Implementation and Status of Biogas Technology in Ethiopia- Case of Tigray Region

In Ethiopia, like most developing countries, the majority of households depend on wood and charcoal as their cooking energy resources. This energy has a direct impact on the forest coverage and its emissions have significant health issues. Biogas technology has introduced to address these problems and reduce energy poverty in developing countries. However, the success of this technology depends on many factors such as technology appropriateness, available skill, proper introduction, and government support to create favorable financial incentives. The objective of this paper is to make an overview assessment of biogas development programs in Ethiopia, identify development barriers and provide suggestions to mitigate these barriers. The national and regional biogas program of Ethiopia has implemented to give energy for cooking and to some extent for lighting. However, it has shown limited success over the years. The National Biogas Programme of Ethiopia has shown an overall 50% achievement while the Tigray region registered 55% achievement. In addition, the owner of the biogas facility in Tigray reported a 57% functionality rate but the lowest satisfaction level of 15%.  Generally, the region has shown relatively better performance in terms of dissemination and functionality but a low satisfaction rate due to technical limitation, unsteady input, and financial factors.


INTRODUCTION
Energy is a critical requirement for economic development and improved living conditions. Ethiopia, one of the least developed countries in the world with low Gross Domestic Product (GDP) and below average Human Development Index (HDI) has the lowest access to modern energy (Human Development Indices and Indicators, 2018). Its primary energy consumption is predominately derived from biomass and wastes (agriculture, urban and animal wastes), which accounts for 91% of the energy consumed, crude oil provides about 7% of total primary energy © CNCS, Mekelle University 258 ISSN: 2220-184X while hydropower, wind, diesel and coal accounts for only 2% of the total energy demand (Mondal et al., 2017;Berhanu et al., 2017).
The average annual energy consumption in Ethiopia is about 40 000 GWh. The household sector accounts for about 93% of this energy (mainly for cooking and baking Injera), followed by transport sector (5%), and industry and others accounted for 1% (Mondal et al., 2017;Mengistu et al., 2015). Most of this energy comes from bioenergy resources, in which CO2 emissions increased from 5 million tons in 2005 to 6.5 million tons in 2010 and its per capita contribution from 0.06 ton in 2005 to 0.075 ton in 2010 (Mondal et al., 2017). Furthermore, indoor air pollution is causing more than 50,000 deaths annually and causes nearly 5% of the burden of disease from indoor cooking and poor ventilation (Abadi et al., 2017).
Ethiopia's rapid economic growth is creating steep increase in the energy demand across all sectors. While the rise in urban and manufacturing sector demand has attracted more attention, rural energy demand is also on the rise with rapid expansion in the use of biomass fuel sources resulting in environmental challenges related to air quality and deforestation. Biomass fuel is dominant energy supply in the household sector. It makes up 98.6% of the total energy consumption. Specifically, fuel wood, dung, crop residues, and charcoal account for 81.4%, 8.1%, 7.8%, and 1.3%, respectively (Mohammed and Inoue, 2012;Mengistu et al., 2015).
There are numerous disadvantages of using woody biomass as fuel, which includes negative health effects due to accumulation of indoor smoke, deforestation and the timeconsuming and problems in wood fetching (Lemlem, 2016). To alleviate these problems, Ethiopia is pursuing sustainable and ecofriendly energy polices and strategies. Accordingly, investment and development of biogas technology have seen as one of such technology solutions.
This paper presents an overview status of biogas implementation in Tigray region, northern Ethiopia. Tigray is one of the nine regional states in Ethiopia, 6 th largest regional state by area.
According to 2015 population projection, the region has an estimated population of 5.4 million that represents 6.1% of the country's population. The region also has a cattle population of more than 3,630,957 (World Fact book, 2017). The region has 80.5% rural, and 19.5% urban dwellers (Berhe et al., 2017). The region is comprised of seven zones, which in turn sub-divided into 34 rural woredas/districts.
One of the compelling reasons to promote biogas technology in Ethiopia is the livestock population particularly cattle, over 54,000,000 livestock, which is the largest in Africa and © CNCS, Mekelle University 259 ISSN: 2220-184X accounts for 3.68% of global livestock population (World Cattle Inventory, 2015). In addition, the country uses massive chemical fertilizers to improve agricultural yield, however, biogas will have the potential to replace artificial fertilizer with bio slurries. Moreover, the country has enough locally available materials to develop domestic biogas technologies. Table 1 shows the technical potential for domestic biogas in selected regions, based on the availability of livestock and access to water resources. These regions are the homes for roughly 70% of the livestock and over 70% of the population in the country (Gitonga, 1997). Eshete's study shows that biogas technology could benefit about 1.1 to 3.5 million households (Eshete et al., 2006). In order to adopt biogas technology, each region has set up a criteria to meet the demand of the biogas beneficiaries. In Tigray, the potential beneficiary should fulfill the following conditions to be included in the biogas programme (Mekonnen and Paulos, 2008):  Owning at least 4 cows/oxen  Access to water supply  Sufficient area for biogas plant installment  Access to construction materials (sand, crushed and dry stone)  Physical capability to excavate the pit for biogas plant, to muddle up the manure with water, to enter the manure and put out the slurry from the digester In early periods, the biogas implementation in Ethiopia was not a centralized program.
Biogas developments had initiated and implemented by the government, NGO's or both.
Consequently, its distribution and implementation was random. This experience continued until 2009 when the country had developed its first national biogas program of Ethiopia (NBPE). It is a centralized biogas technology developments program in the country that was implemented in partnership with donors and developers. Looking at the impact of NBPE, the government continued the implementation of the second phase in 2012 and currently it is running its third phase, called NBPE+, which focuses on evaluation of NBPE1 and NBPE2. The review of this paper was made by categorizing the implementation as early stage and national biogas programs.

