In the UK considerable resources are being spent on investigating the production, supply and utilisation of unconventional “green” gas, particularly viathe Research & Development of Hydrogen. The ins and outs of these R&D projects may seem unconnected to a heating engineer’s day job, but actually the future of the industry relies upon them.

Acceptable levels of hydrogen are currently specified in the HSE Gas Safety Management regulations and are very low with less than 0.1% being allowed. Some studies suggest that up to 20 % might be feasible.

Current studies

Northern Gas Networks have conducted a feasibility study into 100 per cent hydrogen gas being supplied through the gas grid. Their H21 Leeds Citygate study is arousing considerable interest on the basis that it envisages using the existing gas grid, and conventional heating systems such as gas central heating, but in a completely carbon-free way.

In November 16 National Grid Gas Distribution were successful in receiving funding of £11.6M for two pioneering projects, one of which is HyDeploy.  Northern Gas Networks, Keele University, ITM Power, Health & Safety Laboratory and Progressive Energy have come together for the HyDeploy project, which aims to demonstrate that natural gas containing levels of hydrogen beyond those in the current GS(M)R specification can be distributed and utilised safely & efficiently in a section of the UK distribution network. Keele has its own private gas network, which is seen as ideal for testing different levels of hydrogen-natural gas blends, with the appliances installed on a private, standalone network.

Research projects will continue to provide hard evidence on how appliances and supply infrastructure react to the addition of Hydrogen to natural gas, and potentially demonstrate that these gases are as safe, or safer, than those conventionally supplied.

There are many considerations and areas which require testing when it comes to hydrogen gas injection. The safety and performance of appliances must be closely monitored. We have to remember that there are still a lot of older appliances in use that may not be as versatile as today’s high efficiency, pre-mix gas boilers.

One of the issues with using a hydrogen gas mix is that the flame speed will generally increase, causing the flame profile in gas appliances to flatten.. The implications of this, such as increased burner surface temperatures, will need to be investigated for both old and new appliances.

Odour- Professor Rui Chen from Loughborough University recently gave a presentation to HHIC members on his proposed project to review odorants that can be used for Hydrogen.  Hydrogen is odourless, colourless, and tasteless, making it undetectable by human senses. The aim of his project is to develop suitable odorants for leak detection of hydrogen as a distributed fuel.

As a gas engineer you may think, we already have gas that has a recognisable smell, so why not recreate that? The problem with this is that today’s odorants contain sulphur which give it a pungent recognisable smell but this can have adverse effects on some of the proposed technologies for using hydrogen, such as  catalytic burners and fuel cells. Other  odorants are available, some having an apple or caramel type smell, but the fear is that these “pleasant” aromas may not prompt a consumer or engineer to identify and report a gas leak, as they would with conventional Sulphur-based stenching agents. Conventional odorants have slight effects on electrical generation and so sensors put into the gas mix may be affected, but the research project will evaluate any potential issues here.

It’s an area with many complex challenges but one we must investigate.

So you see there is a hive of activity going on ‘behind the scenes’. Innovation can be disruptive but it must happen.