Resumé of Swiss Nuclear Society´s Autumn Seminar, 2006

by Dr. Peter Leister, Vice-President of the Swiss Nuclear Society and of the European Nuclear Society

Would it be profitable for Switzerland to enter into the hydrogen economy?

The seminar’s focus was on the substitution of fossil fuel based energy for heating purposes using hydrogen as the energy carrier. Bearing in mind that the seminar took place last autumn, to publish a resumé now – when the two parts of the UN Climate Change reports were only recently released – re-enforces the seminar's original focus. Political and economical aspects like independence from imports and stability of fuel prices coincide very much with the requirements for environment protection and the inevitable obligation to reduce CO₂ emissions anywhere in the world, even in Switzerland.

This country imported, in 2005, 610 PJ of fossil energy for heating, 503 PJ of which came from oil and 107 PJ from natural gas .

Issues such as the building blocks of the hydrogen technologies required to replace this amount of fossil fuel, their availability and reliability were addressed by the different presentations during the seminar.

The authors of the contributions to this seminar represent a reservoir of international know-how of the hydrogen economy in view of H₂ production by conventional and advanced processes (Linde, General Atomics, Le Commissariat à l'Energie Atomique). Some represent utilities already operating successfully stationary fuel cells (EnBW) or research institutions participating in the international Generation IV Initiative Forum (GIF). The GIF is driving forward high temperature reactor technology towards its successful application as a heat source forH₂ production or for desalination (Paul Scherrer Institute ) or for use by an international engineering company at any kind of power generation plant (Colenco).

Most of the presentations were given in German but several were in English. Access to all of the contributions is possible via the home page of the Swiss Nuclear Society at:
www.sns-online.ch/fs2007.

The lectures presented in the seminar followed a logical sequence starting with an overview over the current Swiss energy balance, a definition of the building blocks of a hydrogen economy, its requirements and constraints and progressing to a view of what Switzerland has contributed to the further development of modern hydrogen technologies. Moreover, experiences obtained with an initial industrial-scale application were described. A major part of the seminar was dedicated to high temperature processes for hydrogen production and the corresponding heat sources via the high temperature nuclear gas cooled reactors, its further development and programmes for improving materials were dicussed. Last but not least, cost calculations for building up a hydrogen economy in the transport sector, as well as for stationary purposes, were presented.

A. Böhner presented data on Swiss [presentation 1] energy consumption and production based on how the various energy carriers in the different consumption areas offer potential for being replaced by hydrogen and what would be an acceptable technological scenario for using centrally-generated hydrogen to replace imported fossil fuel especially, natural gas for heating Swiss households, public buildings and heat consuming industrial processes. He presented a strategy for the installation of a hydrogen economy and identified its risks and merits. The results of his economical calculations are mentioned at the end of this resumé.

P. Dietrich then explained [presentation 2] which Swiss know-how is available and applicable to a hydrogen economy scenario based on fuel cells. Various Swiss institutions are involved in the further development of components for conventional solar energy based H₂production, for mobile and stationary fuel cell technology and for H₂ storage technologies. For example, Swiss PSI and Material Research EMPA co-operate in the area of metal hydrate storages for hydrogen - a very promising technology. When it comes to an industrial-scale demonstration for mobile applications this technology has already been used for snow track vehicles and for the Michelin/PSI HYLIGHT-Car®. Predictions about when the industrial application of large-scale stationary metal hydrate storages is likely to be on stream range from a period of between 10 to 15 years.

An overview of how state-of-the-art stationary fuel cells can supply apartment buildings, hospitals, etc. by simultaneously producing power and heat production on an industrial scale was presented by B. Heyder in presentation 3. He emphasised that this kind of technology is a mature one based on natural gas being fed into the fuel cells. If hydrogen could be switched over to immediately, its greater efficiency would be clear for all to see.

R. Schiffbauer dedicated presentation 4 to state-of-the-art industrial hydrogen production, pointing out that hydrogen production is a very traditional industry that has worked profitably for more than 100 years. To date, hydrogen is not so much used as an energy carrier but more as a raw material for chemical processes like steam reforming. Furthermore, the distribution of hydrogen via pipelines has proven to be a very safe technology for many decades since the last third of the 19th century, when the gas mains of larger cities distributed gas to households that contained a hydrogen content of more than 50%. For more than 40 years pipelines conveying pure hydrogen have been maintained very safely in European industrial centres like the Ruhr and the area around Lille, France. These pipelines are several hundred kilometers long. Even today existing natural gas pipelines can be converted to hydrogen distribution without much of an effort. Indeed, the transition from pure natural gas to hydrogen operation would not create major technical problems. Introducing a hydrogen economy would hence not require gas and hydrogen pipelines in parallel during a transitional period.

Hydrogen production by steam reforming of hydrocarbons from natural gas has largely replaced the old electrolysis process (world wide this now only accounts for 1% of total H₂ production). Now, however, it is no longer conceivable to use old electrolysis or the steam reforming technology in a hydrogen economy. Swiss experts are of the opinion that renewable energies will never meet the requirements of economical hydrogen production.

L. Brown underlined, in presentation 5, how the only reliable and ecological – hence sustainable - hydrogen production is via nuclear high temperature reactors (HTR) combined with a high temperature chemical process (the sulphur-iodine process) This process, developed by General Atomics, was finally selected amongst 370 H₂-generating chemical processes. The feature of this process is the use of inorganic chemicals only (Iodine and Sulphur) and water as the feeding material, to produce H₂ and O₂. Depending on its chemical effectiveness losses of iodine have to be compensated for. The selection of suitable corrosion-resistant vessel and pipe materials make the equipment expensive.

