Young at heart.

He may be over 90, but he still likes a ride on the combine each year. One of a very small number of brilliant practical engineers I have known - mechanical, electrical, electronic, pneumatic, hydraulic.  In view of the drying summers (2-3mm rain in the last 5 months), our (very) long term project plans have moved from building a hydro-powered electrolyser to produce and store hydrogen, to a wind turbine driven hydrogen producer.