Climate Footprint on Transportation and Storage of Carbon Dioxide (CO2)

INOM

EXAMENSARBETE TEKNIK, GRUNDNIVÅ, 15 HP

STOCKHOLM SVERIGE 2020 ,

Climate Footprint of

Transportation and Storage of Carbon Dioxide (CO2)

JENNIFER ERLANDSSON

FREDRIK TANNOURY

Abstract

In order to combat climate change there is a need to achieve negative emissions. Bio- energy with carbon capture and storage (BECCS) is a promising technology that offers the possibility to remove carbon dioxide (CO

) emissions from the atmosphere. How- ever, this also implies that the BECCS process needs to store more CO

than it emits.

The purpose of this study is to examine the liquefaction, intermediate storage, trans-

portation and long term storage of CO

and evaluate the climate impact of the energy

use and the leakage of CO

. This thesis is based on data collected through an extensive

literature study and several interviews that were performed with relevant actors and

informants. A key finding in this thesis is that the energy use through the examined

steps of BECCS is responsible for the bulk of the CO

emissions. Liquefaction and the

transportation plays an essential role as it has the highest energy usage. Unfortunately

the energy use of injecting CO

into the geological formation remains unknown because

of lack of data. The leakages found throughout the process were often negligible or

even zero. However the leakages from injecting CO

through pipeline and the CO

leakage from long term storage was found to be of some significance. The total BECCS

related carbon dioxide equivalent (CO

e) emissions, are summarised in three scenarios

ranging from approximately 49-58 kg CO

e per stored tonne of CO

. In these scenario

calculations, some assumptions have had to be made. In order to evaluate the true and

total environmental impact of BECCS, further research will be needed.

Sammanfattning

Dagens samh¨ alle st˚ ar inf¨ or avsev¨ arda milj¨ om¨ assiga utmaningar, inte minst d˚ a m¨ angden v¨ axthusgaser (GHG) i atmosf¨ aren kommer beh¨ ova reduceras drastiskt f¨ or att undvika tv˚ a graders uppv¨ armning. Bio-energy with carbon capture and storage (BECCS) ¨ ar en teknologi med potential att avl¨ agsna koldioxid (CO

) inte bara fr˚ an nya utsl¨ app, utan

¨

aven i b¨ asta fall fr˚ an atmosf¨ aren. I det specifika fall som denna rapport tittar n¨ armare

p˚ a, f¨ orbr¨ anns biomassa f¨ or att skapa fj¨ arrv¨ arme, men ist¨ allet f¨ or att CO

sl¨ apps ut i

luften s˚ a f˚ angas den upp och komprimeras till flytande form. D¨ arefter kan CO

trans-

porteras till en injektionsanl¨ aggning f¨ or att slutligen pumpas ner i en geologiskt l¨ amplig

berggrund. Denna process kan resultera i negativa utsl¨ app om mer CO

lagras ¨ an vad

processen skapar och sl¨ apper ut. M˚ alet med detta kandidatexamensarbete ¨ ar att un-

ders¨ oka energianv¨ andningen och l¨ ackaget av CO

under f¨ orv¨ atskningen, den kortsiktiga

lagringen, transporten samt den l˚ angsiktiga lagringen av CO

. Kandidatexamensar-

betet ¨ ar framf¨ orallt baserat p˚ a data insamlad i form av en litteraturstudie. Denna data

har ¨ aven kompletterats med data fr˚ an flertalet intervjuer med forskare och anst¨ allda

p˚ a f¨ oretag som arbetar med BECCS. Flera antaganden har varit n¨ odv¨ andiga d˚ a det i

dagsl¨ aget finns en brist p˚ a information ang˚ aende energianv¨ andningen och l¨ ackaget av

CO

i processens delsteg. Energianv¨ andningen f¨ or injektionen av CO

f¨ orblir ok¨ and

d˚ a det inte fanns n˚ agon relevant information att tillg˚ a. D˚ a l¨ ackaget visade sig vara

f¨ orsumbart eller noll i flera delsteg, utg¨ or energianv¨ andningen en signifikant andel av

de totala utsl¨ appen. De st¨ orsta utsl¨ appen av CO

inom ramen f¨ or BECCS processen

orsakas d¨ arf¨ or av f¨ orv¨ atskningsprocessen och transporten av CO

d˚ a dessa delar ¨ ar mest

energikr¨ avande. Resultatet av kandidatexamensarbetet kan sammanfattas i tre scenar-

ion, ett l˚ agt scenario, ett median scenario och ett h¨ ogt scenario. Slutsatsen var att

samtliga inkluderade steg av BECCS resulterar i ett utsl¨ app mellan 49-58 kg koldiox-

idekvivalenter (CO

e) per ton CO

som lagras. F¨ or att kunna kvantifiera den totala

klimatp˚ averkan av BECCS finns ett behov av ytterligare studier som tar h¨ ansyn till

alla delsteg under processen.

Acknowledgement

We wish to express our sincere gratitude to our supervisor K˚ are Gustafsson, as this

thesis would not have been possible without him. His guidance and experience has

been invaluable to us. We would also like to sincerely thank Mattias Jones and Martin

R¨ od´ en, consultants from Blu Carbon Solutions for participating in an interview and for

answering all our questions. We furthermore want to express our gratitude to Frank

Ollerhead, Shipping Manager at Equinor. He provided important insights regarding

the Northern Lights project and the transportation of CO

. We also want to thank

Knut Bakke, Interface Manager at Northern Lights who provided important insights

and knowledge that were essential in writing this thesis. Finally, we want to express

our gratitude to Peter Haugan who provided vital information on matters related to

geological formations.

Contents

1 Introduction 1

1.1 Aim . . . . 3

1.2 Objectives . . . . 3

1.3 Scope . . . . 3

2 Background 5 2.1 Carbon Capture . . . . 5

2.2 Liquefaction . . . . 5

2.3 Intermediate storage . . . . 6

2.4 Transportation . . . . 7

2.5 Injection of CO

. . . . 7

2.6 Long term storage . . . . 8

3 Method 9 3.1 Defining the thesis aim and system boundaries . . . . 9

3.2 Collecting data . . . . 9

3.2.1 Liquefaction . . . . 12

3.2.2 Intermediate storage in V¨ artan . . . . 13

3.2.3 Transportation . . . . 13

3.2.4 Intermediate storage in Norway . . . . 15

3.2.5 Injection of CO

into geological formation . . . . 16

3.2.6 Long term storage in geological formation . . . . 17

3.3 Calculations . . . . 19

4 Result & Discussion 21 4.1 Energy use . . . . 22

4.2 Leakage of CO

. . . . 24

4.3 Comparison of result with previous studies . . . . 26

4.4 Risks of BECCS . . . . 29

4.5 Further considerations . . . . 33

5 Conclusion 35

References 36

Appendices 41

A Interview questions 41

B Transportation route from V¨ artan to

Naturgassparken 42

C Pipeline route from Naturgassparken to the

Aurora reservoir 43

D Calculations for transportation, LNG usage and emitted CO

44 E Calculations for the energy produced by KVV8 and the energy de-

mand of BECCS 46

List of Figures

1 Illustrating figure of the thesis scope and system boundaries. The figure includes the energy use, GHG emission and CO

leakage throughout the examined steps of BECCS. . . . 4 2 Approximate transportation route from V¨ artahamnen (right) to Natur-

gassparken (left). . . . 42 3 Pipeline route from Naturgassparken (right) to the Aurora field (left). . 43

