Each digester reduces carbonThe installation of a household biogas digester to handle animal manure does not only reduce carbon dioxide emissions, but it helps to improve rural living conditions in many different ways. See below how our programme helps creating a better life for countless rural families. These sustainable development benefits include in particular:
Households in Sichuan traditionally use either coal or firewood as cooking fuel. This does not only cause carbon dioxide emissions from fossil fuels, but also severe air pollution. Several studies have shown that this air pollution causes severe health risks and can reduce average life expectancy significantly. In contrast, reducing the dependancy on coal and firewood and replacing it with clean fuel like biogas can improve the situation especially of women and children considerably.
As the Programme provides clean cooking fuel and reduces the consumption of both coal and firewood, the positive effect is even higher than can be seen from mere emission reduction data. Because firewood in Sichuan is renewable biomass and its reduced consumption does not have an impact on climate change, we do not calculate it. However, what we do calculate is the reduction in coal consumption. So far, our Programme has avoided the combustion of an enormous amount of coal:
In the year 2000, the United Nations agreed on the UN Millennium Declaration, in which they defined the Millennium Development Goals. In goal 7, Ensure Environmental Sustainability, it was defined that the UN targeted to halve, by 2015, the proportion of the population without sustainable access to safe drinking water and basic sanitation.
According to the World Bank, in 2011 65% of the population of China had access to improved sanitation. However, that means, that still more than 470 million people, or nearly the number of people living in the EU, do not have access to clean sanitation.
This is where our Programme supports the rural population. In the very rural regions of Sichuan, it is still not uncommon, that people use an open pit latrine outside the house as a toilet. The digesters installed by the Programme are connected to the toilets and directly flush the digestion chamber, which works similar to a septic tank. This is defined as an improved form of sanitation by the WHO / UNICEF Joint Monitoring Programme (JMP).
Providing the households with access to improved sanitation reduces the risk of many diseases like diarrhoea, trachoma or ascariasis and infections with parasites like hookworms.
A precondition for the households joining the Programme is that they are raising pigs and store the manure in the traditional pit storages below or besides the animal confinements. These open pits do not only generate methane emissions, but they are also imposing a severe health risk for animals and humans. Similar to conventional latrines, they are a source of diseases and parasite infections. Additionally, they impose the risk of zoonotic diseases (diseases that can be passed from animal to human).
By installing a biogas digester with an inlet pipe directly connected to the animal barns, the households can sweep the manure directly into the digester without any further contact. Stored in the septic tank of the digester, both the odour of the degrading manure and the risk of infections are greatly reduced.
Both traditional fuels, coal and gas, come at a price. Coal is usually purchased in the next village and firewood is collected or chopped in nearby woods. Sichuan is a very large heterogeneous province with countless regions that differ in remoteness, infrastructure, forest cover, availability of coal, etc. It is therefore not possible to clearly quantify the costs of fuel like it could be done for a traditional CDM project. However, it can be said that an average household would usually spend 1,500 RMB per year on fuel.
With the installation of a biogas digester, these expenses can be saved as the households produce their own fuel and achieve energy autonomy to a large extent.
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Biogas is generated in the digester and delivered to the gas cooker through a rubber hose. As long as there is gas in the digester, it can easily be extracted and is available within seconds. Whereas households need to always keep a sufficient stock of coal and wood, the gas is generated constantly and therefore does not need to be stored.
Furthermore, the gas cookers do not need to be fired up, but just switched on and off. It is therefore much easier to use just the amount of fuel needed to prepare food, instead of having to waste a lot before and after the actual cooking process.
