renewable electricity. biogas in germany is primarily extracted by the co-fermentation of energy crops (called 'nawaro', an abbreviation of nachwachsende rohstoffe, german for renewable resources) mixed with manure. the main crop used is corn. organic waste and industrial and agricultural residues such as waste from the food industry are also used for biogas generation. in this respect, biogas production in germany differs significantly from the uk, where biogas generated from landfill sites is most common. biogas production in germany has developed rapidly over the last 20 years. the main reason is the legally created frameworks. government support of renewable energy started in 1991 with the electricity feed-in act (streg). this law guaranteed the producers of energy from renewable sources the feed into the public power grid, thus the power companies were forced to take all produced energy from independent private producers of green energy. in 2000 the electricity feed-in act was replaced by the renewable energy sources act (eeg). this law even guaranteed a fixed compensation for the produced electric power over 20 years. the amount of around 8 ¢/kwh gave farmers the opportunity to become energy suppliers and gain a further source of income. the german agricultural biogas production was given a further push in 2004 by implementing the so-called nawaro-bonus. this is a special payment given for the use of renewable resources, that is, energy crops. in 2007 the german government stressed its intention to invest further effort and support in improving the renewable energy supply to provide an answer on growing climate challenges and increasing oil prices by the 'integrated climate and energy programme'. this continual trend of renewable energy promotion induces a number of challenges facing the management and organisation of renewable energy supply that has also several impacts on the biogas production. the first challenge to be noticed is the high area-consuming of the biogas electric power supply. in 2011 energy crops for biogas production consumed an area of circa 800,000 ha in germany. this high demand of agricultural areas generates new competitions with the food industries that did not exist hitherto. moreover, new industries and markets were created in predominately rural regions entailing different new players with an economic, political and civil background. their influence and acting has to be governed to gain all advantages this new source of energy is offering. finally biogas will furthermore play an important role in the german renewable energy supply if good governance is focused. developing countries domestic biogas plants convert livestock manure and night soil into biogas and slurry, the fermented manure. this technology is feasible for small-holders with livestock producing 50 kg manure per day, an equivalent of about 6 pigs or 3 cows. this manure has to be collectable to mix it with water and feed it into the plant. toilets can be connected. another precondition is the temperature that affects the fermentation process. with an optimum at 36 °c the technology especially applies for those living in a (sub) tropical climate. this makes the technology for small holders in developing countries often suitable. simple sketch of household biogas plant depending on size and location, a typical brick made fixed dome biogas plant can be installed at the yard of a rural household with the investment between us$300 to $500 in asian countries and up to $1400 in the african context. a high quality biogas plant needs minimum maintenance costs and can produce gas for at least 15–20 years without major problems and re-investments. for the user, biogas provides clean cooking energy, reduces indoor air pollution, and reduces the time needed for traditional biomass collection, especially for women and children. the slurry is a clean organic fertilizer that potentially increases agricultural productivity. energy is an important part of modern society and can serve as one of the most important indicators of socio-economic development. as much as there have been advancements in technology, even so, some three billion people, primarily in the rural areas of developing countries, continue to access their energy needs for cooking through traditional means by burning biomass resources like firewood, crop residues and animal dung in crude traditional stoves. domestic biogas technology is a proven and established technology in many parts of the world, especially asia. several countries in this region have embarked on large-scale programmes on domestic biogas, such as china and india. the netherlands development organisation, snv, supports national programmes on domestic biogas that aim to establish commercial-viable domestic biogas sectors in which local companies market, install and service biogas plants for households. in asia, snv is working in nepal, vietnam, bangladesh, bhutan, cambodia, lao pdr, pakistan and indonesia, and in africa; rwanda, senegal, burkina faso, ethiopia, tanzania, uganda, kenya, benin and cameroon. in south africa a prebuilt biogas system is manufactured and sold. one key feature is that installation requires less skill and is quicker to install as the digester tank is premade plastic. india biogas in india has been traditionally based on dairy manure as feed stock and these "gobar" gas plants have been in operation for a long period of time, especially in rural india. in the last 2–3 decades, research organisations with a focus on rural energy security have enhanced the design of the systems resulting in newer efficient low cost designs such as the deenabandhu model. the deenabandhu model is a new biogas-production model popular in india. (deenabandhu means "friend of the helpless".) the unit usually has a capacity of 2 to 3 cubic metres. it is constructed using bricks or by a ferrocement mixture. in india, the brick model costs slightly more than the ferrocement model; however, india's ministry of new and renewable energy offers some subsidy per model constructed. biogas which is mainly methane/natural gas can also be used for generating protein rich cattle, poultry and fish feed in villages economically by cultivating methylococcus capsulatus bacteria culture with tiny land and water foot print. the