Biogas plants: a promising area for shifting towards renewables in rural Kyrgyzstan
Biogas plants have the fastest payback time of all renewable sources in the Kyrgyz Republic. However, as with all renewables, large upfront investments are needed for the construction of a biogas plant. When does it make sense to invest in a biogas plant?
Let's look at an example of the newest biogas plant in the Kyrgyz Republic - the first one built in the Batken province. Akbarali Zhoroev, the owner of the famous Texas cafe, says: “I started my business with building a toilet - a clean, modern toilet on the Osh-Isfana highway. I specially bought quality plumbing, did everything with care, even installed mosquito nets on windows to ensure there were no insects inside. Then we began to build cafe, expanded, built a hotel. We try to provide quality services for our customers, and we see their response. For example, we sell our own kefir. We serve in large reusable glass jars. Customers love our delicious kefir so much that many people order several servings first thing at the doorstep.” The Texas café continues to expand its business towards renewable applications, such as biogas power plants.
The main customers of Texas cafe are local residents and those who drive along the Osh-Isfana highway. In addition to the cafe, Akbarali owns retail space for food and livestock, where he constantly keeps several cattle. A 2-hectare cherry and apricot orchard for 500 trees is the most recent addition to his establishment.
When deciding on the construction of the biogas plant, Akbarali received advice within the framework of the UNDP-OPEC Fund for International Development (OFID) project “Development of small and medium-sized businesses for access to energy” on the possibilities of using biogas technology products in business, but he himself has already made the main economic calculations.
“I have known about biogas plants for a long time - I have graduated as an agronomist. I have long wanted to build my own circular non-waste production, and now, finally, I have such an opportunity”, Akbarali says. One of the key goals that Akbarali wants to reach through the construction of a biogas plant is to increase the productivity of the cherry garden with the help of biofertilizers. He also aims to reduce heat and cooking bills – which cover a large part of his expenditure, by shifting towards environmentally friendly renewable technologies and using produced biogas.
Kyrgyzstan has its own manufacturer of biogas plants, operating for over 20 years. With the support of various UNDP projects, PF Fluid contributed to the development of biogas technologies not only in Kyrgyzstan and Central Asia, but also in the distant North Korea.
The appropriate size of a biogas plant, measured in cubic meters of the digester, can be calculated based on the number of cattle heads - 1 cubic meter per head. The best biogas production results, however, are obtained by using a mixture of various types of wastes - manure, green and food waste.
According to National Statistical Committee of the Kyrgyz Republic, as of 2019, there were 1,680,750 head of cattle in Kyrgyzstan. Processing of all collected livestock waste (40%) in Kyrgyzstan will make it possible to obtain up to 16 million tons of liquid fertilizers which could fully satisfy the country's agricultural needs for fertilizers.
As calculated in the 2017 edition of the Manual on Biogas Technologies, first developed with UNDP support in 2006, along with the production of liquid fertilizers, as a result of anaerobic processing of animal waste, 268 million cubic meters of biogas per year, or 745 thousand m3 of biogas per day, can be produced and used to provide for energy and motor fuel needs of the rural population.
This volume of biogas, after deducting the biogas used for heating the biogas plants themselves, will be enough to heat 2.6 million square meters of residential and industrial areas, that is, 52 thousand medium-sized (with an area of 50 m2) rural houses - about 6% of the rural population. If produced biogas would be used for cooking, it could satisfy the needs of 15% of rural households with additional benefit from conserving forests, reducing greenhouse gas emissions and alleviation of female labor.
The biogas plant for Akbarali Zhoroev is designed to process waste from 50 cattle heads and costs about 23.5 thousand US dollars. To reduce the cost of biogas plant, PF Fluid makes it possible to use materials and vessels already owned by the customer - if desired, he can make purchases according to the specifications provided. Of great help to Akbarali was the assistance received from the EBRD's business development program, which supported 75% of the costs of consulting services for the construction of the biogas plant.
