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Is Energy Recovery from Waste

Incineration the Best Option for Waste

Management in Cornwall? A Quantitative Study of the Proposed Energy from

Waste Plant in Cornwall

By

Nicholas M J Entwistle

5/1/2010

FdSc Renewable Energy Technologies (2008)Supervised by

Michael Hunt



Is Energy Recovery from Waste Incineration the Best Option for Waste Management in Cornwall?


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ABSTRACT

This project attempts to quantify claims made of the performance and energy

available to the energy recovery plant proposed by Sita, as the replacement to land

filling for waste management in Cornwall. This is done through collection of data

from documents produced on behalf of Sita by its environmental consultant

Environmental Resource Management, as part of its planning and environmental

permit applications. Data is also collected from papers produced in a study of

Cornwalls‟ waste streams carried out by Measurement Evaluation and Learning on

behalf of Cornwall County Council. This is done in order to evaluate the amount of

energy in the waste, the energy output from the plant and the efficiency of the

plant. This report concludes that ERM have overstated the amount of energy that

there is available in the waste and thus the amount of energy the plant will generate

annually. It is also concluded that the plant does not meet the levels of efficiency

required by the EU to be considered a recovery plant.





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1 CONTENTS

1. INTRODUCTION.......................................................................................................................... 4

1.1 Literature Review ................................................................................................................ 5

1.2 Questions Raised ................................................................................................................ 7

1.3 Limitations of Study ........................................................................................................... 9

2 METHODS.................................................................................................................................. 11

2.1 Is the ERM NCV figure Accurate? ................................................................................... 11

2.2 Hydrogen Content Calculations ........................................ Error! Bookmark not defined.

2.3 ERM NCV Calculation....................................................................................................... 15

2.4 What is the NCV for the CCC Waste Composition?..................................................... 16

2.5 What is the efficiency of the CERC? ............................................................................... 16

2.6 What affect do differing CV‟s have on the energy output of the plant? .................. 21

3 RESULTS..................................................................................................................................... 22

3.1 NCV Calculation for ERM and CCC Compostions. ....................................................... 22

3.2 What is the efficiency of the CERC? ............................................................................... 25

3.3 What affect do differing CV‟s have on the energy output of the plant? .................. 26

3.4 Summary of Results.......................................................................................................... 26

4 DISCUSSION.............................................................................................................................. 26

4.1 Is the ERM NCV figure Accurate? ................................................................................... 28

4.2 Possible Source of ERM NCV figure............................................................................... 29

4.2.1 Implication of Increased net GHG emissions ............................................................ 31

4.3 What is the efficiency of the CERC? Does the efficiency meet EU requirements for

recovery?........................................................................................................................................ 32

4.4 Method Improvements .................................................................................................... 34

4.5 Suggestions for Future Study ......................................................................................... 35

5 THE CONCLUSION.................................................................................................................... 38

6 GLOSSARY ................................................................................................................................. 40

7 BIBLIOGRAPHY.......................................................................................................................... 41

APPENDIX 1....................................................................................................................................... 43





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1. INTRODUCTION

It has been widely recognised that the available landfill in Cornwall is rapidly

becoming exhausted, of the two operational landfill sites in Cornwall one (United

Mines) is due to cease operation in October 2010, the other site (Connon Bridge) is

due to reach its consented capacity by 2014. However, an extension to the

consented capacity at Connon Bridge could allow the site to operate until 2017

(Sita, 2009). In addition to the impending exhaustion of available landfill, the taxes

for landfill are due to rise drastically in the coming years to encourage methods of

waste management which do not result in the waste being land filled. These taxes,

which are currently set at £48 per tonne from the 1st of April 2010, are due to rise to

£72 per tonne by 2013 (Sita, 2009). Therefore, the need to find an alternative

solution to waste management in Cornwall is an urgent issue.

Sita are a waste management company who from 2006 hold a 30 year contract with

Cornwall County Council (CCC) for the management of its waste. In order to

manage the aforementioned issues Sita have proposed the construction of the

Cornish Energy Recovery Centre (CERC,) an energy from waste (EfW) incinerator to

deal with the county‟s waste whilst recovering useful electricity and heat from the

combustion of the waste.

In this report the author will quantify claims made by Sita of the proposed CERC, in

respect to its suitability as a successor to majority landfill in Cornwall. A

retrospective calculation will be made in order to ascertain whether the amount of

energy in the input waste (Calorific Value, CV), stated as 9.8GJ/tonne by ERM, is

accurate using their own waste composition breakdown and hence questioning its

proposed energy output. The nature of the composition of Cornish waste will also

be investigated and compared to the composition given by Environmental Resource

Management (ERM) on behalf of Sita. The aim of this comparison will be to find out

how the nature of the composition of the waste locally, and its associated differing





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CV‟s will affect the potential energy output of the Incinerator, production a more

realistic figure and again questioning ERM‟s proposals.

Although Sita and ERM make no claims about the proposed plants efficiency, they

do provide sufficient information in their Environment Agency permit application

document (ERM, 2008) to be able calculate it. Within this document they do make

claims as to the calorific value (CV) of the waste which is to become the feedstock of

the incinerator and hence energy produced by the incinerator. These claims are in-

substantiated in the document, however they do give a breakdown of the waste

that they are basing their calculations on, which quote national sources for the

information. The generation figures which they give are based on this national CV,

although the figure that they give is at odds with a figure for the CV of municipal

solid waste (MSW), given by the Digest of UK Energy Statistics (DUKES) which gives

an estimated net CV figure of 6.7 GJ per tonne (DUKES, 2008), ERM give a figure of

9.8 GJ per tonne in their documentation (ERM, 2008).

1.1 Literature Review

The contention surrounding the proposed CERC has reached a fever pitch in spring

2010 with the commencement of the appeals process by which Sita hope to

overturn the previously refused planning permission for the plant.

One reason for objecting to the plant is that it results in the destruction of the

waste, much of which is an important reusable or recyclable resource. Broadhurst

states that incineration is fundamentally wrong” (Broadhurst, 2010) because it is a

waste of resources in a world where resource depletion is an increasing problem.

A further reason for objection to the incinerator is that suitable plant efficiency can

only be achieved through the operation of one large plant for the whole of Cornwall

which “precludes localised operation” (Broadhurst, 2010). The problem with one large

plant is that road transport of waste from the whole of Cornwall, compared to





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alternative distributed recovery and recycling systems, produces over double the

amount of CO2 emissions for road transport alone (Broadhurst, 2010). This

objection is highlighted by Charmian Larke of Atlantic Energy, who has given figures

of 6671tpa of CO2 emissions for centralised systems vs. 3000tpa for decentralised

recovery systems, See figure 1 below (Larke, February 2009). Alongside increased

road transport, Larke points out that the operation of the incinerator will increase

CO2 equivalent (eq) emissions; “ The incinerator releases 3 million tonnes extra CO 2

eq over 25 years from its operations, and compared to the landfill option releases an

e xtra 3.6 million tonnes CO2 e over the same period.” (Larke, February 2009)

An alternative calculation of the comparative GHG emissions between waste

management options can be found in Figure 1below. This calculation, produced on

behalf of the Transition Cornwall Network, differs greatly from ERM‟s calculation

due to the inclusion of biogenic GHG emissions, as much of these emissions are

sequestered by land filling.

Figure 1 Emissions for each option tpa CO2e (avoided as -). (Larke, Charmian, 2010) i

This objection that the CERC will increase greenhouse gas (GHG) emissions

highlights a further issue, since the UK government Planning Policy Statement

advises “ planned provision for new development and its spatial distribution should

contribute to mitigating climate change through improvements in carbon

performance.” (Department for Communities and Local Goverment, 2006). As





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pointed out in the previous paragraphs above by both Larke and Broadhurst

“improvements in carbon performance” are challenged.

