SLCP emissions from small-scale woodcombustion in the Nordic countriesA project financed by the Nordic Council of Ministers June 2013 - December 2017

Ingrid Mawdsley 2017-05-11

Background

Focus on Black Carbon/EC (but also OC, PM2.5, CH4, NMVOC).

2013-2015: Background analysis and identification of knowledge

gaps

– Report available at http://dx.doi.org/10.6027/TN2015-523

– Background analysis provided basis for designing a measurement

program

2015-2017: Emission measurements (residential biomass

combustion), development of emission factors, inventory

methodology

2016-2017: Identify relevant actions/measures for reduced

emissions of SLCP in the Nordic countries

Residential biomass combustion

Emission factors for PM in the Nordic countries based on different

measurement standards.

Generally lower emission factors for PM2.5 in Sweden, based on hot flue

gas measurements (without condensables), while e.g. Danish and

Norwegian emission factors are based on diluted sampling (with

condensables).

Differences may also be due to different assumptions regarding

operational conditions, e.g. the extent of bad firing habits (incomplete

combustion due to restricted air supply) which will produce higher

emissions.

Measurement program

Residential biomass appliances representative for the Nordic countries

EC, OC, PM2.5, CH4, NMVOC

Test methods (operational conditions and firing schemes):

– Boilers: EN 303-5

– Room heaters: EN 16510 series, including part load (according to proposed revision)

– Startup phase (ignition) sampled separately

Sampling: Dilution tunnel (according to Norwegian standard 3058)

Performed in cooperation by SP Technical Research Institute of Sweden

(boilers) and Danish Technological Institute (DTI) in Denmark (stoves)

The boiler population

P1 Inverse combustion and λ-probe

P2 Inverse combustion and flue gas fan

P3 Inverse combustion and flue gas fan

P4 Inverse combustion and natural draught

P5 "Simple" boiler

P6 Old combination boiler (oil+wood)

P7 Traditional pellet burner in an oil or combination boiler

P8 Advanced pellets burner in boiler designed for pellet firing

P9 Pellet boiler with integrated grate burner

P10 Wood chip boiler

Modern

Old

Pellets

The stove population

A0 Modern medium class wood stove

A1 DIY wood stove (simple ”building market stove”)

A2 Modern popular wood stove

A3 State of the art wood stove

A4 Traditional Nordic cast iron stove

A5 Traditional Nordic tiled stove

A6 Traditional Nordic slow heat release appliance

A8 European type pellets stove

A9 Traditional Nordic sauna stove

Modern stoves

A1 Simple A2 Modern A3 State-of-the-art

A4 Cast iron stoveA5 Tiled stove

A6 Slow heat release

A8 Pellets

A9 Sauna

Example of results – individual boilers

0

50

100

150

200

250

300

350

400

450

500

PM2.5(mg/MJ)

EC (mg/MJ) OC (mg/MJ) CH4 (mg/MJ) NMVOC(mg/MJ)

mg/MJ

P1 λ-probe

P2 flue gas fan

P3 flue gas fan

P4 natural draught

P5 old tech

P6 old combi

P7 "old" pellet burner

P8 adv pellet burner

P9 pellet boiler

P10 wood chip

Modern log wood boilers

(41 samples, 6 cycles)

0

50

100

150

200

250

300

PM2.5(mg/MJ)

EC (mg/MJ) CH4 (mg/MJ) NMVOC(mg/MJ)

mg/MJ

Measured EF (nominal load,standard fuel)

GB - Advanced/ecolabelledboilers and stoves

Moist fuel

X1.5

X1.5

X1 X1

0

100

200

300

400

500

600

PM2.5 (mg/MJ) EC (mg/MJ) CH4 (mg/MJ) NMVOC (mg/MJ)

mg/MJ

Measured EF (nominal load,standard fuel)

GB - Conventional boilers <50kWh

Traditional log wood boilers

(14 samples, 2 cycles)

Moist fuel

X1.5

X>1.5

X>1.5

X>1.5

Part load

x4

x1

X>3

X>3

Modern stoves

(25 samples, 8 cycles)