At the end of March 2020, the biogas unit was commissioned into operation and can already process more than 3 tons of raw materials (with 89-92% moisture content) per day. The unit can produce more than 3 tons of biofertilizers per day - sufficient for fertilizing 0.5 hectares daily, as well as 90 m3 of biogas, sufficient for heating around 300 m2 of premises. The biogas produced will be used by Akbarali for cooking and heating the interior of the cafe. Due to internal production of biogas and biofertilizer, energy costs of Akbarali’s business can be reduced by more than 50%, and cherry yield growth, can increase by 15% – 200%.
Akbarali plans to sell the surplus of biofertilizer on the local market, and will share it for free in the first year of plant operation, so that farmers can test the results of applying biological fertilizers on their own farms.
How does the system work?
The main part of the biogas plant - the digester - is a hermetically sealed container where at a temperature of 37 ℃ anaerobic digestion of the organic mass of waste occurs with the formation of biogas. Waste - most often manure, vegetable and food waste - is collected daily, ground up and diluted with water until the desired moisture content is reached. After that, the finished raw material is heated to 20 ℃ and introduced into the digester, where it is processed by methane bacteria.
The resulting biogas, consisting of 65 - 70% methane, after purification, is collected and stored until use in a gasholder. From the gasholder biogas is carried out through gas pipes to the place of use in gas appliances. In addition to internal use, biogas can be sold to other farms or businesses aligned with the national standards developed by the UNDP-OFID Energy Access SME Development Project, namely General technical conditions” and “Gas distribution systems for biogas”, technical regulation “On the safety of biogas distribution networks” and the methodology “Determining costs for the calculation of tariffs for biogas”.
How efficient is the system?
Calorific value of one cubic meter of biogas is, depending on the methane content, 20-25 MJ / m3, which is equivalent to the combustion of 0.6 - 0.8 liters of gasoline; 1.3 - 1.7 kg of firewood or the use of 5 - 7 kW of electricity. The raw materials processed in the digester of the biogas plant, converted into biofertilizers, are unloaded daily and applied into the soil or used as a feed additive for animals.
Biofertilizer – liquid methane effluent, contains organic substances that increase soil permeability and hygroscopicity, prevent erosion and improve general soil conditions. Organic matter is also the basis for the development of microorganisms, which convert nutrients into a form easily absorbed by plants. Practice shows that applying 5-7 tons of biogertiliser per ha the yields of plants increase from 15% to 200%, and most weed seeds are destroyed.
On average, the payback time of a biogas plant is 1-2 years. Let's make a calculation for a specific biogas unit of Akbarali Zhoroev: the equipment cost is 23,500 USD, plus construction - the total cost of the unit will be about 30,000 US dollars. With the price of natural gas in March 2020 equal to 17.6 - 21.3 soms (0.22 - 0.27 USD) per cubic meter, biogas, with an efficiency equal to 65% of natural gas, will cost 0.14 - 0.17 USD per cubic meter. The installation of Akbarali will produce 59,400 m3 of biogas per year - or the equivalent of 10,000 US dollars, as well as 1,200 tons of biofertilizers, which, at a cost of 6 USD per ton, will save 7200 US dollars.
Increasing the yield of the cherry garden even by a minimum of 15% - from 20 tons per hectare to 23 tons per hectare - will bring 112500 soms or 1.5 thousand US dollars per hectare - or 3000 USD per year for the farm of Akbarali Zhoroev. That is, the total annual benefit from the installation will be about 20,000 US dollars, and the payback period is 1.5 years.
At the same time, it should be understood that a biogas plant is more a living organism than a machine, since methane bacteria, which are sensitive to both temperature and regular feeding, do the main work on processing the wastes. About 2 hours should be spent on the maintenance of the biogas plant per day by trained operators.
Like any living organism, a biogas plant is quite demanding - it needs regular nutrition, water, favorable temperature, but in return it produces energy and nourishes the soil, helping to increase the quality and quantity of the obtained crops. But anything is possible if you have the right incentives and support mechanisms in place for SMEs.