A key consideration to which the CERC

development must adhere, is that they must

meet efficiency targets in order to be classed as

„recovery‟ rather than „disposal‟ on the waste

hierarchy (Figure 2). The proposal given by the

„Directive of the European Parliament and of the

Council on Waste‟ states that the “settling of

difficult distinctions via the setting of efficiency

criteria” (Commision of European Communities, 2005) will help in the definition of a

disposal or recovery operation. The efficiencies stated by the commission to

distinguish energy recovery from disposal are “ 0.60 for installations in operation and

permitted in accordance with applicable Community legislation before 1 January

2009 and 0.65 for installations permitted after 31 December 2008” (Commision of

European Communities, 2005). The importance of this is supported by the UK

government in its Planning Policy Statement 10, where it is stated that it intends to

improve waste management in the UK “Through more sustainable waste

management, moving the management of waste up the „waste hierarchy‟ of

reduction, reuse, recycling and composting, using waste as a source of energy, and

only disposing as a last resort” (Office of the Deputy Prime Minister, 2005). This

political intention enshrines the requirement for the CERC to move up the waste

hierarchy in UK planning policy to permit its implementation.

1.2 Questions Raised

Through an investigation of the literature four important questions have become

apparent in order to allow an appraisal of the CERC. These are the questions on

Figure 2 (DEFRA, 2007)





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which this report will be focused and they are:

1. Is the ERM NCV figure Accurate?

This will be investigated by retrospectively calculating the NCV for ERM

waste composition and Gross Calorific Values (GCV).

2. What is the NCV for the CCC Waste Composition?

This will be calculated similarly to above though using the CCC waste

composition as its basis. This will allow a comparison between the NCV of

local waste with the national waste breakdown given by ERM.

3. What is the efficiency of the CERC?

Through calculating the efficiency of the plant for both the CCC and the ERM

input values a conclusion can be reached regarding the efficiency of the

CERC incinerator and whether it reaches the EU requirements for recovery

4. What affect do differing CV’s have on the energy output of the plant?

Once the CV‟s calculated from ERM and CCC waste compositions are

available it will be possible to make predictions as to their effect on the

energy output of the CERC.





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1.3

Limitations of StudyAlthough this study seeks to answer the questions raised in Section 1.2 as

thoroughly and as accurately as possible, there are a few limiting factors which must

be considered. The study will be limited to the use of secondary source data in

order to produce figures comparable with those given by ERM. This limitation is

because the time and resources required to carry out a detailed investigation into

the composition of Cornish waste streams, are not available to this study. Similarly,

to ascertain the CV‟s of waste through primary techniques is not a feasible for this

study. This means that the same data for GCV of the fractions of the waste

composition will be used in each case (ERM and CCC) to calculate net CV in order to

produce comparable results.

In order to calculate the efficiency of the plant it is only feasible that the author can

do so through data available on technical papers provided by ERM. No primarystudy can be carried out in this respect as the plant is only in the planning phase

and time and resources do not permit this.

Due to time constraints, detailed calculations regarding the comparable CO2 eq

outputs will not be calculated although previous studies in this area will be

referenced in section 4.2.2. In this section there is also a simple calculation of the

effect of differing CV‟s on avoided emissions, but no detailed modelling of the GHG

emissions of the plant are included due to time constraints.

This report is a basis for a comparison with alternative waste management

technologies and techniques. This report quantifies the credentials of the CERC,

however the comparisons are not contained in this report due to time constraints

and the emphasis is placed on quantifying the CERC for the use in future

comparisons





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Consequently, having reviewed the literature, raised the questions regarding the

validity of the CERC proposed incinerator and highlighted the limitations of this

study the remainder of this document will describe the methods used and results

found.





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2 METHODS

2.1 Is the ERM NCV figure Accurate?

ERM documentation gives a figure of 9.8GJ per tonne for the waste feed stock for

the CERC. This figure is an average net CV figure based on the individual gross CV‟s

of the various fractions of the waste. See Table 1 below for each of the fractions of

waste as specified by ERM in their „Cornwall Energy Recovery Centre‟ document

(ERM, 2008). Net calorific value is the gross calorific value less the latent heat of

evaporation of the water that formed during combustion of the fuel.

Table 1

Waste Composition

Paper and card

Plastic film

Dense plastic

Textiles

Combustibles (Inc absorbent hygiene

products)

Non-combustibles

GlassOrganic (inc wood)

Ferrous metal

Non-ferrous metal

Fine material

WEEE

Hazardous household waste

In order to ascertain whether the NCV value is true, the waste compositions whichrepresent the feedstock from which the CERC will be generating energy were





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obtained. These waste compositions are made available in the ERM document

„Assessment of Number of Facilities – Final Report‟ and can be found in Table 1 of

Appendix 1. The formula used to calculate the NCV of each fraction of waste was

retrieved from the Department for Energy and Climate Change guidance notes on

combined heat and power stations (CHPQA) (Department of Energy and Climate

Change, 2008) and was:

Where:

GCVdry = gross calorific value, MJ/kg taken from „Carbon Balances and The

Energy Impacts of the Management of UK Waste‟. (ERM & DEFRA, 2006)

NCVdry = net calorific value, MJ/kg

H = hydrogen content, weight %. See section 2.2.

2.442 = latent heat of vaporisation of water at 25°C, MJ/kg

8.936 = kg of water formed by combustion 1-kg of hydrogen

See the spreadsheet in Appendix 2 for the calculations for the NCV‟s of each

fraction

2.2 Hydrogen Content Calculations

In the formula above the hydrogen content of each fraction had to be calculated

prior to calculating the NCV. It was calculated from data given by a paper entitled

“ water content measurements in household waste using neutron probe; experiences

from field digestion cell and laboratory” (Bergund, 1999) see Table 2 below.





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Table 2 H2 content of MSW

The hydrogen contents available did not fit exactly the same waste breakdown

categories as ERM‟s own waste breakdown structure so some approximate

calculations were made as to the hydrogen contents.

For “Paper and Card” H2 contents for paper and cardboard were separately

available from Bergund (1999). In order to calculate the H2 content of “paper

and card” the subdivisions of the category given in Table 1 in Appendix 1, as

given by ERM, were sorted into paper or card. It was calculated that 77.5% of

“paper and card” was paper with 5% H2 content while 22.5% was card with

9.4%H2 content (see Table 3). Overall H2 content of the category was

calculated by:

Where:

Paperc = Paper % composition of paper and card category

Paperh2 = Paper % H2 content

Cardc = Card % of composition of paper and card category

Cardh2 = Card % H2 content.





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Table 3 H2 content from Paper and Card Composition

Plastic film, dense plastic and textiles: H2 contents for these fractions of

the waste were taken directly from Table 2 above as the Bergund and ERM

categories matched.

Non Combustibles, Glass, ferrous and non-ferrous metals: H2 contents for

these fractions of the waste were unnecessary as they contribute very little to

the combustion process as they have very low or no calorific value, see Table

3 Appendix1.

Organic (Inc Wood): H2 content was calculated using the same technique as

the “paper and card” fraction, see Table 4 below, allowing Bergunds

categories of Wood and Food Waste to be accumulated under the ERM

heading of Organic (inc Wood).

Table 4 Organic (inc Wood) H2 Content

Combustibles: As the breakdown of the waste category “combustibles”

was made up of very vague sub categories; “unspecified combustibles”

and “other combustibles” and “furniture”, it was not within the resourcesand time available to this study to produce an accurate H2 content for the





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combustibles fraction. As all the categories in H2 content table (Table 2)

were combustible, a figure for the average of all these H2 contents was

taken and used as the H2 content for combustibles.

Unclassified Fine Material: Is generally unidentified and so without

primary study of the composition of miscellaneous fine material an

accurate H2 content cannot be calculated. In order to obtain H2 content

for this study the CV‟s of all the fractions were compared and the most

similar to miscellaneous fines was assumed to have similar values for H2

content. Therefore unclassified fine material has been modelled as

“organic kitchen waste” with an H2 content of 4.7%.

Waste Electrical and Electronic Equipment (WEEE): similarly to fines

was difficult to classify. The fraction of the waste was small and for the

purpose of this study the effect of the net CV of WEEE is negligible and

therefore it is acceptable to estimate it this way. Therefore WEEE has been

modelled as textiles with an H2 content of 3.3%

Hazardous Household waste: Again the HHW H2 content was not

available from Bergund and its value was omitted, since the effect that

the omission of a value on the CV calculation is negligible to the accuracy

required by this study this was considered acceptable.