List of Tables

1 The maximum quantity of compounds allowed in the liquid in addition to CO

(Equinor, 2018). . . . 7 2 The capacity, speed, distance, pressure and temperature found during

BECCS . . . . 11 3 The travel time for transportation and LNG consumption . . . . 20 4 CO

emissions from the energy use and leakage [kg CO

e per stored

tonne of CO

] . . . . 21 5 Total energy use [kWh/tCO

] . . . . 22 6 CO

emissions caused by the energy use [kg CO

e per stored tonne of

CO

] . . . . 24 7 Leakage of CO

[tonnes/year] . . . . 25 8 Comparison between the thesis findings and previous studies . . . . 28 9 Two scenarios presenting the impact of a low level leakage and an un-

controlled blowout of CO

(DECC, 2012 ). . . . 31

Nomenclature

barg Bar gauge

BECCS Bio Energy Carbon Capture and Storage

C Carbon

CHP Combined Heat and Power CO

Carbon dioxide

CO

e Carbon dioxide equivalents FEED Front-End Engineering Design FP Fully Pressurised

GHG Greenhouse Gas

HPC Hot Potassium Carbonate

IPCC Intergovernmental Panel on Climate Change KVV8 Stockholm Exergi CHP plant in Stockholm kWh Kilowatt-hour

LCA Life cycle assessment LNG Liquefied natural gas LPG Liquefied petroleum gas

MW Megawatt

MWh Megawatt-hour

NDCs Nationally Determined Contributions NETs Negative emission technologies

ppm Parts per million

tCO

Tonnes of Carbon Dioxide

1 Introduction

The Paris Agreement was founded on the mutual understanding that actions to mitigate and adapt to climate change are a necessity. All signing member states need to work diligently on decreasing their carbon dioxide equivalent (CO

e) emissions in order to halt global warming (UNFCC, 2020). The agreement stipulate that global temperatures should not rise more than 2

C above pre-industrial levels. However, limiting the rise to 1.5

C is encouraged, if it’s within a nation’s capacity (ibid.). Beside lessening global warming, the agreement also requires nations to bolster their resilience against effects from climate change (ibid.). According to a plan called Nationally Determined Contri- butions (NDCs) which details how every nation will implement measures for achieving the Paris Agreements goals, it is expected that once peak release of Greenhouse Gases (GHGs) have been reached, sinks can be used in order to remove these gases (UNDCC, n.d.).

The carbon budget stated in the Intergovernmental Panel on Climate Change (IPCC) fifth assessment report illustrates the amount of carbon dioxide (CO

) that can be re- leased before extending the 2

C temperature limit. The current trajectory shows that the 1.5

C goal will soon be exceeded (Fuss et al., 2018). The reason for this is the foreseen lack of decarbonization in the coming years. This has led to the surfacing of the concept of CO

removal done by Negative Emission Technologies (NETs) (ibid.).

Removal of CO

is a concept that has been discussed for more than a century and the understanding of CO

reduction affects global temperature is as old as the discus- sion about climate change (Minx et al., 2018). IPCC have assessed the role that NETs could have as a climate change mitigation option. Amongst the techniques evaluated was bioenergy with carbon capture and storage (BECCS) (ibid.).

BECCS is a method in which biomass is used to produce energy and the CO

emitted during the combustion is captured and stored, rather than released into the atmosphere.

This CO

was originally absorbed from the atmosphere through photosynthesis by the growing trees (Pour, Webley & Cook, 2017). The CO

captured from the flue gas is then shifted to liquid phase by compression. The absorbed and liquefied CO

can then more conveniently be transported by ship or pipelines to a location where it can be stored permanently in a geological formation (ibid.). The technology is promising and could be an essential tool to reduce CO

emissions. However, the environmental, economic and social impacts of BECCS varies depending on what biomass resource is used e.g.

wood chips, how the sequestration is performed, what conversion technology is applied

and how the CO

is stored (ibid.). BECCS can result in negative emissions if all steps

are done accordingly (Consoli, 2019). The BECCS technology is still being developed

by companies such as Stockholm Exergi and DRAX. Yet there are still uncertainties

regarding storage capacity, leakage and costs (Hansson et al., 2018).

DRAX was the first European company to start a BECCS pilot program (DRAX, 2019). The UK based company started the BECCS project in October 2018 and are planning to scale it further if the project proves to be successful. The project goal was to become the first carbon negative power station in the world and the company plans to store the CO

in ocean bedrock under the North Sea (ibid.).

Stockholm Exergi started cooperating with other European companies to establish the transportation and storage of CO

in September 2019. The participating companies include Air Liquide, Arcelor Mittal, Ervia, Fortum, Preem and Equinor (Stockholm Exergi, 2019a). In addition, Stockholm Exergi started a pilot BECCS plant in 2019 (Stockholm Exergi, 2019b). The facility is connected to KVV8, the biomass fire com- bined heat and power plant (biomass fire CHP plant) in V¨ artan, Stockholm. This operation has been an important first step towards creating a carbon sink in Stockholm (ibid.). Stockholm Exergi estimates that the carbon capture potential is 800000 tonnes of CO

(tCO

) every year from KVV8 in V¨ artan alone. When considering other in- dustries and emissions in Stockholm, the potential increases to as much as two million tonnes a year, which is equivalent to twice as much as the CO

emissions from the Stockholm car traffic each year (ibid.).

The BECCS method creates opportunities for companies and industries that strug-

gle with emission reduction. BECCS is one potentially important tool to reduce the

impact of man-made emissions. Further research is needed to evaluate its potential as

the BECCS process itself leads to new CO

emissions. The energy utilization and the

leakage of CO

throughout the process are two examples of new emissions caused by

the BECCS implementation. In order to achieve negative emissions, BECCS therefore

needs to store more CO

than it emits. There is currently a lack of studies on the topic

of BECCS related CO

leakage and emissions. This thesis aims to help fill that gap.

1.1 Aim

To quantify the amount of leakage and emissions of greenhouse gas emitted during the storage, liquefaction and logistical phase of the BECCS planned by Stockholm Exergi.

1.2 Objectives

1. Assessing the amount of GHG emitted and leaked from liquefaction, shipment and storage of CO

with the intention of collecting already existing data.

2. Data collected from all phases will be analysed and quantified so it can be used in future studies by Stockholm Exergi.

1.3 Scope

This thesis is the result of a project given by Stockholm Exergi to evaluate parts of the emissions caused by BECCS. The thesis focuses on the liquefaction of CO

from KVV8, short term storage of liquefied CO

in V¨ artan and the transportation of CO

by ship from V¨ artan to Naturgassparken in Norway. Furthermore, the thesis also looks into the intermediate storage in Norway as well as the long term storage of CO

in the Johansen formation south of Troll called Aurora. There are different possibilities for transporting liquefied CO

. This thesis focuses on a ship model similar to a fully pressurised (FP) liquid petroleum gas (LPG) ship as described by Equinor as well as pipeline transportation of liquefied CO

from Naturgassparken to the Aurora reservoir.

