2010-Ctv044 Introducing Combined Heat and Power

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Introducingcombined heat

and powerA new generation o energy and carbon savings

Technology guide

enter



Contents

Why choose ground source 00

heat pumps?

Th bnts o grond sorc hat pmps

Assessing easibility 00How to assss th sitability o yor sit,

inclding grond rsarch and tst drilling

Design, procurement 00

and installation

Why gathring th right xprinc,

stting p contracts, tam dynamics

and cost control mattr

Ensuring best perormance 00

Factoring mtring and maintnanc

into th arlist dsign stags.

20-30%reduction in energy billscan be achieved with CHP

Contents

Introdction 1

Technology overview 2

What is combind hat and powr? 3

Bnts o combind hat and powr 8

Combind hat and powr tchnologis 16

Taking action 24

Scoping stdy 25

Dtaild asibility stdy 39

Finance options 42

On balanc sht 43

O balanc sht 46

Nxt stps 50

Glossary 51

Appndix – stam trbin cincis 54

Frthr inormation 55



1Introducing combined heat and power

Introduction

For many organisations, combined heat and power (CHP) oers the mostsignifcant single opportunity to reduce their total ossil uel consumption

rom on-site boilers and the power stations they import electricity rom.

The average primary energy saving rom CHP

in the UK in 2007 was around 18%, but

savings o around 28% are more typical or

small packaged CHP schemes. This, in turn,

reduces cost and CO2 emissions.

Unlike primary energy savings, the average cost

savings are more dicult to quantiy, because

energy prices vary widely rom site to site and are

constantly fuctuating over time. However, sites

typically see annual savings o up to 20%.

A CHP unit only generates economic and

environmental savings when it is running,

soit will only be viable i you have a high and

constant demand or heat – as a rule, at least

4,500 hours per year. However, it could still be

suitable on some sites with a lower demand

or heat, particularly i there is a high demand

or cooling, so it could still be worth exploring.

In this CHP technology guide we introduce the

main energy saving opportunities or businesses

with appropriate simultaneous heat and power

demands, and demonstrate how taking action

can save energy, cut costs and increase prot

margins. We also explain the dierent types

o CHP system available, outline the nancing

options and set out the key steps to take i

you are thinking about installing CHP.

4,500 hrs o high and constant heat

demand is needed to make

CHP economical

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Introducing combined heat and power 2

TechnologyoverviewCombined heat and power (CHP) is the

simultaneous generation o usable heat and

power (usually electricity) in a single process.

The electricity is generated on or close to

your site, allowing you to capture and usethe resulting waste heat or site applications.




What is combined heat and power?

CHP, also reerred to as ‘cogeneration’ or ‘total energy’, is the simultaneous generationo usable heat and power within a single process. The power generated is usually electricity,

but can also be mechanical power or driving equipment such as pumps, compressors and ans.

Denition o CHP

In a heat engine, heat rom a hot fuid is used

to do mechanical work. Once this work has

been carried out, heat remains in the fuidwhich either dissipates into the surroundings

or can be recovered and used. Combined heat

and power is dened as the recovery and

use o waste heat rom power generation.

This means there are three stages to CHP

which must occur in sequence:

1.Power generation

2.Heat recovery

3.Heat use.

Heat rom a CHP plant can also be used to

generate cooling by using an absorption chiller

unit. CHP that produces heat, electricity and

cooling is termed ‘tri-generation’.

A site with a large and continuous cooling

demand, and perhaps a declining demand

or heat, may consider replacing a conventional

electrical cooling system with absorption cooling.

Converting an electrical load into a heat load in

this way has a number o advantages:

it reduces the site’s demand or electricity•

it increases the options or heat use•

it ‘irons out’ some o the seasonal peaks and•

troughs in the requirement or heat.

In some cases, using heat or cooling can turn

a marginal CHP case into a viable option.

How CHP works

At the heart o a CHP installation is something

called the ‘prime mover’ (heat engine). This is

the equipment in a CHP system that providesthe motive power to drive the electrical generator

and produces the heat. It is generally a gas turbine,

steam turbine or internal combustion engine.

The dierent types o prime mover available mean

that CHP can use a variety o uels and provide or

various heat demands – either in the orm o hot

water or steam. As such, CHP is very fexible and

can be tailored to the requirements o each site.

It can be used across a wide range o sectors andcan provide cost-eective energy solutions or

large and small energy users alike.

We explain more about how CHP works, and the

dierent technologies involved, on pags 16-23

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CHP applications can be categorised either

as ‘large-scale’, ‘small-scale’ or ‘micro’.

Large-scale CHP reers predominantly to large

industrial applications where the plant is custom-built. Small-scale CHP usually applies at small

industrial sites, buildings and community heating

schemes where CHP is usually supplied as

packaged. Micro-CHP is normally used in domestic

and small commercial applications, such as care

homes. Generally packaged CHP systems are

employed or small-scale applications because

they are designed in a modular ashion and are

manuactured on a large scale – beneting rom

economies o scale. Custom-built CHP systems

are less common because they have a bespoke

design intended or a specic application.

Cstom-bilt CHP has electrical power outputs

ranging rom the equivalent o one megawatt

(MWe) to over 100MWe. These are mainly

installed in industrial sectors such as chemicals,

oil-rening, paper, ood and drink, and in large

community heating schemes such as hospitals

and universities.

Where can it be used?

CHP can be considered at any site where there

is sucient heat (or cooling) demand – particularly

i that demand is or extended periods. It’sparticularly suitable or the industrial, public and

commercial sectors.

Units used in this guide

A sit’s hat dmand is typically

commnicatd in trms o instantanos

dmand, and is sally in trms o:

kWth = kilowatts (thermal)

MWth = megawatts (thermal)

1,000kWth = 1MWth

A sit’s annal hat consmption

is typically commnicatd in trms

o nrgy and is sally in trms o:

kWhth = kilowatt hours (thermal)

or MWhth = megawatt hours (thermal)

1,000kWhe = 1MWhe

A sit’s lctrical dmand is typically

commnicatd in trms o instantanos

dmand and is sally in trms o:

kWe = kilowatts (electrical)

or MWe = megawatts (electrical)

1,000kWe = 1MWe

A sit’s annal hat consmption

is typically commnicatd in trms

o nrgy, and is sally in trms o:

kWhe = kilowatt hours (electrical)

or MWhe = megawatt hours (electrical)

1,000kWhe = 1MWhe

Where is CHP being used?

In th uK, thr indstrial sctors accont

or almost 76% o CHP lctrical capacity

– chmicals (33%), oil rnris (32%), and

papr and pblishing and printing (10%).

Typical applicationso custom-built CHP

• Industrialsectors:

– chmicals

– oil-rning

– papr– ood and drink

• Largecommunityheatingschemes:

– hospitals

– nivrsitis

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Packagd CHP has electrical power outputs

o less than 1MWe and is oten supplied as

a complete unit ready or installation.

