The Thesis in a Wider Context
The thesis has, quite necessarily, taken a focussed and technical approach to the development of the novel tri-generation system. However, this section takes a step back and critically evaluates the presented work in a wider context.
The hydrogen economy was discussed in Sect. 1.4. The developed tri-generation system has a clear role to play in a hydrogen economy. Currently, the majority of fuel cell applications operate on hydrogen derived from steam reforming of a hydrocarbon fuel or, in the case of a SOFC, internally reforming a hydrocarbon fuel. This is the cheapest form of production; however it has the disadvantage of emitting modest amounts of environmentally harmful pollutants. Many countries employing large scale renewable energy devices face the issue of managing excess electrical capacity when supply is high and demand is low. A possible solution is to use excess renewable electrical capacity to generate clean hydrogen through the electrolysis of water. Hydrogen can be stored inter-seasonally to fill the gap between supply and demand. Due to increased renewable energy capacity, the falling unit cost of renewable electricity and improved electrolysis technology; the large scale transition to clean, zero carbon hydrogen production using the electrolysis of water is expected in the next 30 years (Berger 2015). It is proposed that the current use of hydrocarbon-fed fuel cells is an essential stepping stone in developing and refining the necessary technology for when the wide-spread transition to clean zero carbon hydrogen production can occur.
This thesis has presented the design, development and testing of a novel SOFC liquid desiccant tri-generation system that can provide highly efficient, zero carbon energy conversion in a decentralised manner. The developed system is a viable option for applications that require simultaneous electrical power, heating and dehumidification/cooling. Thus this thesis demonstrates the potential role of the tri-generation system in the transition to a future hydrogen economy.
Over forty years ago Schumacher in his seminal book Small is Beautiful (Schumacher 1974) argues the vision for a transition towards more efficient energy utilisation and away from a dependence on energy derived from fossil fuel as a global necessity. He puts forward the point that humanity is treating fossil fuels as income items even though they are capital. Furthermore, Schumacher states that one of the most fateful errors of our age is the belief that “the problem of production” has been solved. We need to consider not the fossil fuel resource as income but renewable energy resources as income.
This thesis commenced with an assertion based on this vision:
Humanity is now at a global tipping point. Serious decisions regarding the future of world
energy supply and demand need to be made.
The work presented in this thesis provides one small and very specific way to contribute to this vision; but a contribution nonetheless.