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This section provides the analysis of spillovers and depicts the localization of the global knowledge outflows. It is more convenient to first describe the spillovers and only in a second step the economic value because the results obtained during the analysis of geography of spillovers will be used for the analysis of the economic value.
Geographical Localization of Spillovers
As we have shown in Sects. 1 and 2, the presence of citations in other regions indicates technological knowledge flows to these regions. The number of citations indicates the intensity of spillovers. We analyze different periods for two types of technologies. For e-mobility technologies, this period lasts from 1977 to 2011 and for fuel cells from 1990 to 2010. The number of patents as well as the number of citations in the fuel cells technological field is much smaller in comparison to e-mobility. It tells us that the quantity of inventions in the field of e-mobility is higher than for fuel cells. We start with an in-depth look into the e-mobility case. There have been 4184 references during the observation period on the patents protecting inventions in e-mobility technologies in the Stuttgart region. Figure 2 shows the development of aggregate patent and citation counts for e-mobility over the observation period. Remarkable is the sharp increase in the number of patent applications while the number of citations remains relatively stable in the 1990s.
As expected, German applicants made the largest number of the citations of the patents related to e-mobility, namely 1597 (from outside the region of Stuttgart). This fact is consistent with the theoretical assumption that most of the citations are made within the domestic country. Second is Japan with 1032 references and third the US with 747. Let us consider the geography of spillovers more precisely. The total list of the countries-recipients of e-mobility technologies includes 35 countries, taking Germany into account. In order to better understand the geographical allocation of the technological spillovers, the countries were sorted in groups
Fig. 2 Number of e-mobility citations (source: own calculations) according to their region. The first group consists of Western European countries and includes the following states: Germany (1598), France (567), Italy (187), Great Britain (144), Switzerland (94), Sweden (73), Netherlands (62), Austria (52), Luxembourg (37), Spain (36), Belgium (20), Finland (12), Denmark (12), Ireland (2), Portugal (1), Norway (1). The Czech Republic (7), Russia (2), Slovenia (1), Hungary (1) and Poland (1) form the group of Eastern European countries. The USA (747) and Canada (15) are taken together in one group. Japan (1032), the Republic of South Korea (46), China (7) and India (1) represent the group of Asian countries. The last group “Rest of the World” includes the following countries: Australia (9), Brazil (2), Turkey (3), South Africa (1), New Zealand (1), Malta (1) and Iceland (1).
Figure 3 illustrates the percentage rates of the total number of citations that go to each group of countries in the period of time from 1977 till 2009 and provides a clearer understanding of the geographic localization of spillovers. More than 60 % of all the retrieved citations are registered in the patent documents of Western-European countries, including Germany. Hence, Western Europe is a major recipient of technologies developed in Stuttgart region. However, German citations make up more than half of Western European citations (see Fig. 4).
Both figures together make clear that citations mostly localize in Germany, other Western European countries, Asia and the US. Asian citations are mainly made by Japan: 1032 out of 1086 references. The other countries have just a very small number of citations and hence the technological outflows are not intensive to these countries. The US is considered together with Canada. However, Canadian firms and research institutes made only 15 citations out of 762.
After France, the following positions are taken by Italy, Switzerland, Great Britain, Switzerland, Sweden and the Netherlands. It means that in these countries there are a lot of researchers and engineers working in the field of electromobility and the technologies build upon or are similar to the German ones. Ireland and Norway have cited one and two patents respectively. It indicates that they either are
Fig. 3 Percentage of e-mobility citations by regions (source: own calculations)
Fig. 4 Percentage of e-mobility citations by regions and Germany (source: own calculations)
not conducting extensive researches in this technological field or that the technologies differ a lot. However, the automotive sector is not essential for their national economy. Notably, the size of a country cannot serve as an explanation for the number of citations since there is no obvious correlation between the number of citations and the size of the country. For instance, Russia is the world’s largest country but has only two citing patents. In contrast, Japan is a relatively small country but has relatively many patents. Eastern Europe is not worth of being analyzed country by country since the amount of citations is very small, even less than 1 % of the overall number of references. This fact might mean that these countries are either not very much involved in the development of electromobility technologies or that have a completely different knowledge base in this area. Figure 5 shows the number of citations of selected countries over time. The sharp drop in the early 1990s could be causes by a crisis in the German automotive industry reducing R&D efforts and thus patent output. An alternative explanation would be that e-mobility knowledge created in the region of Stuttgart became less relevant for the global automotive industry. Figure 6 demonstrates with great circles the geographic location of knowledge flows.
As for the fuel cell technology, the situation is interesting because Japanese firms made the largest number of citations. To be exact, there have been 22 citations in the period from 1990 to 2010. Germany and the USA have the same number of citations (11). Among the citing countries there are also France, Switzerland and Canada (2 citations per country). This statistic can be interpreted in the following way: there is knowledge flowing above all to Japan, the USA and German regions outside of Stuttgart. The flows to Western, European countries and Canada are less intensive. However, the overall small number of citations does not give the precise information about the intensity of knowledge flows. Figure 7 visualizes this information.
In a nutshell, the citations of the patents of both technologies tend to localize in Germany, Japan and the US. However, in case of electromobility, while
Fig. 5 Citations of selected countries (source: own calculations)
Fig. 6 Knowledge flows (source: own illustration)
Fig. 7 Fuel cell technology spillovers (source: own calculations)
Fig. 8 Citing US firms (source: own calculations)
aggregating the countries by groups, the largest number of citations is made by European, more precisely Western European countries. The fact, that domestic knowledge flows in fuel cell technology are not the most intensive can be explained by the early stage of the technology and that there is no hard fundament, on which the new knowledge can be built.
If we now turn away from the country perspective and focus more on individual firms, we analyze the total number of citations made by each applicant (mostly firms and research institutes). Figure 8 shows which US firms cited Stuttgart region patents most frequently. It is not surprising to see in this list such companies as Delphi, Ford and GM on the first places.
Figure 9 provides the list of major Japanese firms citing electromobility technologies out of Stuttgart. It provides information about how many citations have been made by each of those firms. Most of them are world known firms.
As for the fuel cells, there are 36 companies over the globe citing this technology. We cannot talk about the intensity of knowledge flows to the specific firms due to already described fact: the little amount of citations and also a small number of firms. However, we can still have a look at the firms cite the patents filed in the region of Stuttgart. The full list of the citing companies in each country is given in Table 4.
Figure 10 illustrates the development of the number of fuel cell patents (applications) and the citations. The numbers are overall relatively small. What we see however is a relatively strong increase in patenting activities in the second half of the 1990s and a backdrop afterwards.
Fig. 9 Citing Japanese firms (source: own calculations)