ef (GJ/year) Energy efficiency η = (Ep -( Ef + Ei)) / (0.97 x (Ew + Ef))

  8. Recovery or Disposal? • If η > 0.6 for existing plants • >0.65 for plants permitted • after 31 December 2008, • then Recovery • If less, then Disposal

  9. Efficiency EfW plants are claimed to be low efficiency – 17 to 27% often quoted; If this is compared with the 65% required for Recovery under WFD, then at first sight it may appear unattainable without use of a high efficiency thermodynamic cycles but…… NOT ALL EFFICIENCIES ARE THE SAME!

  10. The Statistician’s View Efficiency is a criterion by which to compare unbiased estimators. For scalar parameters, one estimator is said to be more efficient than another if the first has smaller variance. For multivariate estimators, one estimator is said to be more efficient than another if the covariance matrix of the second minus the covariance matrix of the first is a positive semidefinite matrix………… www.about.com:Economics

  11. The Economist’s View “ Efficiency is a relationship between ends and means. When we call a situation inefficient, we are claiming that we could achieve the desired ends with less means, or that the means employed could produce more of the ends desired…. Thus, economic efficiency is measured not by the relationship between the physical quantities of ends and means, but by the relationship between the value of the ends and the value of the means. Terms such as “technical efficiency” or “objective efficiency” are meaningless. From a strictly technical or physical standpoint, every process is perfectly efficient. ……… Ref: Library of Economics & Liberty

  12. Another Definition Wikipedia: η = What you get What you pay for

  13. ERF Efficiency ERF Incinerator Lower efficiency, lower Carbon emissions Coal Fired Power Station Higher efficiency, higher Carbon emissions

  14. Let’s ask DEFRA Seasonal efficiency of different boiler types Old boiler (heavy weight) 55% Old boiler (light weight) 65% New boiler (non-condensing) 78% New boiler (condensing) 88% Extract from the Boiler Efficiency Database

  15. Boiler Losses

  16. Efficiency Limitations Efficiency of a Rankine cycle is usually limited by the working fluid or the materials from which the boiler is made. This gives a theoretical of around 63% maximum.

  17. Thanks to WFPP for use of this slide

  18. Thanks to Afval Energie Bedrif for use of this slide

  19. Combined Cycle Thanks to www.global-greenhouse-warming.com for use of diagram

  20. Sheffield Distributed Energy Scheme

  21. Population 525,800 50,000 students 225,000 households - 80% houses - 20% flats/maisonettes/apartments Generates approx. 240,000 t/yr of municipal waste - Recycles 25% - Recovers energy from 60% - Landfills 15% Limited landfill space available About Sheffield

  22. Raising the Efficiency

  23. Sheffield Distributed Energy Network • The UK’s largest DE system • Currently 45km of pipeline • Water distributed by pumps • Temperature up to 120°C • Pressure up to 16 bar • Backed up by 87MW of boilers • Potential for further development

  24. District Energy Steam raised at 44 bar and 400˚C Condensing turbine Extraction point at 2 bar, approx 150˚C Reduced reliance on fossil fuels Improved air quality – reduced NOx emissions Carbon footprint 30% that of gas Sheffield DE Scheme

  25. Annual Electrical Generation 125,000 MWhe Annual Thermal Output 95,000 MWh Annual District Heating Sales 110,000 MWh Energy per Tonne Waste 1050 kWh WFD Efficiency Rating (full-year average) 67% Energy Output Equivalent to a saving of 168 g CO2 per kWh

  26. Our Customers 2 Universities 4 Swimming Pools 3 Theatres 3 Art Galleries 2 Cinemas 1 Radio Station 1 Greenhouse 3 Hotels 21 Private Developments Sheffield CC Housing Corporate Buildings Student Accommodation

  27. Issues with the R1 Efficiency Formula • Ambiguity - applies to MSW. What of C&I wastes? • Ep is annual energy produced. Therefore is actual production, but is it gross or net? • Ef is annual input from other fuels. How is the CV measured? • Ew is annual energy of TREATED waste. What does “treated” mean? How is its LCV determined? • Ei is annual energy imported but not used for steam production & excluding Ew & Ef. What about flu-gas recirculation? • The energy losses are generalised & initiatives that decrease thermodynamic losses are not rewarded. • There are unintended consequences – disadvantages hot countries, encourages large plants etc. • BUT…..

  28. We can do it! The R1 formula is achievable for most moving grate plants above 100,000 tpa without resorting to district heating/CHP. The formula is likely to become a focal point for planning & permitting – developers & planners take note! The drive for lower carbon electricity supply will drive a push for increased efficiency – suppliers need to respond. We must move anyway to more efficient thermal cycles, although some barriers need to be removed.

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