Hence this is the most likely solution to be implemented by Stockholm Exergi.

Data associated with the energy and fuel used throughout the process is also pre-

sented. The energy mix used as a reference in this thesis is the average Nordic energy

mix. This particular energy mix is chosen because the electricity that will be used

throughout the BECCS process, comes from both the Swedish and the Norwegian na-

tional grid. This thesis takes into consideration the energy used for liquefaction, shore

power, transportation, keeping the CO

at the right temperature and pressure through-

out the transportation as well as the transportation of CO

through pipes to the long

term storage. The thesis furthermore provides insights regarding the potential risks of

long term storage of CO

. However, the thesis does not take into account the energy

use and CO

leakage from the CHP plant or the carbon capture process. Nor does

the thesis cover the energy use and emissions associated with monitoring the long term

storage site after the CO

is injected. Furthermore, the thesis does not cover the emis-

sions caused by infrastructure installation or consider the financial aspects of operating

BECCS. Figure 1 provides a simple illustration of the thesis scope.

Figure 1: Illustrating figure of the thesis scope and system boundaries. The figure

includes the energy use, GHG emission and CO

leakage throughout the examined

steps of BECCS.

2 Background

The background chapter provides general descriptions regarding the carbon capture, liquefaction, intermediate storage, transportation and injection process. The chapter also provides some general insights regarding the long term storage. Further information related to the Stockholm Exergi requirements, energy use and leakages will be presented in the method chapter.

2.1 Carbon Capture

The carbon capture process is performed by absorbing the CO

from the flue gas and transporting it from the CHP plant to the liquefaction process (Stockholm Exergi, 2019b). Stockholm Exergi have decided to work with a Hot Potassium Carbonate (HPC) process since this technology fulfils their requirements for energy efficiency and utilisation of space. The HPC process is also considered a more environmentally friendly option with the possibility to scale the process further in the future (ibid.).

The captured CO

from the CHP plant needs to be transported from the capture plant to the liquefaction plant. The gas can be transported through a pipeline using an electric fan that increases the pressure of the CO

from 1 to 2 bars (Jones, 2020).

The energy used to increase the pressure will decrease the energy use in the liquefaction plant and therefore the total energy usage will remain virtually the same. This means that the only increase in energy use relates to the efficiency loss during transport. This loss comes from the efficiency losses in the electric fan and from the pressure drop that occurs between carbon capture and the liquefaction plant (ibid.). Under normal cir- cumstances there would be no leakage during the transport of CO

from the CHP plant to the liquefaction process (ibid.). The effects relating to the carbon capture and the transport between the carbon capture and liquefaction will not be considered further in this thesis, as these effects are considered to be outside the system boundaries.

2.2 Liquefaction

To efficiently transport and store CO

it needs to be compressed into liquid form.

Liquefied CO

is more easily transported since it is more compact and can thus be

transported in greater volumes than CO

in its gaseous form (IPCC, 2018). There

are generally two different processes to consider when it comes to compressing and

liquefying CO

commercially (Zahid et al., 2014). The first method is a low pressure

process that dries and compress the CO

and then utilises a refrigeration system to

cool the gaseous CO

so that it condensates. Ammonia is often used as a refrigerant as

it is considered an efficient, easily accessible and environmentally friendly option. The

second method is a high pressure compression that uses free liquid expansion. The CO

is liquefied by self-refrigeration as CO

is compressed to the critical point

(ibid.).

2.3 Intermediate storage

To transport the liquefied CO

from the liquefaction process to the ship, an interme- diate storage will be needed, as it is not feasible to transport CO

directly to the ship (Zahid et al., 2014). This temporary storage is especially vital when CO

from multiple sources are to be collected and transported to one or several different locations (ibid.).

Additional advantages of using intermediate storage tanks is that the tanks can enable an even flow of CO

to the ship which provides safe transmission and operation. Fur- thermore, intermediate storage can also act as a buffer storage if any delays of transport are to occur (ibid.).

The tanks are used in three stages: loading, short term storage and discharging CO

(ibid.). The CO

stored in the intermediate storage tanks exists in equilibrium, mean- ing the CO

is in liquid phase but partly also in gaseous form. The pressure in the tanks depends on the temperature (ibid.). Therefore it is essential to achieve the correct temperature and pressure to keep the CO

in liquid form. Gaseous, liquid and solid CO

can coexist at or above the triple point

, –56.6

C and 5.2 bar. Below the triple point only gaseous CO

and solid dry ice can exist in equilibrium. Furthermore liquid CO

can not exist below the triple point or at atmospheric pressure (ibid.).

The procedure to fill the tanks is to feed them with a continuous stream of lique- fied CO

from the liquefaction plant (Zahid et al., 2014). As the CO

enters the tanks, there is a level build up which results in gaseous CO

rising to the top of the tank, placing itself on top of the liquid. To prevent excessive pressure, the CO

vapor needs to be extracted from the tank and put back into the liquefaction plant. The discharging phase is over when the tank is filled with liquid CO

(ibid.). The liquid can then be stored until it is time for the transportation phase. When discharging the liquid CO

, the pressure in the tank will decrease which can result in solidification of the CO

. The tanks needs to be fed with gaseous CO

to avoid a pressure drop and solidification while discharging the liquid CO

(ibid.).

The CO

should be transferred from the intermediate storage to the ship at a pres- sure between 13 and 15 bar gauge (barg) with the corresponding equilibrium tempera- ture (Equinor, 2018). Furthermore, the liquefied CO

should have a pressure between

1

A substance acts like a super critical fluid when it reaches its critical volume/temperature. The physical properties changes and it is not possible to differ gas from liquid above or at the critical point (Nationalencyklopedin, 2020b).

2

The triple point can be described as a state where a substance can coexist in its gaseous, liquid

and solid form (Nationalencyklopedin, 2020b).

13 and 18 barg when discharged from the ship to the intermediate storage plant at Naturgassparken (ibid.).

2.4 Transportation

This thesis examines the planned usage of a ship presented by Equinor. The ship is planned to transport CO

from V¨ artan in Sweden to the onshore facility Natur- gassparken in Norway (Jones & R¨ od´ en, 2020). The ship is a hybrid that runs on Lique- fied Natural Gas (LNG) and battery power. The ship uses shore power for loading and discharging CO

in the harbours, while the LNG is used as fuel for the transportation of the liquid CO

(ibid.). Furthermore, the ship is described as very similar to a FP LPG ship (Ollerhead, 2020). The main difference between a regular FP LPG ship and the Equinor ship is the tank material, engine configuration and added insulation, that makes the ship more suitable for CO

transportation. The ship is planned to travel at a speed of 13-13.5 knots (24-25 km/hour) (ibid.).

Table 1: The maximum quantity of compounds allowed in the liquid in addition to CO

(Equinor, 2018).

