Is a peltier-based dehumidifier a good choice to prevent condensation?
Peltier elements need 2 separated air (or water) flows on the cold and warm side.
Even if those elements are run with only 20% of the rated current, the installation effort, space and power consumption will be still much higher compared to the solution of re-using an old PC fan and a small old plug-in power supply. 

That power supply  should be available in one of the next drawers or boxes with redundant electronics, and a low voltage fan could be harvested from an old PC. Hair dryers normally do also use low power motors, but mostly 20V or more. 
All should be also available for no or minimal cost at the next recycling yard. If the fan is a 12V type, any voltage between 7 and 12V should be working well.
Hair dryers anyway have a 50% switch where the fan's voltage is reduced accordingly.

From a similar question:

An alternate method avoiding high electricity bills and the water drain for the dehumidifier: Installing a fan of an old PC at the Luv side, connected to a small power supply from an old phone or similar and a timer. If the fan runs only in the night, it pushes in statistically colder and dryer air. In 1 or 2 weeks the space will be much dryer. Electricity cost below 1$ per month.