NOVELTY - The hydrogen generator comprises a container, a first reactant storage area present within the container, a reaction area within the container, a fluid passage placed from the first reactant storage area to the reaction area, an effluent storage area (18) present within the container, an effluent passage positioned from the reaction area to the effluent storage area, an initially compressed filter present within the effluent storage area, a liquid impermeable, gas permeable component present in fluid communication with the effluent storage area, a hydrogen outlet, and a biased component.    USE - The hydrogen generator is useful for a fuel cell system, where the fuel cell is useful for portable electronic devices.    ADVANTAGE - The disposable or refillable hydrogen generator exhibits improved volume efficiency and compact size, and is easy and economical to manufacture.    DETAILED DESCRIPTION - The hydrogen generator comprises a container, a first reactant storage area present within the container, a reaction area within the container, a fluid passage placed from the first reactant storage area to the reaction area, an effluent storage area (18) present within the container, an effluent passage positioned from the reaction area to the effluent storage area, an initially compressed filter present within the effluent storage area, a liquid impermeable, gas permeable component present in fluid communication with the effluent storage area, a hydrogen outlet, and a biased component. The first reactant storage area has a volume, is configured to contain a fluid comprising a first reactant and a second reactant, and comprises flexible enclosure having a volume configured to contain the fluid comprising the first reactant. The reaction area has a volume, and comprises a flexible enclosure having a volume. The effluent storage area has a volume, and comprises a flexible enclosure having a volume configured to store hydrogen gas and an effluent produced by a reaction of the first reactant within the reaction area. The initially compressed filter is configured to expand to contain a portion of the effluent. The effluent storage area volume is configured to increase and the first reactant storage area volume and/or the reaction area volume is configured to decrease during an operation of the hydrogen generator. A moveable partition separates the effluent storage area from the first reactant storage area and/or the reaction area. A portion of the filter is attached to the moveable partition. The first reactant reacts to produce hydrogen gas. The hydrogen gas passes through a portion of the effluent storage area to reach the hydrogen outlet. The filter is configured to apply a force for reducing the first reactant storage area volume, the reaction area volume or both during the operation of the hydrogen generator, has areas of different porosity before a compression, and comprises a material that has an affinity for a liquid in the effluent, an open cell foam, and an elastic material. The biased component is configured to apply a force for reducing the first reactant storage area volume, the reaction area volume or both during the operation of the hydrogen generator. The area of greatest porosity before the compression is closest to the effluent passage and to the outlet. A portion of the filter proximate the liquid impermeable, gas permeable component has an affinity for the liquid in the effluent. The moveable partition comprises a flexible effluent enclosure within the effluent storage area and a rigid wall adjacent to the flexible effluent enclosure, and pulls the filter to expand the filter. The flexible effluent enclosure has a volume. The filter is contained within and attached to a portion of the flexible effluent enclosure, and expands as a result of a reduction in a compressive stress in the filter. The volume of the flexible effluent enclosure is configured to increase during the operation of the hydrogen generator. The first reactant is initially contained within a flexible first reactant enclosure within the first reactant storage area. The fluid passage is placed from the first reactant storage area enclosure to the reaction area enclosure. The effluent passage is placed from the reaction area enclosure to the effluent storage area enclosure. The flexible effluent enclosure separates the effluent storage area from the first reactant storage area and/or the reaction area.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic cross-sectional view of a hydrogen generator.    Housing (12)    Effluent storage area (18)    First reactant composition (20)    Fluid outlet passage (34)    Fluid inlet passage. (40)