In this guide we have only considered packagedschemes that generate between the equivalent

o 25 kilowatts (kWe) and 1MWe o electricity.

These are usually reerred to as small-scale or

‘mini’. Where installed, small-scale CHP has

proved to be ecient and reliable. Results have

shown that it is cost-eective to install and

operate in a wide range o sites and applications.

It is generally used in the public and commerce

sector, although smaller industrial sites can alsoinstall these units. Typical applications include

hotels, leisure centres, hospitals and small

community heating schemes.

Packaged schemes with electrical power outputs

o less than 50kWe are usually reerred to as

‘micro-CHP’. These tend to be used in very

small businesses and in the domestic sector.

Find out more

Rad mor abot packagd CHP at

www.chpocs.com

Yo can also download spcic gids

on CHP sag in hotls, nivrsitis, tc.

rom or wbsit www.carbontrst.co.k

Micro-CHP Accelerator

Or Micro-CHP Acclrator involvd

a major ld trial o 87 nits in both

domstic and small commrcial

applications, masrd against ovr

30 condnsing boilr installations.

Th trials showd savings o p to

20% whr micro-CHP systms wr

installd as th main boilr.

Rad mor abot th Accelerator

and its results.

Typical applicationso packaged CHP

hotls •

lisr cntrs •

hospitals •

small commnity hating schms •

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http://www.carbontrust.co.uk/emerging-technologies/current-focus-areas/pages/micro-combined-heat-power.aspx







How does it save energy?

CHP makes more ecient use o primary uel

or producing heat and power than separate

conventional methods, i.e. on-site boilersand power stations. That means it can deliver

signicant environmental benets and cost

savings, given the right balance o technical

and nancial conditions.

This is illustrated in Figure 1, which shows that the

UK average ossil uel electricity generator has an

eciency o around 40%. The remaining 60%

o the energy is lost, mostly as heat via cooling

towers and to a smaller degree in electricitytransmission. Packaged CHP that is correctly

sized and designed can have an overall conversion

eciency o primary uel to usable energy

(power and heat) o around 75%.

For 100 units o uel, a packaged CHP would

typically produce around 30 units o electricity

and 45 units o heat. To produce an equivalent

level o heat and electricity, a conventional power

station and boiler would need around 139 unitso uel, so CHP yields primary energy savings

o around 39/139 or 28%.

Figure 1 Energy savings through typical new small-scale packaged CHP compared

to conventional sources o heat and power generation (shown in units o energy)

Electricity

Electricity

Total primaryfuel input: 139

Total primaryfuel input: 100

Total useful energy: 75

Primary energy savings: = 39/139 = 28%

Heat

Power station and

distribution losses: 49

Power stationfuel input: 79

Boiler fuelinput: 60

CHP fuelinput: 100

Boiler losses: 15 CHP losses: 25

30

Buildingservices

45

Heat

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CHP in operationThere are 1,438 CHP schemesin operation in the UK. O these,328 are in the industrial sectorsand 1,110 are in commercial,public administration, residential,transport and agriculture sectors.




Benefts o combined heat and power

CHP can cut costs, reduce carbon emissions, ensure a more secureenergy supply and improve overall energy efciency.

CHP requires signicant capital investment in

plant and resources. However, the high capital

outlay is balanced by:

lower costs•

a better environmental perormance•

a more reliable and secure energy supply.•

CHPQA jdgs th nrgy cincy o CHP

on its lctrical cincy and on a Qality

Indx (QI). Th QI is a masr o th ovrall

nrgy cincy o CHP and th lvl o

primary nrgy saving that it can dlivr

compard to th altrnativ orms o

sparat hat and powr gnration.

Th QI is calclatd by adding th prodcts

o lctrical cincy with an X actor and

thrmal cincy with a Y actor so

QI=X . ηelec + Y . ηheat

Th X and Y actors vary dpnding on CHP

l, tchnology and siz. Thy ar dsignd

to nsr a qaliying schm also mts

th eropan CHP Dirctiv rqirmnts.

Th CHP is considrd Good Qality i th

lctrical cincy is abov 20% and th QI

xcds 100. I ithr is blow thn thr ar

mchanisms to scal back th l and/or

lctricity that will qaliy or scal bnts.

Yo can nd mor dtails on th CHPQAprogramm on th CHPQA wbsit at:

www.chpqa.com

CHPQA Good Quality CHP standards

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CCLexemptionorreduction

I you pay the Climate Change Levy (CCL),

you may be eligible or reductions or even

a ull exemption on your payments by usingCHP. You will need to register it with CHPQA,

and the size o reduction will depend on

how ecient it is.

I you export power rom your CHP you may

receive a Levy Exemption Certicate (LEC).

You can either sell these on, with the exported

electricity, or sell them separately to a

buyer who can then gain exemption on the

corresponding number o units o electricity.

The 2009 budget committed to continuing

these benets or CHP to 2023.

Read HMRC’s guidance on the Climat Chang

LevyandCHPschemes

There is also more inormation on the CHPQA

website at www.chpqa.com

Lower costs

CHP has been shown to reduce energy bills

by 20-30%.

As well as reduced energy bills, CHP also oers

other nancial incentives, which can reduce tax

liabilities, i it qualies as ‘Good Quality’ under

the CHP Quality Assurance Programme (CHPQA).

As well as measuring electricity eciency,

this judges CHP schemes on something called

a Quality Index (QI), which measures overall

energy eciency.

I you have Good Quality CHP, registered

with the CHPQA, you can benet rom the

ollowing where applicable:

a reduction o exemption rom your Climate•

Change Levy (CCL)

an Enhanced Capital Allowance (ECA)•

a business rates exemption•

preerential treatment in the Renewables•

Obligation (RO)

preerential treatment in the EU Emissions•

Trading Scheme (EU ETS).

There are also a number o proposed policies

that could bring more benets to those with

CHP schemes.

What is the ClimateChange Levy?

TheCCLispartofarangeofmeasures

dsignd to hlp th uK mt its lgally

binding commitmnt to rdc grnhos

gas (GHG) missions. It is chargabl

ongas,electricity,coalandLPG(liquid

ptrolm gas) consmd in bsinss

and indstry.

All rvn raisd throgh th lvy is

rcycld back to bsinsss throgh a

0.3% ct in mployrs’ National Insranc

contribtions – introdcd at th sam

timeastheCCL–andsupportforenergy

cincy and low carbon tchnologis.

TheCCLratesarecurrently0.47p/kWhfor

lctricity and 0.164p/kWh or natral gas.

Ths ar rviwd annally and incrasd

with infation.

