Investigation of the Multi-Point Injection of Green Hydrogen from Curtailed Renewable Power into a Gas Network

Abstract

Renewable electricity can be converted into hydrogen via electrolysis also known as power-to-H2 (P2H), which, when injected in the gas network pipelines provides a potential solution for the storage and transport of this green energy. Because of the variable renewable electricity production, the electricity end-user’s demand for “power when required”, distribution, and transmission power grid constrains the availability of renewable energy for P2H can be difficult to predict. The evaluation of any potential P2H investment while taking into account this consideration, should also examine the effects of incorporating the produced green hydrogen in the gas network. Parameters, including pipeline pressure drop, flowrate, velocity, and, most importantly, composition and calorific content, are crucial for gas network management. A simplified representation of the Irish gas transmission network is created and used as a case study to investigate the impact on gas network operation, of hydrogen generated from curtailed wind power. The variability in wind speed and gas network demands that occur over a 24 h period and with network location are all incorporated into a case study to determine how the inclusion of green hydrogen will affect gas network parameters. This work demonstrates that when using only curtailed renewable electricity during a period with excess renewable power generation, despite using multiple injection points, significant variation in gas quality can occur in the gas network. Hydrogen concentrations of up to 15.8% occur, which exceed the recommended permitted limits for the blending of hydrogen in a natural gas network. These results highlight the importance of modelling both the gas and electricity systems when investigating any potential P2H installation. It is concluded that, for gas networks that decarbonise through the inclusion of blended hydrogen, active management of gas quality is required for all but the smallest of installations.

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.…”

Profitability Model of Green Hydrogen Production on an Existing Wind Power Plant Location

“…A large volume of the literature also includes the possibility of injecting green hydrogen into the gas grid [19][20][21][22][23]. Hydrogen injection into the gas grid enables the transmission system operator to manage congestions by utilizing the flexibility of energy storage, thereby deferring the necessary investments in the transmission network.…”

A Comparative Life Cycle Assessment of Hydrogen Production & Storage with Renewable Energy Source and Grid Electricity Source

“…The distance from the production site to the storage site is around 50 to 57 km. The pipeline size is assumed to be 0.6m (600mm) to transport hydrogen over a distance of 50 to 55km as per the reliable data collected from Gas Network Ireland [18]. The material of the pipeline is selected as polyethylene as it has less impact over than other materials.…”