Component Concentration, ppm (mol)

Water, H

0 6 30

Oxygen, O

6 10

Sulphur oxides, SOx 6 10

Nitric oxide/ Nitrogen dioxide, NOx 6 10

Hydrogen sulfide, H

S 6 9

Carbon monoxide, CO 6 100

Amine 6 10

Ammonia, NH

6 10

Hydrogen, H

6 50

Formaldehyde 6 20

Acetaldehyde 6 20

Mercury, Hg 6 0.03

Cadium, Cd 6 6

The maximum allowed quantities of other compounds in the liquid CO

are presented in Table 1 (Equinor, 2018).

2.5 Injection of CO ₂

The process of injecting CO

into geological formation, according to Heinrich et al

(2003), is not new. The process is called Enhanced Oil Recovery (EOR) and has been

maturing since the 1970’s. EOR was invented to better extract petroleum by injecting CO

into the reservoir. Lelieveld et al. (2005) also claims that the practice of injecting CO

is practiced in another field, namely at gas separation plants. Injection of CO

and impurities is done into geological formations to collect gas from reservoirs.

The pipeline planned for Naturgassparken will be made of seamless carbon-manganese steel (Equinor, 2018). The choice of seamless carbon-manganese steel according to Equinor (2018) is to counteract the corrosive nature of dry CO

. To prevent an inci- dent called running ductile fracture stated by Equinor (2018), the minimum thickness has to be 11.5 mm. Furthermore, Equinor (2018) states that running ductile fractures occurs when a small fracture in the pipeline goes in both directions and damages the pipeline.

2.6 Long term storage

To safely store CO

far below the surface of the earth, it is important that the ocean bedrock has the right qualities (Zero Emissions Platform, n.d.). This procedure can be explained as an attempt to imitate nature, as CO

is stored similarly to how nature stores oil (ibid.). For successful and safe storage, the ocean bedrock needs to have a porous quality with a thick cap rock layer in order to keep the CO

from leaking.

Other criteria is that the reservoir must be capable of storing an adequate volume of CO

(ibid.). Expected temperature and pressure for the long term storage in Aurora reservoir is approximately 100

C and between 200 and 300 barg respectively (Northern Lights, n.d.). The minimum storage capacity expected of the storage site is 100 million tons of CO

(ibid.)

After the CO

is injected into the ocean bedrock, three additional key mechanisms work to keep the CO

in place as well as increasing the storage safety. These three mechanisms are residual trapping, dissolution trapping and mineral trapping (Zero Emissions Platform, n.d.). Residual trapping can be explained as when a liquid, or in this case CO

, is trapped between small pores unable to move. Dissolution trapping is when parts of the CO

is dissolved into the saltwater (ibid.). The CO

infused saltwater will sink since it has a higher density than the regular salt water. Mineral trapping is when saltwater enriched with CO

reacts to form minerals (ibid.).

All three trapping mechanics are also known as “secondary trapping”. How efficient

the secondary trapping performs depends on given storage site as well on the struc-

ture, hydrology and geology of the reservoir (Benson et al., 2019). The efficiency of

secondary trapping mechanism can by itself be enough to diminish the risks of CO

leakage (ibib.).

3 Method

This thesis was performed with the following steps.

1. Defining the thesis aim and system boundaries 2. Collecting data

3. Calculate the total emissions caused throughout the examined steps of BECCS

3.1 Defining the thesis aim and system boundaries

In order to achieve the aim of this study, i.e. to quantify the greenhouse gas emissions caused during the examined steps of BECCS, the leakage and energy use throughout the process have to be assessed. These findings are then combined in order to find the overall environmental impact of BECCS. As outlined in chapter 1.3, the system boundaries that sets the scope of this thesis, exclude the impact from the CHP plant, carbon capture process and any infrastructure installation impact mainly because several other studies already describe these processes. Furthermore, Stockholm Exergi is running a working pilot plant today, meaning they already have experience in this part of the process. The later stages on the other hand, i.e. leakage and energy use throughout the liquefaction, intermediate storage in V¨ artan, transportation, intermediate storage in Naturgassparken and the geological leakage has not been documented to the same extent, which is why these were included in the scope.

3.2 Collecting data

This thesis is partly based on sources provided by Stockholm Exergi and information gathered from an extensive literature study. This thesis gathers insights obtained from several different studies regarding BECCS. To collect data, several search engines were used, such as GreenFILE, Google Scholar and Web of science. The key words that were used to find relevant reports includes ”BECCS”, ”CCS”, ”LCA”, ”energy use”

and ”leakage”. Furthermore, since there are limited studies on the energy use and leak- age of CO

throughout the different sections of BECCS, some data was also collected through interviews.

The interviews were performed over phone and email, using questions prepared in ad- vance in order to fit the project aim as well as role and responsibility of each interviewee.

The first interview performed was with Mattias Jones and Martin R¨ od´ en, consultants

from Blu Carbon Solutions, currently working for Stockholm Exergi. They answered

questions regarding Stockholm Exergi’s requirements and needs relating to BECCS, as

well as general information regarding the liquefaction process, intermediate storage and

transportation of CO

. Three interviews were performed with Frank Ollerhead working for Equinor. Ollerhead provided insights regarding the Northern Lights project and the transportation of CO

. Furthermore, an interview with Knut Bakke, Interface Manager at Northern Lights was performed. Bakke provided information regarding the interme- diate storage at Naturgassparken in Kollsnes and key findings of a life cycle assessment (LCA) report. The last interviewee was Peter M. Haugan, a professor at University of Bergen in Norway. Haugan provided expertise regarding geological formation acting as long term storage for captured CO

. All interviews performed provided insights, data and reports that are not always available to the public. The most relevant interview questions can be found in Appendix A.

The data and information used in this thesis is the most relevant findings from the literature study and interviews. Unfortunately not all requested data was found re- garding leakage and energy use since there is limited previous studies on the subject.

Therefore some necessary assumptions had to be made. A summary of the found ca-

pacity, distance, pressure and temperature is presented in Table 2.

Table 2: The capacity, speed, distance, pressure and temperature found during BECCS

Capacity Speed & distance Pressure & temperature

Liquefaction

Approximately 800 000 tCO

/year (Stockholm Exergi, 2019b)

N/A

7 bar, -50

C 15 bar, -25

C

(Jones & R¨ od´ en, 2020)

Intermediate storage V¨ artan

15000 m

(« 16515 tCO

) (Stockholm Exergi, 2020).

3-5 storage tanks (Jones & R¨ od´ en, 2020)

N/A

7-15 bar & corresponding temperature

(Stockholm Exergi, 2020)

Transportation

Two tanks with a total (100 %) capacity of 7500 m

(« 8258 tCO

).

Estimated outturn

is 7050 m

(« 7762 tCO

) (Ollerhead, 2020).

13-13.5 knots (Ollerhead, 2020).

1795 km (Ports, n.d.).

