ORIGI NAL ARTICLE
Carbon dioxide submarine storage in glass containers:
Life Cycle Assessment and cost analysis of four case
studies in the cement sector
Beatriz Beccari Barreto1 &Stefano Caserini1&Giovanni Dolci1&Mario Grosso1
Received: 7 August 2018 / Accepted: 21 February 2019 # Springer Nature B.V. 2019
Abstract
This paper describes the potential application of a new patented technology for the storage of carbon dioxide (CO2) in glass containers into the deep seabed (confined submarine carbon
storage (CSCS)) to cement plants located in four different locations in the world. This technology is based on the bottling of liquid CO2at high pressure inside capsules made of
glass that are delivered to the bottom of the ocean via a proper pipeline. A Life Cycle Assessment that considers all the stages of the process and 13 impact categories, with a focus on climate change, shows an impact in the four case studies between 0.084 and 0.132 ton of CO2equivalent (eq) per ton of CO2stored. Since carbonation of cement materials over their
life cycle is a significant and growing net sink of CO2, the capture and storage of CO2
emissions generated during the production of cement might lead to negative emissions. A cost analysis was also performed, including the capital costs and the operational costs, even considering the funding structure through financing and equity. The costs of the four case studies are from 16 to 29 $/tCO2. Although further work is needed to assess in detail some
aspects of the design, the result of this stage of the research allows concluding that the application of the CSCS in cement plants is an interesting option for achieving negative emissions, even if limited due the slowness of CO2 uptake during the lifetime of cement
materials.
Keywords Cement . CO2storage . Carbon capture and storage . Carbonation . Submarine storage
Electronic supplementary material The online version of this article ( https://doi.org/10.1007/s11027-019-09853-w) contains supplementary material, which is available to authorized users.
* Beatriz Beccari Barreto beatriz.beccari@polimi.it
1
Dipartimento di Ingegneria Civile e Ambientale, Politecnico di Milano, Via Golgi 39, 20133 Milan, Italy
1 Introduction
The United Nations Framework Convention on Climate Change 21st Conference of the Parties, Paris, France, was signed in 2015 to strengthen the global response to the threat of climate change. It has set the ambitious goals of keeping the average global temperature increase well below 2° C above pre-industrial levels and to pursue efforts to limit this increase even below 1.5° C (UNFCCC 2015). Meeting the Paris Agreement goals will require a dramatic reduction of greenhouse gas (GHG) emissions in the next decades, a decrease in carbon dioxide (CO2) emission from land use as well as a rapid scaling up of CO2removal
by technical means known with the general term of NET (negative emission technologies) (Rockström et al.2017).
According to many authors (i.e., Rogelj et al.2015; Fuss et al.2018) and also to the latest Intergovernmental Panel on Climate Change (IPCC) report of 1.5 °C (IPCC 2018), the removal of CO2 from the atmosphere is an essential requirement to keep the temperature
increase below 2 °C or 1.5 °C. The search for innovative approaches and technologies should be embraced in every sector, including those in which mitigation is more difficult, such as industrial activities not related to energy production.
1.1 CO2emission and removal during cement lifecycle
Cement does not have a proper substitute in the foreseeable future, and in 2015 its production was responsible for 8% of the global GHG emissions, almost equally split between the calcination of limestone and the fossil fuels used in the process (Oliver et al.2016). However, the calcium oxide in cement materials is not stable over time, and cement hydration products slowly uptake atmospheric CO2employing a physical-chemical process called carbonation (Xi
et al.2016; Pade and Guimaraes2007; Andersson et al.2013). Thus, cement carbonation is a sink of CO2that offsets part of the CO2released during cement production, despite a consistent
time lag: while the emissions of CO2during cement manufacturing are instantaneous,
carbon-ation is a slow process that takes place throughout the entire life cycle of cement-based materials. Furthermore, if the CO2generated during cement production is captured and stored,
carbonation reactions allow achieving negative emissions during the life cycle of the cement (process described in the Eqs.1,2, and3; source: Xi et al.2016).
Ca OHð Þ2þ CO2→CaCO3þ H2O ð1Þ
3CaO∙2SiO2:3H2O
ð Þ þ 3CO2→3CaCO3∙2SiO2∙3H2O ð2Þ
3CaO∙Al2O3∙6H2O
ð Þ þ 3CO2→2Al OHð Þ3þ 3CaCO3þ 3H2O ð3Þ
1.2 Carbon capture and storage
Since 2005, with the publication of the IPCC Special Report (IPCC2005), carbon capture and storage (CCS) has developed at a slow pace (IEA 2016). There has been technological progress, but more incisive actions are needed to accelerate its development (IEA 2013;
Nemet et al.2018). Today there are 23 initiatives under construction or in operation world-wide. The primary type of storage is enhanced oil recovery (EOR) used in 17 of the 23 (GCCSI 2018). Different researchers have discussed the feasibility and limitations of CCS (Rubin and Davison2015; Gale2015; Kemper2015; Nelder2015; Pawar and Carey2015). According to Gale (2015), even if CCS is ready for large-scale deployment, the problems related to the overall cost, the storage risks, and the negative public perception (Aminu et al. 2017) in many places have severely hindered the growth pace of the technology. According to the International Energy Agency (IEA2015), while the capture is the most expensive phase, storage is the most critical, since it takes from 5 to 10 years to thoroughly assess a new saline formation potentially suitable for CO2 storage. Furthermore, it should be considered that
although the theoretical storage potential is enormous, theBpractical^ and Bmatched^ capacity as defined by the BGeologic CO2storage capacity pyramid^ (IEAGHG2008), has severe
limitations in many regions (Dooley2013), and the access to geological storage could be the most critical constraint to the dissemination of the CCS deployment (IEA2016).
