In its most likely future incarnation, the "Hydrogen Economy" is described in terms of a "Fuel Chain", comprising the transformation of a primary energy source to generate hydrogen to feed Fuel Cells, which in turn provide power for a range of stationary or vehicle applications. The key stationary application foreseen for the hydrogen/fuel Cell system is to provide Combined Heat and Power (CHP) for homes and businesses, either via centralised/distributed energy or through "microgeneration" of electricity (and heat) on site.
The primary energy sources from which hydrogen can be generated include fossil fuels, light, wind and wave power, nuclear and biomass. In the short to medium term it is expected that the bulk of the hydrogen produced in the UK will continue to be derived from the reformation of fossil fuels, with the associated expansion of the need for CO2 capture and sequestration .
The risks associated with the storage of hydrogen (under high pressure or cryogenically in liquid form) and its use in Fuel Cell applications, are well appreciated by HSE and a comprehensive Guidance Note (HSG 243) has already been issued on the subject. In addition, work is already underway on various aspects of the fire and explosion hazards at the Health and Safety Laboratory, including investigations into the perceived risk of spontaneous combustion and modelling of potential designs for re-fuelling stations for vehicles.
- There are implications for safety for aspects of all elements of the fuel chain from conversion of the primary energy source, through a number of possible transportation, storage and delivery stages, to use of the hydrogen for power generation.
- There may also be implications for safety arising from the process design of alternative sources of hydrogen production, as these are developed. These include eg the use of photovoltaic processes for the electrolysis of water and pilot scale projects on hydrogen generation from various sources of biomass (plants, by-products and waste materials).
- In the future it is possible that major infrastructure developments will be needed to distribute hydrogen either alone or mixed with natural gas (as "Hythane"), via existing or new pipeline networks. If so, the risks and hazards associated with this approach will need to be considered.
- For transport applications of hydrogen, there will be a need to distribute the material in some form direct to the end user, analogous to the operation of petrol stations at present.
- In addition to the hazards associated with hydrogen, the need to consider the electrical safety implications of its use in Fuel Cells has been identified, including the fact that the cells tend to operate at relatively high voltages and as such could represent a danger to fire fighters and others in the case of an accident.