Legal framework: permissions and restrictions (and Ownership constraints (unbundling))

This LAP concerns the injection of hydrogen into the gas grid at the TSO level and the legal framework status covering authorised bodies and varying hydrogen concentration levels in the TSO transmission system along with potential changes to the regulatory framework to support enhanced hydrogen injection and utilisation


The existing national legal framework for the DSO to carry out hydrogen activities, which is normally restricted to natural gas. Ownership constraints refer to the constraints related to ownership associated with the process of injecting.
Is it a barrier?
Type of Barrier
Structural barriers, Operational barriers, Economic barriers, Regulatory gap
Assessment Severity


Question 1 Which is the responsible authority/legal entity for the permission of the connection/injection of hydrogen in the gas grid?
On distrubution grid level it is the DSO who has to decide whether hydrogen can be injected in the gas grid - so in analogy to the decision of a TSO. Once construction works take place - so the facility will be connected to the gas grid, the DSO has to take care of the technical requirements, subsequently has to follow the Trade, Commercial and Industry Regulation Act. If the facility is having an impactt on the economics of the DSO - which is of course the case - one has to follow the natural gas act 2011. So the responsible authority is the regulator authority for energy.
Question 2 What is permitted or restricted according to national legislation under your responsibility as DSO regarding the transmission of pure hydrogen and mixtures of hydrogen and natural gas.
The connection to the gas grid is dealt with in line with the lTrade, Commercial and Industry Regulation Act (so <= 150.000 tons per year) in technical terms/requirements , where the county administration acts as an One Stop Shop. In other words, the county administration takes care of all other obligations in line with the relevant laws. Otherwise the Environmental impact assessment law UVP–G 2000 has to be followed. In case of an eased environmental impact assessment it is the Government of the Austrian Bundesländer which acts as a one stop shop; the results of the assessment are notified to the applicant in a concerted/concentrated decision. This decision summarizes the assessments of the relevant experts. Similar to the TSO. A DSO has to take care of the safe and reliable operation of the distribution system, thus the DSO will allow the feed in of gas which matches the specified quality. Restrictions see question 3 et sqq
Question 3a - Is there a maximum concentration defined that you are allowed to transport as a DSO? (e.g. are you allowed to transport 100% hydrogen)
In Austria max. 4% Mol–Percent can be injected into natural gas grids; see standard:/guideline ÖVGW 31 in combination with ÖVGW 33.
Question 3b - In case the maximum hydrogen concentration in your transmission grid (system) is less than 100%, is it allowed to inject pure hydrogen- 100%? into gas grid on transmission level (up to the allowed concentration)?
In Austria max. 4% (Mol–basis) can be injected into natural gas grids. In other words, after injection of hydrogen, the mixture may contain 4% (Mol) hydrogen; see standard:/guideline ÖVGW 31 REMARK. : Directive 2009/73/EU defines transmission grid as a high pressure grid used as trunk lines; distribution grid is different to transmission grid; It has not been clarified yet whether it is allowed to inject pure hydrogen into the gas grids (so the amalgamation takes place in the grid). The amount of injected hydrogen has to follow the demand fluctuation of the energy in order not to exceed or to fall below the threshold, which means that a storage possibility for hydrogen might be needed or the hydrogen producing device is capable to operate on a strongly fluctuating basis without shortening the life time expectations of the device significantly.
Question 3c - If no, who is responsible for the blending with natural gas? Is there an obligation for the TSO to provide the necessary natural gas for blending the hydrogen (with several EU Directives transposed into national legislations the functions of gas grid operator and natural gas supplier are separated)
c - Not clarified yet BUT following the so far used approach, the TSO/DSO is responsible for the safe, cost efficient and reliable operation of the transmission grid. If the quality of the gas to be injected into the system doesn’t meet the specifications, the TSO has to reject injection in the gas grid; the same is valid for a DSO. So in case of injection of hydrogen in the gas grid, the mixture has to be achieved within the gas grid, hence the provisions have to be amended.
Question 4 If the concentration for injection is different than the maximum allowed concentration (question 2 and 3) question please answer this question What is the maximum allowed concentration in your country for injection in the gas grid on transmission level?
Basically one can inject 100% – so pure hydrogen in the gas grids but in the subsequent mixture with natural gas, the amount of4% (Mol–basis) shall not be exceeded. This means that some kind of mixing device is needed on the transmission or distribution grid level. Since there is a need to feed in the gas grids on a fluctuating basis in order not to exceed the 4% threshold,a storage possibility for hydrogen might be required
Question 5 Are there specific requirements for increasing or decreasing the admissible threshold of hydrogen concentration (upstream and downstream networks, infrastructure elements and appliances with lower tolerance)? If yes: please describe.
The maximum amount results from technical restrictions (brittleness of the pipeline material and technical equipment material like for example valves). Since it would cause extremely high hurdles to cope with different hydrogen contents (billing purposes and Wobbe index) it is strongly recommended to operate the system at a determined level)
Question 6 Are there specific restrictions/permissions for the transport of hydrogen other than “concentration” and “quality”, if yes which ones?
Since hydrogen changes the gross calorific value, the gas quality requirements have to be adapted. In the worst case scenario, the hydrogen– gas mixture is not everywhere in the gas grid the same, then one can face very serious bill of discharge and Wobbe Index problems because it is the gross calorific value the customer pays for and not for the consumed volume respectively the changed Wobbe Index probably requires the adaptation of the burner nozzles
Question 7 If it can be guaranteed that the gas is on the required quality specification (on spec) at the next customer, is it allowed to feed in off-spec gas (read: a higher concentration of Hydrogen)?
Since hydrogen changes the gross calorific value, the gas quality requirements have to be adapted. In the worst case scenario, the hydrogen– gas mixture is not everywhere in the gas grid the same, then one can face very serious bill of discharge problems because it is the gross calorific value the customer pays for and not for the consumed volume. From this perspective a feed in of off–spec–.gas might be very complex if not impossible. Besides, the TSO or DSO will not be prepared to accept feed in of off spec gas, since it is the TSO/DSO who is responsible for the safe, cost efficient and reliable operation of the system.
Question 8 Which part of the connection facility (the injection installation is part of the connection facility) is owned by or under the responsibility of the DSO?
Basically the DSO is obliged to accept gas at the specified quality - if there is sufficient transportation capacity available. So it is up to the hydrogen producer to transport the hydrogen – at the required quality – to the grid and take care of the proper mixture. So the hydrogen producer is owner of the facility, the connection pipeline etc. The injection installation – following the so far used approach – has to be owned by the TSO/DSO since the device probably has to be embedded into the grid operated by the TSO/DSO. Very likely the hydrogen producer will have to take care of the investment and OPEX of the injection installation. The mentioned requirement is difficult to be fulfilled since some kind of “mixture device has to be installed in the grid.
Question 9 As TSO, do you see legal and administrative restrictions with regard to the ownership of your part of the connection facility (the injection installation is part of the connection facility) of hydrogen into the grid?
Definitely yes, since the obligation of the DSO is to take over gas at the required quality - if sufficienta transportation capacity is available - but in case of hydrogen injection, the mixture probably has to be created in a mixture device – like a diffusor or mixture drum. So far this issues have not been finally clarified.
Question 10 Is there a difference in legal and administrative restrictions between connections for hydrogen injection into TSO and DSO-networks? If so could you please specify the differences?
No, it is up to the TSO and DSO to operate their grids safely and in a cost efficienta and reliable manner, hence they have to accept gas – intended to be injected into the – at the specified quality only. From the technical layout both applications have to follow the same provisions
Question 12 Is it foreseen to review the current regulation to consider hydrogen injection into natural gas network and if yes on which term?
So far not