1.3 Confined submarine carbon storage
A new form of carbon storage called confined submarine carbon storage (CSCS) was developed by CO2Apps and has been presented in Caserini et al. (2017). The basic concept of the CSCS is to store the captured CO2in a compressed liquid form inside glass capsules and
transport them through offshore pipelines into the ocean. The proposed CSCS system is composed of different stages: a furnace for the glass capsules manufacturing, a station for filling and sealing each capsule, a launcher, and the pipe. Through the tube, capsules are transported from the land to the bottom of the sea at depths where the hydrostatic pressure exceeds the internal pressure of the CO2, typically between 1000 and 2000 m (Fig.1).
Fig. 1 Confined submarine carbon storage applied to cement plants and subsequent carbonation of cement-based materials
Since the CSCS technology aims to represent a long-term storage solution, the diffusional loss of CO2through the glass over thousands of years should be avoided. This topic could be
the subject of future research on this technology. However, according to the scientific literature (Shackelford2014; Norton1952; Opyd et al.2007), the diffusional loss should be negligible because of the relatively big size of the carbon dioxide molecule.
Another possible critical aspect is the durability of glass materials in seawater. The dissolution and leaching of different types of glasses in saltwater were studied for the vitrification process of nuclear wastes (Havlova et al. 2007). Among the extensive family of glass materials, some glasses can stand seawater corrosion for a very long time (Hekinian and Hoffert 1975) because of their chemical composition (like the borosilicate glasses) or due to their superficial treatment. The specific glass composi-tion to be used to minimize the risk of corrosion of glass capsules in the deep sea is another topic of future research.
A Life Cycle Assessment (LCA) for different combinations of geographical and technological parameters, as well as a preliminary risk assessment and a cost analysis, was carried out in Caserini et al. (2017), considering three different scenarios (worst, best, and most likely) to simulate a range of results. The Bmost likely^ scenario represents the average conditions that can be considered for a generic CSCS plant, given different combinations of the geographical, technological, and economic context in which the technology could be implemented. TheBworst^ scenario assumes conservative values of the parameters, leading to higher costs (as well as energy consumption and GHG emissions); vice-versa for the Bbest^ scenario. Geographical, technological and economic parameters, energy consumptions, and efficiencies of the processes were changed across the situations, along with the lifespan of the plant. The LCA showed an average impact of 0.10 ton of CO2eq per ton of stored CO2(range 0.06–0.19), while
the cost analysis resulted in an average levelized cost of US$17 (12–30) per ton of CO2.
One of the main advantages of the CSCS technology is its modularity and its suitability for small-size emission sources (i.e., few MtCO2/year) where geological storage is not available at
a distance where pipeline and transport with vessels could be competitive. Although programs focused on CO2transportation through pipelines have been proposed (i.e., trans-European CO2
transport network, Morbee et al.2010), they are convenient for plants (or clusters of plants) with high emissions much bigger than the size of the cement plants studied in this work (about 1 MtCO2/year). The option of a pipeline is not convenient for small quantities of CO2
transported (Roussanaly et al.2013), whereas the cost of transport of liquid CO2with vessels
increases with the distance, due to the increase of the fuel consumption.
The most relevant risks of the technology come from the possible loss of CO2due to the
breakage of the capsules. In this case, the contact between CO2and seawater will generate CO2
hydrates, and therefore, a slow release of carbon in the environment (Adams and Caldeira 2008; IEA Greenhouse Gas R&D Programme2004). In case of an occasional loss (few broken capsules), there will be a temporary pH reduction in a limited area, causing short-term and localized effects. The simultaneous breakage of a vast number of capsules could potentially cause a pH and habitat alteration, with toxic effects on marine life. In any case, the potential risk is substantially lower than that related to direct ocean storage of CO2.
The possible risk of breakage of the capsules will be tackled by including continuous monitoring, based on breakage sensors that send real-time data about the capsule integrity. Checking of physical and chemical parameters of the water and sediments could also be included.
The primary goal of this study is to evaluate the application of the CSCS technology, already presented in Caserini et al. (2017), to the cement sector. The economic and environ-mental aspects of the use of the CSCS technology to store CO2emitted by cement plants are
evaluated by applying a LCA and a cost analysis. This study is also aimed at understanding the extent of negative emissions that can be achieved by the absorption of carbon in the cement in 40 years and 100 years to come, as well as its cost.
2 Methodology
Four cement production plants were analyzed located near the seashore in four different countries: Italy (case A), Spain (B), Bulgaria (C), and Morocco (D). The operators provided the necessary information and operating data:
& The annual CO2emission;
& The cost of purchasing electric energy from the grid; & The electrical energy consumption at the site;
& The price to supply the raw materials for glass production (i.e., sand); & The labor cost for cement production; and
& The availability and costs of natural gas. 2.1 Life cycle assessment
The LCA methodology was applied to the four case studies to evaluate the environmental performances of the examined CSCS technology in each context.
