Constructing a Biogas Plant for a Boarding School in Cape Coast

Constructing a biogas plant for a boarding school in Cape Coast, Ghana. Draft Report Submitted to the NSBE Consulting Design Olympiad (CDO) Competition to be held at the 37th NSBE National Convention in St. Louis, Missouri, March 23-27 2011

Team members: RWTH Aachen University, Aachen, Germany (NSBE Aachen Chapter) 1. Richard Tamnjong 2. Joseph Addy 3. Constantine Tita Nfor 4. Onipaba Kwasi-Baafi

Morgan State University, Baltimore, Maryland, USA Chapter 1. Justin Potillo 2. LaKeeVia Jackson 3. Joshua Chuckukwa 4. Triston R. Young

Final Report Submitted on: 18 March 2011

@ 2011: NSBE Aachen & Morgan State University Chapters. All rights reserved.

ABSTRACT This report looks at the potential use of biogas to provide fuel and improve sanitation at the Mfantipim Boys Senior High School in Cape Coast, Ghana. The 50m3 puxin biogas plant is used to provide fuel equivalent to providing 3kW of power. The gas will be used to fuel two 1.2kW biogas generators and the rest will be used for heating and cooking at the school. The power produced by the generator powers a pump for filling a tank or reservoir and the rest is used for lighting and other purposes at the school. Part of the water used for the bio-latrine and the biogas digester is treated and recycled in the plant to help conserve water. This report argues that the use of alternative sources of energy, like renewable energy as a whole and biomass in particular, in the developing world is essential for development while at the same time keeping the environment clean and improving the lives of the people. Biomass energy is of paramount importance to Africa because it accounts for nearly 60% of the primary energy supply in Sub-Sahara Africa and satisfies the cooking and heating needs of 90% of the population reflecting the comparatively low level of industrialization on the continent. With the world population increasing rapidly, the demand for energy is also increasing greatly around the world and for Africa to be competitive its per capita primary energy needs to be increased. Presently, energy is mostly obtained by governments in Africa investing much money in conventional forms of energy production, with little emphasis on the mitigation of high emission of CO2 from burning fossil fuels. Apart from the fear that the world fossil fuel supplies risk depletion if the current rate of consumption continues, concern has grown over the years on the effect of CO2 emissions on the environment. The depletion of the ozone layer, which has led to increasing global temperatures, has been blamed on the increase in CO2 emissions due to human activities. On the average about 4.1 billion tonnes of CO2 is produced per annum and the principal cause has been fossil fuel consumption and deforestation. Governments, the United Nations and other world bodies and individuals have therefore directed their attention on developing alternative sources of energy that would have less impact on the environment. In Africa, biomass is the dominant source of energy, especially at the informal level, and one reason is because agriculture is the main occupation of the people on the continent. This is also true for Ghana, which is considered in the case study in this report. The report begins with an introduction and a literature review followed by a case study that looks at the design of the plant in details. The cost-benefit analysis of the plant is performed to show that the return on investment is below five years, which is within a reasonable period of time. This is followed by the discussion of how the project is financed and the benefits of the project to the society and environment. The report is finalized with a summary and conclusion.

ACKNOWLEDGMENT Members of the two teams that worked on this report are very grateful to Mr. Richard Arthur, a lecturer at the Koforidua Polytechnic, Koforidua, Ghana and Mr. Edem Bensah, a lecturer at the Kumasi Polytechnic, Kumasi, Ghana, for providing us with the technical advice and data for carrying out this work. Without their help, this report will be incomplete. We are also thankful and indebted to James Willie, who served in a support role during this project. Yaw Asare also played a crucial role in supporting the project to bring it to a successful completion. To all those who helped in one way or the other and whose names are not mentioned we are grateful.