2.3 ERM NCV Calculation

In order to check ERM‟s NCV of 9.8GJ/tonne, the NCV for each fraction needed to

be weighted according to its percentage of the composition and its percentage dry

matter (obtained from the ERM CERC Carbon balances document (Table 2,

Appendix 1)).The moisture content of the waste does not contribute to the

combustion and the, therefore it was important to calculate the % composition of

each waste fraction adjusted for its moisture content using;

(Table 5).





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Table 5 Waste Composition – Moisture content

ERM ERM

Waste Composition Composition % % Dry Matter (3) % dry matter of wastePaper and card 13.9% 76.0% 10.6%

Plastic film 3.4% 71.5% 2.4%

Dense plastic 4.0% 89.5% 3.6%

Textiles 3.6% 80.9% 2.9%

Combustibles (Inc absorbent hygiene products) 11.5% 70.0% 8.1%

Non-combustibles 17.1% 94.4% 16.1%

Glass 5.4% 98.2% 5.3%

Organic (inc wood) 27.2% 49.3% 13.4%

Ferrous metal 1.8% 89.0% 1.6%

Non-ferrous metal 0.3% 84.6% 0.3%

Fine material 4.9% 59.0% 2.9%

WEEE 3.6% 89.9% 3.2%

Hazardous household waste 3.3% 89.6% 3.0%

The NCVs were subsequently calculated for each fraction and weighted according

to dry matter and composition, see Appendix 2.

These weighted NCV figures were then summed and the overall NCV of the wastewas obtained. The sum of the weighted NCV‟s discounted the non combustible

fractions of the waste which do not contribute to the production of energy. This

enabled me to calculate an overall NCV for the ERM waste composition and thus

answer question 1 in section 1.1.

2.4 What is the NCV for the CCC Waste Composition?

In order to answer Question 2 raised in Section 1.2, CCC data regarding the

composition of waste in Cornwall was used to calculate a NCV for the local waste,

based on the waste categories defined by ERM and shown in Table 1. The CCC data

was obtained from a study carried out on behalf of the Council by Measurement

Evaluation and Learning (MEL, 2007) and can be found in Appendix 1.

The study of Cornwall‟s waste took into account waste from every economic

demographic category and was divided into 2 phases, phase 1 and 2. The phases





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represented the year split into 2, the winter months (phase 1) and the summer

months (phase 2). In order to produce a fair representation of the composition of

the waste it was important to take an average figure for the composition between

these 2 phases.

Where the CCC waste categories did not exactly match the ERM categories,

categories were amalgamated and weighted according to each fraction percentage.

These amalgamated categories were matched in both the ERM and CCC waste

breakdown so that a direct comparison could be made. For example, the organic

waste in the CCC study was named “Putrescibles” and included wood. In the ERM

composition, wood was separate to organic matter so the categories could not be

directly compared. Therefore, the “wood” category in the ERM breakdown was

added to the organic category.

Once the waste breakdown was obtained the same procedure was applied to

determine the NCV for CCC as with ERM in Section 2.1 above. The same figures for; % dry matter, H2 content, and GCV were used, meaning that any differences

highlighted by the comparison was purely due to variation in composition.

2.5 What is the efficiency of the CERC?

In order to calculate the CERCs efficiency and position in the Waste Hierarchy

efficiency calculation, in accordance with EU directives, was carried out using thestated figures for energy input and output given by ERM in their documentation.

The formula used in the calculation was taken from the „Directive of the European

Parliament and of the Council on Waste‟ (Commision of European Communities,

2005) and was:

( )

( )

Where:





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Ep = annual energy produced as heat or electricity. It is 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 = annual energy input to the system from fuels contributing to the

production of steam (GJ/year)

Ew = annual energy contained in the treated waste calculated using the net

calorific value of the waste (GJ/year)

Ei = annual energy imported excluding Ew and Ef (GJ/year)

0.97 is a factor accounting for energy losses due to bottom ash and

radiation.

Guidelines for the use of the equation are as follows: Figure 3 (Commision of European Communities, 2005)

To use this equation a spreadsheet was produced to collate all of the relevant

information (see Table 2, Appendix 2). It was also important to take into account

that “ Use of electricity for the flue gas cleaning system is considered as being made

available to users – otherwise the threshold would have an inhibiting effect on

strengthening the air polluting standards beyond the levels set by the Waste

Incineration Directive.” (Commision of the European Communities, 2005). This





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means that the grid electricity used for flue gas treatment (FGT) was considered to

be part of the energy produced (Ep). Other parasitic loads and losses, such as

electricity used on site for administration (lighting etc), are taken into account in the

0.97 “correction factor” in the equation. The factors contributing to the efficiency

calculation were assembled as follows:

Ew was taken from Table 5 below and checked against ERM annual waste

through put of 240000tpa at 9.8 MJ using

= 653333MWh/yr (ERM,

2008)

Ef was taken from Table 5 below. Taking note of the fact that only half of the

oil used contributes to the generation of electricity only half the given oil

consumption figure was used

MWh/yr

Ep was calculated using 125,110MWh/yr taken from Table 5 plus the

electricity used in FGT taken from Table 6, all multiplied by 2.6 as per EU

guidelines. The heat was taken from Table 5 as 35800 MWh/yr and multiplied

by 1.1 as per the guidelines. The resulting equation was: ( ) MWh/yr

Ei Was taken as the annual parasitic imported MWh from Table 6 below and

was 650 MWh/yr





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Table 5; Breakdown of Annual Overall Delivered Energy Consumption, heat supplied to Goonvean and IMERYS.

(ERM, 2008)

Table 6: Breakdown of Annual Delivered Energy Consumption by Activity Area (ERM, 2008)

After using the spreadsheet to collate or calculate the required information for the

efficiency calculation as outlined above. It was possible to ascertain the efficiency of

the plant and determine whether or not it meets EU guidelines to be classed as

recovery.





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2.6 What affect do differing CV’s have on the energy output of the plant?

To calculate the potential output of the plant based on the ERM and the CCC NCV‟s,

its efficiency was a constant in order demonstrate of the effect of changing the NCV

(see Section 4.5)

Each factor in the efficiency calculation was calculated as a percentage of the total

energy in the waste, for example for the electricity produce it would be:

as a percentage, or

showing that electricity

produced is 19.09% of the total feedstock value of 653333MWh.

It was then assumed that for every initial amount of energy in the waste, that

electricity would make up 19.09% of the total. This assumes that the efficiency of

the plant remains the same even at differing calorific values which is unrealistic and

a limitation of this research. This proportion was calculated for every part of the

efficiency calculation.

This was then the basis of the breakdown of the differing energies available under

differing NCV‟s. The total energy in the waste was calculated as 240000tpa (annual

waste throughput) multiplied by the NCV (divided by 3.6 to convert to MWh). Then

each factor of the efficiency calculation was calculated using their percentage of the

total energy in the waste for that NCV.

Through the use of the methods outlined above, the intention was to gain the

results required to allow the author to tackle the questions raised in Section 1.2. The

results gained from these methods are outlined below in the Results chapter and

followed by a discussion which summarizes the meanings and consequences of the

results obtained.





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3 RESULTS

3.1 NCV Calculation for ERM and CCC Compositions.

In this section the results for the NCV calculation are displayed below in Table 7.

This is in order to answer the questions; „Is the ERM NCV figure Accurate?‟ And

„what is the NCV for the CCC Waste Composition?‟ as raised in section 1.2. These

questions are combined in this section in order to allow a comparison to be drawn.

The entire workbook can be found in Appendix 2.

Table 7 NCV per Waste Fraction with Overall NCV for ERM and CCC Compositions.

