Int. J. Hydrogen Energy, Vol. 9, No. 4, pp. MS. 319-325, 1984. Printed in Great Britain.

0360-3199/84 $3.00 + 0.00 Pergamon Press Ltd.

1984 International Association for Hydrogen Energy.

THE SECONDARY ENERGY CARRIER H Y D R O G E N REVIEW OF DFVLR-ACTIVITIES

W. PESCHKA and C. J. WINTER

Deutsche Forschungs- und Versuchsanstalt fiir Luflund Raumfahrt e.V. (DFVLR), Stuttgart, Federal Republic of Germany

(Received for publication 4 May 1983)

Abstract--This paper describes a review of programmatic and experimental activities as well asstudy work of DFVLR--Deutsche Forschungs- und Versuchsanstalt fiir Luft- und Raumfahrt. Intending to achieve a consensus among those concerned with energy in the Federal Republic of Germany, a programmatic paper entitled "Hydrogen as a secondary energy carrier" was presented in 1981 by DFVLR as a proposal for a research and development programme. The programme outlines the objectives and indicates the technological problems of introducing hydrogen into the energy scenario of a national economy; it recommends appropriate research and development activities as well as study and demonstration work. The programme accepts the fact that non-fossil hydrogen, produced from water, will not be a competitive secondary energy carrier within the next few decades. It is, however, important to open up the secondary energy carrier options which are compatible with any of the development paths and thus to maximise maneuvrability in future energy policies. A review of this programme is given, including some results of DFVLR research activities and the more important promotional steps already taken. Finally, a suggestion is made for future research, development and demonstration activities in the international arena.

INTRODUCTION

Finding substitutes for crude oil and subsequently for natural gas has become one of the imperatives of energy policy throughout the world. Because of their depend- ence on fossil primary energy, and favoured by their technological and economic capabilities, the industrial- ized countries should take the lead. Future energy sup- ply strategies include:

Development of energy conservation techniques in all areas of energy generation, distribution and final use;

Long term availability of the main sources of primary energy (coal, natural gas, nuclear energy and renewable energy);

Demonstration of supply and end user systems for new secondary energy carriers;

Adaptat ion and improvement of existing energy con- sumer technology.

The strategies must recognize that continuous tran- sition to ultimately non-fossil energy systems should be possible without serious technological problems, unac- ceptable economic collapse or intolerable ecological damage.

The favourable properties of a hydrogen energy econ- omy have often been commended, especially for the storage and transportation of all sorts of renewable energies, for peak power management in existing nuclear, fossil or even hydropower energy networks. The continuous increase in the price of fossil energy now makes hydrogen a serious option.

The main conclusion is that policy decisions on a reliable long term energy supply can only be made on the basis of proven knowledge in all the technical

specialities concerned, and also require a wide consen- sus of understanding.

THE IMPORTANCE OF THE H Y D R O G E N OPTION

In the present state of knowledge, it appears abso- lutely necessary to transfer the future energy supply to substantially non-fossil primary energy carriers, in order to maintain the energy supply of the industrialized coun- tries and to give the fast developing countries the opportunity of extending their use of fossil energy.

It is still too early to decide which of the possible development paths will lead to this replacement of fossil energy or to what extent it will be possible to establish and maintain a world-wide non-fossil energy economy based on mainly nuclear and renewable energy.

It seems therefore important to keep open those secondary energy carrier options which are compatible with the various future development paths. Hydrogen provides such an option. Hydrogen favours the tran- sition to non-fossil energy supply structures and permits continuous transition between various secondary energy carriers. It also enables industrialized countries to use their main advantages---knowledge of modern tech- nology and the availability of capital. Although hydro- gen does not need really new technologies because all the individual steps of a future hydrogen energy system are already known, they do require further development.

Non-fossil hydrogen will probably not become a com- petitive secondary energy carrier within the next two decades. However, an early decision is necessary on the actual path leading to a substantially non-fossil energy

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320 W. PESCHKA AND C. J. WINTER

future. Meanwhile, it is highly desirable to use the available time to implement all the parts of a future compatible hydrogen energy system.

Provided we are right in thinking that mankind will use a worldwide hydrogen energy network in the next century, then it is high time to begin preparing--step by step--the production provisions, the distribution means, the end user technologies and to demonstrate to the public that the inherent risks associated with hydrogen--although specific to that fuel--are not higher than those associated with the energy carriers to which we are accustomed.

ADVANTAGES OF A H Y D R O G E N ECONOMY

Against the background quoted, hydrogen appears to have the following advantages as a carrier of sec- ondary energy:

(1) Complete compatibility with other gaseous energy carriers permits a continuous transition from natural gas via SNG to hydrogen.

(2) With respect to production, transport, storage and end use, hydrogen requires the introduction of new technologies only in a few very special cases, subject to the normal further development of existing technologies.

(3) Hydrogen is highly compatible with other carriers of secondary energy and their existing infrastructures such as electricity, district heating and synthetic hydro- carbons. A close association with electricity is of import- ance for peak power management, especially in coun- tries where the lack of hydropower does not permit extension of traditional hydropower peak load management.