EARLY STAGE BIOGAS IMPLEMENTATION IN ETHIOPIA
As per their chronological order, the early stage of biogas technology development and implementation in Ethiopia could be categorized into three generations.

First Generation of Biogas Technology Implementation
The first generation refers to the implementation of domestic biogas until 1965. The first biogas technology introduced in Ethiopia was in 1957 at Ambo Agriculture College to supply energy for welding of agricultural tools (Abadi et al., 2017;Kamp and Forn, 2016;Roopnarain and Adeleke, 2017). The installed system was batch digester unit, in which all the raw materials (water and waste materials) were added at the same time and kept for three to four weeks to decompose and subsequently the gas and bio-slurry were removed at the same time (Samer, 2012). The shortcoming of this technology is that it cannot continuously supply methane gas as it did not allow continuous feeding of slurry, this makes the technology inefficient and unacceptable. Nevertheless, government agencies in Ethiopia and the Food and Agriculture Organization (FAO) have made efforts for couples of years to promote and accelerate this type of technology in the country (Smith et al., 2011). During 1970s, two biogas plants were introduced by FAO as pilot projects to further promote the technology in Ethiopia (Kamp and Forn, 2016). Though, SNV 2018 report (NBPE+, 2018) has indicated that two biogas digesters were installed at Ambo in 1962 but their size is unknown.

Second Generation of Biogas Technology Implementation
It refers to the implementation of biogas technology during 1980 to 2000. In this period, more than 1000 biogas plants were constructed, with a size range between 2.5 and 200 m 3 , by private and government agencies in different communities across the country (Abadi et al., 2017;Kamp and Forn, 2016;Roopnarain and Adeleke, 2017;NBPE+ 2018;Yilma, 2011). This implementation period focused at demonstrating the performance of different biogas technologies (Nigatu et al., 2012;Curry and Pillay, 2012). During this period, different models including fixed dome, Indian floating drum and bag digesters, were tested.
The cost-benefit analysis of fixed dome biogas model in Ethiopia indicates that its adoption has significant positive net present value for both households, who collect their own energy sources and for those that rely on purchasing their entire energy sources (Mohammed and Inoue, 2012;Gwavuya et al., 2012). However, approximately 60% of the installations were not operational (Abadi et al., 2017;Kamp et al., 2016;Roopnarain and Adeleke, 2017). In general, the fixed dome digester performed poorly and has little success in realizing market oriented, self-financing, and sustainable biogas programme. These shortcomings of the fixed dome digester lead to negative impact on the dissemination of biogas technology and discouraged potential users. However, this generation has opened a way to the third biogas technology program in the country.

Third Generation of Biogas Technology Implementation
This generation includes biogas developments that extended up to 2005. During the end of 1990s, Ethiopian and Germany governments have collaborated to update the biogas technology development in Ethiopia. Accordingly, 60 fixed-dome biogas digesters were built between 1999 and 2002 in Addis Ababa and Adama (NBPE+, 2018;Kellner, 2002;Yacob, 2017). The implementation in this generation also include the construction of the biogas digester locally and ensuring the promotion with successful installation and close surrounding. This triggered and motivated the local to construct additional biogas plants. In addition, SNV report has also shown that about 150 biogas digesters were constructed in Tigray in 2005 (NBPE+, 2018).

NATIONAL BIOGAS PROGRAM ETHIOPIA (NBPE)
Ethiopia has implemented nationally planned biogas program starting from 2009 (Smith et al., 2011 Gumuz, Gambela and Afar regional states) have included in the programme. The funding for NBPE+ was obtained from European Union (EU) and the Ethiopian government.
The NBPE activities comprises of eight major components, which are promotion and marketing, training, quality management, research and development, monitoring and evaluation, institutional support, extension, and gender mainstreaming. The overall objective of the NBPEs is to facilitate the expansion of access to modern energy services through the introduction and development of biogas energy for rural households and communities. Hence, this programme is aimed to provide clean and safe energy for cooking and lighting in these communities. This approach could replace the use of wood and charcoal as well as chemical fertilizer to improve agriculture, health and livelihood conditions of the rural (Boers et al., 2008 is expected that potential users would benefit from reduced costs and the business opportunities will grow through an increasing demand for biogas technology.

