what if !
I''m not sure I understand your question properly. By "motor", I assume you mean an electric motor. When you say "auxiliary power source that would not need any oil, thus filters, to run", I''m confused.
One type of auxiliary power source you can use to supply an electric motor''s power needs is a generator coupled with a mechanical power source of some kind. This is usually an internal-combustion engine running on diesel or gasoline, but the four-stroke designs need lubricating oil to function. Two-stroke gasoline designs mix a small amount of lubricating oil in with the fuel to lubricate the bearings and thus don''t have a traditional oil pan and filters.
Getting away from internal combustion engines altogether, you can couple that generator to a wind vane, or to a water-turbine that you tow while under sail. In the latter case you are still converting wind power to electric power if you are making way, or tidal currents to electrical power if you are anchored in a fierce current (at least theoretically speaking).
Keep in mind that for every conversion from one type to another (wind-mechanical-electric; chemical fuel-mechanical-electrical; sunlight-electrical), there is a loss.
So, did anything I said answer any questions you had? I''m still not sure where the "filter" concern comes in.