National legislation:

EU Legislation:

  • Directive 2009/73/EC concerning common rules for the internal market in natural gas
    Directive 2009/73/EC establishes common rules for the transmission, distribution, supply and storage of natural gas.

    Its provisions and obligations apply to Hydrogen Gas by virtue of Article 1 (2), which states that the rules established by this Directive for natural gas, including LNG, shall also apply in a non–discriminatory way to biogas and gas from biomass or other types of gas in so far as such gases can technically and safely be injected into, and transported through, the natural gas system.

    Article 25 establishes the “Tasks of the distribution system operator” which include: ensuring the long-term ability of the system to meet reasonable demands for the distribution of gas […];shall provide any other distribution, transmission, LNG, and/or storage system operator with sufficient information […] as well as to ensure that the system operator does not discriminate between system users or classes of system including, including e.g. when setting rules for the charging of system users, etc

    Article 32 sets the rules on “Third party access”: access to the transmission and distribution system, and LNG facilities shall be based on published tariffs, applicable to all eligible customers, including supply undertakings, and applied objectively and without discrimination between system users.
  • Regulation 715/2009 on conditions for access to the natural gas transmission networks
    Regulation 715/2009 sets non-discriminatory rules for access conditions to (a) natural gas transmission systems; (b) LNG facilities and storage facilities taking into account the special characteristics of national and regional markets

    To achieve this, it sets harmonised principles for tariffs, or the methodologies underlying their calculation, for access to the network, but not to storage facilities, the establishment of third-party access services and harmonised principles for capacity-allocation and congestion-management, the determination of transparency requirements, balancing rules and imbalance charges, and the facilitation of capacity trading.
  • Regulation (EC) No 713/2009 of the European Parliament and of the Council of 13 July 2009 establishing an Agency for the Cooperation of Energy Regulators
    Article 1 Project matter and scope
    This regulation aims at:
    (a) setting non–discriminatory rules for access conditions to natural gas transmission systems taking into account the special characteristics of national and regional markets with a view to ensuring the proper functioning of the internal market in gas;

    Article 8 “Tasks as regards terms and conditions for access to and operational security of cross border infrastructure
  • Commission Regulation (EU) 2015/703 of 30 April 2015 establishing a network code on interoperability and data exchange rules
    The network code on interoperability aligns the complex technical procedures used by network operators within the EU, and possibly with network operators in the Energy Community and other countries neighbouring the EU.Article 7, Measurement principles for gas quantity and quality. In addition to interconnection points, Article 17 shall apply to other points on transmission network where the gas quality is measured. Article 18 shall apply to transmission systems. This Regulation may also apply at entry points from and exit points to third countries, subject to the decision of the national authorities.