One point he made: Getting Desertec done is not a question of technology. It is a question of politics and regulation.
I agree. Germany has reached 31 GW of solar PV in a very short time frame because of the Law on Priority for Renewable Energy, not because it has the best solar resources in the world or because German engineers are extremely well qualified (though they probably are).
Jeworrek also notes that the recent DII conference has attracted a record number of attendants, much more than he expected.
Lenz Blog 