UGS emission sources: methane, carbon mono and dioxide, nitrogen oxide.

Footprint and measures for their reduction

First results

Christian Coti, Lukas Kopal

Approach Theoretical: Which describes the sources of emissions (CH4, CO2, CO and NOx) from

individual parts of UGS technology, causes of their origin and usually used methods how to reduce them to comply with limits in legislation

Mapping: Checking the real data from emission sources types per UGS and UGS operator. This will give us an overview and quantification what emission sources are the most significant, how they vary between size and types of storages, usage of different technology, etc. We expect interlink between IGU UGS database

Scope of Work Emissions quantification according to the features of storage plants: size, type, used

turbines (size, power, flow capacity, etc.), dehydration system and different methodologies of detection and calculation of emissions.

Definition of mitigation actions to hit emission reduction targets

Quantification of emission is a complex task. Complementary approaches to quantify methane, NOx and CO emissions through a combination of measurement, calculations and modelling to fit each situation have to be developed (KPIs)

It is necessary to improve the accuracy of the national inventory reports. Collaboration between national authorities and the gas industry should be enhanced to improve the quality of the data

Harmonisation of quantification and reporting methodologies (specific for the gas sector, covering all the different types of methane emissions and the entire gas value chain) is very important.

Critical aspects

Natural gas emission sources,Example of storage plant scheme

Gas (Injection)

Gas (Withdrawal)

TEG

Gas stripping and regenerator

Symbol legend

TransmissionNetwork

CompressionStation

Wells

Reservoir

Separators Regenerator

Furnace

Columns/LTS

Gas Vent

Natural gas emissions sources (CH4) :

‐ Dehydrators‐ gas vent‐ fugitive emissions‐ gas actuators

Treatment

Nox and CO emission sources,Example of storage plant scheme

Gas (Injection)

Gas (Withdrawal)

TEG

Gas stripping and regenerator

Symbol Legend

TransmissionNetwork

CompressionStation

Wells

Reservoir

Separators Regenerator

Furnace

Columns/LTS

Gas Vent

Exhaust gas (NOx, CO) emission points:- Turbines- Heaters

- Regenerators- Furnaces- Gas heaters, boilers

Compression station

Treatment

EmissionsNatural gas emissions are divided up, in accordance with international methods, into:

fugitive emissions: emissions due to leaks from seals: valve stems, flanges, connections, safety valve bodies;

Vented emissions (vent): emissions attributable to discharges into the atmosphere, due to both intentional releases and uncontrollable releases;

pneumatic emissions: emissions deriving from regulation equipment (for example gas actuated valves through the discharge of compressed gas) and from gas analysis plants (chromatographs, densitymeters, analyzers).

emissions due to incomplete combustion: emissions contained in the exhaust fumes of the combustion plants.

NOx emissions are common to all combustion processes at high temperature. They depend on the quantity of oxygen available for combustion and on the flame temperature at which the nitrogen-oxygen reaction takes place

CO gas forms primarily when carbon fuels are not burned completely. It is produced in combustion for any value of gas mixing.

Mitigation actions

Example of some EPA recommended technologies to control Natural Gas emissions:

Replacing the starter expansion turbine with an electric motor starter (similar to an automobile engine motor starter)

Test and repair pressure safety valves

Rerouting the condensate separator gas, called skimmer gas, to the reboiler firebox or other low pressure fuel gas systems for fuel use

Replace glycol dehydration units with methanol injection

Optimize glycol circulation and install flash tank separators in glycol dehydrators

Installing BASO valves. BASO® valves are snap-action valves activated by a thermocouple that senses the pilot flame temperature, When the flame is extinguished, the valve automatically shuts off the fuel gas flow, preventing continued fuel loss and methane emissions

Mitigation actionsTo control NOx emissions, it is useful:

burn the fuel by reducing combustion temperature;

pre-mix the fuel with the combustion air upstream of the flame, in order to to make the combustion temperature as uniform as possible, avoiding "hot spots" with high production of nitrogen oxides.

