In a previous post I commented on the lack of growth in patent filings at the European Patent Office. The World Intellectual Property Indicators - 2013 Edition confirms this lack of growth [see Fig. A.1.1.2 at page 46] and the low numbers of patent filings at the EPO compared with other leading offices [see Fig. A.2.1.2 at page 52].
On renewal fees for the unitary patent, I have commented in a first and second post on what might be a "fair" level.
Assuming that the level of fees is not so high as to be a deterrent, what might be the effect on demand? The following graph plots number of European patents renewed in each country of validation, against total GDP for the countries concerned, and extrapolates this to a market just the size of DE+FR+GB and to a market the size of the unitary patent assuming all participating states (except Poland) sign up. As a sanity check, the number of patents in force in USA, China and Japan is indicated.
As can be seen, this implies a considerable increase in demand. A unitary right covering a market with a GDP of nearly €10 trillion is likely to be highly sought. It is also probable that those who think ahead will start to file more European patents once the unitary patent starts to look a reality.
It would appear that the EPO should be planning now for what they will do if there is a surge in demand. I would expect such a surge to occur once the level of renewal fees is apparent [fear is usually worse than reality].