0

50

100

150

200

250

300

350

400

PM2.5 (mg/MJ) EC (mg/MJ) CH4 (mg/MJ) NMVOC (mg/MJ)

mg/MJ

Measured EF (nominal load,standard fuel)

Measured EF, including ignition

GB Advanced/ecolabelledstoves and boilers

GB Energy efficient stoves

Moist fuel

X5

X5

X1

X2

Part load

x2x2

x1

X1.5

0

100

200

300

400

500

600

700

800

900

1000

PM2.5 (mg/MJ) EC (mg/MJ) CH4 (mg/MJ) NMVOC (mg/MJ)

mg/MJ

Measured EF (nominal load,standard fuel)

GB Conventional stoves

GB Energy efficient stoves

Tiled and masonry stoves

(6 samples, 2 cycles)

Moist fuel

x1x1

x1x1

x2

Part load

X1.5x1

x2

0

5

10

15

20

25

30

35

0

200

400

600

800

1000

1200

1st 2nd 3rd 4th 5th 6th 7thEC

PM

2.5

an

d O

C

PM2.5 (mg/MJ) OC (mg/MJ) EC (mg/MJ)

EC emissions do not correlate with PM2.5

emissions

EC/PM2.5Nominal: Standard fuel

Modern log wood boilers 18%

Traditional log wood boilers 7%

Pellet-fired boilers 17%

Wood chip boilers 2%

Modern stove 28%

State-of-the-art 3%

Older stove 9%

Tiled and masonry stove 52%

Pellet stove 10%

Sauna stove 50%

Can the new EFs be used outside of the Nordic

countries?

EFs are general for specific installation type

Different user practices are reflected by the factors for moist fuel and part

load combustion

Wood type – judged to be less importance compared to other factors (moist

fuel and poor combustion)

Application of emission factors𝑬𝑭𝑾𝒆𝒊𝒈𝒉𝒕𝒆𝒅= 𝑬𝑭𝑵𝒐𝒓𝒎𝒂𝒍 × 𝑺𝑵𝒐𝒓𝒎𝒂𝒍

EFNormal = Emission factor under normal combustion conditions

SNormal = Share of fuel used in the specific technology burned under normal

combustion conditions

RatioPart/Nominal = Factor showing increased emissions during part load firing

SPart = Share of fuel used in the the specific technology burned under part load

conditions

RatioMoist/Nominal = Factor showing increased emissions during firing of moist wood

SMoist = Share of moist fuel used in the specific technology

+𝑹𝒂𝒕𝒊𝒐𝑷𝒂𝒓𝒕/𝑵𝒐𝒎𝒊𝒏𝒂𝒍 × 𝑬𝑭𝑵𝒐𝒓𝒎𝒂𝒍 × 𝑺𝑷𝒂𝒓𝒕

+ 𝑹𝒂𝒕𝒊𝒐𝑴𝒐𝒊𝒔𝒕/𝑺𝒕𝒂𝒏𝒅𝒂𝒓𝒅 × 𝑬𝑭𝑵𝒐𝒓𝒎𝒂𝒍 × 𝑺𝑴𝒐𝒊𝒔𝒕

Some conclusions

All measurements in dilution tunnel = with condensables.

Lower emissions for wood log boilers and older/traditional stoves

than Guidebook EFs.

However EC emissions for stoves more consistent with Guidebook

factors.

EC emissions not strongly affected by heat load or fuel moisture.

Part load increases PM emissions, especially for boilers, up to 4

times.

Moist fuel increases PM emissions, especially for stoves, up to 5

times.

