A method for producing hydrogen gas (H2) from sweet sorghum (Sorghum bicolor (L.) Moench) comprising: (i) preparing materials; (ii) creating a first temporary mixture; (iii) creating a second temporary mixture; (iv) creating a third temporary mixture; (v) creating a first base mixture; (vi) fermenting the first base mixture under dark conditions to produce a first hydrogen gas and a dark fermented base mixture; (vii) creating a second base mixture; (viii) fermenting the second base mixture under light conditions to produce a second hydrogen gas; and (ix) purifying the first hydrogen gas and the second hydrogen gas to obtain a hydrogen gas purity of over 99%.
