Full Idea
Some say Schopenhauer would be less misunderstood if he had used 'force' or 'energy' rather than 'will' to characterise inner natures. But this would have steered his idealism towards materialism, of which he was an avowed opponent.
Gist of Idea
Schopenhauer can't use force/energy instead of 'will', because he is not a materialist
Source
comment on Arthur Schopenhauer (The World as Will and Idea [1819]) by Peter B. Lewis - Schopenhauer 4
Book Reference
Lewis, Peter B.: 'Schopenhauer' [Reaktion Books 2012], p.94
A Reaction
I presume therefore that Nietzsche's will to power is a commitment to materialism, since it occurs in material objects as well as minds.