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Energy Saving for Soft Fruit Day – Oct 14

CO2 Sources and Measurement

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Energy Saving for Soft Fruit Day – Oct 14

CO2 Sources •kg of CO2 per m3 gas, per litre of kerosene

•Boilers v’s CHP

•Pure CO2

•Cost of CO2

How much CO2 do you use? •m3 gas / 1,000m2

•tonnes / hour

•tonnes p.a.

CO2 Sources

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Energy Saving for Soft Fruit Day – Oct 14

Natural gas

• How do we measure/record gas consumption? – By volume: m3, ft3

– By old energy: Therms, BTU

– By new energy: kWh, MJ, GJ

• How do these compare?

• How do we calculate kg of CO2?

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Energy Saving for Soft Fruit Day – Oct 14

Measuring gas

• Gas meters don’t read kWh – They measure volume

– m3, ft3 or 100ft3 (HCF)

• Need to correct for – Temperature variations

– Pressure variations

– ‘Correction factor’ (c.f)

• Calorific value then applied – MJ/m3

• kWh calculated finally using this value

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Energy Saving for Soft Fruit Day – Oct 14

Natural gas

• Volume (m3 / ft3) kWh ?

Multiplier (x10, x100)

Gas meter reading

divide by 3.6 = kWh

100 ft3 to m3 (x 2.83)

x Calorific value (MJ/m3)

x Correction factor

√

√

Vary from 1.0 to 1.3 30% difference

Vary from 39.2 to 40.3MJ/m3

3% difference

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Energy Saving for Soft Fruit Day – Oct 14

Variation in calorific value by region

Up to 2.7% difference in UK 12.6 % difference to Holland

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Energy Saving for Soft Fruit Day – Oct 14

Example Calculation

3,254.5 m3

1,150 HCF

div by 3.6 to get kWh

100 ft3 to m3 (x 2.83)

3,417.2 m3

Correction factor x 1.05

√

√

Calorific value – 39.2MJ/m3

133,955.2 MJ

37,209.8 kWh

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Energy Saving for Soft Fruit Day – Oct 14

Natural gas

• 1 ‘corrected’ m3 of gas typically contains:

11.1 kWh 2.1 kg CO2

0.38 therms (1 therm = 29.3 kWh)

0.19 kg CO2 per 1 kWh

5.6 kg CO2 per 1 therm

With

With 2.1 kg CO2

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Energy Saving for Soft Fruit Day – Oct 14

Natural gas

• Cost of CO2 from natural gas

– Cost of the fuel only

– Assumes all heat is

thrown away

Cost of gas p/therm

Cost of gas p/kWh

Cost of CO2 £/t

20 0.7 £ 36

30 1.0 £ 54

40 1.4 £ 72

50 1.7 £ 90

60 2.0 £ 108

70 2.4 £ 126

80 2.7 £ 144

90 3.1 £ 162

100 3.4 £ 180

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Energy Saving for Soft Fruit Day – Oct 14

Kerosene

• A lot easier than gas!

• Buy it by the litre

• 1 litre contains

10.3 kWh 2.5 kg CO2 0.25 kg CO2 per 1 kWh

With

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Energy Saving for Soft Fruit Day – Oct 14

LPG

• Also buy it by the litre

• 1 litre contains

7.4 kWh 1.5 kg CO2 0.20 kg CO2 per 1 kWh

With

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Energy Saving for Soft Fruit Day – Oct 14

Kerosene + LPG

• Cost of CO2 from Kerosene and LPG

– Cost of the fuel only

– Assumes all heat is

thrown away

Cost of Fuel pence/litre

Cost of LPG derived CO2 £/t

Cost of Kerosene derived CO2 £/t

20 £ 133 £ 79

25 £ 166 £ 99

30 £ 200 £ 119

35 £ 230 £ 139

40 £ 266 £ 159

45 £ 300 £ 178

50 £ 333 £ 198

55 £ 366 £ 218

60 £ 400 £ 238

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Energy Saving for Soft Fruit Day – Oct 14

Boiler vs CHP

Boiler

Boiler 1m3 gas (11.1 kWh)

9.4kWh heat

2.1kg CO2

0.22kg CO2 per

1 kWh heat

CHP

4.4kWh heat

2.1kg CO2

0.5kg CO2 per

1 kWh heat

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Energy Saving for Soft Fruit Day – Oct 14

Pure CO2

• Cost of pure CO2

– Not just the cost per t delivered • £100 - £150/t

– Cost of tank rental & maintenance • £2000 p.a

– Energy to vaporise the liquid CO2 (160kWh/t) • £3 /t

– Energy to keep the tank cool • £xxx

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Energy Saving for Soft Fruit Day – Oct 14

The cost of CO2 - summary

• Pure CO2

– Cost per tonne delivered

– Tank rental

– Heat for vaporisation

• CHP – Fuel – Maintenance (can be

significant) – Value of the heat (if any) – Income from electricity

sales

• Boiler – Fuel

– Maintenance (already paid for?)

– Value of the heat (if any)

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Energy Saving for Soft Fruit Day – Oct 14

Leaky system

• You’ll only get what you ask for if the system doesn’t leak!!

• Where? – Dampers at the CO2 fan

– Pipe joints

– Ripped distribution pipes

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Energy Saving for Soft Fruit Day – Oct 14

Summary

• What does CO2 really cost you?

• How much do you actually use?

• What is the capacity of your system ?