2.1.1 System description and boundary
The boundary of the system includes the following stages (Fig.2): & The production of glass and the capsules;
& The life cycle of the glass furnace; & The capsule quality check; & The capsule filling with sand; & The construction of the suction pipe; & The building of the filling magazine;
& The capsule filling with carbon dioxide and its pumping into the transport pipe; & The installation of the transport pipe; and
& The plant services and monitoring.
2.1.2 Functional unit
2.1.3 Impact categories and characterization methods
Since the focus of the paper is a process for negative CO2emissions, climate change is the
main impact category considered, represented by the emissions in the atmosphere of different greenhouse gases characterized by their Global Warming Potential (GWP). GWPs100 (100 years of timespan) indicated in the Fourth Assessment Report (AR4) of the Intergovern-mental Panel on Climate Change (IPCC2007) and implemented in the ILCD 2011 method (version 1.08) were considered (EC2013).
Besides, to take into account the broadest range of environmental issues, other 12 impact categories were evaluated at the midpoint level by using the characterization models recom-mended by the Joint Research Centre of the European Commission (EC2013):
& Ozone depletion;
& Human toxicity—cancer; human toxicity—non-cancer effects; & Particulate matter;
& Photochemical ozone formation; & Acidification;
& Eutrophication—terrestrial; eutrophication—freshwater; eutrophication—marine; & Ecotoxicity for aquatic fresh water; and
& Mineral resource depletion; fossil resource depletion.
Fig. 2 The main stages of the process, and the respective inputs and outputs, considered in the LCA are represented
For each category, Table SM1 indicates the impact category indicator and the impact assessment model (used to quantify the causal relationships between the material/ energy inputs and emissions associated with the product life cycle and each impact category).
Finally, the energy performances of the system were evaluated employing the Cumulative Energy Demand indicator, calculated according to the method described in Hischier et al. (2010), considering either direct or indirect (associated with the energetic content of materials) energy utilization. The data processing was performed with the SimaPro software (version 8.2.3).
2.1.4 Life cycle inventory
For the case studies modeling, primary data on the production process provided by the cement company were acquired. The vertical temperature profile of the sea and the depth of the seabed are needed to calculate the density of the water that influences the amount of sand to be added inside the capsule for maintaining the required deposition velocity. The pipeline length, the carbon intensity of electricity generation, and the characteristic of the natural gas used by the plants were also assessed considering specific values for each country, as shown in Table 1. The ecoinvent database (version 3.1) was used to support the analysis.
The sea temperature profile in the A, B, and C cases were taken from MISIS (2014) and Reseghetti (2008), while for case D (Morocco) a constant conservative value of 15 °C was assumed, due to a lack of literature data. Regarding the seabed depth and the distance between the plant and the place of capsule release (pipeline length), the European Marine Observation and Data Network (EMODnet 2016) was consulted. For each country, the specific electricity mix was chosen according to data provided by the Shift Project Data Portal (2016) for the year 2014. As for the CO2
emission factor of natural gas extraction and transportation, country data from the ecoinvent database were considered for case A and B, whereas data from Russia (due to the similar geography) and global data were used for cases C and D, due to a lack of more specific information.
In theSupplementary Material, all the consumptions of materials and energy are detailed for each stage included in the system boundary (Tables SM2). The analysis was performed with the ecoinvent processes indicated in Caserini et al. (2017).
Table 1 Parameters of the LCA case studies are shown (offshore distance represents the distance from the coastline to the point of capsule placement)
Property Unit Case A Case B Case C Case D Average
CO2emissions MtCO2/year 0.36 0.75 1 0.55 0.67
Sea temperature °C 13 13 9 15 12.5
Seabed depth M 1700 1400 1500 1500 1525
Offshore distance km 30 70 60 30 48
Suction pipeline length km 4 4 4 4 4
Emission factor for electricity and transportation
2.2 Cost analysis
2.2.1 Funding structure and CAPEX
The general structure of the cost analysis followed the one proposed by Rubin et al. (2013). The funding structure is the same used by Caserini et al. (2017). Eighty percent of the fund will be derived from financing and 20% from equity, with a 6% interest rate and a 10% capital cost. The lifespan of the project and all the machines is 40 years, except for the glass furnace that has a lifespan of 8 years and then it will be rebuilt at half the initial cost. The Capital Expenditure (CAPEX) is divided into capsules production, capsules filling and launching, capsules transportation and MMV (measurement, monitoring, and verification).
2.2.2 OPEX
The operational expenditures (OPEX) is split into fixed and variable costs, with fixed costs being the labor and the external ship inspection, and the variable costs of the following: sand for filling the capsules (filling-sand), glass materials, electricity, natural gas, MMV, royalties, other materials, and fixed costs for overall production.
2.2.3 Case studies data
All the cost data provided by the company were given in euros and were converted to dollars using the average conversion of July 2016, equal to 1.108 $/€. The following additional data were needed (Table2):
a. Cost of the natural gas;
b. Cost of the sand to be introduced in the capsules and of the raw materials for the production of glass;
c. Price of steel, polyethylene (PE), and glass fiber for the pipeline; and d. Labor cost.
The website Eurostat provided the cost for the natural gas for the case studies in Europe (Eurostat 2016a). The natural gas cost for Morocco was assumed being the highest price among the three other cases since no reliable data were found in the literature.
