A Preliminary Assessment of the Potential of Low Percentage Green Hydrogen Blending in the Italian Natural Gas Network

Abstract

The growing rate of electricity generation from renewables is leading to new operational and management issues on the power grid because the electricity generated exceeds local requirements and the transportation or storage capacities are inadequate. An interesting option that is under investigation by several years is the opportunity to use the renewable electricity surplus to power electrolyzers that split water into its component parts, with the hydrogen being directly injected into natural gas pipelines for both storage and transportation. This innovative approach merges together the concepts of (i) renewable power-to-hydrogen (P2H) and of (ii) hydrogen blending into natural gas networks. The combination of renewable P2H and hydrogen blending into natural gas networks has a huge potential in terms of environmental and social benefits, but it is still facing several barriers that are technological, economic, legislative. In the framework of the new hydrogen strategy for a climate-neutral Europe, Member States should design a roadmap moving towards a hydrogen ecosystem by 2050. The blending of “green hydrogen”, that is hydrogen produced by renewable sources, in the natural gas network at a limited percentage is a key element to enable hydrogen production in a preliminary and transitional phase. Therefore, it is urgent to evaluate at the same time (i) the potential of green hydrogen blending at low percentage (up to 10%) and (ii) the maximum P2H capacity compatible with low percentage blending. The paper aims to preliminary assess the green hydrogen blending potential into the Italian natural gas network as a tool for policy makers, grid and networks managers and energy planners.

The Role of Green and Blue Hydrogen in the Energy Transition—A Technological and Geopolitical Perspective

“…A potential option to gradually upscale hydrogen pathways is the integration in existing natural gas networks. This is being proposed in different European countries [32][33][34] to exploit existing assets and start to decrease the carbon intensity of natural gas by using clean hydrogen. However, such strategy has the strong limitation of not fully exploiting the higher value associated with pure hydrogen, by mixing it with natural gas to be used in combustion processes.…”

Analysis of the Role of the Latvian Natural Gas Network for the use of Future Energy Systems: Hydrogen from Res

“…Preliminary assessments and tests in the EU countries [3], [5]- [7] show that it is urgent to evaluate at the same time (i) the potential of green hydrogen blending at low percentage (up to 10%) and (ii) the maximum of available P2H capacity compatible with low percentage blending. If the first estimates purely theoretically calculate the maximum possible amounts of hydrogen gas that can be filled into the existing national NG networks at low impurity concentrations [5], [6], then real experiments are performed in separate network sections, e.g., in Germany and Denmark with "windgas", France (Dunkerque), the UK (Keele, Leeds), Italy (Salerno).…”

“…In Italy, two different networks are operated [6]: the transportation and the distribution networks. More than 90 % of natu-ral gas is imported from foreign countries through 7 points.…”

“…Therefore, hydrogen blending is assumed only in the Italian transmission gas system, which is considered an option for location of P2H plants. Even if the Italian regulation allows for hydrogen concentration for blending only up to 1.0 % [6], as defined for biomethane injection, experimental activities have been already performed in existing networks: 5 % blending has been already tested in a small closed network near the southern city of Salerno (see references in [6]). Up to 8100 ton/year of green hydrogen blending, i.e., 715,000 Sm 3 /year can be injected right now in the existing Italian NG network with a proper location and sizing of P2H plants with an installed capacity of about 78 MW of electrolyzers and about 488 MEUR of investment.…”

Aspects of Hydrogen and Biomethane Introduction in Natural Gas Infrastructure and Equipment

“…In an investigation of the impact of hydrogen in power-to-gas networks where the entire system was analysed from a material aspect standpoint, Gondal states that only a 2% of H 2 by volume can be blended in the networks with negligible effects, particularly due to the impacts on specific end applications such as gas turbines and engines [17]. Recently, Pellegrini et al, in a study assessing the potential of green hydrogen blending in the Italian natural gas network, concluded that grid adaptations in critical components and adjustments to the end-user will be necessary to deliver the ambitious goals of the European hydrogen strategy [18].…”