Biogas
Biogas is a gaseous renewable energy source[1] produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste, wastewater, and food waste. Biogas is produced by anaerobic digestion with anaerobic organisms or methanogens inside an anaerobic digester, biodigester or a bioreactor.[2] The gas composition is primarily methane (CH
4) and carbon dioxide (CO
2) and may have small amounts of hydrogen sulfide (H
2S), moisture and siloxanes. The methane can be combusted or oxidized with oxygen. This energy release allows biogas to be used as a fuel; it can be used in fuel cells and for heating purpose, such as in cooking. It can also be used in a gas engine to convert the energy in the gas into electricity and heat.[3]
After removal of carbon dioxide and hydrogen sulfide it can be compressed in the same way as natural gas and used to power motor vehicles. In the United Kingdom, for example, biogas is estimated to have the potential to replace around 17% of vehicle fuel.[4] It qualifies for renewable energy subsidies in some parts of the world. Biogas can be cleaned and upgraded to natural gas standards, when it becomes bio-methane. Biogas is considered to be a renewable resource because its production-and-use cycle is continuous, and it generates no net carbon dioxide. From a carbon perspective, as much carbon dioxide is absorbed from the atmosphere in the growth of the primary bio-resource as is released, when the material is ultimately converted to energy.
Chelmsford (/ˈtʃɛlmzfəd/) is a city in the City of Chelmsford district in the county of Essex, England. It is the county town of Essex and one of three cities in the county, along with Southend-on-Sea and Colchester. It is located 30 miles (50 kilometres) north-east of London at Charing Cross and 22 miles (35 kilometres) south-west of Colchester. The population of the urban area was 111,511 in the 2011 Census,[1] while the wider district has 168,310.[2][3]
The demonym for a Chelmsford resident is "Chelmsfordian".
The main conurbation of Chelmsford incorporates all or part of the former parishes of Broomfield, Newland Spring, Great Leighs, The Walthams, Great Baddow, Little Baddow, Galleywood, Howe Green, Margaretting, Pleshey, Stock, Roxwell, Danbury, Bicknacre, Writtle, Moulsham, Rettendon, The Hanningfields, The Chignals, Widford and Springfield, including Springfield Barnes, now known as Chelmer Village.
The communities of Chelmsford, Massachusetts, Chelmsford, Ontario and Chelmsford, New Brunswick are named after the city.
Chelmsford's population consists of a large number of City and Docklands commuters, attracted by the 30–35-minute railway journey into Central London via the Great Eastern Main Line.