Data are presented for both “claimed priorities” (CP) (i.e. inventions for which protection is sought in at least two countries) and “singulars” (i.e. inventions protected only in one country). This distinction is useful because it indicates different market value of the inventions patented (see OECD, 2011). With respect to energy storage, there was significant “take-off” around 1990, with a six-fold increase in singulars since that point. Claimed priorities have tripled in the same period.