MELITA TRANSGAS HYDROGEN READY PIPELINE

Engineering

The project promoter started to perform the first project development activities in 2012 and has successfully completed the Pre-Feasibility Study in 2015 and the Basic Design Study in 2017. Both these studies have been co-funded by EU, the former through the TEN-E program and the latter through the CEF program.

The overall conclusion of these completed studies identified a 22 inch diameter hydrogen ready pipeline between Gela (Sicily – Italy) and Delimara (Malta) with an annual operational capacity of 1.2 Bcm/year for natural gas and 4.2 Bcm/year if operating on pure hydrogen as the most technically and economically feasible solution.

MAIN TECHNICAL
PARAMETERS
  • Starting Point – Gela, Sicily
  • Landing Point – Delimara, Malta
  • Outside Pipeline Diameter – 22” (560mm)
  • Offshore Route – 151 kilometres
  • Onshore Route (IT- Gela-Sicily) – 7 kilometres
  • Onshore Route (MT – Delimara) – 0.7 kilometre
  • Max water depth – 160 m b.s.l.
  • Max. Operational Capacity (Natural Gas) – 1.2 Bcm/year
  • Max. Operational Capacity (Pure Hydrogen) – 4.2 Bcm/year
  • Pipeline Design Pressure – 93 barg
  • Min. Guaranteed Pressure (Gela) – 50 barg
  • Delivery Pressure – 38 barg
  • Pipeline Design Temperature – 10/ +60 °C
  • Inlet Temperature (Gela) – 15 °C

The characteristics of the SRG (Snam Rete Gas) National Network in Sicily and the pressure requirements of the current design of the MTG Pipeline are such as not to require the construction of a compressor station downstream of the connection.

In order to guarantee access and interface to the gas transmission network, SRG will be constructing a terminal station adjacent to the MTG Terminal Station in Gela. The new interconnection point will be located between the two Terminal Stations and the MTG pipeline shall be connected to the existing Gela-Enna main gas transmission header.

Additionally, the design of the pipeline system has been upgraded in such a way as to cater for the possibility to transport a blend of hydrogen/natural gas up to 100% Hydrogen. This capability will give more options to Malta to achieve the decarbonisation goals in line with EU Green Deal objectives for reaching net-zero global warming emissions by 2050.

PRELIMINARY MARINE
ROUTE SURVEY

A Preliminary Marine Route Survey (PMRS) was required during this preparatory phase of the project prior to its implementation.

For this scope, following a public call for tenders, a contract for the marine survey was awarded to the specialized company Lighthouse. This contract was 50% co-financed by the European Union under the Connecting Europe Facility program.

The survey was carried out on the 1.2 km wide and 151 km long offshore pipeline routing corridor between Malta and Sicily.

The campaign involved geophysical, geotechnical and environmental activities in order to determine the characteristics for an optimal pipeline design with minimal environmental disturbance. Following the survey, a post survey assessment (PSA) was then carried out in order to formalize and investigate the actual findings.

The PMRS survey was carried out using a number of different vessels depending on the location and the type of intervention. First, the geophysical survey was carried out using various equipment including a multi-beam echosounder (MBES), a side-scan sonar (SSS), a magnetometer and a sub-bottom profiler (SBP). With this equipment, it was possible to determine the bathymetry and morphology of the area.

Furthermore, the resolution of the survey allowed the mapping
of all obstructions along the routes such as existing cables,
natural formations, anthropogenic objects and other artefacts.
Additionally, the geological stratigraphy was also obtained for the corridor under investigation to allow the interpretation of the
shallow geology.

Following the geophysical survey, a geotechnical and environmental sampling campaign was executed. These activities called for the use of different vessels and equipment from that mentioned above including the use of drilling barges for boreholes, gravity corers, box corers, core penetration testers (CPT), niskin bottles and plankton nets.

This geotechnical phase of the survey allowed the determination of the subsurface properties through investigation of the seabed whilst the environmental study allowed the investigation of the seabed ecology and biodiversity by analysing the sea water quality and sediment characterization.