Yo can nd mor dtails in HMRC’s

Introduction to the Climate Change Levy

and in sction 7.37 o ‘Bdgt 2009

Bilding Britain’s Ftr’

at www.hm-treasury.gov.uk

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http://customs.hmrc.gov.uk/channelsPortalWebApp/channelsPortalWebApp.portal?_nfpb=true&_pageLabel=pageVAT_ShowContent&propertyType=document&columns=1&id=HMCE_PROD_008750



http://customs.hmrc.gov.uk/channelsPortalWebApp/channelsPortalWebApp.portal?_nfpb=true&_pageLabel=pageVAT_ShowContent&propertyType=document&columns=1&id=HMCE_CL_001174

http://customs.hmrc.gov.uk/channelsPortalWebApp/channelsPortalWebApp.portal?_nfpb=true&_pageLabel=pageVAT_ShowContent&propertyType=document&columns=1&id=HMCE_CL_001174








Rnwabl Hat Incntiv

The Renewable Heat Incentive (RHI) is expected

to come on line in April 2011. Under the latest

drat proposal, renewable heat-generatingtechnologies – including heat rom CHP uelled by

renewables – will be eligible or RHIs. The recent

consultation proposed that no CHP will be eligible

or simultaneous ROC uplits and RHI. Instead,

CHP uplits will be removed at the next RO review

in 2013. In addition, schemes installed under the

current RO banding will have a choice – to be

made during the period between the April 2011

and the 2013 reviews – o continuing with the

uplit, or oregoing the uplit to gain eligibility

or the RHI.

The recent consultation on RHI can be ound

on the DeCC wbsit where the mechanisms,

values and interactions o ROCs, FITs and RHIs

are explained in ull.

Bsinss rats xmptions

There are also business rates exceptionsgranted or CHP. For denitive guidance on

Rating methodology, and how the Rateable

Value o a Hereditament is determined, contact

the Valuation Oce Agency (Assessors Oce,

Scotland). You can also visit the CHPQA

website and download Gidanc Not 43

or more inormation.

O the thermal generating technologies applicable

to CHP, only anaerobic digestion (AD) up to

5MWe and ossil-uelled micro-CHP up to 2kWe

are eligible or FITs. CHP uelled by solid or liquid

biomass and mature renewable gas technologies,

such as sewage gas and landll gas, continues

to be supported under the RO at all scales. Under

the FITs scheme there is no additional incentive

or heat recovery rom AD power generation,

but this is likely to be eligible or the proposed

Renewable Heat Incentive planned or April 2011.

Fossil-uelled micro-CHP up to 2kW is eligible or

FITs where ossil-uelled power-only micro-

generation is not. A domestic scale micro-CHP

pilot will support up to 30,000 installations, with

a review when 12,000 installations are completed.

Micro-CHP projects supported through the

pilot will have to use the Micrognration

Crtication Schm (MCS) in order or their

eligibility or FITs to be conrmed.

Read the ull legal statute ‘The Renewables

Obligation Order 2009’ rom the

Oc o Pblic Sctor Inormation

Or you can read a more concise summaryo bandings in the Ogem document,

‘Rnwabls Obligation: Gidanc or

gnrators‘

A summary relevant to CHP can also be ound on

the CHPQA website under Gidanc Not 44

Under the current RO, there remains no additional

incentive or heat recovery rom dedicated energy

crop-uelled power generation, or liquid or gas

renewable-uelled power generation. However,

this is likely to be eligible or the proposed

Renewable Heat Incentive planned or April 2011.

Fd-in taris (FITs)

The FITs scheme was introduced on 1 April 2010

to incentivise small-scale (less than 5MWe) low

carbon electricity generation by those not

traditionally engaged in the electricity market. This

‘clean energy cashback’ will allow many people to

invest in small-scale low carbon electricity, in return

or a guaranteed payment – both or the electricity

they generate and the electricity they export.

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http://www.decc.gov.uk/

https://www.chpqa.com/guidance_notes/GUIDANCE_NOTE_43.pdf

http://www.microgenerationcertification.org/


http://www.opsi.gov.uk/si/si2009/draft/ukdsi_9780111473955_en_1

http://www.ofgem.gov.uk/Pages/MoreInformation.aspx?file=2010%20RO%20generator%20guidance%20final%20for%20publication.pdf&refer=Sustainability/Environment/RenewablObl






http://www.opsi.gov.uk/si/si2009/draft/ukdsi_9780111473955_en_1




http://www.decc.gov.uk/




Ftr policis

Proposed uture policies that will benet those

with CHP include:

Renewable Heat Incentive (RHI), anticipated April•

2011. Under the latest drat proposal, renewable

heat generating technologies, including any CHP

uelled by renewables, will be eligible or RHIs.

However, it is likely that the RO policy would

then be revised so that CHP schemes would

not receive both RHIs and extra ROCs over

and above power-only generators.

The mechanisms, values and interactions•

o ROCs, FITs and RHIs are explained on

DeCC’s wbsit

EU ETS Phase III, rom Jan 2013. Under the•

latest drat proposal, the direct benets to CHP

are designed to be in direct proportion to the

overall CO2 saving, and credit or displaced gas

in boilers awarded or CHP heat.

eu eTS

I you participate in the EU ETS, you will also

see the benets o having CHP on your site.

We are now in Phase II o the scheme, which

runs rom 2008-2012 to coincide with the rst

Kyoto commitment period. Under this phase,

organisations with CHP schemes registered

with CHPQA are given a greater carbon emission

allocation than they would be without registration.

This is because a CHP plant emits more locally,

but less globally, the longer it’s in operation.

So you will be given a bigger allocation to cover

your on-site emissions, based on the act that

you are saving emissions on a global level.

As well as this direct benet, the EU ETS

indirectly enhances the economic benets o

CHP. This is because power stations are only

allocated a proportion o their emissions and

pass on the cost o the additional allowances

to the consumers by increasing the price o

electricity. Using CHP to generate power

on-site avoids this increase.

Find out more about the eu eTS

What is the EU ETS?

Th eu eTS was introdcd across erop

in Janary 2005 to tackl missions o CO2

and othr GHGs and combat th srios

thrat o climat chang. Yo will qaliy

or eu eTS i yor bsinss has

combstion plant capacity o mor than

20 mgawatts (MW).

As part o th schm, yor bsinss

will hav bn givn an allocation o CO2

prmits. each yar, yor actal missions

will thn b calclatd, basd on masrd

ossil l consmption and l typ. I

ths xcd th allocation yo’ll nd to

by mor CO2 prmits and i it’s lss yo

can sll prmits lswhr.