ERM CCC

Waste Composition

Net CV

per

fraction

/MJkg

Net CV

per

fraction

/MJkg

Paper and card 1.2 1.5

Plastic film 0.5 0.7

Dense plastic 0.8 1.5

Textiles 0.4 0.5

Combustibles (Inc absorbent hygiene products) 1.2 0.9

Non-combustibles 0.0 0.1

Glass 0.0 0.0

Organic (inc wood) 0.8 1.3

Ferrous metal 0.0 0.0

Non-ferrous metal 0.0 0.0

Fine material 0.1 0.1WEEE 0.2 0.1

Hazardous household waste 0.4 0.1

Total 5.6 6.6

These results show us that:

The NCV based on ERM figures for composition, gross CV and moisture

content prove to be considerably lower than their claimed 9.8MJkg-1

at just 5.6MJkg-1.





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The NCV value based on the CCC figures for composition and ERM

figures for moisture content and GCV is higher than the NCV based on

ERM composition figures. However it is still lower than the stated 9.8MJ

figure at 6.6MJkg-1

The results also show the calorific breakdown of the overall NCV,

indicating which fractions of the waste composition differ between ERM

and CCC. This is indicated in Figure 3 below.

Figure 4 Comparative NCV per Waste Fraction

From Figure 3 it is evident that the CCC composition contains higher NCV‟s for,

most notably, dense plastic and organic (including wood). The ERM composition

contains higher NCV‟s for Combustibles, Fines, WEEE and HHW. However, since the

GCV, H2 content and moisture contents remained constant for the ERM and CCC,

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

ERM Net CV per fraction /MJkg-1 CCC Net CV per fraction /MJkg-1





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the varying NCV‟s are indicative of the varying percentage compositions of each

fraction.





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3.2 What is the efficiency of the CERC?

The result of the efficiency calculations are shown below in Table 8.

Table 8 Plant Efficiency Calculation based on ERM stated Figures

Energy efficiency = (Ep - (Ef + Ei))/(0.97 × (Ew + Ef)) ERM Stated

Energy in feedstock MWh / yr 653333

Ep

Electricity (MWh) 125,110

Used in FGT (MWh) 6261

Electricity x 2.6 (MWh) 341564.6

Heat (MWh) 35,800

Heat x 1.1 (MWh) 39380

Total 380,945

Ef Fuel oil (MWh) 2,950

1475

Total 1,475

Ew Annual tonnage 240,000

waste net CV GJ/tonne 9.8

Total (MWh) 653,333

Ei Electricity (MWh) 650

Total 650

System

Efficiency 59.64%

As can be seen the efficiency of the plant, as per EU Combined Heat and Power

Efficiency guidelines, was 59.64%. This shows us that the plant does not meet the EU

guidelines of 65% efficiency, as required to be considered a recovery operation.





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3.3 What affect do differing CV’s have on the energy output of the plant?

The energy output from the CERC incinerator when both the ERM and CCC CV figure

is input are summarised in Table 9 below. The spreadsheet used to calculate these

figures along with the efficiency calculation is contained in Table 1Appendix 2.

Table 9 Showing Energy Input/output Altering with Alternative NCV’s

ERM StatedERM

Calculated

CCC

Calculated

DUKES

Stated (1)

waste net CV GJ/tonne 9.8 5.6 6.6 6.7

Annual tonnage 240000 240000 240000 240000Electricity (MWh) 125,110 71468 84340 85257

Heat (MWh) 35,800 20450 24134 24396

Total Generated (MWh) 160911 91918 108474 109653

Total Energy in Waste

(MWh)653,333 373,209 440,429 445,219

% deviation from ERM

Stated-42.7% -32.4% -31.6%

Table 9 shows that with the calculated NCV‟s, the total energy in the waste is

considerably lower than stated by ERM, and as a consequence the amount of

electricity and heat generated is also considerably lower. This is highlighted by a

percentage deviation from the stated 9.8 MJ/kg NCV given in Table 9, with the ERMs

stated output being nearly double that as has been calculated in this research.

For comparison reasons, a column entitled “DUKES Stated” has been added (1). This

column is calculated based on the estimated NCV of MSW of 6.7GJ/tonne given by

the Digest of UK Energy Statistics (DUKES, 2008). This is included to highlight the

similarity between this and the CCC figure calculated by this study, and also because

it is considered that DUKES are a respectable and un-bias source for this information.

3.4 Summary of Results





27 | P a g e

Is the ERM NCV Figure Accurate? The stated ERM NCV figure of 9.8GJ/tonne

is inaccurate as, according to the results of this report the overall NCV of the

waste composition given by ERM is 5.6GJ/tonne.

What is the NCV for the CCC Waste Composition? According to this report

the NCV for the waste composition given by CCC is 6.6 GJ/tonne.

What is the efficiency of the CERC? With the stated ERM NCV figure of 9.8

GJ/tonne and with the calculations in this report carried out in accordance

with EU guidelines, the efficiency of the plant is 59.64%.

What affect do differing CV’s have on the energy output of the plant?

The energy output of the plant would be reduced considerably from that

stated in ERM documentation.

This section has introduced the reader to the results gained by using the methods

outlined in chapter 2. These are the results required by this study to address the

questions introduced in section 1.2. The following chapter will discuss the results and

how they relate to the questions, answers for which are sought by this study.





28 | P a g e

4 DISCUSSION

In this section the results of the study will be analysed and the consequences of the

results found will be discussed. The impact of the lower CV‟s, reduction in the energy

output from the plant and the plants efficiency will be discussed in terms of their

effects on the suitability of the CERC as a replacement for land filling in Cornwall.

The impacts will also be discussed in terms of their effect on the position within the

waste hierarchy that the CERC will occupy. Conclusions will be drawn as to whether

the CERC is the best option and some comparisons will be made with alternative

options in terms of their comparative global warming potential and position on the

waste hierarchy and feasibility for Cornwall.

4.1 Is the ERM NCV figure Accurate?

The results of this report have shown that the ERM NCV figure is inaccurate. In this

section the possible reasons behind this inaccuracy are discussed.

The fact that the NCV calculated from ERM data is much lower than that provided by

ERM could be indicative of a few things;

Over Estimation of NCV of MSW by ERM on behalf of Sita; it may be case that

ERM and Sita have overestimated the amount of recoverable energy in the

available waste deliberately in order to increase the energy outputs of the

proposed plant (see Section 4.1.2). This seems unlikely though as it is a

dangerous strategy for an application which is so clearly going to meet with

much contention and scrutiny.

ERM figure was not based on waste composition; it is possible that ERM have

not based their figure directly on the waste composition. The author has

drawn this conclusion because the GCV is not made available in any of the

CERC related documents or composition tables, nor any indication of where





29 | P a g e

the 9.8MJ/kg figure comes from is given. The GCV‟s used in this study were

taken from a previous study by ERM and DEFRA not relating to the CERC (ERM

& DEFRA, 2006)

Error within the study; The guidelines provided by the CHPQA (Department of

Energy and Climate Change, 2008) document have provided a firm basis for

the calculation of NCV‟s for combined heat and power, leading to the authors

confidence in the results achieved. When the results achieved are compared

with the estimated NCV stated by DUKES they stand up favourably with the

DUKES figure standing at 6.7MJkg-1 compared with 6.6MJkg-1 resulting from

local waste composition from this study.

4.2 Possible Source of ERM NCV figure

Where did the ERM NCV figure of 9.8GJ/tonne come from? It is possible that ERM

calculated their overall feedstock NCV retrospectively from plant output and volumesof waste input. ERM state that their method for calculating the electrical output of

the plant is based on an extrapolation of electrical outputs from 3 plants of differing

size (AEA, 2007). These figures can then be used to calculate the overall NCV as

described below. This extrapolation could be interpreted as an erroneous calculation

by ERM, being based on only 3 data points. If the curve represented by the data is

recreated (Figure 6 below), and extrapolated using trend lines, the fit is good.

However, it is clear that this model is not perfect because it shows a plant with 0 tpa

capacity generating 360kwh/t, which is impossible.





30 | P a g e

Figure 5 Table showing existing plants operating statistics with recreation of extrapolation used by ERM to determine

output of a 240ktpa plant.

