Abstract
This review aims to dispel the myths, misinformation and fake facts about hydrogen burner flames in the literature. These are creating resistance the adoption of hydrogen for decarbonising heat. Trials of hydrogen heat in hydrogen villages have been opposed in the UK by outside groups generating unsubstantiated fears about the safety of the use of hydrogen and influencing Government policy on the decarbonisation of domestic and industrial heat. There are many myths about the use of hydrogen for heat (Hy4Heat), most of which relate to safety, which ignore all the work done under UK Government Hy4Heat contracts, that show that hydrogen will be as safe as natural gas (NG) in use, in domestic and industrial heat applications. Some claim that the manufacture of hydrogen from NG will generate more greenhouse gases (GHG) than burning it directly (Rosenow, 2022), which is shown to be not true for modern low plants. Domestic and industrial electricity is delivered by the electricity grid, which currently cannot operate without 35% of the electricity from NG fired combined cycle gas turbines (CCGT), as this fills in the supply gaps when the wind is low and the sky cloudy. This means that electric heat pumps are not zero carbon and are shown to have higher carbon emissions than hydrogen made from NG using the latest technology. In contrast hydrogen, can be manufactured from NG or by electrolysis directly by solar and wind farms, without any connection to the electricity grid and fed into the gas transmission system, with only relatively low cost modifications. Hydrogen burners can be designed to meet all current NOx standards and even have lower NOx than on NG and will not be allowed to emit higher NOx than for NG. Practical hydrogen burners for heat applications have orange flames and very visible not invisible, as many in the literature claim. The UK and other countries in 1900 - 1965 built coal gasification plants on a large scale to feed the gas grid with coal gas (about 40% hydrogen), then replaced the gas with natural gas in the 1965 – 1975 period, fuel switching to hydrogen is conventional gas engineering and achievable over a 10-15 year period. In the UK the gas grid in 2022 supplied 784TWh of energy compared with 320 TWh of electricity with only 99 TWh of this from solar/wind/hydro. It is obviously grossly misleading to say that gas energy can be replaced by increased solar/wind/hydro on any sensible timescale. Switching the 300 TWh of domestic heat from gas to electricity in addition to switching transport energy to electricity, cannot be met on the required timescale by increased solar/wind/hydro in the UK. Net zero can be met on a 10-15 year timescale if NG is switched to hydrogen, which enables net zero electricity, as well as net zero heat.