7 bar, -50

C 15 bar, -25

C

(Jones & R¨ od´ en, 2020)

Intermediate storage

Naturgassparken

Total capacity of 9150 m

(« 10074 tCO

)

(Equinor, 2018)

Discharge of CO

from ship is planned as 800 m

/h

(« 881 tCO

/h) (Ollerhead, 2020)

Typically 15 barg, -26

C (Bakke, 2020)

Injection of CO

Up to 171 tCO

/h (Equinor, 2018)

« 110 km long pipeline (Sandberg, 2019)

Minimum 45 barg, above 1

C

(Equinor, 2018) Long term

storage

At least 100 million tCO

(Northern lights, n.d.) N/A

« 200-300 barg, 100

C

(Northern lights, n.d.)

Table 2 presents a brief summary of the capacity, speed, distance, pressure and tem-

perature that was found during the interviews and literature study.

3.2.1 Liquefaction

Stockholm Exergi have not yet determined what type of liquefaction plant will be most efficient and suitable for liquefying the CO

from KVV8 (Jones & R¨ od´ en, 2020). The liquefaction plant would preferably be in direct connection to KVV8, but because of the lack of space it is more suitable for it to be located in V¨ artahamnen (Stockholm Exergi, 2020). Stockholm Exergi requires a CO

liquefaction plant with an area of ap- proximately 2500 m

as well as an intermediate storage facility of up to 6000 m

(ibid.).

Stockholm Exergi has determined that the preferable properties of the liquefied CO

in the liquefaction process is to keep it at a pressure of 7 bars and at a temperature of -50

˝

C as these properties are well suited for transport in a multi-gas ship (Jones & R¨ od´ en, 2020). This could potentially mean that the ships could be used for several purposes e.g. by shipping liquefied CO

to Norway and then LPG back to Sweden. Using the ships for several purposes could be beneficial as it is more cost effective and the ships do not travel without any cargo more than necessary (ibid.). Ships used for several purposes would also be a beneficial for Stockholm Exergi as they do not operate the CHP plant or produce any CO

to store during the summer. The ships could then be chartered by another company to transport LPG or similar (ibid.).

The Northern lights project have in the first phase decided to work with the regu- lar food-grade properties, 15 bars/-25

C and up to 7000 tonnes sized ships (ibid.).

Northern Lights have decided to work with these properties in the initial phase since they do not want to take any unnecessary costs and risks by building larger port fa- cilities for larger ships (ibid.). In the second phase, they will most likely also accept 7 bars pressure deliveries. There are other available storage sites such as Acorn in UK, which will accept both 7 and 15 bar deliveries (ibid.).

According to a report written by Blu Carbon Solutions (2019), a liquefaction plant designed to liquefy the CO

from KVV8 would have an electricity use of 125-140 kWh/tCO

. According to Jones and R¨ od´ en (2020) the energy demand depends on the scale of the liquefaction plant. A small package plant has an energy demand of 160-170 kWh/tCO

and a large scale plant which utilize other technology to purify and liquefy the CO

requires 110-130 kWh/tCO

.

There is no leakage of CO

relating to the piping in-between the liquefaction plant

and the intermediate storage. However, leakage can potentially occur if there is a

malfunction or any flaws in the pipes (Jones, 2020). The leakage of CO

that occurs

during liquefaction depends on the size of the liquefaction plant as well as the type of

liquefaction technology (Jones & R¨ od´ en 2020). Liquefaction plants used in food-grade

cannot be compared with the small scale liquefaction plants that will liquefy CO

for

BECCS (ibid.). A small packaged liquefaction plant for food-grade that normally lique-

fies 20000-40000 tonnes of CO

up to 100000 tonnes per year if the plants are parallel, have a process leakage of approximately 6-7 % of CO

to the atmosphere (ibid.). Sup- pliers state that larger scale plants that liquefy more than 300000-400000 tonnes CO

has no process leakage of CO

(ibid).

3.2.2 Intermediate storage in V¨ artan

Stockholm Exergi requires an intermediate storage with the capacity to store up to 15000 m

of liquid CO

(Stockholm Exergi, 2020). Stockholm Exergi has been in con- tact with different suppliers to find the most cost efficient alternative. The outcome was that spherical tanks with a high pressure level of 7-15 bar would be the most suit- able solution. The desired pressure depends on the phase of storage and the receiver chosen (ibid.). Stockholm Exergi will need 3-5 spherical tanks to fulfill the need for the intermediate storage (Jones & R¨ od´ en, 2020).

As the CO

is stored in an intermediate storage, electricity is needed in order to keep the CO

at the right temperature and pressure (Jones & R¨ od´ en, 2020). To avoid unde- sirable leakage the tanks needs to be kept at a cold temperature continuously through a connected cooling facility. The tanks cooling facility has a demand of 8-12 kWh/tCO

whilst passing through the intermediate storage period (ibid.). Furthermore, a report written by Blu Carbon Solutions states that the intermediate storage in V¨ artan to store the liquid CO

from KVV8 would require an electricity use of 10-15 kWh/tCO

(Blu Carbon Solutions, 2019). There is under normal circumstances no leakage of CO

dur- ing the intermediate storing (Jones & R¨ od´ en, 2020).

The Northern lights project consists of two phases, where the first phase stretches from 2024-2026 and can be described as a testing phase. If phase one is successful and the demand for storage increases, phase two will begin. Phase two is planned to start in 2026 and involves greater volumes of stored CO

(Northern Lights, n.d). For Stockholm Exergi to be able to deliver CO

during the first phase, there is a need for an inter- mediate storage with an approximate storage capacity of 15000 m

(Stockholm Exergi, 2020). Stockholm Exergi would furthermore need four ships, each with a capacity of 7000 m

, working in shuttle traffic which is not optimal. The ideal solution would be to have two larger ships transporting liquid CO

between Stockholm and Naturgassparken in Bergen (ibid.).

3.2.3 Transportation

The ship is equipped with two tanks for CO

storage (Ollerhead, 2020). These tanks are

made out of Ni-steel (Nickel steel), with a 2.5 % nickel content, which allows the tanks

to handle lower temperatures. This is necessary, as transporting liquid CO

should be

done at -35

C. Ni steel tanks used for LNG typically use 9 % nickel (ibid.). The tanks

on the Northern Lights ships have the capacity to transport a total of approximately 7500 m

of CO

with a loading capacity of 98 %. However, the tanks can not be emptied completely as approximately 4 % of the CO

is expected to be needed to keep the tanks cold during the return trip. The out-turn of CO

is therefore estimated to be closer to 7050 m

(ibid.).

A Front-End Engineering Design (FEED) study made by Equinor estimated how much LNG is consumed during the transportation phase. Ollerhead (2020) stated that in Equinor’s calculations, several assumptions had to be made. Examples on assumptions made according to Ollerhead (2020) was what route the ship will take, what kind of weather condition the ship will be subjected to and what type of sea the ship will traverse. Equinor’s conclusion was that the transportation ship consumes 14 tonnes of LNG per day when loaded and 12 tonnes per day when empty. On average, the consumption rate is at 13 tonnes of LNG per day. Ollerhead (2002) noted that the value on the consumption rate should be regarded as conservative due to assumption made in Equinor’s calculation.