This High Temperature Water Splitting process absorbs most of the reactor’s fission heat and has the potential to achieve up to 70 % efficiency. The total efficiency of the chain of hydrogen production, distribution and conversion of fuel cells into power and heat is comparable to that of modern natural gas burning co-generation or district heating plants. It has the advantage of zero consumption of fossil resources and does not emit climate change-inducing carbon dioxide. The fundamental viability of this water splitting process will be demonstrated by 2010 and in 2020 an industrial scale engineering demonstration plant on will be operational.

State-of-the-art HTR technology, its international development and the time required for further materials research was covered by presentations 6 and 7. Presentation 8 was dedicated to cost considerations of the several building blocks needed to support the hydrogen economy in a small but well-industrialized country like Switzerland and in a larger industrialised nation like France.

In presentation 6, K. Foscolos gave a short overview of recent developments in reactor technologies and presented in detail HTRs - both existing ones (Generation IV) and future ones like improved HTRs called “VHTRs.” The latter will produce fission heat at a level of up to 900° centigrade. Switzerland is an active member of the GIF, in which the most important nations contributing to this research co-operate with each other.

The experts believe that the full potential of these reactors must be exploited so that they can become the work horses of a hydrogen economy. Light water reactors will play a minor role in such a scenario. As far as the availability of uranium as a main fuel resource is concerned it is concluded that – in contrast to the declarations made by “anti nukes” – by using the advanced VHTRs uranium becomes nearly inexhaustible since uranium can be extracted cost effectively from sea water by using heat from VHTRs. Such a process makes uranium in sea water exploitable.

One important step towards the operation of VHTRs concerns the selection of materials for reactor components, which must be resistant to very high temperatures. According to W. Hofelner [in presentation 7] at least 15 years of further development are required to make VHTRs available on an industrial scale within 25 years.

F. Werkoff devoted his lecture [presentation 8] to economic calculations of the investment costs for the H₂ economy and presented helpful formulae. In addition, he explained the High Temperature Electrolysis (THE) process working during the vapour phase of water. This new process has, above all, the potential to compete with the S/I process but with the advantage that THE can be used with heat sources like conventional biomass, domestic incinerators and even light water reactors to produce hydrogen. For France it was calculated that within the next 45 years 85 % of the French car and truck fleet could be converted to using H₂ fuel cells requiring 16 light water reactors of the type EPR instead of 75 HTRs. When it comes to using LWRs in a hydrogen economy, the CEA obviously differs from the HTR-community.

This precise and detailed information lead the authors of presentation 1 to the conclusion that with respect to the different building blocks needed to support a hydrogen economy only two blocks determine the critical path of a solution tailor-made for Switzerland:

• cheap, large scale H₂ storages based on metal hydrates

• suitable, corrosion-resistant materials for VHTRs

The corresponding time span of 15 years would enable the start-up of a 20 year demonstration project aimed at achieving a smooth transition from imported natural gas to hydrogen. Such a project would comprise of the following steps:

• Installation of stationary fuel cells into every newly constructed apartment building with more than 10 flats for a period of 20 years

• Connection of fuel cells to the electricity grid for feeding generated power into the grid

• Construction of local H₂-gas grid sections

• Supply of fuel cells first by natural gas and later on by conventionally produced H₂ supplied by tanker lorries

• Successive construction of H₂-storage tanks at strategic points of the gas grid (according to the progress with the availability of metal-hydrate storages)

• Start of the design and construction of one HTR- H₂ production plant, comprising of two 600 ME reactor blocks

• Adaptation of existing gas grid to increase H₂-concentration

• Connect H₂-plant to gas grid

• Increase H₂-content of gas grid to 100 %

This sequence of steps corresponds to the illustration in Fig.1, starting with the part on the right hand side (stationary fuel cells, initial supply of FC by natural gas from public grid then mobile H₂-transportation, installation of H₂-storages and finally realisation of a HTR & H₂-generation plant, lefthand side)

This sequence of steps would:

• enable Swiss small and medium sized enterprises to be prepared for switching over to an H₂ infrastructure

• make consumers and suppliers acquainted with use of H₂

• enable reimbursement of fuel cell produced electricity fed to the grid

• allow for the correction of any project that shows misleading results

• give the utilities time to master the decentralized production of electricity by the fuel cells

After a successful demonstration of the feasibility of this small part of a hydrogen economy in Switzerland another 15 years period should be sufficient to extend the hydrogen economy to cover the whole of Switzerland. The calculation on an investors level show that within this demonstration project, starting with conventionally produced H₂, total operational cost of this part of a Swiss Hydrogen Economy is significantly below the operational cost of the equivalent gas/oil burning for the apartment houses (gas/oil prices exceed .095 US$/kWh and .0702US$/kWh respectively). The question raised in the seminar’s title can now clearly be answered.

Moreover, the reduction of the CO₂ emissions by the demonstration project corresponds to 34 % of consumption of gas and oil fuel used for heating so far. It is about three times the amount of the energy forecast to be produced in Switzerland in 2035 by renewable energy. If all Swiss gas and oil consumption for heat production were to be replaced by hydrogen Switzerland could contribute fighting climate change and be a model for other industrial nations to follow. The technologies exist and are available. In a hydrogen economy the savings obtained from constant energy prices would be considerable.

Fig. 1 Concept of a Demonstration Project for replacing fossil fuel by hydrogen and fuel cells to heat private and public houses (source Nuclear News, September 2001)

References