Hydrogen (green) is an important path to decarbonisation. The hydrogen economy is on the rise, the worldwide demand for hydrogen as an energy carrier is expected to grow considerably in the coming decades.

Hydrogen has been used safely in industry for many decades. With the rapid development of hydrogen applications it is important to ensure new designs take account of the specific physical characteristics of processing and handling hydrogen for all users. Awareness of hydrogen hazards is critical so that early precautions can be taken, to ensure the design of a safe and reliable hydrogen system. Characteristic aspects that could have an impact are:

• The hydrogen molecule is small which makes hydrogen systems more prone to leakages compared to natural gas systems. Therefore, hydrogen requires better sealing of equipment and piping to prevent leakages.
• Due to hydrogen’s low ignition energy, hydrogen is especially prone to auto-ignition of leaks and atmospheric vents. This tendency towards auto-ignition, combined with a flame that is difficult to see, make small hydrogen leaks a serious potential risk.
• Hydrogen has unique corrosion properties and may react with steel and other metals. This induces material brittleness which may lead to fractures.
• Hydrogen is lighter than air. A leakage will rise upwards, and it is therefore important to avoid possibilities of hydrogen accumulation above potential leakage points. Hydrogen leakages will in general disperse quickly.
• Ignition of hydrogen vapor clouds in modules tends to give higher explosion loads than corresponding natural gas clouds because of the speed of the flame front.

These characteristic hydrogen aspects hydrogen will have design implications on the following aspects:

• Gas & fire detection
• ATEX requirements
• Ventilation (natural or forced) to prevent accumulation of H2
• Explosion protection measures
• Vent design
• Material selection

What can Treecon do?

• HSE in design: HAZOP/HAZID, LOPA and SIL verification
• Fire and Explosion Risk assessments (including CFD)
• Dispersion calculations (including CFD)
• ATEX classification (drawings)
• FMECA/RAM assessment
• HSE/Technical Safety Engineering Support

Treecon experience:

• Conceptual design H2 offshore pilot project in the Netherlands
• HAZOP H2 offshore pilot project in the Netherlands
• HAZOP/LOPA application of liquid stored and H2 fuel cell powered superyacht.
• ATEX classification H2

The last ten years the offshore wind energy has grown to a major contributor to the palette of renewable energy sources. This is especially evident in Europe where the demand for wind energy has shifted from onshore to offshore to provide the required increase in renewable energy. A key component in the offshore wind farms is the offshore substation where the power from multiple windturbines is gathered and the voltage of the produced electricity from the wind turbines is transformed and converted to minimize the losses during the cable transport to shore.

The main safety challenges for offshore substations are:

• The AC high voltage transformer stations are based on well-established and broadly applied onshore concepts, but are relatively new within the offshore application
• The offshore substations have accelerated the development of DC converter stations which brings new challenges for the offshore platform design, in terms of lay-out and mechanical handling
• The substations are unmanned remote operated installations, requiring high reliability and a high availability level
• The High Voltage equipment introduces additional fire and explosion risks.

What can Treecon do?

• HSE in design: HAZID, HAZOP, HSE Design philosophies, Fire and Explosion protection concepts, Escape and Evacuation and Rescue concepts
• Reliability Availability and Maintenance studies, including FMECA, Availability analysis (RBD, FTA), Maintenance and Spare parts strategies
• Fire and Explosion Risk Assessment (including CFD)
• Escape, Evacuation and Rescue Assessment

Treecon Experience:

• Support on HSE and RAM for more than a decade to
  • FEED and EPC projects for several AC Transformer and DC Converter offshore substations ranging from 200 MW to 2 GW capacity
  • Substations that must be complaint with international standards and national regulations in Dutch, German, Belgian, UK and US waters.

The IPCC and IEA emphasizes that Carbon Capture and Storage (CCS) on an industrial scale is a necessary part of reaching The Paris Agreement climate targets. Although debates are still ongoing regarding whether CCS is decreasing the pace towards fully renewable sources, a majority considers CCS as required in the transition towards a zero-emission future.

Carbon dioxide has been widely used in the industry for a long time, however the transport and storage of CO2 in depleted (offshore) gas fields brings new safety risks that need to be considered.

There are specific characteristics of CO2 which need special attention in the risk assessment:

• CO2 is asphyxiating and toxic and it is 1,5 times heavier than air. Relatively small leaks could cause accumulation of CO2 in certain not well-ventilated areas, which – if undetected – can be lethal to personnel.
• It has a strong Joule-Thomson (JT) effect, which can cause low temperatures. These low temperatures can be challenging for material selection and can also cause flow assurance issues.
• CO2 has corrosive properties when in contact with water, which could lead to rapid decrease of wall thickness of piping and/or pipelines due to corrosion.
• Low pressures in depleted gas fields, phase transitions of the CO2 in the pipeline (or in other transport systems) can cause operational challenges.

What can Treecon do?

• Gas dispersion studies to optimise the location of gas/air detectors to avoid spots or areas with undetected CO2 accumulation. Dispersion studies include the use of CFD, which can be used as input into mapping studies.
• HSE in design: HAZOP/HAZID, LOPA and SIL verification
• Dispersion and venting studies

Treecon Experience:

• Conceptual HAZID offshore CO2 receiving / injecting facilities for multiple CCS projects in the Netherlands
• HAZOP offshore CO2 receiving / injecting facilities