1. The international drive to reduce CO2 emissions has led to the proposal of blending hydrogen with natural gas for heating.
2. Research has looked at the steady state and transient distribution of hydrogen in a natural gas pipeline and its influence on pressure drops and resistance.
3. Injecting pure hydrogen into natural gas in a pipe flow via a simple 90° branch can create a blended mixture, but this introduces two diametrically opposite constraints from energy delivery and material selection.
The article is generally reliable and trustworthy, as it provides evidence for its claims through references to other research papers, such as , , , , , , , , , , ,  and . It also presents both sides of the argument equally, noting both the potential benefits of blending hydrogen with natural gas for heating, as well as the potential risks associated with it. The article does not appear to be biased or one-sided in any way, nor does it contain any promotional content or partiality.
However, there are some points that could be explored further in order to make the article more comprehensive. For example, while the article mentions possible risks associated with blending hydrogen with natural gas, it does not provide any details on what these risks might be or how they can be mitigated. Additionally, while the article discusses potential material selections for pipelines carrying blended mixtures of hydrogen and natural gas, it does not explore counterarguments or alternative materials that could be used instead. Finally, while the article mentions that different countries have different laws regarding maximum concentrations of hydrogen in pipelines, it does not provide any information on what these laws are or how they differ from each other.