Techniques for reducing CO are the following:

Improve atomization to obtain greater homogeneity (for example: airblast atomizer

accurate fluid-dynamic design of the combustion chamber

Increase the residence time in the primary zone (which, however, increases NOx production)

Reduction of cooling air especially in the primary zone

Appropriate distribution of the fuel between the various injectors, blocking some in order to increase the performance of the others (greater ∆p, greater atomization) in partial load conditions.

Source:Industrial Emissions Directive 2010/75/EU

Mitigation actions performed in Italy Exhaust gas (NOx, CO) emissions:

- repowering of gas turbines with DLE (Dry Low Emission) technology

- Replacement with gas turbines by electric compressors

Moreover, all turbines are equipped with a specific system for continuously monitoring emissions into the atmosphere, that can reduce the flow rate or stop the turbine so as not to exceed the limit value.

The reduction in NOx emissions following the upgrade of all the turbines with the DLE / DLN system was approximately 80 %.

CH4 emissions:

- Vented Emissions: replacement of "male" valves with "ball" valves related to the vent and pressurization turbochargers.

- Pneumatic emissions: are minimized through the adoption of new low-emission components or the replacement of existing models with new low-emission or even emission-free equipment. (e.g.: air actuators). Replacing gas actuators by air actuators resulted in a reduction of 7% of Natural gas emissions.

- For fugitive emissions, a Leak Detection And Repair (LDAR) approach is being taken. LDAR allows to identify the inefficient components, to verify the suitability of the corrective actions and to direct the choice of the best corrective action within a formalized improvement plan.

Mitigation actions performed in iGS (CZ) Exhaust gas (CO2, NOx, CO) emissions:

- Installation of new low NOx burners (heating, preheating, reg TEG)

- Decentralization of heating (more but smaller emissions sources)

- Low NOx CHP unit installation (replacement of steam boilers by CHP and hot water boilers)

- Solar turbines equipped with SoLowNOx burning chambers

- Replacement of gas turbine by electric drive

Investments into Low NOx burners mainly driven by more strict emissions limits for NOx and CO requested by EU.

OPEX savings behind improved energy efficiency related to less generated heat bring also CO2 emission decrease.

Overall iGS CO2 emissions strongly dependent on UGS usage esp. UGSs with gas turbine compressor drive.

CH4 emissions:

- Vented Emissions: existing methane emissions are mainly related to reconstruction projects, well‘s workovers or maintenance process which requires depressurization of the technology and emergency depressurization

- Pneumatic emissions: 30 wells at UGS Tvrdonice still have gas actuators on closing armatures, Exchange of gas actuators by electric drive is already on-going.

- For fugitive emissions, a Leak Detection And Repair (LDAR) approach is being taken. Esp. Leaks through compressor‘s dry packings are continuously measured and replaced when leak increases.

MARCOGAZ methane emission by source type for UGS

Based on EN 15446 fugitive emissions represent the most part of methane emission in gas storage

Based on API 4589 fugitive methane emissions are 100 times lower due to different emissions factors

What figure is correct? How many m3 of natural gas are you missing in your UGSs?

Would it be useful to extend this reporting at worldwide scale?

Data collection• Year 2018

• From companies SNAM (ITA), iGS (CZ), iGS NWE (GER), GSPL (PL), SPP Storage (CZ)

• Total UGSs: only 17 :o(

• Only emissions related to UGS operation, no car fleet emissions, no HQ emission, no accidents, only measured volumeAnnual emissions 2018

State CZ CZ CZ CZ CZ CZ CZ GER GER GER GER ITA ITA ITA ITA PL PL

UGSHaje Dolni Dunajovice Tvrdonice Lobodice Stramberk Tranovice Dolni Bojanovice Staßfurt Epe L‐Gas Epe H‐Gas Xanten Brugherio Cortemaggiore Ripalta Settala Kosakowo Mogilno