Table 2 Main elements of the cost analysis for the case studies are demonstrated
Property Unit Case A Case B Case C Case D Average
Labor cost ($/h) 20 18 10 15 15.8
Natural gas delivered ($/GJ) 9.5 9.5 8.5 9.5 9.3
Electricity ($/MWh) 110 65 65 65 76
Glass material ($/ton) 2.0 4.5 4.5 2.5 3.4
Sand for the glass production ($/ton) 2.0 4.5 4.5 2.5 3.4 Sand for filling the capsule ($/ton) 2.0 4.5 4.5 2.5 3.4
PE for pipeline ($/kg) 1.8 1.8 1.8 1.8 1.8
Glass fiber for pipeline ($/kg) 2.2 2.2 2.2 2.2 2.2
The costs of the filling-sand and as raw material for the production of glass were hypothesized as being the same as the cost of the materials used to produce the cement.
The prices of steel, PE, and glass fiber for the pipeline were equal to those assumed in the most likely scenario in Caserini et al. (2017), due to the minimal information regarding the exact cost of the materials.
The labor cost used in the numeric model is based on the data from Eurostat (2016b) and was adapted considering the information of the labor cost for the cement production given by the company.
The costs of the electric energy were based on those reported by Eurostat (2016c) and were also adapted according to the cost of electricity stated by the company in each cement plant. Regarding the cost of the pipeline, in all cases the Manning number (a parameter related to the roughness of the material of the pipeline used in the Manning equation to calculate the velocity of the liquid in a pipeline) was equal to 0.30, in order to keep the speed of the capsule inside the pipeline below 2 m/s.
3 Results and discussion
3.1 Life Cycle Assessment
The calculated impact for the climate change category ranges between 84 (case B) and 132 (case D) kilograms of CO2equivalent for the storage of 1 ton of CO2(Fig.3). In other
words, this means a GHGsBpenalization^ between 8.4% and 13% for the storage of CO2
with CSCS. The results of all the case studies noticeably lie well between the range of the best and worst scenarios (6–19%) assessed in Caserini et al. (2017). Thus, the variation of the results due to different assumptions is very likely within the range previously evaluated. Tables SM8–SM11in the Supplementary Materials report the results of the impact assessment for all the examined impact categories, for both the total system and each stage in the four considered case studies.
In all the case studies, the capsule production is always responsible for the most significant contribution (from 60 to 80%) to the climate change impact category, as shown in Fig.4. The capsule filling with CO2and the transportation stage has a much more significant impact in
Morocco (case D), due to the high emission factors of the electric energy generation (1143 kgCO2eq/MWh).
Concerning the capsule production stage, the most relevant impact contribution is the direct CO2emission from the combustion of natural gas and the calcination taking place during the
production of glass. This contribution is intrinsic to the glass production and therefore shows small variations among the cases. For the same reason, the influence of the type of glass materials on the LCA results should be considered of minor importance.
The second contribution is the electric energy consumption. Bulgaria and Morocco are still very dependent on coal; on the other hand, Spain has a more varied mix (Table1).
3.2 Cost analysis
The cost of CO2storage is estimated between 16 (case C, Bulgaria) and 29 $/tCO2(case A,
Italy), as shown in Table 3. These costs are within the range 11–34 $/tCO2 assessed by
The electricity cost has a considerable impact (Table 4), with case A (Italy) being the highest, followed by case D (Morocco). When the electricity cost is doubled, the overall cost increases by about 15% in all cases. The natural gas also has a notable impact on the total cost, with an average 20% overall cost increase when its delivery cost doubles.
All the calculations are based only on secondary data. However, when changing other parameters one by one, while keeping the rest constant, similar to a sensitivity analysis, these three parameters (electricity, natural gas, and amount of CO2stored) were the sole that affected
the results by more than 10%.
Fig. 3 LCA results for the climate change impact category are illustrated. The dotted line represents the most likely scenario in Caserini et al. (2017)
Fig. 4 Impact contributions of the different stages of the examined CSCS technology, for the climate change impact category, in the four case studies
The CAPEX costs for cases A, B, C, and D are 8.1, 5.9, 4.7, and 6.2 $/tCO2, respectively.
Only the CAPEX cost for case A resulted considerably higher than the average, which is probably related to the small amount of carbon dioxide stored.
As shown in Table 4, the OPEX varies from 11.1 to 20.8 $/tCO2, with an average
of 15 $/tCO2.
The electricity is the parameter which shows the most extensive range, from 2.8 to 10.6 $/tCO2, with an average of 5.4. Other settings have a significant variability, such
as the filling-sand, which is approximately three times the price from case C to A. Nevertheless, it remains a small contribution inside the total OPEX. Thus, its vari-ability is less relevant.
MMV includes the monitoring and verification of the capsules and the entire process, at the cost of 0.5 $/tCO2.