Two different sources have made calculations in order to indicate the distance be- tween port V¨ artahamnen and port Bergen, which is approximately where Kollsnes port is located. The two calculations gave different results, where Ports (n.d.) gave the distance 969 nm (1794.588 km) while sea-distances (n.d.) gave 879 nm (1627.908 km).

The longest distance Ports (n.d.) was used in this thesis. The reason for using the longest distance is that it will limit the risk of under estimating the total consumption of LNG. A picture of an approximate route from V¨ artahamnen to Naturgassparken can be found in Appendix .

There should under normal circumstances not be any leakage of CO

from the ship tanks during transport (Jones, 2020). Yet a leakage of CO

might take place if the transport is considerably delayed on its planned voyage. This should however only oc- cur if there is no available cooling mechanism on the ship (ibid.). If it would occur, an unwanted leakage is caused by a temperature rise in the tanks which will increase the pressure. If this were to happen, the safety valves on the tanks will allow small amounts of CO

to escape to avoid the overpressure (ibid.). An increase in pressure is normally not an issue as ships should be designed to handle these types of issues without having to release any amount of CO

(ibid.).

The IPCC technical summary (2005) found that leakage could happen during trans-

portation of liquefied CO

. An estimation of the total loss to the atmosphere is between

3-4 % of its total content per 1000 km. In their calculation they considered boil-off and

exhaust from the ship engine. Options for reducing boil-off exists, like “capture and

liquefaction” and “recapture”. Applying these methods reduces boil-off per 1000 km to

1-2 %. Boil-off, explained by Ollerhead (2020) in an interview, occurs when the liquid CO

evaporates into gas due to changes in temperature. When the amount of evapo- rated CO

increases, more pressure is being built-up inside the storage tanks (ibid.).

This pressure, if required, can pass through pressure relieve valves in line with standard industry practice (ibid.).

The storage tanks on the ship according to Ollerhead (2020) will be able to handle the accumulated pressure for up to two weeks (excluding external help). The trip from V¨ artahamnen in Sweden to Naturgassparken in Norway takes about 3 days, but un- foreseen events could delay the trip. If that happens, there is countermeasures that has been considered, namely the use of ”spray” or controlled venting. If the risk of over-pressurising the storage becomes too great, venting all CO

could be necessary.

It has been assured by Ollerhead (2020) that this procedure will be done in a safely manner to prevent harming the crew and people nearby.

In regards to leakage or boil-off, Ollerhead (2020) referred to the results from a demon- stration project related to Equinor; no leak of CO

or boil-off will occur during the transportation phase due to sufficient storage tank insulation. Lastly, Ollerhead (2020) also claimed that keeping the CO

liquefied during transportation does not require sup- plementary power.

During 30 minutes prior to arriving and after departing, the ship will run on bat- tery power (Equinor, 2018). For the rest of the voyage the ship will use LNG (ibid.).

When docked, the ship can begin to transfer its content unto the onshore storage plant (ibid.). To do that, it needs two pumps which in this case were originally designed for transferring LPG (ibid.). They are compatible with liquid CO

but due to the differ- ences in density, transferring CO

is therefore slower (Ollerhead, 2020), 400 m

/hour per tank in comparison to 500 m

/hour for LPG (Ollerhead, 2020). The total energy use while discharging the CO

varies between 800 kW and 1 MW (Ollerhead, 2020).

The assumption is that out of 800 kW, the two pumps has an energy demand of 600 kW whilst 200 kW is used to supply the ship’s ”hotel load” (ibid.). Hotel load entails en- ergy used by crew member doing various activities, such as cooking, showering, lights, air conditioning etc (ibid.). The electricity used for transferring CO

to the storage plant is drawn from the national grid in Norway (Bakke, 2020; Ollerhead, 2020). The amount of CO

leaked during the procedure has been determined too insignificant to be measured (Ollerhead, 2020).

3.2.4 Intermediate storage in Norway

The discharging of CO

from the cargo ship unto the onshore storage plant will be oper-

ated by the ships internal pump, powered by energy available onshore (Equinor, 2018).

Moreover, the rate which the process is designed for is 800 tCO

/h. While the transition is made, the pressure in both tanks will change. Pressure in the ships tanks will fall due to its content being emptied while the opposite will happen to the onshore tanks (ibid.). With the help of the vapour return line that is attached to the onshore tanks and ship tanks during the discharging procedural ensures that no gas is leaked (ibid.).

However, Bakke (2020) and Ollerhead (2020) both states that the only loss from load- ing and discharging CO

at Naturgassparken comes from the purging procedure of the loading arms. Bakke (2020) and Ollerhead (2020) explained that to avoid contaminat- ing the liquefied CO

with moisturised air, purging with a small amount of CO

is thus necessary. Bakke (2020) states that the vented volume is negligible compared to stored volumes. Furthermore, Ollerhead (2020) stated that the amount of CO

used for purg- ing has been estimated to be low enough to be negligible when reporting CO

emissions.

Through a collaboration between Equinor and Gassnova, a project concept report for Northern Lights was created and finalized in November 2018. The project concept re- port (Equinor, 2018) states that the onshore facility at Naturgassparken will handle the discharging operation from transportation ships. Moreover Naturgassparken has an in- termediate storage plant, responsible for storing CO

until it is appropriate to transfer it into the geological storage (ibid.). Currently the storage plant is planned to consist of 12 cylindrical, vertical tanks with an inner diameter of 6.25 m and and a height of 25 m, making the total storage capacity of CO

approximately 9150 m

(ibid.). The capacity is 22 % larger than the capacity of planned ships which has 7500 m

(idib.;

Bakke, 2020). The purpose of the additional volume of the intermediate storage tanks is to provide operational flexibility (Bakke, 2020). Furthermore the temperature and pressure in the liquid CO

while stored in the intermediate storage tanks will be about -26

C and 15 barg respectively (idib.).

Most of the energy required to handle CO

in the intermediate storage plant is when the liquid CO

is being pumped (Bakke, 2020). No energy is required to keep the pres- sure or temperature at a desirable level due to the storage plant’s isolation capacity.

The retention time for CO

is small and any boil-off created during that time will be used to replace injected volume (ibid.). If there is an inadequate amount of boil-off to replace injected volume then more can be generated by using heaters installed to the intermediate storage plant (ibid.). Lastly, the storage plant uses electricity produced domestically in Norway for activites such as pumping and running of utilities (ibid.).

3.2.5 Injection of CO

into geological formation

According to Equinor (2018), the thickness of the pipeline will be 17.5 mm for the

first 7 km and 15.9 mm for the remaining part. As reported by Equinor (2018), the

total length of the pipeline will be decided when an appropriate storage site has been

chosen. An approximation given by Equinor (2018) is 107.4 km whilst Sandberg (2019) stated that the pipeline will be 110 km. An approximation of the pipeline route can be found in Appendix 3. Bakke (2020) explained that the rate of injection will depend on several factors: the geological storage sites capacity, available liquid CO

in the intermediate storage tanks and on the arrival of transported CO

. It is estimated that Naturgassparken will be able to inject 1.5 Mt of liquid CO

per year (Equinor, 2018).

