Modern Building Services

MODERN BUILDING SERVICES MARCH 2022 13 FEATURE HEATING rather than the emissions associated with gas combustion. The challenge is to ensure that the hydrogen is producedwithout emissions. The preferred production method is to split water into hydrogen and oxygen using electricity from renewable sources (so-called green hydrogen) as this method has zero net emissions. However, with a parallel push for heat pumps and electric cars, there is going to be considerable pressure on the capacity of the renewable electricity infrastructure. Another option is to bring natural gas and steam together to release both hydrogen and carbon dioxide (blue hydrogen). With carbon dioxide as a waste product, this must be used in conjunction with carbon capture and storage to avoid emission of greenhouse gases. Also, of course, the steam will need to be generated by heating water so there is a balance to be achieved here. The current timetable for introducing hydrogen is to begin blending it into themains gas supply by 2023 and, by 2030, most of industry will be expected to have switched to either a blended fuel or have fully switched fromnatural gas. HVO Whilst gas is the dominant fossil fuel used for heating, there is also a significant amount of oil-fired heating equipment in use. A prom- ising replacement is Hydrotreated Vegetable Oil (HVO), derived from used cooking oils and waste fats. Recent research has shown this to be a direct drop-in for gas oil in larger heating appliances and a near drop-in for kerosene in resi- dential installations. Summary For all of the reasons discussed here, there are many obstacles to overcome in the path to net zero carbon. To meet these challenges, we need to be looking at how we make use of the most appropriate technologies for each project, potentially using sophisticated control to optimise performance across a mixed heating system that integrates several technologies. Building services engineers have played a pivotal role in the progress that has already been made in reducing carbon emissions. They will continue to do so by working closely with manufacturers to apply the various technologies available in the most efficient manner.