Patent Data Sets for Analysis

The backward tracing elements of the study starts from the set of all geothermal energy patents, while the forward tracing starts from the set of geothermal energy patents attributed to DOE funding. Neither of these data sets existed; both had to be constructed for this the study.

E.5.1 Identifying DOE-Attributed Geothermal Energy Patents for Forward Tracing

Identifying patents funded by government agencies is often more difficult than identifying patents funded by companies. When a company funds internal research, any patented inventions emerging from this research are likely to be assigned to the company itself. To construct a patent set for a company, one simply has to identify all patents assigned to the company, along with all of its subsidiaries, acquisitions etc.

In contrast, a government agency such as DOE may fund research in a variety of organizations. For example, DOE operates a number of laboratories and research centers. Patents emerging from these laboratories and research centers may be assigned to DOE, or they may be assigned to the organization that manages the laboratories or research centers. For example, patents from Sandia may be assigned Lockheed Martin, while Livermore patents may be assigned to the University of California.

A further complication is that DOE does not only fund research in its own labs and research centers. It also funds research carried out by private companies and universities. If this research results in patented inventions, these patents are likely to be assigned to the company or university carrying out the research, rather than to DOE.

To identify geothermal patents resulting from DOE-funded research, the study first searched within the set of patents identified by the geothermal patent filter and matched this patent set to three sources to identify those attributable to DOE funding:

• OSTI Database – The first source used was a database provided by DOE’s Office of Scientific &

Technical Information (OSTI) for use in DOE-related projects. This database contains

information on research grants provided by DOE since its inception. It also links these grants to the organizations or DOE centers carrying out the research, the sponsor organization within DOE, and the U.S. patents that resulted from these DOE grants.

• Patents assigned to DOE – The study identified a number of U.S. patents assigned to DOE that

were not in the OSTI database because they have been issued since the latest version of that database. These patents were added to the list of DOE-attributed patents.

• Patents with DOE Government Interest – A U.S. patent has on its front page a section entitled

“Government Interest,” which details the rights that the government has in a particular invention. For example, if a government agency funds research at a private company, the government may have certain rights to patents granted based on this research. The study identified all patents within the set identified by the geothermal patent filter that refer to “Department of Energy” or “DOE” in their Government Interest field, along with patents that refer to government contracts beginning with DE- or ENG-, since these abbreviations denote DOE grants. Patents in this set that were not in the OSTI database and were not assigned to DOE were added to the list of DOE- attributed patents.

In addition to this procedure, the study identified DOE-attributed geothermal patents found through a search of DOE reports. These reports detail the history of DOE funding in geothermal energy (for example the 2006 report “Geothermal Power Today” http://www.nrel.gov/docs/fy06osti/39479.pdf). The DOE reports often identify specific geothermal patents resulting from funding by DOE. These patents were added to the DOE-attributed patent set resulting from the geothermal filter. The reports also in some cases identify organizations whose geothermal energy research has been funded by DOE, the period of funding, and technologies funded. By matching the organizations, time periods, and

technologies from these documents with patent data, it was possible to identify additional patents from these organizations that are likely to have been funded (at least in part) by DOE, even if they did not formally acknowledge DOE’s support.

The next step was to send the list of candidate patents identified through this multistep process to DOE scientists and program managers. They in turn provided feedback on which of the candidate patents should be included in the study’s final set of DOE-attributed patents and which should be omitted.

E.5.2 Identifying the Set of All Geothermal Energy Patents for Backward Tracing

To identify the set of all geothermal patents for the backward tracing, the study designed a patent filter. To identify U.S. patents, the filter used a combination of keywords and Patent Office Classifications (POCs). Meanwhile the filter to identify EPO and WIPO patents used a combination of keywords and International Patent Classifications (IPCs). The patent filter consisted of four separate searches, as described in detail in the source report.

Patents identified by any of the four searches were considered for inclusion in the final set of geothermal patents. The titles of all these candidate patents were read individually, and irrelevant patents removed from the set. This resulted in a final geothermal patent set consisting of 871 U.S. patents, 180 EPO patents, and 234 WIPO patents.

The design of the patent filter has important implications for the backward tracing element of the analysis presented in this report. It is this filter that determines which patents are included in the geothermal patent set used as the starting point for this backward tracing. More specifically, keyword restrictions require that a patent must refer specifically to a geothermal, hot rock, or hot spring application in its title or abstract in order to be considered a geothermal patent.

The keyword restriction is included because of the nature of geothermal technology. Some technologies are relatively self-contained, and their patents use unique terminologies. This is not the case with geothermal technology, which shares many similarities with oilfield technology. For example, technologies such as drill bits, downhole sensors, data transmission techniques, and well cements and casings may have applications for both the oilfield and geothermal industries. Including all such patents would swamp the geothermal patents with the much larger set of oilfield patents (for example, there are over 11,000 U.S. patents in POC 175 “Boring or Penetrating the Earth” alone). The keyword restriction is designed to prevent this from happening. The effects of this approach is to produce a conservative

estimate of geothermal patents for the backward tracing analysis; one that focuses more on geothermal power plants and geothermal fluid treatments that tend to make specific reference to their geothermal focus.

This highlights the benefit of carrying out the analysis in two directions, since the forward tracing element helps demonstrate DOE’s impact on patents that do not specifically refer to a geothermal application but may be related to geothermal technology.