Yo can nd ot mor abot th

EU ETS on DECC’s website

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http://www.decc.gov.uk/en/content/cms/what_we_do/uk_supply/energy_mix/renewable/renewable.aspx

http://www.carbontrust.co.uk/policy-legislation/Energy-Intensive-Industries/Pages/EUETS.aspx

http://www.decc.gov.uk/en/content/cms/what_we_do/change_energy/tackling_clima/emissions/eu_ets/eu_ets.aspx

http://www.decc.gov.uk/en/content/cms/what_we_do/change_energy/tackling_clima/emissions/eu_ets/eu_ets.aspx

http://www.carbontrust.co.uk/policy-legislation/Energy-Intensive-Industries/Pages/EUETS.aspx

http://www.decc.gov.uk/en/content/cms/what_we_do/uk_supply/energy_mix/renewable/renewable.aspx






A more reliable and secure supply

CHP can enable you to generate power

independently, helping you meet demand and

reducing your dependence on electrical imports.It can be used to balance your maximum electrical

demand and help you avoid penalty payments or

exceeding your maximum agreed supply levels

rom the national grid.

I you use a synchronous generator (see pag 20),

CHP can also work completely independently o

the mains supply, and provide emergency power

in the event o a mains power ailure. It can also

be congured so your site can operate ullyindependently o the national grid, which means

your energy supply is more secure.

The best time to consider installing CHP

is at the design stage or a new installation

or building, as it can be ully integrated into

the design specication. However, it can also

be successully retrotted into existing sites,

particularly i you are upgrading energy plant

(such as a boiler) that could easibly bereplaced by CHP.

A better environmentalperormance

CHP improves a site’s environmental

perormance because:

the primary uel consumption per unit•

o energy generated is lower

uels with high GHG emissions can be•

replaced with cleaner uels

electrical losses are reduced because•

the electricity is generated at, or close to,

the point o use and is not transmitted

over large distances.

By installing CHP, you can demonstrate your

commitment to reducing energy consumption,

improving sustainability and your awareness

o environmental issues, all o which are o

increasing interest to shareholders, customers

and other stakeholders.

CHP capacity

At th nd o 2007, th total capacity

o Good Qality CHP in th uK was

5,450MW. This rprsnts 6.6% o th

total uK installd lctricity-gnrating

capacity (82,964MW). Thr was d

to b 5,469MW o capacity by th

nd o 2008.

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This equated to 2.71 milliontonnes o CO2 or every

1,000MWe o installed capacity

14.76 million tonneso CO2 saved by CHPsystems in 2007

14.76

2.71






Steam turbines

These use a steady stream o high-pressure

steam generated in a boiler to drive the turbine.

Electrical eciency is maximised when thesteam is condensed and pumped back to the

boiler as hot water just below boiling point.

The thermodynamic cycle is the Rankine cycle.

The utility scale ully-condensing steam turbines

used in large coal and nuclear power stations have

average electrical eciencies o about 36 -38%.

But in CHP applications, where the steam

extraction reduces their electrical output, they

have typical electrical eciencies o 10.7-20%.Their overall eciency ranges rom 77.6-82.5%.

The electrical eciency o steam turbines in

CHP mode depends on the size o turbine and

the pressure at which steam is extracted.

S Appndix A or a breakdown.

Steam turbines can be deployed as the prime

mover or custom-built CHP plant by recovering

some o the heat at one o the ollowing stages

in the process:

a.as medium-pressure steam between turbine

stages (‘pass-out’) at the expense o a reduction

in power generation

b.as low-pressure steam slightly above

atmospheric pressure exiting the nal stage

o the turbine (‘back pressure’)

c. as low-grade hot water (about 30ºC) recovered

rom the secondary cooling circuit in the

condenser with no consequent loss o power.

This is the most ecient option but is not

common as such low grade heat is only o

use in a ew applications such as liqueed

natural gas vaporisation.

Steam can also be diverted to the process

beore entering the turbine but, as mentioned

earlier, this is not CHP, where the working fuid

must rst generate power.

Heat can then be used or process or space

heating. Such turbines are particularly appropriate

or CHP when steam is needed, or where the uel

available cannot be burned directly in the prime

mover. They are typically suited to large-scale

applications or where the amount o heat required

is much greater than the amount o power.

Steam turbine

They are usually used in packaged CHP units, along

with heat exchangers to recover heat rom one

or more o the ollowing waste heat sources:

engine cooling circuit•

engine exhaust•

oil•

intercooler.•

Where to use internalcombustion engines?

Rsidntial homs or th ldrly •

extra car schms •

Shltrd accommodation •

univrsity stdnt accommodation •

Hospitals •

Leisurecentres •

Hotls •

Schools •

Luxuryhouses •

emrgncy srvics •

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New and emerging technologies

In addition to the more established types o

prime mover, Stirling engine, uel cell and ORC-

based CHP are emerging in the UK market but

are still essentially under development.

Heat can be recovered rom the steam turbine

cycle in the same way as with steam turbine

only systems. All combined cycle turbine CHP

schemes are custom-built.

Gas turbines

These use a steady stream o burning uel to drive

a turbine to generate the motive power. The heat

rom the turbine’s exhaust gases can be recovered

and used or space or process heating.

They are usually employed in large-scale custom-

built schemes, larger than 1MWe, although there

are small-scale ‘mini turbines’ o between 80kWe

and 100kWe in some packaged CHP systems.

Their electrical eciency ranges rom around 21%

or mini turbines, to 25% or the smallest standard

turbines o around 1MWe, and up to about 36%

or very large turbines (above 100MWe).

Gas turbines have a higher electrical eciency

than steam turbines, as they operate at higher

temperatures, but require a cleaner uel (natural

gas). Typically, they have lower electrical

eciencies than internal combustion engines

but are smaller and require less maintenance.

Combined cycle gas turbine systems

These use the high temperature exhaust rom

a gas turbine to generate high-pressure steam

which then passes through the steam turbines

to generate more power. This combination

provides very high power eciencies o up

to 55% (averaging around 52%) and is typically

used in large-scale power generation.

Gas turbine

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Th hat rcovry qipmnt

Heat recovery equipment captures the heat

rom the prime mover either or process use

(generally steam) or heating and hot water.

Generally, or internal combustion engines, the

heat recovery equipment comprises plate heat

exchangers, whereas or gas turbines the heat

is recovered in a heat recovery steam generator

(HRSG or HiRSiG). In some cases, the HRSG

itsel has additional uel burned in it (called

supplementary ring), in which case it’s

reerred to as a ‘red HRSG’.

In systems with a steam turbine, the heat is

usually used directly. However, in some cases,

its pressure may need to be reduced beore use.

Th lctrical gnrator

The generator converts the mechanical shat

power o the prime mover into electricity.

Generators or CHP can be categorised assynchronous (‘sel-controlled’) or asynchronous

(‘grid-controlled’).

Synchronous generators can operate completely

independently o the grid in what is known

as ‘island mode’. This means they are suitable

or stand-by electricity generation i the grid

power ails.

Asynchronous generators require a constant

connection to the grid and will shut down in

the event o a grid power ailure. So they are

not suitable or stand-by generation.