TABLE OF CONTENTS 1. INTRODUCTION......................................................................................................... 1 2. LITERATURE REVIEW ............................................................................................ 6 2.1 Types of Biogas Digesters…………………………………………………….7 2.2 Application of Biogas ………………………………………………………...9 3. CASE STUDY-DESIGN OF 20 SEATER ANAEROBIC DIGESTER BIOGAS PLANT ............................................................................................................................. 11 3.1 Plant Design………………………………………………………………... 11 3.2 Expected Biogas Yield……………………………………………………….14 3.3 Twenty (20) Seater Sanitation Facility ……………………………………...14 3.4 CO2 Emissions Reductions through the use of Biogas as fuel ……………...15 3.5 Costing the Project …………………………………………………………..15 3.5.1 Cost-Benefit Analysis ……………………………………………..16 4. PROJECT FINANCING ............................................................................................ 18 4.1 Detailed description of the Participating Agencies ………………………….18 4.1.1 African Development Bank …………………………………... 18 4.1.2 Development Market Place……………………………………… 18 4.1.3 The Global Environment Facility (GEF) ………………………… 19 4.1.4 Swedish Energy Agency (STEM)…………………………………19 5. PROJECT IMPACT ……………………………………………………………......21 6.CONCLUSION.…………….………………………………………………………. 22 REFERENCES………………………………………………………………………….23 APPENDIX A: BUDJET PRICING, BIOGAS PLANT, MFANTIPIM SEIOR HIGH SCHOOL, CAPE COAST, GHANA…………………………………………..24 LIST OF FIGURES FIGURE 1: FIXED DOME DIGESTER 7 FIGURE 2: FLOATING DOME DIGESTER 8 FIGURE 3: PUXIN DIGESTER 9 FIGURE 4: PICTURE OF STOVE THAT IS RUN ON BIOGAS IN A HOUSEHOLD IN GHANA 10 FIGURE 5: A TYPICAL BIO-LATRINE THAT IS COMMON IN USE IN TOWNS AND VILLAGES IN GHANA 10 FIGURE 6: LINE DIAGRAM OF THE BIOGAS PLANT WITH SANITATION FACILITY AT THE MFANTIPIM SENIOR HIGH SCHOOL, CAPE COAST, GHANA 14 LIST OF TABLES TABLE 1: SUMMARY OF ITEMS USED IN THE BIOGAS PLANT DESIGN 11 TABLE 2: GENERAL SUMMARY OF ITEMS NEEDED FOR THE DESIGN OF THE BIOGAS PLANT 13

TABLE 3: SUMMARY OF THE PARAMETERS AND THEIR VALUES USED IN THE DESIGN OF THE BIOGAS PLANT 13 TABLE 4: SUMMARY OF ROI FOR BIOGAS PLANT BUILT AT A SCHOOL IN CAPE COAST, GHANA 16

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1. INTRODUCTION Today the global primary world energy demand is about 11.5 billion TOE (tonnes of oil equivalent) per year, rising to 23 billion TOE per year by 2050 and the main source of energy, crude oil, is depleting at a rampant rate. Due to the increase in global temperature levels and the increase in energy demand in the developing and emerging economies like China, India, Brazil, and parts of Africa, the need for finding alternative sources of energy has increased. The two broad alternative sources of energy are nuclear and renewable energy. Nuclear power is clean but it presents a challenge in that proper disposal of its waste is needed. The cost and security concerns, especially in the world today makes this option not very attractive for many countries in Sub-Saharan Africa. Renewable energy on the other hand is clean and it offers no waste disposal problems. Renewable energy refers to energy resources that occur naturally and repeatedly in the environment and can be harnessed for human benefit without the consumption of exhaustible resources such as fossil fuels. It produces few or no hazardous emissions or pollutants, and has a minimal impact on fragile economies [1]. The main types of renewable energy are hydroelectricity, biomass (organic matter), geothermal, solar, wind and biofuels. The most used form of renewable energy is traditional biomass like burning wood which contributes to about 18% of the global energy consumption. Renewable energy encompasses many different types of technology at different stages of development and commercialisation, from the burning of wood for heat in the residential sector (traditional and low-technology) to wind-generated electricity (widespread and technically proven) to processes such as biomass gasification for electricity generation (still under development although some plants are operating) [2]. The market is growing for many forms of renewal energy with conservation of water and energy being the main reasons for using these technologies. Alternative fuels, such as ethanol, can be developed to power hybrid vehicles in order to decrease the dependence on oil. The market for renewable energy is likely to increase sharply when its cost equals current energy sources and its benefits, such as energy efficiency, are realized on a global scale. At present, many countries do not make significant use of renewable resources to meet their energy needs. Lack of incentives and shortage of land and space are the key factors limiting the deployment of renewable energy systems. Large hydropower, traditional biomass and geothermal energy are not feasible in many countries of which African countries are the heavily affected because of the local conditions and resources. Only a few projects around the globe have extensively adopted some forms of renewable energy, such as solar water heating, biogas for heating and cooking, etc. Nevertheless, with growing concerns about energy and the environment, many countries have been working hard in the past decade to develop energy efficiency programs and to find ways to minimise the environmental impact of energy production and use [1, 2]. Renewable energy technologies provide many benefits that go well beyond energy alone. More and more, renewable energies are contributing to the three pillars of sustainable development, namely, the economy, the environment and social well-being. It also increases diversity of energy supplies and can be used to replace diminishing fossil fuel resources over the long run [3]. Renewable energy sources can meet many times the present world demand, so their potential is enormous. They can enhance diversity in the energy supply market, secure long-term sustainable energy supplies, and reduce local and

