TECHNOLOGY FOCUS - ENVIRONMENT - Preferred process: Coupling of thermal energy with a photovoltaic process for hydrogen production (by electrolysis) permits total consumption of carbon dioxide for methanol synthesis. The primary energy source is methane, either of geogenic origin or produced by anaerobic fermentation of biomass (manure or green matter). When the thermal energy is not required for communal purposes, it is used to power chemical synthesis from natural raw materials, e.g. fat or oil cleavage, esterification or epoxidation of fatty acids. Methanol may also be reacted with unsaturated fatty acids to produce 'biodiesel' fuel. The thermal energy is produced in a gas turbine, and combustion is supported by oxygen (from the electrolysis stage or following preliminary air separation), not air. This means that nitrogen oxides are not generated, also sorption/desorption steps for carbon dioxide removal are not required. Any sulfur dioxide, generated from organic sulfur compounds, is removed as sulfurous acid by expansion and cooling of the combustion gases to below the dew point of water. Where the biogas to be burnt has a high sulfur content, the sulfurous acid may be used in a redox reaction to eliminate hydrogen sulfide or mercaptans from the unburnt gas, in the form of sulfur.    TECHNOLOGY FOCUS - POLYMERS - Preferred polymers: Carbon dioxide formed by combustion or fermentation can also be used for synthesis of poly(alkylene carbonates) or cyclic carbonates (CC), by reaction with oxiranes. Reaction of methanol with CC produces dimethyl carbonate (a starting material for polyurethanes or polycarbonates). EXAMPLE - Daily production of 1 ton methanol and generation of 1 MWh electrical energy requires about 12000 N cubic m of biogas containing 30% methane. The photovoltaic unit must generate an addition 12 MWh and (between March and October) this will require a collector surface of about 30000 square m (for biogas, about half this size if pure methane is burnt). Hydrogen from the associated electrolysis unit is used for methanol synthesis and the oxygen is used in the combustion stage, from which the carbon dioxide is distributed to the various synthesis stages.