• Industry begins to pay attention to the development but, in general and for the time being, is reluctant to invest as there is no short-term market in sight.

• Money mostly comes from government authorities who can afford an interest in long-term energy issues. In general, funds have been increasing during the last five to ten years. As an example, Switzerland spent almost nothing on solar chemistry ten years ago. Today the annual budget is about 2 million dollars, which corresponds to roughly $0.30 per inhabitant. Provided good proposals will be available, this budget could possibly double or triple during the next five years.

The R&D objectives in Europe are similar to those in the United States, although priorities might be different. The main issues are

• synthetic secondary energy carrier (e.g., hydrogen or methanol; probably higher priority than in the U.S.).

• production of high value chemicals; and

• detoxification of hazardous waste (probably lower priority than in the United States).

To reach these goals, all different forms of solar chemistry are investigated:

1. photochemistry (near ambient temperature)

2. thermochemistry (using solar heat)

3. electrochemistry (using solar electricity) and the combinations thereof:

4. photoelectrochemistry

5. photo-assisted thermochemistry

6. high temperature electrochemistry

Topics 1, 2, 4, and 5 are the fields receiving most attention at present. Topics 3 and 6 are not always considered to belong to solar chemistry, which is a mistake (at least in my opinion). The solar-specific boundary conditions may lead to requirements which go beyond those of ordinary electrochemistry, and their consequences should not be underestimated.

In Europe the splitting of water and the reduction of CO₂ seem to be the dominant issues. The "scientific background" is given by 20 years of research in photography, photochemistry with lasers, and investigations of natural photosynthesis. Research is concentrated in universities and scientific research institutes. Basic research problems clearly dominate. They are the same in Europe as in the United States, e.g., charge transfer questions in redox systems or corrosion mechanisms in photoelectrochemistry.

Countries involved are Germany, Italy, Switzerland, Sweden, Great Britain, and France. The order given corresponds more or less to the importance of the efforts in the respective countries (according to a necessarily somewhat subjective judgment of a colleague of mine, working personally in the field).

International contacts are made and cooperation is stimulated mainly by the biannual International Conference on Photochemical Conversion and Storage of Solar Energy, the proceedings of which usually appear in the Journal of Photochemistry (last conference: Palermo, 1990).

In Europe, topics 5 and 6 are intimately connected to the International Energy Agency's Small Solar Power Systems Project (IEA-SSPS-Project).