In this contribution, an investigation on bio-derived hydrogel electrolytes for dye-sensitized solar cells is proposed. When opportunely developed and optimized, aqueous solar cells can be considered a truly low impact photovoltaic device with non-toxic components. Moreover, the possibility of gelling the electrolyte into a polymeric matrix can reduce the leakage outside the device, thus increasing the long-term stability. Above all, bio-derived polymers appear promising being renewable and easy available with low cost. Different aqueous electrolytes gelled with carboxymethylcellulose (Na-CMC) or xanthan gum have been prepared with both I-/I3- and Co2+/3+ redox mediators. These gelled systems show good photovoltaic performances, maintaining over 90% efficiency of liquid DSSCs, as well as enhanced long-term stability. Moreover, we demontrate the use of Experimental Designs (DoE) as a powerful chemometric technique for the concurrent investigation of a number of experimental factors that directly influence the photovoltaic performances of solar cells. Results obtained enlighten that a solid mathematical-statistical approach is fundamental to support the researchers and effectively drive the experiments towards the achievements of optimal operating conditions for aqueous solar cells.