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.
The City of Leeds is a city and metropolitan borough in West Yorkshire, England. The metropolitan borough includes the administrative centre of Leeds and the towns of Farsley, Garforth, Guiseley, Horsforth, Morley, Otley, Pudsey, Rothwell, Wetherby and Yeadon.[4] It has a population of 793,139 (mid-2019 est.), making it technically the second largest city in England by population behind Birmingham, since London is not a single local government entity. It is governed by Leeds City Council.
The current city boundaries were set on 1 April 1974 by the provisions of the Local Government Act 1972, as part a reform of local government in England. The city is a merger of eleven former local government districts; the unitary City and County Borough of Leeds combined with the municipal boroughs of Morley and Pudsey, the urban districts of Aireborough, Garforth, Horsforth, Otley and Rothwell, and parts of the rural districts of Tadcaster, Wharfedale and Wetherby from the West Riding of Yorkshire.
For its first 12 years the city had a two-tier system of local government; Leeds City Council shared power with West Yorkshire County Council. Since the Local Government Act 1985 Leeds City Council has effectively been a unitary authority, serving as the sole executive, deliberative and legislative body responsible for local policy, setting council tax, and allocating budget in the city, and is a member of the Leeds City Region Partnership. The City of Leeds is divided into 31 civil parishes and a single unparished area.