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global atmospheric emissions [4]. Finally, renewable energy is proving to be commercially viable for a growing list of consumers and suppliers. In the following, a brief description of the various forms of renewable energy are discussed and at the end of the introduction the focus is shifted to the use of biogas for generating power at a boarding school in Cape Coast, Ghana. (a) Wind energy Much of Africa straddles the tropical equatorial zone of the globe and only southern and northern regions overlap with temperate zones of high wind speeds. Apart from SouthAfrica and Morocco, little has been done in this sector as compared to solar energy. Although low wind speeds and frequencies largely contribute to the under development of this energy source, its high investment cost and the low level of technical skills and awareness of its potential should not be overlooked. (b) Geothermal Geothermal energy is the natural heat from the earth’s interior stored in rocks and water within the earth’s crust. The main source of this energy is the constant flow of heat from the earth’s interior to the surface. Volcanoes are visible evidence of the great reservoir of heat that lies beneath and within the earth crust. This energy can be extracted by drilling wells to tap concentrations of steam at high pressure and at depth shallow enough to be economically justifiable. The steam is then let into pipes to drive generating turbines. Less than one percent of the estimated 9,000 MW potential is used today mainly in East Africa. Although it’s environmental advantages and above all its independency to weather conditions are incentives enough to make this energy source very attractive, its high investment costs and lack of awareness are reasons why it is still underutilized. (c) Hydropower Hydropower, though under exploited, constitutes more than 80% of sub-Saharan Africa’s electricity production excluding South-Africa. The used potential stands at 7% today and the hydroelectric potential resides on the Nile River, the Zambezi River and the Inga River in the DR Congo with an estimated potential of 100 GW. Ongoing projects are geared towards interconnecting the African grids in order to make this energy available to needy countries. Hydropower enjoys a certain monopoly on the agenda of most governments and in most cases is an inheritance from former colonial masters. However growing concern on the impact of Hydropower on the ecosystem and biodiversity of rivers has led at least to the postponement of some major projects. Hydropower highly depends on rainfalls, making droughts of any levels a severe threat to electricity supply so that electricity providers are forced to ration supplies, which can only be harmful to the already shaky economies. Another major drawback of Hydropower is the lost of installed power with time, due to the silting of dams. An example is the case of Cameroon whose installed hydropower has dropped from 800 MW to 625 MW within 30 years.

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(d) Solar Solar energy, as one of the renewable sources of energy, has an amazing potential. With correct information of the solar presence in Africa, this latent energy can be harnessed for usage in various capacities ranging from domestic to industrial usage. The simplest energy systems readily available to man are all based on solar power, and, thanks to newly-developed technology; we are now able to make use of this in a number of different ways. Surprisingly, this energy comes from the sun as radiations in small packets called photons. The conversion of these packets of energy for our usage lies the future of a cheap and clean energy. Direct solar energy can broadly be categorised into solar photovoltaic technologies, which converts solar energy directly to electricity and solar thermal technologies which use sun energy directly for heating, cooking and drying. Solar energy can also be used indirectly to produce electricity and process heating; this, however, involves sizeable investment costs for the construction of solar farms or towers and a technological transfer from countries that set the pace in this field. African nations have made considerable advances in the use of photovoltaic (PV) power especially in rural areas where decentralised grids require lower investment burden. Kenya, Zimbabwe, Zambia, Namibia and South Africa with the cooperation of international organisation and certain Western countries have created small PV plants which in some cases are more than a decade old. The majority of countries do not include solar energy in their strategic energy plans, sometimes because of the fear of the lack of qualified persons in the institutions in charge, in most cases the ministry of energy and power. Solar energy, however, has enormous potential and its main source is abundant on the continent of Africa. In most African countries, hot water for bathing and other purposes is generated from the use of electric heaters and cookers, which consume considerable amount of electricity and heating gas respectively. The demand on the national grid as a result of this consumption is considerably high, especially during the peak hours of the day. This condition can sometimes lead to power outages and to high levels of fluctuations in the power supply. With the use of solar collectors, hot water can easily be provided for use in hospitals and homes across the continent [5]. (e) Biomass Africa is the world’s largest consumer of biomass energy (firewood, agricultural residues, animal wastes and charcoal) calculated as a percentage of the overall energy consumption. Biomass as an energy source can be divided in two categories: Large scale biomass utilisation encompasses direct combustion for process heat, ethanol production, gasification, biogas production and briquetting. The best known large scale biomass energy systems with sound economic track records are cogenerations using biomass as fuel stock and the production of ethanol as a substitute for petroleum fuel. Cogeneration is used by agro-based industries to meet their power requirements. Some of the industries involved are pulp and paper, sugar, wood and rice. Cogeneration offers substantial opportunities for generating electricity and or heat energy with limited investments, while avoiding the negative environmental impact of increased fossil fuel combustion. It also allows these industries to be located at remote areas without connection to the national grid. For industries close to the grid, sales of surplus to the national utility will increase