Figure 6 Extrapolation of Capacity vs. Output

Since ERM have calculated their generating capacity through an extrapolation of data

from existing sites; did they use this generating capacity to retrospectively calculate

their NCV? The same document which explains the extrapolation outlined above

(ERM, 2008), contains the following equation to calculate energy output:

kWh/t

Rearranging this equation it is possible to recreate the 9.8MJ/kg figure given by ERM

using the extrapolated electrical output as its basis. (In the source ERM quotes for the

data found in Figure 5, “Electrical output” is entitled “Output” so the author assumes

this includes heat)

y = 0.0019x2 + 0.7692x + 370.72R² = 1

0

100

200

300

400

500

600

700

800

0 50 100 150 200 250 300

k W h / t

ktpa

Extrapolation of Capacity vs Output

kWh/t

Poly. (kWh/t)





31 | P a g e

Where:

E= Energy Output as given by the extrapolation of AEA data

η = the efficiency of the incinerator, i.e. output/input not including factors in

the EU calculation such as consideration for FGT, electricity or heat multipliers.

Taking information for output given by ERM documentation/extrapolated

input, an η of = 0.24 is resultant. C = Calorific Value

Therefore

C = 9.8MJ/kg

This is exactly the figure that the ERM have used as their NCV.

4.2.1 Implication of Increased Net GHG Emissions

Why should ERM be interested in using a higher NCV in its proposal documentation

than that calculated here for either national or local waste? A higher NCV leads to

higher energy output (see Section 3.3), and thus higher levels of displacement of

energy generated from fossil fuel sources and better perceived carbon performance.

The governments planning policy statement asserts that “ planned provision for new

development and its spatial distribution should contribute to mitigating climate change

through improvements in carbon performance.” (Department for Communities and

Local Goverment, 2006). This suggests that, in terms of GHG emissions, it would be

advantageous for ERM to overstate the potential of the plant.

The environmental credentials of the scheme suffer when the NCV is lower. In fact, if

the worst case NCV of 5.6GJ/tonne is used (see section 3.1), it can be assumed that





32 | P a g e

the percentage reduction in annual energy produced equates to the percentage

increase in avoided emissions. This effect of this is shown in Table 11.

Table 11 Consequences of lower NCV on Net GHG Emissions

9.8MJ/kg (1) 5.6MJ/kg

Energy in feedstock MWh / yr 653333 374422

percentage difference 42.70%

Mobilisation emissions tpa CO2 eq 3298 3298

Process Emissions tpa CO2 eq 54130 54130

Disposal Emissions tpa CO2 eq 808 808

Avoided Emissions tpa CO2 eq -94847 -54347.33

total tpa CO2 eq -36611 3889

(1) Taken from (ERM, 2008)

This report shows that with the generating capacity 42.7% less than the ERM has

proposed (worst case); the net GHG emissions are positive at 3888.7 tonnes per

annum compared to ERMs stated negative 36611 tonnes per annum.

The author acknowledges that this is a very simplified representation of the effects

on GHG emissions and is intended only as an indication of the effects on GHG

emissions from reduced output.

In summary, the ERM propose that the CERC will be a negative emitter of -36611tpa

of CO2 eq, however using the figure for NCV calculated by this study sees the CERC

as a positive emitter of 3889tpa CO2 eq. This, alongside the arguments in the

literature given by Larke (Larke, Charmian, 2010) and Broadhurst (Broadhurst, 2010)

(Section 1.1) against the incinerator due to increased GHG, reduce its

appropriateness as a new development since it certainly does not mitigate “climate

change through improvements in carbon performance” as requested by the

(Department for Communities and Local Goverment, 2006)

4.3 What is the efficiency of the CERC? Does the efficiency meet EU

requirements for recovery?





33 | P a g e

The efficiency was calculated using EU guidelines as outlined in section 2.2. The same

guidelines suggest that in order to qualify as a recovery operation, a CHP plant using

MSW for feedstock must meet certain efficiency targets: “0.60 for installations in

operation and permitted in accordance with applicable Community legislation before 1

January 2009 and 0.65 for installations permitted after 31 December 2008” .

(Commision of European Communities, 2005). The calculation carried out by this

study shows that the proposed plant does not meet these guidelines, with an

efficiency of 0.58 (section 3.2, Table 8).

This means that the plant must be classified as disposal and not recovery and

therefore occupies the same level on the waste hierarchy as the existing system of

land filling. This indicates that according to EU guidelines, the CERC will not provide

any environmental advantages when compared to the existing system. This backs up

the argument of Broadhurst when he states that “incineration is fundamentally

wrong” (Broadhurst, 2010) because it is a waste of resources in a world where

resource depletion is an increasing problem. This should seen as a negative for the

implementation of the CERC since in an Environment Agency guidance note entitled

„Your Waste, Your Responsibility‟ which seeks to offer guidance to industry on the

issues of waste and waste management, it is stated that “ You should also consider

government policy. The Government wants the management of waste to „move up the

waste hierarchy ” (Environment Agency, 2007). This guidance from the EA seems

especially applicable, as the information required to calculate the efficiency of the

system was taken from the ERM environmental permit application, which are issued

by the EA.

However, it would be unfair not to point out that the proposal for defining recovery

or disposal operation from efficiency are just that, a proposal. The difficulty with the

equation is that it would apply to plants in the whole of Europe but contains no

provision for variation in localised climactic conditions or weather, which would affect

the efficiency (Commision of the European Communities, 2005). It is possible that if





34 | P a g e

the CERC efficiency were modelled taking climactic conditions into account it could

lie within the 65% efficiency target.

A further argument, which could define the CERC as a recovery operation, is found in

the UK Governments Waste Framework Directive (WFD) which defines an operation

as recovery if “its principal objective is to ensure that the waste serves a useful purpose

by replacing other substances which would have had to be used for that purpose

(thereby conserving natural resources) (DEFRA, 2009). By displacing fossil fuel

generation, the proposed CERC plant satisfies this guideline and should under the

UK‟s WFD be defined as recovery. This shows that current government policy is in

fact in support of the energy from waste despite the EU recommending that

efficiency restrictions should be applied.

4.4 What is the NCV for the CCC Waste Composition?

The NCV calculated for the CCC waste composition was 6.6GJ/tonne. This figure is

higher than that achieved by calculating it using ERM‟s waste composition. It is also

very close to the figure for the NCV of MSW given by dukes which was 6.7GJ/tonne.

It is still considerably lower than the figure of 9.8GJ/tonne stated by ERM. The flaw in

this result however is that this figure does not include the C&IW portion of the

feedstock and so does require further refinement to more accurately represent the

NCV of the feedstock.

4.5 Method Improvements

The author of this report has confidence in these results and subsequent discussion.

However, given more time and resources some parts of the methodology could

benefit from refinements. These include:





35 | P a g e

The accuracy of the H2 contents. The H2 content has some effect on NCV and

therefore is an important consideration. However, for the purposes of this

study, with the result being sought in GJ, the H2 content used serves the

purpose adequately. If any more depth and accuracy is required the H2

content would need to be ascertained through experiment.

The adequacy of the waste breakdown structures may need some review. The

breakdown given by ERM is somewhat ambiguous due to being an average

nationwide figure compiled from multiple sources. The Cornish waste

breakdown, although more relevant, does not include Commercial and

industrial Waste (C&IW) which would alter the resultant CV somewhat. A study

into the actual feedstock destined for the CERC would be required to alleviate

these concerns.

The equation used to calculate NCV from GCV is not 100% accurate. However

with the accuracy being sought in MJ the equation is perfectly adequate.

Should the NCV be required with any more accuracy it would be necessary to

determine it through experiment on waste samples.

The alternatives for the energy generation output from the plant hinged on

the calculated efficiency. This meant that the outputs with lower CV‟s are

actually more generous than would be the case as a lower NCV would lead to

a lower overall plant efficiency. However, this discrepancy is not to the

advantage of the arguments made by this report and therefore cannot be

considered deceitful. Given more time it would be possible to produce anefficiency value for each NCV value, which would further concrete the points

made in this report.

4.6 Suggestions for Future Study

The scope allowed to this project by the time and resources available have meant

that there are matters, which pertain to this study, which it would be prudent to





36 | P a g e

consider for future study. The report itself has raised questions that it is not within

the timeframe available to comment on.