Below 100kWe size, synchronous generators

are signicantly more expensive than

asynchronous generators because o the

additional control equipment. So unless it’s

essential that a site has back-up, asynchronous

generators are usually installed. Above 100kWe

the cost dierences are very small and sosynchronous generators are usually employed.

Choosing th l

In general, the cost o a uel is infuenced by

availability, fexibility o supply, storage and use.

CHP installations can be designed to accept more

than one uel, usually at an additional cost, which

gives more fexibility and means supply is more

secure. However, your uel choice may be limited

in practice by the emission requirements o an

environmental permit.

The uel or custom-built and packaged units is

usually natural gas, though some can operate on

other gases, such as stored propane, butane, LPG

or biogas rom sewage/landll waste. Distillate

uels can also be used, but this is less common.

Steam turbines can burn cheaper uels such as

coal, heavy oils and waste materials, but there

may be additional costs or handling, burning and

meeting environmental standards. You may also

need a back-up uel – natural gas or oil – i you are

burning a solid or waste product, either to bridge

supply shortalls or to initiate combustion.

Fuels such as natural gas and the lighter oils are

o premium quality and value: they are generally

more expensive to buy, but less costly to use.

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Types o CHP plant

As mentioned on pag 4, there is large-scale

and small-scale CHP, as well as micro-CHP, which

reers to systems with an output below 50kWe.The three types will use dierent prime movers,

depending on their size, power and application.

Large-scale,custom-builtCHP

Custom-built CHP plant can range rom 1MWe up

to hundreds o MWe. The plant generally consists

o large and complex systems installed on-site,

although systems can be built or smaller power

requirements.

The prime mover or custom-built CHP units up

to about 40MW is most commonly a simple cycle

gas turbine, or a steam turbine i solid uel and oils

are used. For units larger than 50MWe, a CCGT

is oten used.

In gas turbines, steam is then generated rom

the turbine exhaust. For pass-out steam turbines,

or CCGTs with pass-out steam turbines, high-

pressure steam is extracted rom the turbine,causing a loss o power generation. The trade-o

between heat and power depends on the size

o the steam turbine and the pressure o the

extracted steam.

You can nd more inormation on custom-built

schemes on DECC’s CHP Focus website

www.chpocs.com

Figure 3 Custom-built CHP system

Air

Gas turbine

Hot exhaust gases

Generator

Electricity to site

Heat recovery boiler

Stack

Steam to site

Fuel

Feed water

Gas-turbine CHP CCGT CHP

elctricity otpt (MW) 1.1 4.9 9.7 31.0 53.0 99.8 316.0

Hat otpt (MW) 1.8 7.2 14.5 36.5 40.5 99.3 205.3

Fl inpt (MW) 4.3 16.3 34.0 96.1 134.3 271.6 686.4

Figure 4 Example sizes or custom-built CHP units

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Micro-CHP

Micro-CHP is dened as systems with less

than 50kWe. Systems with more than 5kWe

are oten reerred to as mini-CHP.

Like small-scale CHP, micro-CHP systems are

designed and supplied as complete units, and

contain the engine, generator and heat recovery

equipment, together with all the associated

pipework, valves and controls.

Micro-CHP units can use internal combustion

engines, micro-turbines or Stirling engines.

Typical applications are in the domestic market,

or in small commercial sites such as care

homes or small leisure centres.

Biomass CHP systms ar vn lss carbonintnsiv than gas- or coal-powrd plant,

as thy s a lowr-carbon, mor

sstainabl l sorc.

Althogh still qit ncommon in th uK,

thr ar svral hndrd biomass-lld

CHP plants in opration on th continnt –

th majority sing solid biomass. Sizs vary,

bt most installations hav a ratd boilr

otpt o mor than 5MWth, with only a w

gnrating at blow 50kW. Ths systms

tnd to s a matr combstion tchnology

sch as a stam trbin bt systms sing

th Organic Rankin Cycl (ORC) ar

incrasingly common.

Thr ar also many plants in opration that

s th gas prodcd by anarobic digstion

(AD) o liqid biomass (typically th mthan

prodcd at swag tratmnt works) to

oprat a convntional intrnal combstion

ngin. Ths can oprat ctivly at

smallr scals (down to 330kW).

Othr convrsion tchnologis or biomass

CHP incld:

Gasication

This is a procss o convrting th biomass

to a gas mixtr – known as ‘syngas’ – by

combining it at high tmpratrs with

controlld amonts o oxygn or stam to

crat a raction.

Pyrolysis

Dring this procss th biomass

dcomposs, whn hatd in a controlld

amont o oxygn, to prodc a varity

o prodcts sch as a l gas, char, bio-oil

and tar – all o which can b sd to

gnrat hat and powr.

Both o ths tchnologis, howvr, ar

considrably lss tchnically matr thanstam or ORC convrsion mthods.

A cleaner alternative: biomass combined heat and power

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Introducing combined heat and power 24Introducing combined heat and power



Introducing combined heat and power 24Introducing combined heat and power

Taking action First carry ot a scoping stdy to dtrmin

i yor sit’s basic inrastrctr is sitabl or

CHP. This shold incld an initial tchnical

assssmnt. I this is sccssl, ollow it p

with a dtaild asibility stdy, to mak sr

it is dnitly a viabl option.

Yor nrgy and acilitis managr can complt

th initial scoping stdy and tchnical assssmnt,

bt yo may nd hlp rom a spcialist consltant

or th dtaild asibility stdy.

I th initial invstigations show that CHP is a

viabl option, yo can arrang or yor CHPschm to b dsignd and installd.

Scoping study

including initial

technical assessment

Detailed easibility

study

Detailed design

Installation andcommissioning














Monthly gas and electricity bills

You should be able to get these rom your landlord

or your energy manager or the last calendar year.

But they may not be comprehensive records and

there may be errors in the bills.

Alternatively, your electricity supplier may

have inormation on consumption taken rom

hal-hourly meter readings. This can be supplied

electronically and can be analysed using

a spreadsheet.

Ideally, it should cover one year and should be

based on hal-hourly measurements o heat

and power consumption.

I you don’t have enough inormation about

energy consumption, you may need to estimate

it. Your monthly uel bills will provide an indication

o seasonal variation, but you may need to do

some short-term monitoring to determine the

weekly and daily proles. This will help you

understand the operating patterns on your

site – or both the building and any processes

you carry out.

Get as close as reasonably possible to hal-hourly

consumption gures and avoid assessing demand

rom data averaged over long periods o time.

1 Dtrmin yor nrgy prols

You should produce energy proles to evaluate

the heat and power demands o your site.

This will also give you an indication o what

size o CHP unit you’ll need.

To calculate these proles, you need to collect

data on how your site uses energy. There are

two main ways to do this:

Building management systems (BMS)

Many buildings have some orm o computer-

controlled energy management system that keeps

historical data o energy usage. Your energy or

acilities manager will know i you have one.