UGS Operator iGS iGS iGS iGS iGS iGS SPP Storage iGS NWE iGS NWE iGS NWE iGS NWE SNAM SNAM SNAM SNAM GSPL GSPLSource  [tons] [tons] [tons] [tons] [tons] [tons] [tons] [tons] [tons] [tons] [tons] [tons] [tons] [tons] [tons] [tons] [tons]

CH4 CH4 _depressurization 8 147 150 27 98 5 60,36 36,75 124,38 101,18 29,78 25 88 130 136CH4 _other 0 46,287 187,721

CH4_total: 8 147 150 27 98 5 60,36 36,75 124,38 101,18 29,78 25 88 130 136 46,287 187,72098CH4_total (mil. m3) 0,0111 0,2048 0,2090 0,0376 0,1365 0,0070 0,0841 0,0512 0,1733 0,1409 0,0415 0,0348 0,1226 0,1811 0,1894 0,0645 0,2615

CO2 CO2_NG combustion in gas turbines 2502,33766 0 0 0 1294,22454 9507,61815 0 0 0 0 0 0 16937,3 26887,7 41790,8 8 200,535

CO2_NG combustion in gas engines/CHP 4,97439 0,0064 2,39906 0 1,6099 10,1253 6985,66 0 0 0 0 0 0 0 0 3 957,760 992,871CO2_NG combustion in boilers for preheating 421,63659 246,87385 1316,94223 148,79483 182,60922 143,05983 78,73 196,25 161,25 369 114,75 0 29,1 36,3 104,1 142,608 430,819

CO2_NG combustion in boilers for heating 155,13503 13,21835 41,94521 108,65177 6,19802 8,80135 10,09 117,75 96,75 221,4 68,85 25 55,8 51,7 18,1 33,616 348,427

CO2_NG combustion in boilers for glycol regeneration 39,09981 185,24712 215,71024 114,32721 284,74404 150,15125 38,11 471 387 885,6 275,4 0 660,2 1173,6 1032,8 28,344 99,793CO2_other 0 0 0 0 0 0 1432,13 0 0 0 0 0 0 0 0 0 0

CO2_total: 3123,18348 445,34572 1576,99674 371,77381 1769,38572 9819,75588 8544,72 785 645 1476 459 25 17682,4 28149,3 42945,8 4162,3288 10072,4447

CO2_total (mil. m3) 1,57908157 0,225166796 0,797329552 0,187968838 0,89460142 4,964868573 4,320210432 0,396896 0,326112 0,7462656 0,2320704 0,01264 8,94022144 14,23228608 21,71339648 2,1044734 5,092628042CO CO_NG combustion in gas turbines 0 0 1,25 6 4,15 1,127

CO_NG combustion in gas engines/CHP 11,932 0 0 0 0 0,544 0,136

CO_NG combustion in boilers for preheating 0,002 0 0,013 0,016 0,046 0,020 0,059CO_NG combustion in boilers for heating 0 0,014 0,031 0,028 0,01 0,006 0,064

CO_NG combustion in boilers for glycol regeneration 0,001 0 0,148 0,064 0,191 0,005 0,018

CO_other 0 0 0 0 0 0 0,047 0 0 0 0 0 0 0 0 0 0

CO_total: 0 0 0 0 0 0 11,982 0 0 0 0 0,014 1,442 6,108 4,397 0,5754872 1,40524434NOx NOx_NG combustion in gas turbines 0 0 13,8 14,14 16,65 15,449

NOx_NG combustion in gas engines/CHP 16,44 0 0 0 0 3,869 0,971

NOx_NG combustion in boilers for preheating 0,46 0 0,036 0,045 0,129 0,136 0,421NOx_NG combustion in boilers for heating 0,006 0,026 0,056 0,052 0,018 0,022 0,421

NOx_NG combustion in boilers for glycol regeneration 0,023 0 0,651 1,86 1,282 0,018 0,065NOx_other 0 0 0 0 0 0 1,133 0 0 0 0 0 0 0 0 0 0