One of these tasks for future study would be to determine more accurately the

average NCV of the waste feedstock, as would be provided to the plant and

therefore the estimated output from the plant. This would require the determination

of an average tonne of waste and compilation of said waste. The task from there

would be to test, under lab conditions, the actual calorific value of the waste.

Another way in which the results of the NCV calculation could be further honed

would be in the study of the actual hydrogen contents of a sample from each of the

fractions of waste. This should provide a more accurate figure for the calculation of

the NCV but without the need to compile and test an average sample of the waste as

described above.

Another avenue for further investigation would be to request from ERM the details of

how they calculated the 9.8MJ figure and whether or not it was based on a

retrospective calculations carried out on output estimates extrapolated from the

outputs of existing plants, as suggested in section 4.2.1. It is unexpected however

that this area of future study should turn up much more information as the author

believes, thanks to correspondence with professionals involved with the public

enquiry, that ERM would not be forthcoming with any more data while the enquiry is

underway.

Another important avenue for further study, which would put this report in context,

would be a comparatives study of alternative waste management systems which are

available. The main factors for comparison would be the bankability of the

comparatives systems, and their relative environmental impact in terms of depletion

of resources and global warming potential (GWP). Possible systems to study would

be; increased recycling and re-use using autoclaves for waste treatment and sorting,

or anaerobic digestion to generate energy in the forms of both electricity and heat.





37 | P a g e

In order to carry out comparative studies it would be important to carry out a GWP

appraisal of the CERC based on actual output which is calculated from the actual

NCV of the feedstock waste. It would also be important to carry out an economic

study of the CERC based on new figures for NCV and output. This would enable a

financial comparison to be made with other alternatives





38 | P a g e

5 CONCLUSION

In order to evaluate the suitability of the CERC 4 questions were posed which have

been answered throughout this report and are summarised below.

Is the ERM NCV Figure Accurate?

This report has shown that there is discrepancy within the data provided by ERM. The

conclusion is based on the NCV resultant from calculations carried out using their

own data, and techniques recommended by the UK Government. This is of vast

important as the implications of getting the levels of energy available in the waste

wrong undermine the environmental and economic credentials of the CERC.

What is the NCV for the CCC Waste Composition?

The data regarding the output of the plant is based on extrapolations of data, rather

than detailed study of the local feedstock, this damages the respectability of the

proposed plant before it is built. The feedstock data is compiled from national

reports, which don‟t represent the actual Cornish waste composition or moisture

content. This is done despite the fact that respectable and reliable studies into the

Cornish MSW composition have been carried out at the “black bag” level and are

readily available. The NCV calculated from these sources was shown to be lower than

that stated by ERM but higher than that calculated from ERM‟s waste composition.

What is the efficiency of the CERC? Does the efficiency meet EU requirements

for recovery?

The efficiency of the plant is not within proposals made by the EU to be classed as

recovery, this show a disregard of the future, on the part of ERM and Sita. Sita are

hoping to get their plant constructed to a technological level which experts in the EU

consider inadequate to be classed as energy recovery. However, the definition of

recovery was raised as an issue and SITA could argue this.





39 | P a g e

What affect do differing CV’s have on the energy output of the plant?

The proposed NCV leads to the highest energy output as desired, consequently the

actual lower NCV leads to a lower output. The higher NCV that the ERM proposed

leads to an increase in the avoided emission which could potentially balance the

extra GHG‟s expected from the extra road transport a single large plant demands.

Perhaps ERM have deliberately used a higher than actual NCV in order to maintain

the relatively low GWP of a single large plant despite the extra road transport it

represents. Sita have a vested interest in promoting a single large plant as it is the

best way to achieve the higher efficiencies required to make the plant bankable.

The author of this study is willing to concede that the hydrogen contents used in the

calculation of the NCV may not be as precise as is desirable in a perfect world and

lab work is required to rectify this. However the H2 content in the equation used, acts

to reduce the final NCV and the omission of H2 altogether from the calculation still

results in a NCV much lower than that presented by ERM.

In conclusion, is energy recovery from waste incineration the best option for waste

management in Cornwall? No, planning permission should not be granted for the

plant due to the carelessness of the studies seeking to justify it. The information

provided, to argue for the incinerator by Sita, is built on arbitrary and deficient

foundations.





40 | P a g e

6 GLOSSARY

CCC – Cornwall County Council

CERC – Cornwall Energy Recovery Centre

CHPQA – Combined Heat and Power Quality Assured

CO2 eq – Carbon dioxide equivalent gasses

CV – Calorific Value

DUKES – Digest of UK Energy Statistics

EfW – Energy from Waste

ERM – Environmental Resource Management

EU – European Union

FGT – Flue Gas Treatment

GCV – Gross Calorific Value

GHG – Greenhouse Gasses

GJ – Giga Joule

GWP – Global Warming Potential

HHW – Hazardous Household Waste

MEL – Measurement Evaluation and Learning

MJ – Mega Joule

MSW – Municipal Solid Waste

Tpa – Tonnes Per Annum

WFD – Waste Framework Directive

WEE – Waste Energy and Electrical





41 | P a g e

7 BIBLIOGRAPHY

AEA. (2007, May). An assessment of costs and Environmental Impacts of Single and Multiple

Facilities. Retrieved from www.cornwall.gov.uk:

www.cornwall.gov.uk/m_pdf/8_f_AEA_May2007.pdf

Bergund, C. (1999). Water Content Measurments in Houshold Waste using Neutron Probe;

Experience from Field Digestion Cell and Laboratory. Department of Civil and Environmental

Engineering, Division of Hydraulic Engineering, Royal Institute of , 101.

BERR. (2006). Carbon dioxide emissions and energy consumption in the UK. Retrieved fromwww.berr.gov.uk/files/file43947.pdf

Broadhurst, M. (2010). Power of Cornwall Document WS5 Witness Statement. Power of Cornwall Ltd.

Commision of European Communities. (2005). Directive of the European Parliament and of the

Council on Waste. Retrieved from

www.environ.ie/en/Publications/Environment/Waste/WasteManagement

Commision of the European Communities. (2005). Non-paper on the background of the

development of the Commission proposal on the distinction between energy recovery and disposal

of waste in municipal incinerators. 2.

DEFRA. (2009, October). Environmental Permitting Guidance - The Waste Framework Directive.

Retrieved from www.defra.gov.uk/environment/policy/permits/documents/wfd-guidance.pdf

DEFRA. (2007). Waste Strategy for England. The Stationery Office.

Department for Communities and Local Goverment. (2006, December). Planning Policy Statement:

Planning and Climate Change. Retrieved from www.communities.gov.uk.

Department of Energy and Climate Change. (2008). Combined Heat and Power - Quality Assured;

Guidance Note 29 Alternative Fuels Energy Inputs. CHPQA programme , 4.

DUKES. (2008). Estimated average calorific values of fuels (DUKES A.1-A.3). Department of Energy

and Climate Change.

Environment Agency. (2007, May). Your Waste, You Responsibility - Guidance Notes. Retrieved from

environment-agency.co.uk: www.environment-

agency.co.uk/static/documents/NetRegs/GEHO0507BMQS-e-e.pdf

ERM & DEFRA. (2006, December). Carbon Balances and Energy Impacts of the Managment of UK

Wastes - Defra R&D Project WRT 237. p. 18.





42 | P a g e

ERM. (2008, March). Assesment of Number of Facilities - Final Report. p. 7.

ERM. (2008, March). CERC Carbon Balance - Final Report. p. 9.

ERM. (2008). Cornwall Energy Recovery: Environmental Permit Application. Cornwall: Sita.

Larke, C. (February 2009). TCN Incinerator Objection. Atlantic Energy.

Larke, Charmian. (2010). Transition Cornwall Networ Proof of Evidence Proposed Incinerator

Restorwrack Farm.

MEL. (2007). Cornwall County Council Waste Compostion Study - Comparison Report – Ref 07048.

Office of the Deputy Prime Minister. (2005). PPS10: Planning for Sustainable Waste Managment .

The Stationary Office.

Sita. (2009). Cornwall Energy Recovery Centre Appeal - FAQ. SVEZ Environment.





