A process and/or system for producing fuel that includes providing biogas, removing carbon dioxide from the biogas, transporting the upgraded biogas to a hydrogen plant; providing the transported upgraded biogas and fossil-based natural gas as feedstock for hydrogen production. The carbon intensity of the fuel is less than 11 gCO.sub.2-eq/MJ, at least in part because carbon dioxide removed from the biogas and carbon dioxide from hydrogen production is captured and stored.

A power generation system comprises a fuel gas supply device 13 for controlling methane concentration or carbon dioxide concentration in a mixed gas MG containing methane and carbon dioxide within a setting range for the concentration in the fuel gas of a gas engine 11, and for supplying the mixed gas MG to the gas engine 11 as the fuel gas, and a gas concentration sensor 14 for measuring the carbon dioxide concentration or the methane concentration of the mixed gas MG. The fuel gas supply device 13 comprises a carbon dioxide removal device 16 for removing carbon dioxide in the mixed gas MG, and an operating condition control device 17 for controlling an operating condition that affects an increase or decrease of a carbon dioxide removal rate of the carbon dioxide removal device 16, and the operating condition control device 17 controls the operating condition of the carbon dioxide removal device 16 based on the measurement result of the gas concentration sensor 14, thereby controlling the concentration of methane and carbon dioxide in the mixed gas.

Compositions and methods for producing aldehydes, alkanes, and alkenes are described herein. The aldehydes, alkanes, and alkenes can be used in biofuels.

In a device for separating methane from a gas mixture containing methane, carbon dioxide and hydrogen sulfide, comprising a gas compressor, two or three membrane separation stages downstream of the compressor and a hydrogen sulfide adsorber, comprising a bed of activated carbon having catalytic activity for oxidizing hydrogen sulfide with oxygen, arranged upstream of the membrane separation stages, oxygen content and relative humidity can be adjusted for optimum adsorption capacity of the hydrogen sulfide adsorber by recycling permeate from the second membrane separation stage, which receives the retentate of the first membrane separation stage, to a point upstream of the hydrogen sulfide adsorber.

A process for production of biofuels from algae can include cultivating an oil-producing algae by promoting sequential photoautotrophic and heterotrophic growth. The method can further include producing oil by heterotrophic growth of algae wherein the heterotrophic algae growth is achieved by introducing a sugar feed to the oil-producing algae. An algal oil can be extracted from the oil-producing algae, and can be converted to form biodiesel.

A system including biogas purification and provides biogas as feedstock to a solid oxide fuel cell. The biogas purification treatment process provides a polished biogas that is substantially free of carbonyl sulfides and hydrogen sulfide. The system uses a biogas treatment apparatus, that includes apparatus such as a packed columns, comprising copper oxide or potassium permanganate packing material, and an activated carbon component configured to treat the biogas by polishing it to remove carbonyl sulfides and deleterious trace residues, such as hydrogen sulfide, that were not removed by any prior bulk H2S removal steps. In addition, an oil removal device is used to remove any entrained fine oil droplets in the biogas. A polished biogas having in the range of 60% methane is charged to the fuel cell. Electricity generated may be fed into a grid or used directly as energy to charge electrical-powered vehicles, for example. Energy credits are tracked in real time and are appropriately assigned.

Compositions including metal nano- and/or micro-particles in solution with photosynthetic bioproduct producing microorganisms. These light harvesting complexes increase growth rates and photosynthetic efficiency of the constituent microorganisms, reducing the light required for a specific production level, or increases production for a specific light level.

Solid waste that includes a mixture of wet organic material and dry organic material can be are separated using mechanical separation to produce a wet organic stream enriched in wet organics and a dry organic stream enriched in dry organics. The separated wet organic stream and dry organic stream are separately converted to renewable or recyclable products using different conversion techniques particularly suited for the separated wet and dry organic streams.

Some embodiments are directed to an apparatus for forming discrete biomass receptacles from a base material that is created via cultivating or processing algae for biofuel production. The apparatus includes a supplier to supply heat softened biomaterial; a rotatable molder to receive the heat softened biomaterial that includes a heated hollow mold; a rotator configured to rotate the rotatable molder; and a controller configured to control the rotator to rotate the heated hollow mold such that the heat softened biomaterial disperses and adheres to walls of the heated hollow mold, the controller also being configured to control the rotator to continue rotating the heated hollow mold as the heat softened biomaterial cools so as to impede sagging and deformation of the biomass receptables being formed, such that the receptacles that are formed are configured to house algae via at least one of the cultivating and processing of the algae.

A vessel for control of aquatic plant species (100) in seas, rivers and lakes that is configured to extract from the surface of the water and hoist to a deck of the vessel (100) a plurality of plant remains of a given aquatic ecosystem by means of an elevator belt (101); and/or receive from a coastal installation a plurality of aquatic plant remains mixed with grey water from coastal human settlements; and that is characterized in that the remains of aquatic plant species extracted from the surface of the water and/or received from coastal human settlements are deposited in a cooking chamber (102) where they are subjected to controlled temperature conditions configured to modify, ferment and rot said remains preventing their reproduction.