3.3 Sensitivity analysis
3.3.1 Annual storage of 1 Mt of carbon dioxide in all the cases
To understand the impact of the different assumptions, in a first sensitivity analysis, we have assumed the same quantity of CO2 being stored in all the cases, i.e.,
1 MtCO2/year (Fig. 5). For case A, the cost lowers to 19.6 $/tCO2, much less than
28.9 $/tCO2 of the baseline scenario. The average total cost for the four cases
becomes 17.8 $/tCO2, with the CAPEX being 4.7 $/tCO2 and the OPEX 13.1 $/
tCO2. The total cost of case A is 112% of the most likely scenario, of case B 101%,
of case C 92%, and of case D 102%. This analysis shows how important it is to have
Table 3 Cost of CO2storage in each case study are indicated
Case study CO2stored (Mt/year) Total cost ($/tCO2) OPEX ($/tCO2) CAPEX ($/tCO2)
Case A 0.36 28.9 20.8 8.1
Case B 0.75 19.0 13.1 5.9
Case C 1.00 15.8 11.1 4.7
Case D 0.55 21.0 14.8 6.2
Average 0.67 21.2 15.0 6.2
Table 4 OPEX cost breakdown of each case study are described
OPEX item ($/tCO2) Case A Case B Case C Case D Average
Fixed costs Labor cost 1.3 1.1 0.6 0.9 1.0
External ship inspection 0.4 0.2 0.1 0.2 0.2
Fixed costs overall production 1.1 0.5 0.4 0.7 0.7 Variable costs Glass materials (incl. CACO3) 0.3 0.7 0.7 0.4 0.5
Sand for filling 0.2 0.3 0.1 0.4 0.3
Natural gas melting 4.7 4.7 4.0 5 4.6
Electricity 10.6 3.2 2.8 4.8 5.4
Other materials 0.8 0.8 0.8 0.9 0.8
MMV services 0.5 0.5 0.5 0.5 0.5
IP royalties 1.0 1.0 1.0 1.0 1.0
enough quantity of CO2 to store, to achieve a more competitive cost thanks to the
economies of scale.
3.3.2 Best and worst scenarios for each case
A second sensitivity analysis assumes a variation in the parameters as listed in Table5for each case. The best assumes optimistic values of the parameters, leading to lower costs, vice-versa for the worst scenario. Some parameters (cost of labor, natural gas, electricity, glass material, and filling-sand), as well as the seabed depth, the sea temperature, and the offshore pipeline length, have been kept constant. Figure6shows the cost variability for each case, for its own best, most likely, and worst scenarios.
Case A shows the highest cost in all three options, mainly due to energy, labor, and some geographical properties, while case C has the smallest variation between the worst- and best-case scenarios.
3.4 Comparison of the cost of CSCS and other CCS technologies
Table6shows the cost of transport and geological storage phases for CCS plants, as found in the literature. For the transport phase, the reference technology was the pipeline, due to the possibility of comparison with the CSCS. The single transport costs range between 3.4 and 9.5 $/tCO2. The storage technologies were priced from 2 to 18 $/tCO2. The cost of the CSCS
technology (11 to 29 $/tCO2) is slightly higher than the range for onshore storage but still
comparable.
Fig. 5 Cost of each case study considering the amount of carbon dioxide stored equal to 1 Mt CO2/year are
Table 5 The parameters variation between different scenarios
Parameter u.m. Best Base Worst
General Storage of CO2from external
sources
tons/year 1,000,000
Seawater suction temperature oC Constant and dependent on the case
Seabed depth m Constant and dependent on the case Seawater capsules release
depth
m Constant and dependent on the case Ratio between average pipe
depth and capsules release depth
Ratio 0.4 0.5 0.6
Suction pipe length m 3000 4000 10,000
Offshore pipeline length m Constant and dependent on the case
Manning number Ratio 0.024 0.0305 0.013
Glass production plant factor (nominal capacity)
Ratio 0.98 0.95 0.92
Glass production idle energy rate Ratio 0.045 0.05 0.055 Manufacturing security factor—glass mm 1.6 1.6 1.6 Manufacturing security factor—pipe mm 2 2 2
Capsule internal diameter mm 300 300 300
Capsule cylindrical length mm 300 300 300
Cement for anchoring the main pipe
tons/km 18 20 22
Steel for bouys tons/km 0.18 0.2 0.22
Annual operation launching and transportation
h 8585 8322 8059
Capsules Minimum capsule glass thickness
mm 2.7 3.3 4
CaO composition Ratio 18% 20% 22%
Rejected glass ratio % 4 8 12
Young module pressureBE^ MPa 74,000 62,000 50,000
Glass Poisson’s ratio Bv^ – 0.18 0.2 0.22
Operation-specific ratios for glass production
Energy consumption glass melting (furnace)
GJ/ton 2.97 3.3 3.63
Energy consumption cullet glass melting (furnace)
GJ/ton 2.07 2.3 2.53 Energy consumption distribution (forehearth) GJ/ton 0.225 0.25 0.275 Energy consumption annealing lehr GJ/ton 0.113 0.125 0.138 Electricity consumption compressed air kWh/ton 41.4 46 50.6
Electricity consumption mold cooling
kWh/line 20.7 23 25.3
Electricity consumption mixing glass material
kWh/ton 50.4 56 61.6
Electricity consumption (others)
kWh/ton 12.6 14 15.4
Electricity cryo oxygen kWh/ton 158 175 193 Magazine Launch cycle time per
magazine
s/capsule 40.5 45 49.5
Free span in magazine mm 9 10 11
Pump filling pressure Bars 4.5 5 5.5
3.5 CSCS in the cement sector as a negative emission technology
As previously explained, cement-based materials could be a sink of CO2using carbonation, a
slow process that takes place during both the service life and the end of life. The carbonation process can be described by the following equation (Xi et al.2016):
Cuptake¼ C*A*k*Cclinker*γ*Mt*fCaO*t0:5*10−3 ð4Þ
in which
Table 5 (continued)