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APPENDIX 1





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Table 1 Waste Compositions Modelled (weights in tonnes, for year 2020) (ERM, 2008)





45 | P a g e Table 2 Moisture & Carbon Content (ERM, 2008)





46 | P a g e

Table 3 Waste Screening Matrix (ERM & DEFRA, 2006)





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Table 4 Kerbside Residual Composition (% Concentrations) – Phase 1. (MEL, 2007)

Primary

cate ories

Sub-categories ACORN 1 ACORN 3 ACORN 4 ACORN 5 Weighted Average

Concentration (%)

Paper and

card

Newspapers and magazines, brochures and catalogues 3.74% 4.55% 9.12% 9.75% 5.47%

16.83%

Other recyclable paper- white envelopes, junk mail 2.23% 2.45% 3.33% 3.47% 2.60%

Yellow Directories 0.03% 0.00% 0.00% 0.41% 0.06%

Shredded Paper 0.22% 0.05% 0.04% 0.41% 0.16%

All Non-recyclable paper & card inc Brown Envelopes 4.32% 4.74% 4.41% 2.74% 4.27%

Tetrapak Cartons 0.42% 0.42% 0.25% 0.30% 0.38%

Corrugated cardboard, Egg Boxes & Toilet Tubes 1.29% 1.37% 2.53% 1.83% 1.55%

All Thin card inc packaging 2.01% 2.52% 2.56% 2.61% 2.33%

Plastic filmPackaging film 2.73% 2.95% 2.31% 2.07% 2.66%

5.05%Supermarket Carrier Bags 0.77% 0.96% 0.84% 0.94% 0.86%

Other Carrier Bags 0.38% 0.37% 0.45% 0.17% 0.36%

Other film 1.29% 1.12% 1.15% 0.97% 1.17%

Dense

plastic

PET bottles – Type 1 0.57% 0.54% 1.31% 1.19% 0.74%

7.43%

HDPE bottles – Type 2 0.65% 0.56% 1.18% 0.97% 0.73%

Vinyl Bottles – Type 3 0.05% 0.11% 0.11% 0.15% 0.09%

Other plastic bottles 0.07% 0.15% 0.05% 0.08% 0.09%

Polystyrene 0.23% 0.17% 0.06% 0.07% 0.17%

Plastic Food Packaging Trays , Containers and Pots –

2.23% 2.37% 2.04% 2.02% 2.22%

Other packaging 0.85% 0.62% 0.33% 0.44% 0.66%

Other dense plastic 3.20% 2.70% 1.88% 2.22% 2.74%

Textiles

Reusable Textile Clothing 0.22% 0.57% 0.75% 1.11% 0.52%

2.99%Duvets, Sheets, Blankets, Curtains, Towels & Other 0.48% 0.63% 0.00% 1.46% 0.59%

Soft Toys 0.02% 0.31% 0.06% 0.09% 0.13%

Handbags & Hats 0.01% 0.08% 0.57% 0.42% 0.16%

Pairs of Shoes 0.39% 0.62% 1.08% 0.86% 0.61%

Rags 0.87% 1.21% 0.63% 1.16% 0.99%

Misc.

combustible

Unclassified 2.14% 3.15% 5.92% 4.34% 3.25%

10.80%Disposable nappies 4.51% 6.16% 4.21% 1.67% 4.65%

Treated wood 2.08% 3.74% 0.01% 0.95% 2.21%

Non treated wood 0.41% 0.11% 3.66% 0.05% 0.69%

Non-Hazardous Clinical Waste 0.00% 0.00% 0.00% 0.00% 0.00%

Cooking Oil 0.00% 0.00% 0.00% 0.00% 0.00%

Misc. non-

Unclassified 1.21% 1.84% 0.90% 0.70% 1.31% 1.31%

Glass

Green Bottles 0.51% 0.51% 0.72% 1.76% 0.70%

2.75%Brown Bottles 0.25% 0.10% 0.18% 0.43% 0.22%

Clear Bottles 0.58% 0.11% 1.27% 0.91% 0.56%

All Jars 0.68% 0.70% 2.72% 1.28% 1.03%

Other glass 0.37% 0.23% 0.04% 0.08% 0.24%

Ferrous

metal

Cans 0.73% 0.91% 1.72% 1.67% 1.04%3.04%Aerosols 0.10% 0.12% 0.10% 0.26% 0.13%

Other Ferrous Packaging 0.17% 0.25% 0.00% 0.00% 0.15%

Other ferrous 3.48% 0.49% 0.56% 0.44% 1.73%

Non-ferrous

metal

Cans 0.12% 0.05% 0.35% 0.26% 0.14%0.46%Aluminium foil & Aluminium Food Trays 0.21% 0.18% 0.30% 0.20% 0.21%

Aerosols 0.09% 0.07% 0.15% 0.07% 0.09%

Other Non-ferrous 0.02% 0.01% 0.00% 0.00% 0.01%

Putrescibles

Soft garden waste 6.83% 11.27% 1.22% 9.23% 7.85%

45.14%

Woody garden waste 0.00% 0.00% 0.00% 0.00% 0.00%

Raw fruit and vegetable matter 18.88% 15.88% 12.69% 11.08% 16.10%

Cooked & Prepared fruit and vegetable matter 0.80% 0.74% 7.35% 0.54% 1.61%

Raw / Uncooked meat and fish 0.67% 0.60% 0.52% 1.07% 0.68%

Prepared / Cooked meat and fish 15.00% 14.18% 10.34% 19.06% 14.63%

Soil 0.00% 0.00% 0.00% 0.00% 0.00%

Unidentified 5.25% 3.17% 5.78% 2.33% 4.27%

Fines Particles < 10mm 3.05% 2.05% 1.87% 1.54% 2.38% 2.38%

HHW List all inc paint cans, including Batteries & Cooking Oil 1.08% 0.39% 0.14% 0.71% 0.68% 0.68%

WEEE List all 1.53% 0.83% 0.28% 1.47% 1.13% 1.13%

Total Weight 100.00% 100.00% 100.00% 100.00% 100.00% 100.00%

POTENTIALLY RECYCLABLE 21.54% 27.31% 27.34% 35.37% 25.94%





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Table 5 Kerbside Residual Composition (% Concentrations) – Phase 2. (MEL, 2007)

Primary

categoriesSub-categories ACORN 1 ACORN 3 ACORN 4 ACORN 5 Weighted Average

Concentration (%)

Paper and

card

Newspapers and magazines, brochures and 3.33% 4.67% 6.83% 8.98% 4.94%

17.88%

Other recyclable paper- white envelopes, junk mail 1.89% 2.33% 2.31% 7.04% 2.74%Yellow Directories 0.00% 0.06% 0.00% 0.00% 0.02%

Shredded Paper 0.20% 0.07% 0.11% 0.00% 0.12%

All Non-recyclable paper & card inc Brown Envelopes 6.10% 4.66% 5.05% 4.32% 5.26%

Tetrapak Cartons 0.43% 0.44% 0.27% 0.37% 0.40%

Corrugated cardboard, Egg Boxes & Toilet Tubes 1.22% 2.12% 2.10% 5.53% 2.18%

All Thin card inc packaging 2.05% 2.08% 2.30% 3.00% 2.21%

Plastic filmPackaging film 2.39% 2.51% 2.38% 2.09% 2.39%

4.49%Supermarket Carrier Bags 0.48% 0.60% 0.44% 0.53% 0.52%

Other Carrier Bags 0.47% 0.45% 0.30% 0.43% 0.43%

Other film 1.32% 1.11% 0.87% 1.01% 1.15%

Dense

plastic

PET bottles – Type 1 0.44% 0.33% 0.72% 1.09% 0.52%

6.77%

HDPE bottles – Type 2 0.49% 0.50% 0.96% 0.80% 0.59%

Vinyl Bottles – Type 3 0.00% 0.00% 0.06% 0.00% 0.01%

Other plastic bottles 0.07% 0.18% 0.08% 0.14% 0.12%

Polystyrene 0.21% 0.17% 0.05% 0.16% 0.17%Plastic Food Packaging Trays , Containers and Pots – 2.00% 2.15% 2.04% 1.64% 2.01%