(4) Both domestic primary energy sources such as nuclear energy and remote sources such as solar energy, hydropower and windpower can be employed to pro- duce hydrogen. In the latter case application of hydro- gen seems to be the only practical way of overcoming the lack of congruence between power demand and power production.

(5) If solar energy is to be the preferred global future energy option, a hydrogen economy will provide oppor- tunities for continued cooperation with the present oil producing countries---even after the oil era--and with the developing countries in the world's belt of strong solar radiation.

(6) The well known and indisputable ecological advantages of a hydrogen economy will become increas- ingly important in the future. Hydrogen is derived from water and when burnt with oxygen it returns to water.

H Y D R O G E N ECONOMY AND KEY PROBLEMS

The well known elements of a hydrogen energy economy in the industrialized countries are shown in Fig. 1.

(1) Large scale production of non-fossil hydrogen from nuclear energy, solar energy and hydropower, including excess energy from public utilities.

Large Scale Generation

Transport

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.oca] ~upply ~mall Scale ~torage

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Fig. 1. Elements of a future hydrogen energy economy (see Ref. [1]).

(2) Long distance intercontinental transport in gas or liquid form with the associated advantages of decoupling production and consumption.

(3) Inland storage and distribution using the com- patibility with other carriers of secondary energy.

(4) End use of hydrogen providing domestic heating and industrial process heat and power.

(5) Use of gaseous or liquified hydrogen as an alter- nate fuel for terrestrial and aviation purposes.

(6) Use of hydrogen as a raw material in the pro- duction processes of chemicals, iron and steel, in the upgrading of fossil energy carriers and in the production of synthetic liquid hydrocarbons.

In each of the fields mentioned, specific key problems must be solved. The R&D programme suggested indi- cates these key problems, puts them in a priority order and includes proposals for carrying out the necessary work.

The main problem fields and the content of the R&D programme are based on:

(1) Evidence must be provided that large scale pro- duction of hydrogen from water with tolerable require- ments of energy and capital costs is possible, with the investigation of electrolysis having first priority.

THE SECONDARY ENERGY CARRIER HYDROGEN

(2) Evidence of the possibility of large scale trans- portation and storage of hydrogen is important. How- ever, in the light of the present state of the art, this enjoys less priority than production. Together with showing the feasibility of continuous introduction into existing distribution systems, it must be appropriately demonstrated and applied including the necessary safety analyses.

(3) The end use of hydrogen has already been dem- onstrated in many individual cases and there is little fundamental doubt in this area. Nevertheless appro- priate priority should be given to research and devel- opment work, preference being given to applications with larger user potential. Particular attention should be addressed to the demonstration of safety and accept- ability to the end user.

Based on the foregoing, the main open questions and the content of the Research and Development pro- gramme are:

321

A. Production

Improved production methods, especially advanced electrolysis.

Adaptation to renewable primary energy sources. Large hydrogen pipeline systems. Pipeline compressor stations.

B. Transport, distribution, storage

Usefulness and availability of underground storage. Large scale liquid hydrogen containers, tankers. Improved hydrogen liquefaction. Safety and reliability.

C. End-use technology

Further development technology.

of largely known users

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~ r r v ASSOCL~TED ANNUAL ~ A L COSTS

Fig. 2. Typical specific annual costs of large scale overground hydrogen storage facilities as a function of the specific storage capacity (see Ref. [6]).

322

Demonstration projects in hydrogen for heat supply, transportation, hydrogen and electricity, safety and acceptance for the end-user.

For more details of the R&D programme see ref. [1].

W. PESCHKA AND C. J. WINTER

DFVLR RESEARCH AND DEVELOPMENT ACTIVITIES

The Energy Research Department of the DFVLR has devoted significant resources to hydrogen research during the last two decades and is willing to pursue this in the future.

From 1976 to 1980 the activities were concentrated on:

Studies, including the application of hydrogen as a secondary energy carrier [2, 3]. Hydrogen production from water by hybrid pro- cesses* [4]. Investigation of electrolytic hydrogen production from photovoltaic or solar thermal electricity [3, 5]. Theoretical study on cryogenic hydrogen storage and comparison of alternatives* (Fig. 2) [6]. Experimental investigation of hydrogen storage by use of cryoadsorbers* (Fig. 3) [6].

* Supported by a research contract from the Commission of the European Communities.

t Joint programme with Los Alamos National Laboratory (LANL).

Symposium "Hydrogen in Air Transportation" in Stuttgart. Experimental investigation on hydrogen oxygen steam generators for peak electricity (Fig. 4) [7]. Investigation and demonstration of liquid hydrogen as an automotive fuelt (Figs. 5 and 6) [8].

Current activities

Studies on large scale application of solar energy by means of hydrogen, including photovoltaic and solar thermal electricity, economics, energy pay- back time and storage behaviour of intercontinental pipeline systems. Improvement of water electrolysis by new manufac- turing processes delivering highly active electrode surfaces (low pressure plasma spray techniques, LPPS). Liquid hydrogen as a carrier of secondary energy, demonstration of safe handling. (a) Large scale storage. (b) Storage on board a vehicle. (c) Application of cryogenic hydrogen for improving the performance of internal combustion engines (cooperation with automobile manufacturer). (d) Improvement of liquefaction techniques. Solar hydrogen: Design and construction of a 20 kW photovoltaic hydrogen system. Hydrogen oxygen steam generator for electricity generation. Integration in base load powerplants for

Fig. 3. Experimental device for the investigation of the hydrogen storage capacity of adsorbing materials at cryogenic temperatures (65 I. specimen volume) (see Ref. [6]).