Finally, all of the above allowed the determination of the optimal 500 m wide pipeline corridor to be investigated further by the Front-End Engineering Design (FEED) contractor and eventually by the EPC contractor during the final design and construction stage.

Therefore, the results of the survey and their interpretation through the PSA was crucial in order to determine the optimal pipeline route not only from a design point of view but also from a bathymetric profile and an environmental conservation perspective.

FRONT-END
ENGINEERING DESIGN
(FEED)

In November 2018, a contract was signed with the Joint Venture Techfem-SPS for the undertaking of the Front-End Engineering Design and the preparation of an Engineering, Procurement and Construction tender. This contract is being 50% co-financed by the European Union under the Connecting Europe Facility program.

The primary scope of the FEED is to provide the necessary information and design model for the drafting of the tender dossier for the EPC contract and to increase the level of accuracy of the cost estimate necessary to enable the final investment decision to be taken.

The FEED study consists of taking the design into a model, producing Piping and Instrumentation Diagrams (P&IDs), Material Take-Off (MTO), process flow diagrams, layouts, isometrics, etc. to a level of engineering solid enough to develop a cost estimate within +/- 15%, and a level 3 schedule which will provide all the inputs required to produce a tender specification for an EPC contract. Most of these activities have already been completed and the rest are in the stages of finalization, pending updates that will be required following the feedback received from the Competent Authorities.

The FEED contractor has already performed a risk assessment. Geotechnical investigations of the onshore route and the identified site of the terminal stations in Gela (Sicily) and Delimara (Malta) were also conducted as part of the FEED study. Core trials were taken for these investigations and neither destructive tests nor excavations were needed. Additionally, an offshore electrical Resistivity Tomography (ERT) survey was completed offshore Delimara in order to ensure that the rocks in the area are adequate to perform a trenchless microtunnel shore approach to land. 

THE MAIN OBJECTIVES/TASKS OF THE FEED STUDY

  • To ensure the constructability operability and maintainability of the pipeline project and to provide solid technical solutions to avoid or, if not possible, to mitigate the impact on environmentally protected areas, and also identify and propose measures for avoiding potential risks to the pipeline infrastructure safety.
  • Consideration and fulfilment of all HSE requirements, including hazard identification and risk assessment, review of Environmental Impact Assessment and support development of Project HSE Plan.
  • OVERALL PROJECT
    Systems hydraulic design; optimisation of sizing; definition of system and component availability; selection of codes and standards; technical support for permits acquisition; project planning; design of Integrated Control System (ICS) and SCADA (Supervisory Control and Data Acquisition) systems, main and standby telecommunication systems, utility requirements for the project.
  • OFFSHORE PIPELINE COMPONENT
    Route selection based on the Route Identification Study, the PMRS and post-assessment studies as well as the permitting studies in Italy and Malta including any further necessary desktop studies such as bathymorphological characterisation; metocean study; characterisation of fishing and shipping activities; geohazard and probabilistic seismic risk assessment; on-bottom strength analysis; pipeline integrity analysis; pipeline mechanical design; anti-corrosion design; coating design; stability design; protection design; seabed intervention design; cable crossings design; shore approach design; construction specification, landing point issues.
  • ONSHORE PIPELINE COMPONENT
    Route assessment; topographical, geotechnical surveys which shall involve drilling of core trials of the on-shore routes and sites of terminal stations in Delimara and Gela; mechanical design; anti-corrosion design; coating design; additional protection design; design and specification of pipeline components; stability and stress analysis; construction specification, cable and pipeline crossings, road and railway crossings, stream and river crossings, trenching and trenchless procedures.
  • ASSOCIATED ONSHORE FACILITIES
    Terminal station locations and area requirements; foundation requirements, equipment selection; complete multi-disciplinary design for filtering, metering and pressure reduction stations, any heating requirements, vents, pigging stations, valve isolation stations, access and safety requirements.
    The FEED studies were completed in 2020.