Parameter u.m. Best Base Worst
Pumps Compressor specific consumption (manufacture) kWh/m3 0.203 0.214 0.225 Pump efficiency % 63 60 57 Machinery and equipment lifespan
Glass furnace lifespan (refractory material)
Years 9 8 7
Lifespan of all other equipment
Years 44 40 36
emissions factors Emission factor for power generation and distribution
kgCO2eq/MWh constant
Cost parameters Labor cost shared with CO2 emitter
% 75 50 0
Local labor cost $/h Constant and dependent on the case CAPEX maintenance
provision
% 45 50 55
Overall fixed operating cost $/ton 0.36 0.4 0.44 Natural gas delivered cost
(avg)
$/GJ Constant and dependent on the case Electricity cost (avg) $/MWh Constant and dependent on the case Glass material (avg cost) $/ton Constant and dependent on the case Sand for filling cost (avg) $/ton Constant and dependent on the case Steel for pipe liner (avg cost) $/kg Constant and dependent on the case PE for pipeline (avg cost) $/kg Constant and dependent on the case Engineering, procurement,
and construction (EPC)
% 9 10 11
Contingency on projected capital expenditure (not proven)
% 45 50 55
Glass furnace $/tons/day 20,700 23,000 25,300 Forming pressing machines $/tons/day 25,200 28,000 30,800
Annealing $/tons/day 2250 2500 2750
Oxygen generator $/tons/day 27,000 30,000 33,000
Pump for magazines $/kW 450 500 550
Magazines $/magazine 13,500 15,000 16,500
Produced CO2 capturing $/Nm3/h 67.5 75 82.5
Captured CO2 compressor and attachments
$/kW 630 700 770
Main pump $/kW 315 350 385
Fittings and attachments to pipeline
$/m3/h 7200 8000 8800
Electrical, control, and instrumentation
$/m3/h 4500 5000 5500
Cuptake Carbon uptake by cement materials (in this case concrete) over time (kg);
C Cement content in concrete (kg cement/m3);
A Exposed surface area (m2);
k Carbonation rate coefficient of concrete (mm/years0.5);
Cclinker Clinker to cement ratio (−);
γ Proportion of CaO within fully carbonated cement that converts to CaCO3(−);
Mt Ratio to C element to CaO (−);
fCaO Average CaO content of clinker in cement (−); and
t Service life (years).
Based on the hypothesis by Xi et al. (2016), C is assumed 400 kg/m3. Moreover, the
exposed area is supposed to be the six faces of a cube of concrete containing 2.3 ton of cement during the service life, while after demolition, it will be particles with a size > 0.1 m. The
Fig. 6 The total storage cost of the four case studies ($/tCO2)
Table 6 Cost of the different technologies for carbon capture and storage (FOAK, first-of-a-kind, NOAK, n-of-a-kind) are portrayed
Reference Cost range
($/tCO2)
Phase Technology Notes
ZEP (2011)/Rubin and Davison (2015)
4.8 Transport Pipeline Offshore (uncertainty 30–50%)—2013 USD—250 km
IPCC (2005)/Rubin and Davison (2015)
3.4–4.3 Transport Pipeline Offshore 10 MtCO2/year—2013
USD—250 km
Roussanaly et al. (2013) 10.8 Transport Shipping 480 km—2.5 MtCO2/year—conv. Euro
to USD 1.15 rate ZEP (2011)/Rubin and
Davison (2015)
2–18 Storage Onshore storage
2013 USD IPCC (2005)/Rubin and
Davison (2015)
1–12 Storage Onshore storage
2013 USD GCCSI (2011)/Rubin and
Davison (2015)
6–13 Storage Onshore storage
clinker to cement ratio is assumed 0.95; the proportion of CaO within fully carbonated cement that converts to CaCO3is 0.8;Mtis equal to 0.214; the average CaO content of clinker in
cement is 0.65, and the service life is 70 years.
The carbonation rate coefficient of concrete,k, depends on the environmental conditions (exposed, sheltered, indoors, wet, buried), on the concrete strength classes (< 15 MPa, 15– 20 MPa, 25–35 MPa, > 35 MPa) and it should also be corrected depending on the surface treatment and cover and on the use of supplementary cementitious materials (Pommer and Pade2005). In this study, an indoor environment and strength of > 35 Mpa were considered, resulting ink = 3.5 mm/years0.5during the service life and 0.75 mm/years0.5after demolition
assuming it is disposed of in a landfill.
The dynamics of carbon removal that result by applying Eq. (4) is shown in Fig.7; during the average life of the CSCS plant (40 years), only 7.5% of the potential carbon uptake takes place. After the demolition, a more significant amount of carbon is absorbed by the cement. In a 100-year perspective, it is possible to estimate that 34.8% of the CO2 released by the
calcination during the production of cement will be uptake.
If CO2absorption by cement-based products can be considered a mechanism of negative
emission, the costs of this carbon removal depend on the up-front cost of the carbon capture from the flue gas of the cement plant and the cost of carbon storage, partly balanced by the economic gain generated by cement production.
Considering a cost for CO2capture from cement plants of about 50–104 $/tCO2(Barker
2009; Hills et al.2016) and the average cost for CO2storage with the CSCS technology of
21 $/tCO2 (see Table 3), a total cost of about 71–125 $/tCO2 captured and stored can be
estimated.
The cost of the carbon removal in a 100-year timespan—in which the equivalent of 34.8% of the carbon stored is removed from the atmosphere—is approximately 204–359 $/ton negative CO2(204 = 71/0.348). This number is far higher than the cost of many mitigation
measures but comparable to the higher cost of other NETs as direct air capture (Honegger and Reiner2018).