THE SECONDARY ENERGY CARRIER HYDROGEN 323

Fig. 4. Hydrogen-oxygen steam generator (80 bar, 950°C, 15 MWth ) for peak power management. The generator layout is shown in the upper part of the figure, the test facility below (see Ref. [7]).

324 W. PESCHKA AND C. J. WINTER

Fig. 5. DFVLR-LH2 test vehicle and semiautomatic LH2 refueling station (see Ref. [8]).

Fig. 6. LH2-tank in the test automobile at Los Alamos National Laboratory (see Refs. [9, 10]).

THE SECONDARY ENERGY CARRIER HYDROGEN 325

improvement of the transient behaviour (pilot plant in cooperation with utility companies).

CONTACTS AND F U R T H E R ACTIVITIES

Presentations of "Hydrogen as a secondary energy carrier" in the German Federal Ministry of Research and Technology in September 1980 and April 1981.

Membership in the Ad Hoc Executive Group (AHEG) for the promotion of Hydrogen in Air transportation.

Presentation of "Hydrogen as a secondary energy carrier" in the newly founded "Working Party on Renewable Energy" of the International Energy Agency (IEA), 10 December, 1981.

Scientific-technical contacts and cooperation with other international hydrogen groups in the EEC, Can- ada, Japan and U.S.A.

Cooperation with the Executive Committee on Hydrogen Production from water of the International Energy Agency of the OECD.

PROPOSAL FOR F U T U R E INTERNATIONAL R&D WORK

Since the secondary energy carrier hydrogen is by no means a purely national matter, but rather a global concern, DFVLR feels the absolute necessity for further strongly conducted international R&D work on hydro- gen as a secondary energy carrier on large scale safety demonstrations, on production from other than well- known fossil sources, on its feasibility as an alternative automotive fuel and on its public acceptance.

Perhaps international agencies like the EEC, which is already successfully active in the hydrogen field, or the IEA, etc. are the appropriate entities for interna- tional cooperation. However, this does not mean that bilateral ventures of mutual benefit are not necessary.

As far as the ambitious and very farsighted project "Hydrogen in air transportation" is concerned, the DFVLR appreciated the honour of hosting the 1979 international symposium on the subject. Since then, the DFVLR has actively participated in the Ad Hoc Execu- tive Group (AHEG) for the international promotion

of hydrogen as a future aviation fuel. With respect to this problem, the German authorities are convinced that a necessary condition for the introduction of hydrogen into air transport is industrial verification of the safety of hydrogen-- in production, distribution, handling and final use---and that this must be demon- strated well before hydrogen is used in the air.

The DFVLR thus feels committed to promoting all the necessary R&D efforts and is prepared to do so on an international basis. Hydrogen in air transportation is, and will remain, part of this broader approach.

REFERENCES

1. C. J. Winter et al. Wasserstoff als Sekund~iren- ergietr~iger--Vorschlag for ein Forschungs- und Entwicklungsprogramm. DFVLR-Mitt. 81-10 Wissen- schaftliches Berichtswesen der DFVLR, P.O.B. 906058, 5 Koeln 90, FRG (1981). Also available in English trans- lation. Hydrogen as a secondary energy carrier--proposal for a research and development programme.

2. J. Nitsch et al. AGF/ASA Studie Energiequellen fiir mor- gen. Umschau Verlag Breidenstein KG, Frankfurt am Main (1976).

3. J. Nitsch, Sonnenenergie 6, 6 q981). 4. W. Seeger and H. Steeb, H~,andprozesse zur Wasserstof-

ferzeugung. Final Report on Contract FA-056-76 EHD Commission of the European Communities, Briissel (1979).

5. C. Carpetis, Int. J. Hydrogen Energy 7 (1982). 6. C. Carpetis and W. Peschka, Untersuchung der Wasser-

stoffspeicherung mit Kryoadsorbern. Final Report on Pro- ject FA-505-78 4 EHD, Commission of the European Com- munities, Br0ssel (1981).

7. H. J. Sternfeld, H. Wojkowsky and W. Schnurnberger, Studie zur Absch/itzung erzielbarer Wirkungsgrade und Kosten bei der Verstromung yon Wasserstoff. Final Report EUR 7529 DE on Contract FA 404-78-7 EHD, Commission of the European Communities, Briissel (1981).

9. F. W. Stewart (1982). Experimental investigation of liquid hydrogen vehicle onboard storage and refueling system. LA-Progress Final Report.

10. W. Peschka, F. J. Edeskuty and W. F. Stewart, Liquid hydrogen storage and refueling for automotive applica- tions. Proceedings 3rd Miami Int. Conf. on Alternative Energy Sources, Miami Beach, Florida (1980).