It’s an ideal source o data because it’s the most

accurate and likely to cover a number o years.

This inormation should show how normal

(average) demand proles vary with:

a. time o day (are there early morning and early

evening peaks?)

b.day o the week (are there dierent demand

proles at weekends?)

c. season o the year (are there variations in

demand or heating or cooling in certain

months o the year?).

Degree days

Th nrgy data shold b normalisd

to stimat th dmands in an avrag

yar, rathr than th particlar yar inwhich th rcordd nrgy was consmd.

This corrction nds to b applid only

to th proportion o nrgy sd or spac

hating, and so an stimat o this

proportion is rqird.

Th normalisation is don by carrying ot

a ‘dgr day analysis’, whr dgr days

ar compild or a spcic location sing

historic tmpratr data. Th amonto spac hating rqird is broadly in

proportion to th nmbr o dgr days,

and so by comparing th nmbr o dgr

days in an avrag yar with thos in th

tim priod yor nrgy data was

gathrd, an stimat o yor nrgy

dmand or spac hating in an avrag

yar can b stimatd.

Dgr day data can b downloadd romwww.carbontrust.co.uk/degreedays

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I not, you can create your energy proles

by completing the above tables or heat and

electricity, either electronically or manually,

using common units.

Compiling the data

Once you have got your hal-hour consumption

gures, you can generate your energy proles.

I you used a BMS, this may automatically

generate them.

Average day

in period

Winter Oct-Apr

Mon-Fri (kW)

Winter Oct-Apr

Sat/Sun (kW)

Summer

May-Sep

Mon-Fri (kW)

Summer

May-Sep Sat/

Sun (kW)

00:00

02:00

04:00

06:00

08:00

10:00

12:00

14:00

16:00

18:00

20:00

22:00

Month Average demand (kWh)

Jan

Fb

Mar

Apr

May

Jn

Jl

Ag

Oct

Nov

Dc

Figure 9 Typical annual demands Figure 8 Heat and electricity use

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Determine what heat-to-power ratio

the CHP needs to be

Using Figure 11, work out the heat-to-power ratio

your CHP needs to be.

Heat-to-power ratios can range rom 0.6:1 or an

internal combustion engine with only exhaust-gas

heat recovery, to 10:1 or a steam turbine.

Determine the type o prime mover

to use or CHP

The size o CHP system when coupled with

the heat-to-power ratio (both calculated as above)

gives an indication o the type o prime mover

to choose.

4 Mak basic nancial calclations

A basic nancial viability check, when coupled

with the calculations already carried out, will give

you an indication o how economical it is to use

a CHP scheme or a particular application.

The ollowing are some o the things you should

do as part o your calculations. Don’t orget to

consider current and uture gas and electricity

prices, as well as the capital and maintenance

costs o CHP plant.

Determine the nancial base case

The rst step is to establish a nancial base

case (that is, existing energy costs) against which

the proposed CHP scheme can be compared.

To do this, determine the current annual electricityand gas costs using the inormation collected

in Figure 11 to give an overall annual energy cost.

Calculate anticipated CHP running costs

Having sized the CHP unit rom the energy

demand gures, calculate the anticipated annual

running costs o the CHP scheme. This should be

based on estimated gas, electricity, operational

and maintenance costs. The length and cost o

CHP maintenance contracts vary greatly. Typical

ranges are around 0.6p/kWh electricity generated

or large gas turbines and CCGT above 40MWe,

0.8-0.9p/kWh or a gas turbine above/below

7MWe, and around 1.0-1.2p/kWh or a

reciprocating engine above/below 1MWe.

Estimate the capital costs o the CHP scheme

This will vary rom site to site, but or packaged

CHP, average costs in 2008 were around:

£2,000/kWe or 5kWe micro-CHP•

£1,250/kWe or 50kWe schemes•

£800/kWe or 1MWe schemes.•

Custom-built CHP costs were around £1,350/kWe

or a 1MWe gas turbine scheme alling to

around £700/kWe or very large CCGT schemes

above 200MWe.

Determine annual savings

Use the nancial base case and the anticipated

running costs to determine the annual savings

you would see by installing CHP.

Compare this to the capital costs o the unit to

determine whether CHP could be a viable and

cost-eective option or your business.

Focus on nance

Altrnativ mthods o nancial appraisal

– sch as simpl payback, discontd cash

fow, nt prsnt val (NPV) and intrnal

rat o rtrn (IRR) – ar covrd in-dpth

in th CHP Focus website’s nance section.

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http://chp.decc.gov.uk/cms/chp-finance/

http://chp.decc.gov.uk/cms/chp-finance/






Initial calclations and rslts

Period Hours in

period

Electricity purchases Fuel purchases Boiler e

(HHV)

75.00% Site

heat:

power

ratio£ (excl

SC)

kWh p/kWh kW £ (excl

SC)

kWh

(HHV)

p/kWh kWt

May-Sp 3,672 £20,000 200,000 10.00 54 £4,500 150,000 3.00 31 0.56

Oct-Apr 5,088 £20,000 200,000 10.00 39 £13 ,500 450,000 3.00 66 1.69

Yar 8,760 £4 0,00 0 4 00,00 0 10.00 46 £18,000 600,000 3.00 51 1.13

Period Hours in

period

E lec tri ci ty purc hases (var iabl e c ost s) Fuel pur chases Boi ler e

(HHV)

75.00% Site

heat:

power

ratio£ (excl

SC)

kWh p/kWh kW £ (excl

SC)

kWh

(HHV)

p/kWh kWt

May-Sp prodction 3,500 £19,293 194,110 9.94 55 £4,500 150,000 3.00 32 0.58

Non-prodction 172 £707 5,890 12.00 34 £0 0 3.00 0 0.00

Oct-Apr prodction 4,900 £19,227 193,562 9.93 40 £13,500 450,000 3.00 69 1.74

Non-prodction 188 £773 6,438 12.00 34 £0 0 3.00 0 0.00

Yar prodction 8,400 £38,521 387,671 9.94 46 £18,000 600,000 3.00 54 1.16

Yar non-prodction 360 £1,479 12,329 12.00 34 £0 0 3.00 0 0.00

Yar total 8,760 £40,000 400,000 10.00 46 £18,000 600,000 3.00 51 1.13

Nt lctricity gnration 1st stimat, kW 16

Maximm CHP oprating hors 8,400

Gas pric, p/kWh 3.00

Val o lctricity gnratd, p/kWh 10.00

Fird boilr cincy, % (gross c.v.) 75.00%

Largeopencycle gas trbin

Small gas trbin Gas ngin

Otpt hat to powr ratio (Min 1.5 - Max 5 .5 ) (Mi n 1.5 - Max 5 .5 ) (Mi n 0 .6 - Max 1.5)

slctd H:P ratio 2.17 2.17 1.54

Hat rcovry, kW 36 36 25

CHP opration & maintnanc (O&M), p/kW 0.5 0.8 1.4

Nt gnration cinc y, % (gross c.v.) 29% 29% 36%

CHP availability, % 90% 90% 90%

Nt gnration % o ratd otpt 97% 97% 99%

Actal CHP oprating hors 7,560 7,560 7,560

Ratd lctrical otpt o CH P, kW 20 20 20

Annal powr gnratd kWh 146,664 146,664 149,688

CHP kW









Introducing combined heat and power 42



1 4 5 6 7 832

Finance optionsYour fnancing options or CHP can be divided into two key

groups – those that appear on your balance sheet and those that don’t.