National Biogas Program Ethiopia Phase one (NBPE1)
The   The 42.4% failure to achieve the set target of NBPE1 is due to many factors (Tsige, 2017;Fkremariam, 2017;NBPE, 2008). That includes:  Rising cost of construction material, which increase per digester cost.
 Insufficient or lack of skilled labor and expert  Low commitment of stakeholders at regional level and lack of credit facilities in some regions because the beneficial are not well organized financially.
 Lack of continues follow up service after installation and commissioning.
 Limited application of the technology to lighting and light cooking  Available alternative sources to satisfying their energy demand.

National Biogas Program Ethiopia (NBPE2)-Phase two
The second phase (2014-2019) known as scale up program, which targets at biogas dissemination by incorporating the lessons learned during the first phase. Specific objectives frames to be achieved during NBPE2 (Fkremariam, 2017)

Implementation of NBPE1 in Tigray
In Tigray, the Tigray region biogas program coordinating office (

Implementation of NBPE2 in Tigray
TRBPCO, in this phase, has set to accomplish the following goals (TRBPCU, 2017;Tsegu, 2017): Until the writing of this paper, the TRBPCO report shows that the installation of 2406 out of the 3777 initially target for the period of 2014 to 2017 have been achieved (see Table 5). The fulfill adequate cattle dung requirements, inability of digester system to supply energy required to bake Injera and low workmanship of the implemented plants.

Many domestic biogas digesters have installed in Ethiopia since their introduction in 1957. During
Phase I and II of the National Biogas Program, the number of digesters has increased significantly, especially in the four selected regions for implementation of NBPE. Table 7 shows the summary of biogas installations in Ethiopia between 2009 and 2016. The total installed digesters during this period is 15 403, which represent about 45.3% of the target (34 000) in the two NBPE phases. The applications of biogas technology in Ethiopia are mainly for light cooking and lighting at household, institute and commercial levels. Around 43% of the digester owners use biogas for both cooking and lighting, while 10.8% and 3.2 % of them use it for only cooking and only lighting, respectively. On the other hand, 43% of the biogas adopters have not started using biogas due to incomplete installation and technical problems of the biogas plant (Berhe et al., 2017). Size wise, the cumulative biogas installation and distribution in Ethiopia has shown in Table 8. As compared to the four regions in phase I and II, there were very limited efforts in installing bio-digesters in the remaining regions of the country. SNV's baseline study shows that the most widely installed biogas digester sizes were 6m 3 and 8m 3 with 68% and 25% national cumulative installations respectively. It can be seen that there were variations among the regions in terms of size distributions. Among the four common sizes (4 to 10m 3 ), biogas digester of size 4m 3 has been the least installed bio-digester in all regions.  The functionality rate of bio-digesters was found to be different for different regions.
According to SNV baseline study, the functionality rate of biogas digesters in the country was about 54% as shown in table 10 (NBPE+, 2018). While, functionality of digesters in regions report is not consistent. There are different reasons for the non-functionality of biogas digesters, however, slurry feeding and technical problems found the major roadblocks as shown in table 11. The feeding problems arise from irregularity of feeding, over feeding and not enough initial feeding. The Technical problem are also leveled as construction related problems including technical defects of Ethiopia has conducted a national biogas user survey in ten Zones and seventeen Woredas in the four implementing regions and the survey shows the NBPE has achieved about 50% of its plan. The survey shows Amhara region has achieved about 67% of its target, Oromia 43%, SNNPR 59% and Tigray 55% of their targets. It also shows about 89% of the biogas users have installed 6M 3 biogas digester (NBPE, 2008; Report on National Biogas Users' Survey, 2018). In addition, the survey shows a national functionality rate of 77% and 65% in Tigray region. Moreover, it indicated that biogas has significant contributions in improving many aspects of the users' lives and the community in general. Some of the contributions are in terms of forest coverage, health situation with regard to cough, respiratory and eye problems, children's studying time, reduced violence against women and girls and improved women's participation in social and productive economic activities. Furthermore, biogas users are also applying the slurry in their farmyards that helped them to increase their productivity. However, the application of slurry did not significantly reduce the use of chemical fertilizers. On the other hand, the dissemination of biogas technologies requires more promotion, after sales service and new technology for intensive cooking such as Injera baking. The survey has also shown, Tigray region has 56% alternative energy supply options to biogas and show a 15% satisfaction level on the technology.

CONCLUSION
Biogas implementation in Ethiopia generally shows low performance due to technical and nontechnical challenges. The primary target of the national biogas programs is to introduce biogas technology for light cooking and lighting, that has missed to address important cooking activity mainly Injera backing and intensive cooking in general. In addition to limited digester capacity, poor workmanship and related performance problems has limited the success of biogas. Moreover, similar to technical challenges the non-technical factors especially promotion has played a limited role in creating awareness about the versatility of the technology. In some part of Tigray region, the cost of wood fuel is higher than food items and the implementation of biogas was expected to demonstrate a good intervention solution. However, the low satisfaction level in the region has indicated that biogas programs need to upgrade their technical versatility to supply energy for baking, adequate energy for lighting, transportation etc. Furthermore, biogas promotion has to focus on energy poverty reduction, advantage of bio slurry over chemical fertilizer and its subsidy scheme in order to bring a successful implementation.