Fig. 7 Carbon uptake by cement in concrete during its useful life and after demolition (dotted line) in case of landfill disposal is shown. The absorption is expressed as the percentage of the amount absorbed per ton of CO2
4 Conclusion
This study aimed to analyze the economic and environmental viability of individual CSCS projects in cement plants located in different sites as a negative emissions technology, utilizing a Life Cycle Assessment and a cost analysis.
The life cycle CO2penalization of the technology lies in the range 8–13%, with the capsule
production stage always being the most impactful not only on the climate change impact category, but also heavily affecting human toxicity and acidification. As a result, the choice of materials, energy sources, and processes used for capsule production have a major influence on the environmental performances of CSCS. The electricity mix has a strong correlation with the LCA results indeed, especially for the climate change impact category. A carbon-intensive way to produce energy significantly increases the penalization of the technology. As a consequence, to ensure a cleaner overall project, the use of renewable energies is necessary. The costs of CO2
storage (16–29 $/ton) is similar to other technologies under development and is in the range of cost estimated by Caserini et al. (2017).
The modularity of the CSCS technology that allows easy planning regarding installation and financing, without the constraints and uncertainties of other CO2storage technologies is a
critical factor for its future role as a climate change mitigation option.
This research shows that costs and GHG penalization of the CSCS technology applied to the four case studies are comparable with the alternative storage solutions currently under development worldwide.
Finally, it is possible to state that although the proposed CSCS technology represents an interesting alternative for safe CO2storage and deserves further research, the contribution of
cement-based products as a negative emissions source is limited and not competitive, due to the slow uptake of CO2during the lifetime of cement materials.
Acknowledgements The authors would like to thank Italcementi for the data provided.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
References
Adams EE, Caldeira K (2008) Ocean storage of CO2. Elements 4:319–324
Aminu MD, Nabavi SA, Rochelle CA, Manovic V (2017) A review of developments in carbon dioxide storage. Appl Energy 208:1389–1419
Andersson R, Fridh K, Stripple H, Häglund M (2013) Calculating CO2uptake for existing concrete structures
during and after service life. Environ Sci Technol 47:11625–11633 Barker DJ (2009) CO2capture in the cement industry. Energy Procedia 1:87–94
Caserini S, Dolci G, Azzellino A, Lanfredi C, Rigamonti L, Barreto B, Grosso M (2017) Evaluation of new technology for carbon dioxide submarine storage in glass capsules. Int J Greenhouse Gas Control 60:140– 155
Dooley J (2013) Estimating the supply and demand for deep geologic CO2 storage capacity over the course of the 21st century: a meta-analysis of the literature. Energy Procedia 37:5141–5150
EC - European Commission (2013) Recommendation of 9 April 2013 on the use of common methods to measure and communicate the life cycle environmental performance of products and organizations. OJ L, 124, 4.5.2013
EMODnet (2016) European Marine Observation and Data Network, Bathymetry portal. http://www.emodnet-bathymetry.eu/. Accessed 29 Dec 2018
Eurostat (2016a) Natural gas price Statistics.http://ec.europa.eu/eurostat/statistics-explained/index.php/Natural_ gas_price_statistics. Accessed 29 Dec 2018
Eurostat (2016b) Labour cost, wages, and salaries, direct remuneration (excluding apprentices) by NACE Rev. 2 activity—LCS surveys 2008 and 2012.http://appsso.eurostat.ec.europa.eu/nui/show.do?dataset=lc_ncost_r2 &lang=en. Accessed 29 Dec 2018
Eurostat (2016c) Energy price Statistics.http://ec.europa.eu/eurostat/statistics-explained/index.php/Energy_ price_statistics. Accessed 29 Dec 2018
Fuss S, Lamb WF, Callaghan MW, Hilaire J, Creutzig F, Amann T, Beringer T, Garcia WO, Hartmann J, Khanna T, Luderer G, Nemet GF, Rogelj J, Smith P, Vicente JLV, Wilcox J, Dominguez MMZ, Minx JC (2018) Negative emissions—part 2: costs, potentials and side effects. Environ Res Lett 13:063002
Gale J (2015) Special Issue commemorating the 10th year anniversary of the publication of the Intergovernmental Panel on Climate Change Special Report on CO2Capture and Storage
GCCSI (2011) Economic assessment of carbon capture and storage technologies 2011 update. Global Carbon Capture and Storage Institute
GCCSI (2018) The global status of CCS: 2018. Global CCS Institute, Melbourne
Havlova V, Laciok A, Cervinka R, Vokal A (2007) Analogue evidence relevant to UK HLW glass waste forms. Nuclear Research InstituteRez plc
Hekinian R, Hoffert M (1975) Rate of palagonitization and manganese coating on basaltic rocks from the Rift Valley in the Atlantic Ocean near 36°50′N. Mar Geol 19(2):91–109
Hills T, Leeson D, Florin N, Fennel P (2016) Carbon capture in the cement industry: technologies, progress, and retrofitting. Environ Sci Technol 50(1):368–377
Hischier R, Weidema B, Althaus HJ, Bauer C, Doka G, Dones R, Frischknecht R, Hellweg S, Humbert S, Jungbluth N, Köllner T, Loerincik Y, Margni M, Nemecek T (2010) Implementation of Life Cycle Impact Assessment Methods. Ecoinvent report No 3. Swiss Centre for LCI, Dübendorf
Honegger M, Reiner D (2018) The political economy of negative emissions technologies: consequences for international policy design. Clim Pol 18(3):306–321
IEA (2013) Technology roadmap 2035 2040 2045 2050 energy technology perspectives carbon capture and storage. International Energy Agency, Paris
IEA (2015) Carbon capture and storage: the solution for deep emissions reductions. OECD/International Energy Agency, Paris
IEA (2016) 20 years of carbon capture and storage—accelerating future |deployment. OECD/International Energy Agency, Paris
IEA Greenhouse Gas R&D Programme (2004) IEA Greenhouse Gas R&D Programme, 2004. IEA Greenhouse gas R&D Programme
IEAGHG (2008) A regional assessment of the potential for CO2 storage in the Indian subcontinent. International Energy Agency Greenhouse Gas R&D Programme Report 2/2008
IPCC (2005) Special report on carbon dioxide capture and storage. Cambridge University Press, New York ISBN: 92-9169-1190-4
IPCC (2007) Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report. Intergovernmental Panel on Climate Change. Section 7.4.5.1: Minerals—Cement
IPCC (2018) GLOBAL WARMING OF 1.5 °C, an IPCC special report on the impacts of global warming of 1.5 °C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty. Intergovernmental Panel on Climate Change
Kemper J (2015) Biomass and carbon dioxide capture and storage: a review. Int J Greenhouse Gas Control 40: 401–430
MISIS Joint Cruise Scientific Report (2014)BState of Environment Report of the Western Black Sea based on Joint MISIS cruise^ (SoE-WBS), Moncheva S. and L. Boicenco [Eds], 401 pp.