NOx_Total: 0 0 0 0 0 0 18,062 0 0 0 0 0,026 14,543 16,097 18,079 4,0458048 17,3270725WGV (mill. m3(Vn)) 71,1 853,5 498 167,9 474,2 502,6 536,7 542 480 411,6 177,8 313 909 1598 1726 145,5 590

Compressor Power (MW) 4,6 4 4 1,7 2,8 4,64 7,2 24 29,8 19,5 7,7 19,8 43,7 46,5 22,8 10,2 24,4UPS power 0,8 0,45 0,36 0,208 0,65 1,1

Gas motor 1 1 1 1 1 1 3 0 0 0 0 0 0 0 0 3 1

Gas turbine 2 0 0 0 1 4 0 0 0 0 0 0 3 2 2 0 2

Electrical motor 0 4 3 1 0 0 0 4 3 4 3 3 0 0 0 0 0Natural gas emissions/stored gas (%) 0,016% 0,02% 0,04% 0,02% 0,03% 0,00% 0,02% 0,01% 0,04% 0,03% 0,02% 0,01% 0,01% 0,01% 0,01% 0,04% 0,04%

NOx emissions/stored gas (t/mcm)

NOx emissions turbines/installed power ([t/Nm3]/MW)CO2 emissions/stored gas (%) 2,22% 0,03% 0,16% 0,11% 0,19% 0,99% 0,80% 0,07% 0,07% 0,18% 0,13% 0,00% 0,98% 0,89% 1,26% 1,45% 0,86%

CO2 emissions/installed power ([t/Nm3]/MW) 312,32 27,07 127,59 194,85 512,87 499,48 1 186,77 32,71 21,64 75,69 59,61 1,26 404,63 605,36 1 883,59 408,07 412,81

KPIs

Natural gas emissions/stored gas (%)

NOx emissions/stored gas (kg/mcm)

NOx emissions turbines/installed power ([mg/Nm3]/MW)

CO2 emissions/stored gas (kg/mcm)

CO2 emissions/installed power ([mg/Nm3]/MW)

National CO2 emissions/UGS segment CO2 emissions (%)

Correlation with asset dimension (type of turbine, Power ect.)

N means normal reference conditions → t = 0 °C, P = 101325 Pa.

KPI Charts

N means normal reference conditions → t = 0 °C, P = 101325 Pa.

KPI Charts

N means normal reference conditions → t = 0 °C, P = 101325 Pa.

KPI Charts

N means normal reference conditions → t = 0 °C, P = 101325 Pa.

CO2 emissions by the source [tons]

Valid for 17 EU UGSs

KPI Charts

N means normal reference conditions → t = 0 °C, P = 101325 Pa.

CO2 emissions by the compressor powerand WGV

Valid for 17 EU UGSs

First results

Define possible KPIs using collected data from UGS database and from UGS operators

Defines possible mitigation actions to be taken by operators under their own characteristics

Preliminary results with limited data of natural gas emissions show very low level of relation to the size of the UGS. Only vented emissions were analysed.

Vented natural gas emissions are very low about 1/100 of CO2 emissions from UGSs using gas turbines

Fugitive natural gas emissions have high variability based on calculation method, so they were not included in the actual evaluation

First results

The majority of the CO2 emissions is related to gas turbocompressors

We don‘t see correlation of CO2 KPI and size of the UGS (WGV)

Mitigation actions to be taken by operators under their own characteristics, especially focus on improvements of energy efficiency.

The critical point is the quantity and quality of input data (we need your answers and collaboration!)

Based on preliminary results we see low level of CO2 UGS related emissions in comparison with total national CO2 emissions in 2018

Country National CO2 emissions [tons] From UGSs, [tons] remarkCzech Republic 103 200 000 25 651 Data from 3 UGSs missingGermany 725 700 000 3 365 Data only from 4 UGSsItaly 332 800 000 88 802 Data only from 4 UGSsPoland 322 500 000 14 234 Data only from 2 UGSs

Berlin Academy of Sciences

79Nobel Laureates

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Thank you for yourinterest!