A report made by Lelieveld et al. (2005) examined how much natural gas is being leaked from Russia’s pipeline system for transporting natural gas. Russia’s pipeline system consists of pipelines, compressor stations, valve knots and machine halls that adds up to an approximately 2400 km long pipeline system. Lelieveld et al. (2005) concluded that the total loss of methane when transporting natural gas within Russia’s border is 0.7 %, ranging between 0.4-1.6 %. If the whole pipeline system is accounted for, meaning gas spills at wells, then leakage increased up to 1.4 % and ranging between 1.0-2.25 %. Lelieveld et al. (2005) compared their findings with data from a pipeline system in the United States, with a loss of 1.5 %, ranging between 1.0-2.0 %.

The measurements conducted by Lelieveld et al. (2005) for quantifying the leakage in Russia’s pipeline system was done in two steps. The first step is called screening which entails determining the locations of leaks. The second step consisted of measuring the volume leaked by covering the equipment with plastic foil. Tests on venting open- ings and pipes from machines, switches and connectors was directly taken by Lelieveld et al. (2005). Other activities on gas leaks had to be estimated, e.g. repairs, mainte- nance and accidents. Reports from regional gas companies to Gazprom provided the basis of Lelieveld et al. (2005) estimation. The amount of gas leaked due to accidents was estimated on changes in volume and the pressure in the pipelines (ibid.).

In this thesis the leakage of CO

during the pipeline from Naturgassparken to the Au- rora reservoir is assumed to have a linear dependency to the transportation distance.

The Norwegian pipeline length is approximately 4.6 % of the Russian. Therefore the leakage during the pipeline in Norway was estimated to be 0.032 % of the injected CO

. 3.2.6 Long term storage in geological formation

To ensure the safety of the storage, it is important to closely and continuously monitor

it (The Zero Emissions Platform, n.d.). This is achieved by monitoring the well, cap

rock and rock formations thoroughly in order to spot changes in pressure and CO

concentration levels. This monitoring continues after the injection of the CO

is fin-

ished (ibid.). There is an EU law in place to ensure that the injected CO

is safely

stored underground permanently (ibid.). One of the best indicators for identifying CO

movements inside the storage site is pressure-variation monitoring (Benson et al., 2019).

Such monitoring equipment is useful since pressure build-up could occur more than 100 km from the injection zone. If the monitoring equipment senses changes in pressure above the reservoir it can indicate that a leak is happening (ibid.).

Haugan (2020) states that knowing how well a trapping mechanism perform at a large scale is difficult. Haugan (2020) proclaims that tests conducted in labs are too small to reflect realistic results and performing field studies on geological formations are hard to perform due to limited tools for the task. Haugan (2020) does acknowledge that seis- mic sensor, a common, advanced instrument for evaluating the qualities of formations has its merits. Nevertheless, Haugan (2020) believes that data collected by the seismic sensor is too limited to provide a full understanding of the qualities of a geological formation.

Determining the quality of a storage site is a very demanding and costly procedure according to Haugan (2020). The reason being is that many factors affects how capable storage sites are in containing CO

. Haugan (2020) claims that the Johansen forma- tion is notorious heterogeneous, meaning that the formation consists of many faults and fractures, and various degree of porosity. Controlling that there are no faults and fracture in the formation is vital since both could otherwise act as conduits for future leaks. Having high porosity in a storage site means it has good capacity to receive and store injected CO

. According to Haugan (2020), fuel companies determines the qual- ity of a geological formation by the use of seismic sensors before conducting test samples.

Haugan (2020) compared the current project made by Northern Lights to the Sleipner project. The Sleipner project was the first commercial storage project conducted by Statoil, today known as Equinor (MIT, n.d.). Noteworthy is that Equinor is affiliated with both projects. Haugan (2020) states that it was the porous quality of the Utsira formation that made the Sleipner project a success.

As mentioned before by Haugan (2020), the Aurora area is not as favourable and therefore making the Northern Lights project more difficult than the previous project.

Haugan (2020) points out that initially in 2019 the location of the storage site had to be

changed to the Aurora reservoir due to uncertainty with the previous reservoir’s proper-

ties. Furthermore, Haugan (2020) mentioned that the new location in Aurora does not

have a pre-existing well, thus requiring more work to drill a new well. Equinor (2018)

confirms Haugans both statements, adding explanation for their decisions. According

to Equinor (2018), the reason for relocating from the previous Smeaheia reservoir was

that a more detailed study implementing newly available 3D seismic resulted in that

the storage capacity did not match Equinor’s expectations.

3.3 Calculations

To summarize and evaluate the energy use, leakage and total emissions associated with BECCS several calculations were necessary. The collected data was summarised in two different tables, one for energy use (Table 5) and one for leakage (Table 7). Each table contains three scenarios, the first being a low scenario with the lowest values of energy use and leakage found in the literature study. The third scenario includes the highest values found. The middle scenario is simply the median values calculated based on the lowest and highest values. The final step was to calculate the CO

e emissions associated with the energy use and adding it to the total leakage of CO

during the process in order to get the total CO

e emissions. The total emissions of CO

e can be found in Table 4.

The CO

e caused by the electricity use of BECCS are calculated by multiplying the energy use presented in Table 5 with the emissions caused by the electricity use. The energy mix used as a reference in this thesis is the average Nordic energy mix. IVL Sven- ska Milj¨ oinstitutet did a LCA on the Nordic energy mix in 2015. Their report stated that the average CO

e related to the Nordic energy mix is 160 CO

e/kWh (Liljenstr¨ om et al., 2015). It is possible that the emissions caused by the average Nordic energy mix have decreased since 2015 because of the continuous shift in energy production that is taking place on the Nordic market. Additionally, it is possible that the efficiency of liquefaction, transportation and storage will increase in the future, resulting in a more effective and environmentally sound procedure.

Using the steps described, it was possible to calculate the emissions for all stages of

BECCS except for the emission caused by the LNG usage during the transportation

from V¨ artan to Naturgassparken. A slightly different approach was used in order to

calculate the emissions caused by the LNG consumption. The parameters used here

were; the speed of the ship (estimated to be 13 knots « 24 km/h), the distance from

V¨ artahamnen to Naturgassparken (estimated to be 969 nm « 1795 km) and the average

consumption of LNG per day (estimated to be 13 tonnes). These parameter values were

estimated using the lowest speed discovered during the literature study, as well as the

longest discovered transportation distance. Both these values were used to calculate the

maximum quantity of LNG needed for one round trip. The values found are presented

in Table 3 and the calculations are presented in Appendix D.

Table 3: The travel time for transportation and LNG consumption

Transportation time, one way [h] 74.54

Transportation time, round trip [days] 6.2 LNG consumption, round trip [tonnes] 80.75 LNG consumption round trip [kWh/tCO

] 156.9 CO

emissions caused by the LNG consumption [tonnes] 210

Table 3 presents the time needed to transport CO

from V¨ artan to Naturgassparken.

Furthermore, the table also provides information regarding the LNG consumption for the transportation and the CO

emissions caused.