Morbee J, Serpa J, Tzimas E (2010) The evolution of the extent and the investment requirements of a trans-European CO2transport network. JRC Scientific and Technical Report
Nelder C (2015) Why carbon capture and storage will never pay off.www.smartplanet.com. Accessed 29 Dec 2018
Nemet GF, Callaghan MW, Creutzig F, Fuss S, Hartmann J, Jérôme H, Lamb WF, Minx JC, Rogers S, Smith P (2018) Negative emissions—part 3: innovation and upscaling. Environ Res Lett 13:063002
Norton FJ (1952) Helium diffusion through glass. Fall meeting of the glass division. The American Ceramic Society, Ohio
Oliver G, Janssens-Maenhout G, Muntean M, Peters JAHW (2016) Trends in global CO2emissions: 2016
Report. PBL Netherlands Environmental Assessment Agency and European Commission, Joint Research Centre
Opyd M, Frischcat GH, Aigner ML, Köpsel D (2007) Determination of inert gas solubilities in borosilicate glass melts. Glass Technol. Eur J Glass Sci Technol A 48:31–34
Pade C, Guimaraes M (2007) The CO2uptake of concrete in a 100-year perspective. Cem Concr Res 37:1348–
1356
Pawar R, Carey W (2015) Recent advances in risk assessment and risk management of geologic CO2storage. Int
J Greenhouse Gas Control 40:292–311
Pommer K, Pade C (2005) Guidelines—uptake of carbon dioxide in the life cycle inventory of concrete. Nordic Innovation Centre
Reseghetti F (2008) Factors affecting quality of XBT data: results of analyses on profiles from the western Mediterranean Sea. ENEA-C.R:.A.M. Teresa, Lerici, Italy.www.aoml.noaa.gov/phod/goos/meetings/2008 /XBT/F_Reseghetti.htm. Accessed 29 Dec 2018
Rockström J, Gaffney O, Rogelj J, Meinshausen M, Nakicenovic N, Schellnhuber HJ (2017) A roadmap for rapid decarbonization. Science 355:1269–1271
Rogelj J, Luderer G, Pietzcker RC, Kriegler E, Schaeffer M, Krey V, Riahi K (2015) Energy system transfor-mations for limiting end-of-century warming to below 1.5 °C. Nat Clim Chang 5:519–528
Roussanaly S, Jakobsen JP, Hognes EH, Brunsvo AL (2013) Benchmarking of CO2transport technologies: part
I—onshore pipeline and shipping between two onshore areas. Int J Greenhouse Gas Control 19:584–594 Rubin E, Davison J (2015) The cost of CO2capture and storage. Int J Greenhouse Gas Control 40:378–400
Rubin E et al (2013) A proposed methodology for CO2capture and storage cost estimates. Int J Greenhouse Gas
Control:488–503
Shackelford JF (2014) Gas solubility and diffusion in oxide glasses—implications for nuclear wasteforms. Procedia Mater Sci 7:278–285
The Shift Project Data Portal (2016) Datasets on Electricity statistics.www.tsp-data-portal.org/all-datasets?field_ themes_tid=2. Accessed 29 Dec 2018
UNFCCC (2015) Paris Agreement. United Nations Framework Convention on Climate Change, doc. FCCC/CP/ 2015/L.9, 12 December.www.unfccc.int. Accessed 29 Dec 2018
Xi F, Davia SJ, Ciais P, Crawford- Brown D, Guan D, Pade C, Shi T, Syddall M, Lv J, Ji L, Bing L, Wang J, Wei W, Yang KH, Lagerblad B, Galan I, Candrade C, Zhang Y, Liu Z (2016) Substantial global carbon uptake by cement carbonation. Nat Geosci 9:880–883
ZEP - Zero Emission Platform (2011) The costs of CO2capture, transport and storage- post- demonstration CCS
