In general, the potential for fuel cell CHP units in Europe as a large market in the future is well recognised. Although the size of this market is large and is undisputed when the cost targets of m-CHP units is reached, it is often overlooked that it is a very segmented market.
In most studies and projects, often the focus has been on the customer demands of the fuel cell systems. Predictable deviations between heat use between northern and southern Europe have been found. But an important aspect has been neglected in most cases; the differences in natural gas quality and the assurance and legislation around it.
All micro-CHP units, as new heating appliances, will have to be certified against the Gas Appliance Directive (90/396/CE). In this directive all natural gas appliances are certified against one common natural gas reference (EN 437). Within the common reference three different natural gas groups are defined based on their Wobbe Index (Caloric value of the gas divided by the square root of the relative density of the gas compared with air):
However, the actual ranges of Wobbe index that are specified in European countries are quite different from the limits of EN 437. This is usually a legacy of the period before 1993. Contrary to what one would expect, countries are not moving towards the common Gas groups H,L or E. For example, the Netherlands even allowed a further deviation from it to allow the feed-in of biogas and LNG (Liquid Natural Gas).
For a good operating m-CHP system the use of natural gas is most appropriate due to its broad availability. In the past systems based on autothermal reforming (ATR) were developed (Plug Power, Vaillant, Hydrogenics). The disadvantage of these systems was the dilution of the reformate gas with nitrogen from the air required during reforming leading to the use of large and expensive PEM fuel cell stacks. This also resulted in a lower overall system efficiency.
Within the FERRET project, the consortium will improve the technology based on the findings of previous projects such as Reforcell and DEMCAMER and develop a fully functional reactor for use in a current m-CHP unit from HyGear. Within FERRET, we will also design the reactor, balance of plant components and revise the controls to allow the sudden change of natural gas specification that can be expected in field operation in the coming years.
According to the problems mentioned above, FERRET project will:
• Design a flexible reformer in terms of catalyst, membranes and control for different natural gas compositions (effectively tolerant to fluctuating natural gas compositions)
• Use hydrogen membranes to produce pure hydrogen and help with shifting all the possible H2 production reactions towards the desired products, thus reducing side reactions.
• Scale up the new H2 selective membranes and catalyst production
• Introduce ways to improve the recyclability of the membrane
The resulting BoP component (membrane ATR reactor for CHP-systems) will lead to a fuel processor for fuel cell CHP system being flexible throughout Europe or even beyond Europe.