NOVELTY - Producing hydrogen involves: providing an organic waste; fermenting the organic waste in an anaerobic environment, where hydrogen is produced from the fermenting; and directing the hydrogen to one of a fuel cell or a heat engine.    USE - For producing hydrogen from organic waste such as DDGS, Dry Distillers Grains (DDG), garbage, human waste, animal waste, and food waste, used to generate electricity in modular energy systems (all claimed).    ADVANTAGE - The present method of biological production of hydrogen gas offers a sustainable method for the production of fuel with a concurrent minimization of waste. Unlike fossil fuels, combustion of hydrogen does not produce carbon dioxide or sulfur oxides. Hydrogen also has a higher energy yield (120 kJ/g) than hydrocarbons (44 kJ/g, petroleum). Conventional chemical methods for hydrogen production are energy intensive. The biological hydrogen (biohydrogen) production methods utilizing microorganisms potentially offer an economically feasible and sustainable alternative for producing hydrogen. The present method generates renewable energy from organic waste and reduces pollution. The method of using organic wastes for bioproduction of hydrogen is cost effective, reduces pollution in the environment, and provides a source of fertilizer for growing crops. By using DDGS left over from bioethanol production to produce biohydrogen, the total amount of renewable energy created from a given amount of grain is increased. The infrastructure associated with the production of DDGS will be relatively small in comparison with total plant cost and hence it can be assumed that this process has the potential to increase ethanol efficiency by at least 10%.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) method for producing renewable fuel from grains involving: producing ethanol and Dry Distillers Grains plus Solubles (DDGS) from grains; and fermenting the DDGS in anaerobic environment to produce hydrogen gas; and    (2) a modular renewable energy system comprising: a solar collector system for generating heat energy; a bioreactor including a chamber for fermenting organic waste; and one of a fuel cell and a heat engine in gaseous communication with the bioreactor; where anaerobic fermentation of organic waste in the chamber generates hydrogen gas, where the hydrogen gas is directed to one of a fuel cell or a heat engine.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of inputs and outputs of a modular energy system.