carbon dioxide gas produced as by product from these plants can be put to use in cheaper production of algae oil or spirulina from algaculture particularly in tropical countries like india which can displace the prime position of crude oil in near future. union government of india is implementing many schemes to utilise productively the agro waste or biomass in rural areas to uplift rural economy and job potential. with these plants, the non-edible biomass or waste of edible biomass is converted in to high value products without any water pollution or green house gas (ghg) emissions. lpg (liquefied petroleum gas) is a key source of cooking fuel in urban india and its prices have been increasing along with the global fuel prices. also the heavy subsidies provided by the successive governments in promoting lpg as a domestic cooking fuel has become a financial burden renewing the focus on biogas as a cooking fuel alternative in urban establishments. this has led to the development of prefabricated digester for modular deployments as compared to rcc and cement structures which take a longer duration to construct. renewed focus on process technology like the biourja process model has enhanced the stature of medium and large scale anaerobic digester in india as a potential alternative to lpg as primary cooking fuel. in india, nepal, pakistan and bangladesh biogas produced from the anaerobic digestion of manure in small-scale digestion facilities is called gobar gas; it is estimated that such facilities exist in over 2 million households in india, 50,000 in bangladesh and thousands in pakistan, particularly north punjab, due to the thriving population of livestock. the digester is an airtight circular pit made of concrete with a pipe connection. the manure is directed to the pit, usually straight from the cattle shed. the pit is filled with a required quantity of wastewater. the gas pipe is connected to the kitchen fireplace through control valves. the combustion of this biogas has very little odour or smoke. owing to simplicity in implementation and use of cheap raw materials in villages, it is one of the most environmentally sound energy sources for rural needs. one type of these system is the sintex digester. some designs use vermiculture to further enhance the slurry produced by the biogas plant for use as compost. in pakistan, the rural support programmes network is running the pakistan domestic biogas programme which has installed 5,360 biogas plants and has trained in excess of 200 masons on the technology and aims to develop the biogas sector in pakistan. in nepal, the government provides subsidies to build biogas plant at home. china the chinese have experimented with the applications of biogas since 1958. around 1970, china had installed 6,000,000 digesters in an effort to make agriculture more efficient. during the last few years, technology has met high growth rates. this seems to be the earliest developments in generating biogas from agricultural waste. the rural biogas construction in china has shown an increased development trend. the exponential growth of energy supply caused by rapid economic development and severe haze condition in china have led biogas to become the better eco-friendly energy for the rural areas. in qing county, hebei province, the technology of using crop straw as a main material to generate biogas is currently developing. china had 26.5 million biogas plants, with an output of 10.5 billion cubic meter biogas until 2007. the annual biogas output has increased to 248 billion cubic meter in 2010. the chinese government had supported and funded rural biogas projects, but only about 60% were operating normally. during the winter, the biogas production in northern regions of china is lower. this is caused by the lack of heat control technology for digesters thus the co-digestion of different feedstock failed to complete in the cold environment. zambia lusaka, the capital city of zambia, has two million inhabitants with over half of the population residing in peri-urban areas. the majority of this population use pit latrines as toilets generating approximately 22,680 tons of fecal sludge per annum. this sludge is inadequately managed: over 60% of the generated faecal sludge remains within the residential environment thereby compromising both the environment and public health. in the face of research work and implementation of biogas having started as early as in the 1980s, zambia is lagging behind in the adoption and use of biogas in the sub-saharan africa. animal manure and crop residues are required for the provision of energy for cooking and lighting. inadequate funding, absence of policy, regulatory framework and strategies on biogas, unfavorable investor monetary policy, inadequate expertise, lack of awareness of the benefits of biogas technology among leaders, financial institutions and locals, resistance to change due cultural and traditions of the locals, high installation and maintenance costs of biogas digesters, inadequate research and development, improper management and lack of monitoring of installed digesters, complexity of the carbon market, lack of incentives and social equity are among the challenges that have impeded the acquiring and sustainable implementation of domestic biogas production in zambia. associations world biogas association (https://www.worldbiogasassociation.org/) american biogas council (https://americanbiogascouncil.org/) canadian biogas association (https://www.biogasassociation.ca/) european biogas association german biogas association indian biogas association society and culture in the 1985 australian film mad max beyond thunderdome the post-apocalyptic settlement barter town is powered by a central biogas system based upon a piggery. as well as providing electricity, methane is used to power barter's vehicles. "cow town", written in the early 1940s, discusses the travails of a city vastly built on cow manure and the hardships brought upon by the resulting methane biogas. carter mccormick, an engineer from a town outside the city, is sent in to figure out a way to utilize this gas to help power, rather than suffocate, the city. contemporary biogas production provides new opportunities for skilled employment, drawing on the development of new technologies.