Other packaging 1.02% 1.03% 0.45% 0.64% 0.90%

Other dense plastic 2.41% 2.23% 3.01% 2.57% 2.45%

Textiles

Reusable Textile Clothing 1.95% 0.23% 0.75% 2.42% 1.29%

4.34%Duvets, Sheets, Blankets, Curtains, Towels & Other 1.44% 0.17% 1.48% 0.26% 0.88%

Soft Toys 0.01% 0.01% 0.03% 0.00% 0.01%

Handbags & Hats 0.30% 0.11% 0.62% 0.75% 0.34%

Pairs of Shoes 0.26% 0.50% 0.27% 1.75% 0.53%

Rags 1.17% 1.26% 1.56% 1.47% 1.29%

Misc.

combustible

Unclassified 0.99% 1.20% 0.70% 0.24% 0.93%

6.21%Disposable nappies 4.42% 5.53% 6.13% 0.21% 4.48%

Treated wood 0.50% 1.10% 0.67% 0.74% 0.75%

Non treated wood 0.00% 0.17% 0.00% 0.00% 0.05%

Non-Hazardous Clinical Waste 0.00% 0.00% 0.00% 0.00% 0.00%

Cooking Oil 0.00% 0.00% 0.00% 0.00% 0.00%Misc. non-

Unclassified 2.75% 3.55% 2.74% 1.63% 2.87% 2.87%

Glass

Green Bottles 0.90% 0.72% 0.72% 0.72% 0.80%

3.49%Brown Bottles 0.08% 0.54% 0.00% 0.35% 0.26%

Clear Bottles 0.53% 1.80% 1.29% 1.02% 1.11%

All Jars 0.68% 0.75% 0.60% 1.09% 0.74%

Other glass 0.69% 0.64% 0.10% 0.59% 0.58%

Ferrous

metal

Cans 0.96% 0.81% 1.82% 2.49% 1.21%2.79%Aerosols 0.28% 0.14% 0.21% 0.07% 0.20%

Other Ferrous Packaging 0.15% 0.13% 0.25% 0.20% 0.16%

Other ferrous 0.97% 2.09% 0.72% 0.28% 1.22%

Non-ferrous

metal

Cans 0.17% 0.23% 0.13% 0.19% 0.19%0.59%Aluminium foil & Aluminium Food Trays 0.27% 0.31% 0.30% 0.22% 0.28%

Aerosols 0.02% 0.07% 0.03% 0.06% 0.04%

Other Non-ferrous 0.13% 0.04% 0.06% 0.03% 0.08%

Putrescibles

Soft garden waste 2.24% 1.44% 1.80% 0.90% 1.75%

45.11%

Woody garden waste 0.00% 0.00% 0.00% 0.00% 0.00%

Raw fruit and vegetable matter 13.60% 13.72% 13.97% 8.88% 13.09%

Cooked & Prepared fruit and vegetable matter 4.85% 4.11% 4.84% 4.32% 4.54%

Raw / Uncooked meat and fish 1.10% 0.69% 0.28% 0.54% 0.79%

Prepared / Cooked meat and fish 15.10% 16.70% 17.72% 14.80% 15.93%

Soil 0.00% 0.00% 0.00% 0.00% 0.00%

Unidentified 12.48% 9.47% 3.89% 1.78% 9.01%

Fines Particles < 10mm 2.89% 2.44% 3.50% 1.48% 2.65% 2.65%

HHW List all inc paint cans, including Batteries & Cooking 0.30% 0.64% 0.91% 0.54% 0.52% 0.52%

WEEE List all 1.31% 1.00% 1.58% 9.65% 2.29% 2.29%

Total Weight 100.00% 100.00% 100.00% 100.00% 100.00% 100.00%

POTENTIALLY RECYCLABLE 19.29% 19.13% 22.53% 27.41% 20.69%





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APPENDIX 2





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Table 1: Spreadsheet used to Calculate Efficiency and Energy Outputs

ERM Stated % of total ERM Calculated CCC Calculated DUKES Stated

Energy in feedstock MWh / yr 653333 374422 441861 446667

Ep

Electricity (MWh) 125,110 19.09% 71468 84340 85257

Used in FGT (MWh) 6261 0.96% 3577 4221 4267

Electricity x 2.6 (MWh) 341564.6 52.11% 195115 230257 232762Heat (MWh) 35,800 5.46% 20450 24134 24396

Heat x 1.1 (MWh) 39380 6.01% 22495 26547 26836

Total 380,945 58.12% 217,610 256,804 259,597

% difference from stated value 42.7% 32.4% 31.6%

Ef Fuel oil (MWh) 2,950 0.45% 1685 1989 2010

1475 0.23%

Total 1,475 0.23% 843 994 1,005

0

Ew Annual tonnage 240,000 36.62% 240000 240000 240000

waste net CV GJ/tonne 9.8 5.6 6.6 6.7Total (MWh) 653,333 99.68% 373,209 440,429 445,219

Total Input (Ef + Ew + Ei) 655,458 100.00% 374,422 441,861 446,667

Ei Electricity (MWh) 650 0.10% 371 438 443

0.00% 0

Total 650 0.10% 371 438 443

S stem Efficienc 59.64%





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Table 2: Spreadsheet used to Calculate Calorific Values

ERM CCC ERM CCC ERM CCC

Waste Composition

Composition

% (1)

Composition %

(2)

% Dry

Matter

(3)

Composition

x Moisture

content

Composition

x Moisture

content

H2

content -

%

GCV

kJ/kg (3)

NCV

kJ/kg (5)

ERM

Net CV

per

fraction

/MJkg-1

CCC Net

CV per

fraction

/MJkg-1

Paper and card 13.9% 17.4% 76.0% 10.6% 13.2% 5.99 12600.0 11293.8 1.2 1.5

Plastic film 3.4% 4.8% 71.5% 2.4% 3.4% 13.80 23600.0 20590.6 0.5 0.7Dense plastic 4.0% 7.1% 89.5% 3.6% 6.4% 13.80 26700.0 23690.6 0.8 1.5

Textiles 3.6% 3.7% 80.9% 2.9% 3.0% 3.30 15900.0 15180.4 0.4 0.5

Combustibles (Inc

absorbent hygiene

products) 11.5% 8.5% 70.0% 8.1% 6.0% 6.00 15600.0 14291.6 1.2 0.9

Non-combustibles 17.1% 2.1% 94.4% 16.1% 2.0% 2800.0 2800.0 0.0 0.1

Glass 5.4% 3.1% 98.2% 5.3% 3.1% 1500.0 1500.0 0.0 0.0

Organic (inc wood) 27.2% 45.1% 49.3% 13.4% 22.2% 4.80 6895.8 5849.1 0.8 1.3

Ferrous metal 1.8% 2.9% 89.0% 1.6% 2.6% 0.0 0.0 0.0 0.0

Non-ferrous metal 0.3% 0.5% 84.6% 0.3% 0.4% 0.0 0.0 0.0 0.0

Fine material 4.9% 2.5% 59.0% 2.9% 1.5% 4.70 4800.0 3775.1 0.1 0.1

WEEE 3.6% 1.7% 89.9% 3.2% 1.5% 3.30 7600.0 6880.4 0.2 0.1

Hazardous household waste 3.3% 0.6% 89.6% 3.0% 0.5% 12400.0 12400.0 0.4 0.1

Total 5.6 6.6

(1) Source: SITA Cornwall – CERC Carbon Balance, (2008), Suk-yi Lo ERM

(2) Source: MEL Cornwall County Council Waste Composition Study, 2007

(3) Source Carbon Balances and Energy Impacts of the Management of UK Wastes, Table A1.26 Estimated UK MSW Composition, ERM 2006

(4) Source: Table 1. Hydrogen content in household waste components (Cossu et al, 1996; Holmen,1999).

(5) Source: Guidance note 29 , quality assured for combined heat and power, dept of energy and climate change 2008





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(6) Source Pushpa Iyengar, East point college of Engineering, Bangalore, fuel

inc inert or project final

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