Detailed activity data (technologies) and assumptions regarding

operational conditions essential for emission inventory

Thank you for your attention

Project group

Karin Kindbom, Erik Fridell, Ingrid Mawdsley, IVL, Sweden

Ole-Kenneth Nielsen, Morten Winther, AU, Denmark

Kristina Saarinen, SYKE, Finland

Kári Jónsson, Umhverfisstofnun, Iceland

Kristin Aasestad, SSB, Norway

New EF - boilers

Nominal: Standard fuel

(N:S)N:S min

N:Smax

Ratio moist fuel to

standard fuelN:M/N:S

Ratio part load to

nominal loadP:S/N:S

Guidebook2016

Modern log wood boilers (41,6)Advanced/ecola

belled boilers and stoves

PM2.5 (mg/MJ) 35 24 45 1.5 93

EC (mg/MJ) 6 2 15 1.0 26.04

CH4 (mg/MJ) 15 10 19 1.0 11*

NMVOC (mg/MJ) 85 32 141 1.5 250

CO (mg/MJ) 1160 233 2037 1.0 2000

Traditional log wood boilers (14,2)Conventional

boilers <50kWhPM2.5 (mg/MJ) 320 317 320 1.5 4.0 470

EC (mg/MJ) 25 19 27 >1.5 1.0 75.2

CH4 (mg/MJ) 75 47 103 >1.5 >3.0 11*

NMVOC (mg/MJ) 470 462 477 >1.5 >3.0 350

CO (mg/MJ) 3270 2963 3578 1.5 2.0 4000

Pellet-fired boilers (15,3)Pellet stoves and boilers

PM2.5 (mg/MJ) 35 15 57 3.0 29

EC (mg/MJ) 6 1 14 1.5 4.35

CH4 (mg/MJ) 2 1 4 5.0 11*

NMVOC (mg/MJ) 15 9 22 6.0 10

CO (mg/MJ) 295 120 631 4.0 300

Wood chip boilers (5,1)

PM2.5 (mg/MJ) 50 1.5 5.0

EC (mg/MJ) 5 5.0 6.0

CH4 (mg/MJ) 5 3.0 15.0

NMVOC (mg/MJ) 50 2.0 15.0

CO (mg/MJ) 366 5.0 12.0

* IPCC EF: Utility source EF (wood/wood waste boilers)

New EF – room heaters (I)

Nominal: Standard fuel

N:Smin

N:Smax

N:S including ignition N:M/N:S P:S/N:S Guidebook

2016

Modern stoves (incl state-of-the-art) (25,8)

Advanced/ecolabelled

stoves and boilers

PM2.5 (mg/MJ) 84 60 106 105 5.0 2.0 93

EC (mg/MJ) 20 3 42 25 1.0 1.0 26.04

CH4 (mg(MJ) 90 31 153 90 2.0 1.5 258-2190**

NMVOC (mg/MJ) 76 19 144 96 5.0 2.0 250

CO (mg/MJ) 1582 919 2287 1582 2.0 1.5 2000

Older stove (3,1)Conventiona

l stoves

PM2.5 (mg/MJ) 147 185 2.5 740

EC (mg/MJ) 13 16 1.0 74

CH4 (mg(MJ) 49 50 3.0 932*

NMVOC (mg/MJ) 132 165 2.5 600

CO (mg/MJ) 1165 1165 2.0 4000

Tiled and masonry stove(6,2) Convention

al stove

PM2.5 (mg/MJ)140 82 198 175 1.0 2.0 740

EC (mg/MJ)72 22 122 90 1.0 1.5 74

CH4 (mg/MJ)114 61 167 115 1.0 2.0 932*

NMVOC (mg/MJ)181 133 229 225 1.0 1.0 600

CO (mg/MJ)2365 1585 3145 2355 1.0 1.0 4000

* IPCC EF: Wood stoves** IPPC EF: Conventional wood stoves

New EF – room heaters (II)

Nominal: Standard

fuelN:Smin

N:Smax

N:S including ignition N:M/N:S P:S/N:S Guideboo

k 2016

Pellet stove (3,1)

Pelletstoves and

boilers

PM2.5 (mg/MJ) 100 125 1.5 29

EC (mg/MJ) 10 13 1.0 4.35

CH4 (mg(MJ) 1 1 2.5 258-2190*

NMVOC (mg/MJ) 4 5 3.5 10

CO (mg/MJ) 189 190 2.5 300

Sauna stove (3,1)

PM2.5 (mg/MJ) 104 130 1.5

EC (mg/MJ) 52 65 1.0

CH4 (mg/MJ) 43 45 2.0

NMVOC (mg/MJ) 85 105 2.0

CO (mg/MJ) 1405 1405 1.5

* IPCC EF: Wood stoves