Capital purchase or‘on balance sheet’ nancing

Financd by:intrnal nding •

dbt nanc •

lasing. •

Operating lease or‘o balance sheet’ nancing

Financd by:qipmnt spplir •

nrgy srvics company •

Privat Financ Initiativ. •








Financ las

With a nance lease arrangement you pay

regular rentals to the leasing organisation over

the primary period o the lease. This allows

the leasing company to recover the ull cost –

plus charges – o the equipment.

Although you don’t own the equipment, it appears

on your balance sheet as a capital item and you

are responsible or maintenance and insurance.

At the end o the primary lease period, you

can either take out a secondary lease – with

much reduced payments – or sell the equipment

second-hand to a third party, with the leasing

organisation retaining most o the proceeds

o the sale.

With nance leasing, the leasing organisation

gets the tax benets. These are passed back

to you, in part, in the orm o reduced rentals.

In principle, the rental can be paid out o your

energy savings, thereby assisting cash fow.

With this route, your level o nancial and technical

risk is similar to that o a sel-nanced project.

Figure 13 What’s the best ‘on balance sheet’ fnancing option or you?

Type o nancing Pros Cons

Intrnal nding You retain ull ownership and control

o the project and should reap themaximum potential benets.

You bear a considerable element

o technical and nancial risk.

Dbt nding You retain the ull ownership, control

and benets o the installation.

You will accrue interest on any

borrowed capital.

The nancial risk is spread over time. As with ull internal nancing,

you retain the technical and nancial

risks, apart rom those that lie with

suppliers and contractors.

Hir prchas The nancial risk is spread over time. You don’t own equipment until it is

paid or but you are still taxed or it

and responsible or operation costs.

You will usually need to pay an

interest charge.

Financ las As with debt nancing, the nancial

risk is spread over time.

Although you never own the

equipment, you are responsible

or maintenance and insurance

– and or tax purposes you are

the owner o the equipment.

May have tax advantages over

internal and debt nancing i you have

insucient taxable prots to benet

rom the tax allowances available on

capital expenditure.

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O balance sheetCommon arrangements o o balance sheet fnancing or CHP plant

are via equipment supply fnance, an Energy Services Company (ESCO)and a Private Finance Initiative (PFI).

Equipment supplier nance

An equipment supplier may, as an alternative

to outright purchase, oer a leasing package or

CHP. Under this arrangement, it will normally

design, install, maintain and sometimes operatethe CHP system.

A common commercial arrangement is or the

energy to be supplied at prices that incorporate

agreed discounts on the open market price.

This means you pay or the uel and buy the

electricity and/or heat generated rom the

CHP at the agreed price.

To assure the equipment supplier o a continued

income throughout the 5-10 year contract period,

you may be required to pay a substantial standing

charge, a lease payment or a high ‘take or pay’

volume o the energy supplied.

This orm o nancing arrangement is oten used to

nance small, packaged engine-based CHP systems.

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Your savings when unding a CHP plant through

an ESCO arrangement will normally be less than

under a capital purchase arrangement because

the ESCO contractor needs to recover the cost o

the capital investment and cover operating costs,

overheads and prot.

However, under certain circumstances, the

savings can be greater. For example, your ESCO

contractor may be able to size a CHP plant to

meet your heat requirement and produce surplus

electricity that can be exported and sold. You will

still receive only part o the value o the energy

savings but, because the energy savings are

greater, your share may have a value greater than

the savings you would have got under a smaller

capital purchase scheme.

The ESCO contractor will also be able to increase

the benets compared with an in-house solution

by avoiding the learning curve costs.

Energy services company (ESCO)

An ESCO is a company set up to provide a total

energy supply service, taking responsibility or

provision, nancing, operation and maintenance

o energy acilities.

An ESCO arrangement can vary widely. In some

instances, the ESCO contractor will design, install,

nance, operate and maintain a CHP plant on your

site. In other cases, you might subcontract only

the operation and maintenance o CHP plant that

has been installed by other contractors, under

a design and manage or turnkey arrangement.

In both cases, the ESCO contractor supplies heat

and power at agreed rates. The ESCO contractor

may also take responsibility or buying uel and

or your other on-site energy plant.

From a nancing point o view, the basis o this

type o agreement is that the CHP plant capital

and operating costs are transerred rom the end

user to the ESCO contractor – together with all

the technical and operating risks o CHP.

Is a turnkey arrangement rightor you?

A trnky projct is on in which a singl

contractor – or xampl, an qipmnt

spplir – taks rsponsibility or

implmnting th whol projct. That

inclds th dtaild dsign, prchasing

and installation, as wll as commissioning

and tsting. This mans yo hav lss

infnc ovr slcting yor plant, and

how it is congrd, and it ’s yor

contractor’s rsponsibility to nsr

that all th plant itms work togthr.

Whn th projct has bn compltd, th

contractor will hand th plant ovr to yo;

yo pay or it and own it rom that point

onwards. Yo may dcid to oprat and

manag th plant yorsl – assming

rsponsibility or plant prormanc and

rliability, and also rtaining all o th cost

savings. Or yo cold appoint an

intgratd nrgy srvics company

(eSCO) to oprat and manag th planton yor bhal.

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An ESCO contractand fnance are

not intrinsicallylinked. You canenjoy the core benefts o anESCO arrangement

irrespective o the fnance route you choose

Privat Financ Initiativ (PFI)

The PFI applies i you are a public sector

organisation hosting CHP plant.

Under this arrangement, you sign a contract

with a private sector consortium, technically

known as a Special Purpose Vehicle (SPV),

and usually ormed or the specic purpose

o providing the PFI.

The PFI is owned by a number o private

sector investors. It usually includes a construction

company or building and reurbishment projects

(o which CHP oten orms a part), a CHP supplier

and oten a bank as well. The consortium’s

unding will be used to build the acility and to

undertake maintenance and capital replacement

during the lie cycle o the contract.

I you are installing a CHP in an existing building

you should consider a PFI arrangement. Where

a new building is being proposed, explore the

possibility o installing a CHP scheme within

a wider PFI or the building.

