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.
Greater Manchester is a metropolitan county and combined authority area in North West England, with a population of 2.8 million;[2] comprising ten metropolitan boroughs: Bolton, Bury, Oldham, Rochdale, Stockport, Tameside, Trafford, Wigan, and the cities of Manchester and Salford. Greater Manchester was created on 1 April 1974, as a result of the Local Government Act 1972, and designated a functional city region on 1 April 2011. Greater Manchester is formed of parts of the historic counties of Lancashire, Cheshire and the West Riding of Yorkshire.
Greater Manchester spans 493 square miles (1,277 km2),[3] which roughly covers the territory of the Greater Manchester Built-up Area, the second most populous urban area in the UK. Though geographically landlocked, it is connected to the sea by the Manchester Ship Canal which is still open to shipping in Salford and Trafford. Greater Manchester borders the ceremonial counties of Cheshire (to the south-west and south), Derbyshire (to the south-east), West Yorkshire (to the north-east), Lancashire (to the north) and Merseyside (to the west). There is a mix of high-density urban areas, suburbs, semi-rural and rural locations in Greater Manchester, but land use is mostly urban—the product of concentric urbanisation and industrialisation which occurred mostly during the 19th century when the region flourished as the global centre of the cotton industry. It has a focused central business district, formed by Manchester city centre and the adjoining parts of Salford and Trafford, but Greater Manchester is also a polycentric county with ten metropolitan districts, each of which has at least one major town centre and outlying suburbs.
Greater Manchester is governed by the Greater Manchester Combined Authority (GMCA), which consists of political leaders from each of the ten metropolitan borough councils, plus a directly elected mayor, with responsibility for economic development, regeneration and transport. Andy Burnham is the inaugural Mayor of Greater Manchester, elected in 2017. For the 12 years following 1974, the county had a two-tier system of local government; district councils shared power with the Greater Manchester County Council. The county council was abolished in 1986 and so its districts (the metropolitan boroughs) effectively became unitary authority areas. However, the metropolitan county continued to exist in law and as a geographic frame of reference,[4] and as a ceremonial county, with a Lord Lieutenant and a High Sheriff. Several county-wide services were co-ordinated through the Association of Greater Manchester Authorities between 1985 and 2011.
Before the creation of the metropolitan county, the name SELNEC was used for the area, from the initials of "South East Lancashire North East Cheshire". Greater Manchester is an amalgamation of 70 former local government districts from the former administrative counties of Lancashire, Cheshire, the West Riding of Yorkshire and eight independent county boroughs.[5] Since deindustrialisation in the mid-20th century, Greater Manchester has emerged as a major centre for services, media and digital industries, and is renowned for guitar and dance music and its association football teams.[6]