The CO

emissions from the transportation are calculated differently, since there is no electricity use. The CO

emissions are instead based on the emissions caused by the LNG consumption. The CO

emissions caused by transporting one tonne of CO

was calculated by dividing the total CO

emissions from one round trip with the total quantity of transported CO

, 7050 tCO

. The emitted CO

was then converted to kg.

The CO

e caused by leakage of CO

from the pipeline and the long term storage are

simply calculated by converting the data from tonnes of leaked CO

per year to kg

CO

e per stored tonne of CO

.

4 Result & Discussion

The result of this thesis is that the leakage of CO

within the considered system bound- aries is rather insignificant in comparison to the energy use. More specifically, the largest cause of CO

emissions is the energy use of the liquefaction process that amounts to ap- proximately 18-22 kg CO

e per stored tonne of CO

. As well as the LNG consumption for the transportation, that amounts to approximately 30 kg CO

e per stored tonne of CO

. The total BECCS related CO

e emissions range from approximately 49-58 kg CO

e per stored tonne of CO

. The overall findings of this report are summarized in Table 4 and a further break down for both energy use and leakage can be found in Table 5 and 7 respectively.

Table 4: CO

emissions from the energy use and leakage [kg CO

e per stored tonne of CO

]

Scenario Low Median High

Liquefaction 17.6 20 22.4

Transportation of CO

through pipes from the liquefaction plant to the intermediate storage in V¨ artan

0 0 0

Intermediate storage (V¨ artan) 1.28 1.84 2.4

Loading to ship 0.02 0.02 0.02

Transportation by ship 29.79 29.79 29.79

Discharge from ship 0.02 0.02 0.02

Intermediate storage (Naturgassparken) 0 1.28 2.4 Pipeline transportation to long term storage 0.18 0.32 0.73

Long term storage 0 0.05 0.1

Total 48.9 53.3 57.9

As can be seen in Table 4 the main contribution of CO

emissions comes from the high energy use of the liquefaction process and the LNG consumption used for transporta- tion.

The emissions and energy use associated with BECCS can vary significantly depending

on the procedure used. The liquefaction plays a significant role, but also the transporta-

tion distance and the amount of CO

being stored has an impact. Few studies actually

mention the different energy useage and CO

losses throughout the whole BECCS pro-

cess. More significantly for this thesis, even fewer studies mention the energy use and

leakage of CO

at the different stages of BECCS. This is an indication that there is

limited data on the subject. To successfully handle and store CO

it is important that

all energy use and CO

losses are accounted for. As mentioned earlier in this thesis,

some CO

losses are assumed to be negligible because of efficient procedures and ma- chinery. However, faults, insufficient studies and mistakes could potentially result in higher amounts of emission and leakage.

4.1 Energy use

The energy usage found during the literature study and interviews were converted to kWh/tCO

and combined in order to evaluate the total energy usage of the examined steps of BECCS.

Table 5: Total energy use [kWh/tCO

]

Scenario Low Median High

Liquefaction 110 125 140

Transportation of CO

through pipes from the liquefaction plant to the intermediate storage in V¨ artan

Unknown Unknown Unknown

Intermediate storage (V¨ artan) 8 11.5 15

Loading to ship (V¨ artan) 0.099 0.111 0.124

Transportation by ship 156.9 156.9 156.9

Discharge from ship 0.103 0.116 0.129

Intermediate storage (Naturgassparken) 0 8 15

Pipeline transportation to long term storage Unknown Unknown Unknown

Total 275.1 301.6 327.2

Table 5 presents the total energy use found when examining the different parts of BECCS. The most energy is used for the ship transportation and the liquefaction pro- cess.

Table 5 is lacking data regarding the electricity use for transporting CO

from the liquefaction plant to the intermediate storage as no such data was available. However, since the plant and storage are likely to be co-located, this electricity use is assumed to be negligible, or very close to zero. In comparison with the large electricity use of the liquefaction plant, the transport to the intermediate storage is unlikely to significantly impact the overall energy usage.

As previously mentioned, Bakke (2020) stated that the intermediate storage in Natur-

gassparken does not have an energy demand to retain liquified CO

. With the reason

of this being the sufficient insulation capacity. This contradicts the findings from Jones

and R¨ od´ en (2020) and Blu Carbon Solutions (2019) who stated that the intermediate

storage in V¨ artan has an energy demand of 8-12 kWh/tCO

and 10-15 kWh/tCO

.

Since it is possible that the energy demand for the two intermediate storages are simi- lar, three different values were used. In the first scenario it was assumed that the energy use is zero, as told by Bakke (2020). For the second scenario the lowest value found for the storage in V¨ artan was used, 8 kWh/tCO

and for the third scenario the highest value was chosen, 15 kWh/tCO

. However, it is possible that these values are incorrect since they are based on the assumption that the two intermediate storages are similar, which is not necessarily the case.

As the ship runs on LNG during the transport, some calculations were necessary to convert the LNG usage to kWh/tCO

. The calculations are presented in Appendix D.

Furthermore, Table 5 lacks data regarding the energy use for injecting CO

into the ge- ological formation. With the reason being that no data was found during the literature study and no interviewee questioned was familiar on the matter. It is however possible that the energy use would be significant, e.g. since the CO

needs to be transported approximately 110 km at a high pressure.

The energy demand to liquefy, transport and store the CO

can be compared with

the total amount of electricity and heat produced by the CHP plant KVV8. The power

plant, when running at full effect, produces approximately 403 MW electricity and heat

for an average of 5000 hours per year (Gustafsson, 2020). This amounts to 2013500

MWh of electricity and heat produced every year. The energy demand of the BECCS

process to liquefy, transport and store 800000 tonnes of CO

(median scenario) is 241280

MWh per year. The energy use is not insignificant in comparison to the produced en-

ergy from KVV8, roughly 12 %. Furthermore, the electricity use of BECCS, is roughly

18.6 % of the electricity produced yearly by KVV8. However, the energy and electricity

use are likely to increase when the energy demand for injecting the CO

into the Aurora

formation is included. The calculations can be found in Appendix E.

Table 6: CO

emissions caused by the energy use [kg CO

e per stored tonne of CO

]

Scenario Low Median High

Liquefaction 17.6 20 22.4

Transportation of CO

through pipes from the liquefaction plant to the intermediate storage in V¨ artan

Unknown Unknown Unknown

Intermediate storage (V¨ artan) 1.28 1.84 2.4

Loading to ship (V¨ artan) 0.02 0.02 0.02

Transportation by ship 29.79 29.79 29.79

Discharge from ship 0.02 0.02 0.02

Intermediate storage (Naturgassparken) 0 1.28 2.4

Pipeline transportation to long term storage Unknown Unknown Unknown

Total 48.7 53 57.1

Table 6 presents the emissions associated with the energy use. The emissions caused by transporting the CO

from the liquefaction plant to the intermediate storage and the emissions caused by injecting the CO

are unknown. The largest energy use and thereby also the largest emission of CO

takes place at the liquefaction plant and the transportation.

4.2 Leakage of CO ₂

The leakages found during the literature study and the interviews were summarized

and converted to tonnes of CO

/year in order to asses the total leakage of CO

.