Dierent ESCO contractors may produce

widely diering proposals, depending on your

requirements and their objectives. Questions

to be answered include:

who will operate the plant on a day-to-day•

basis and, thereore, bear the perormance risk?

who will maintain the plant?•

who will own the plant at the end o the initial•

agreement period o 10-15 years and at what

ongoing cost?

Any transaction with an ESCO contractor

still involves a long-term commitment.

Your audited accounts should contain a summary

o this commitment, and you will need to satisy

your auditors that the arrangement is an operating

lease and not a nance lease. I it is implied or

stated in the contract that ownership o the plant

will transer to you, the arrangement must appear

on your balance sheet.

Remember that an ESCO contract and nance

are not intrinsically linked. You can enjoy the core

benets o an ESCO arrangement – reducing

the cost and transerring the risk – irrespective

o the nance route you choose.

In some cases the organisation hosting the

CHP can also be part o the ESCO.

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Combined heat and power (CHP)

Simultaneous generation o electricity and

production o heat using a source o mechanical

and thermal energy (e.g. internal combustion

engine, gas turbine or steam turbine).

Compression ignition

Ignition o the uel in an engine using compression

on the principle o a diesel car engine.

Condensing steam turbine

The steam turbine mode whereby steam surplus

to site requirements is expanded to the lowest

practicable pressure (vacuum stage) to generate

more electricity, then exhausted to a condenser

where the latent heat in the exhaust stream is

removed by cooling water and resulting

condensate is returned to the boiler.

Building services

The utilities/services required or operation

o a building. Building services include cold water,

space heating, domestic hot water, air-conditioning,

lighting, small power and electricity.

Capital purchase

A unding option where the business buys

CHP equipment using its own unds or own

structured loan.

CHP engine

Type o CHP engine, spark ignition or compression

ignition internal combustion engine uelled by gas

or oil.

Climate Change Levy (CCL)

An environmental tax on energy supplies applicable

to businesses and introduced in April 2001. It isintended to help the UK meet its commitment

to reduce greenhouse gas emissions.

Glossary

Absorption chiller

Equipment that uses heat energy to produce chilled

water in air conditioning. Oten uses spare CHP

heat in the summer when buildings require cooling.

Alternator

A machine, the shat o which is driven by an

engine or turbine and converts rotating mechanical

energy into alternating current (AC).

Back pressure steam

The steam exhausting rom the low-pressure

end o a steam turbine.

Baseload

The minimum expected amount o energy a site

needs to unction.

Building energy management system (BEMS)An electronic control system or building services,

usually linked to a central computer system.

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Spark ignition

Ignition o the uel in an engine, using spark

plugs on the principle o a petrol car engine.

Stack or fue

Chimney or fue through which waste

gases are exhausted rom CHP equipment

or conventional boiler.

Standby

Generation capacity on-site which provides

electricity (or other building services during

supply ailure).

Thermal storageThe storage o heat, usually hot water in a

buer tank so that a CHP sized to meet the

baseload heat demand can meet occasional

peak heat demands.

Utilisation

The percentage o time that the CHP equipment

is operated at ull output (or equivalent).

MWe

Megawatt o electricity, equivalent to 1000kW

o electricity.

Packaged CHP

Sel-contained CHP equipment with all necessary

equipment, oten in a sound- insulated casing.

Primary energy

Chemical energy contained in oil, natural gas,

coal, etc., which is used to provide secondary

power (such as electricity and heat).

Prime mover

Engine or turbine used in a CHP plant to convertuel to mechanical shat power (usually to

generate electricity) and heat.

Remote monitoring

A CHP control system which reports perormance

and problems automatically via telephone to the

maintenance contractor.

Secondary energy

Energy (such as electricity or heat) provided

through the conversion o a raw source

(such as, oil, natural gas and coal).

Heat recovery

Recovery o heat rom the exhaust gases

and cooling system o CHP equipment.

HHV (higher heating value)

The total heat available in complete combustion

including the latent heat o the steam in the

exhaust. It is an alternative phrase or gross

caloric value.

Island mode operation

Mode in which CHP can unction despite a ailure

o mains electricity rom the grid. May be used

in conjunction with standby generation to maintain

ull operating service.

Low temperature hot water (lthw)

Water, typically at 70 – 80ºC and which may or

may not be pressurised. Low pressure hot water

(lphw) is the term sometimes used when water

is not under pressure.

Medium temperature hot water (mthw)

Water at temperatures between 120 and 133ºC

and pressure between 200 and 300kPa.

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CHP Focus

CHP Focus is a DECC initiative to support

the development o CHP in the UK. On the

website you will nd comprehensive inormation

on all aspects o CHP, whether you are new

to CHP or looking or specic inormation.

There is also ree helpline support provided

on 0845 365 5153, where experts can

provide guidance to those who require it.

Visit the CHP Focus website at

www.chpocs.com

Further inormation

Carbon Trust website

You will also nd more inormation about

CHP on our own website.

Visit www.carbontrst.co.k

Combined heat and power quality assurance

You can read inormation about CHP, and also

nd out how to get your system certied, on

the combined heat and power quality assurance(CHPQA) website.

Visit www.chpqa.com

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Go online to get moreThe Carbon Trust provides a range o tools, services and inormation to help you

implement energy and carbon saving measures, no matter what your level of experience.

Carbon ootprint calculatorOur online calculator will help you calculate your

organisation’s carbon emissions.

www.carbontrst.co.k/carboncalclator

Interest-ree loansEnergy Eciency Loans rom the Carbon Trust are

a cost eective way to replace or upgrade your

existing equipment with a more energy ecient

version. See i you qualiy.

www.carbontrst.co.k/loans

Case studiesOur case studies show that it’s oten easier and

less expensive than you might think to bring about

real change.

www.carbontrst.co.k/casstdis

Action plansCreate action plans to implement carbon

and energy saving measures.

www.carbontrst.co.k/apt

Carbon surveysWe provide surveys to organisations with annual

energy bills o more than £50,000*. Our carbon

experts will visit your premises to identiy energy

saving opportunities and oer practical advice on

how to achieve them.

www.carbontrst.co.k/srvys

PublicationsWe have a library o ree publications detailing

energy saving techniques or a range o sectors

and technologies.

www.carbontrst.co.k/pblications

Events and workshopsThe Carbon Trust oers a variety o events and

workshops ranging rom introductions to our

services, to technical energy eciency training,

most o which are ree.

www.carbontrst.co.k/vnts

Need urther help?Call our Customer Centre

on 0800 085 2005

Our Customer Centre provides ree advice on what

your organisation can do to save energy and save

money. Our team handles questions ranging rom

straightorward requests or inormation, to

in-depth technical queries about particulartechnologies.

* Subject to terms and conditions.

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2010-Ctv044 Introducing Combined Heat and Power

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