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their income. In terms of energy use per system, small-scale traditional bio-energy systems appear marginal but their importance lies in the very important number of end users that these systems serve. Bio-fuelled cook stoves meet the bulk of cooking heating and lighting needs of most rural households in Africa. Charcoal is an important household fuel and to a lesser extent industrial fuel. It is mainly used in the urban areas where its ease of storage, high energy content and lower levels of smoke emissions makes it more attractive than wood fuel. Another small-scale biomass energy technology that has attracted considerable attention in the past decade is biogas. The raw material is animal dung which is plentiful in many rural areas of sub-Saharan Africa. The technology appears not to be overly complicated and requires a relatively limited level of investment. Technical viability of biogas technology has been proven in many field tests and pilot projects. The question that arises is what would be the next source of alternative energy available to sustain a fast growing world economy? The World Bioenergy Association published a position paper that claimed bioenergy, and in particular biomass, has the potential to meet the global energy demand by 2050 if best practices and technologies are adopted worldwide and sufficient land is made available for production. Biomass is non fossil organic material and ubiquitous on the earth, biomass includes forestry and agriculture crops wastes, animal residues, municipal solid wastes, sewages and industrial residues. Biomass falls under three categories namely solid fuels, liquid bioenergy and gaseous bioenergy [6]. Solid fuels include wood and wood off-cuts (residues) from industrial forestry and woodland management, from saw mills or from recycling wood, energy wood, i.e. specifically cultivated fast-growing tree species such as poplar and willow. Agriculture residues (straw) can also be used as feedstock in biogas plants. Liquid bioenergy carriers, which are of importance, include sugarcane and palm oil which can be used for the production of ethanol and oil plants such as rapes and sunflowers for the production of vegetable oil. The gaseous bioenergy source which is very essential for this project includes biogas, which is produced by microbial digestion of agricultural residues such as liquid manure (also sewage and landfill). Given the potential biogas has to offer to rural communities in the developing world and the fact that is can be developed purely from locally available materials makes it more attractive over options like solar, wind, etc. The obvious strength it has is the low investment cost. For example, a typical plant that produces 2m3 of biogas in a village in Tanzania that was done by Engineers without Borders, Germany cost $1,112.00 and it is made entirely from local materials. The group final target is to have such small plants designed and constructed for $700.00. The other strength it has is that it can be spread to individual households with enormous benefits. At the formal level, institutions like schools, hospitals, etc can benefit from the use of biogas. In this report, the use of biogas as a source of fuel is presented. In particular, a case study that considers the Mfantipim Boys Senior High School, which is a boarding school in 4

2011 NSBE Consulting Design Olympiad (CDO)-NSBE -Aachen/Morgan State University Chapters

Cape Coast, Ghana, is considered. A biogas plant is proposed and designed for this school to be presented during the NSBE 2011 Competitive Design Olympiad (CDO) competition in St. Louis, Missouri, from the 23rd to the 27th of March 2011. In this project, two teams, one from the NSBE chapter at the RWTH Aachen University, Aachen, Germany and another at the Morgan State University, Baltimore, Maryland, in the USA collaborated via the use of a yahoo user group to work on this project. The report is divided into the following. It begins with a brief literature review in chapter 2, which is followed by the case study that looks at the design and the cost-benefit of a 20 seater biolatrine biogas plant in chapter 3. In chapter 4, the financing of the project is presented followed by the discussion of the impact of the project in chapter 5. Finally, the report is concluded in chapter 6.

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2.

Literature Review

Biogas is a well-established fuel for cooking and lighting in a number of countries. It is a gas mixture comprising of around 60% methane and 40% CO2 that is formed when organic materials, such as dung or vegetables matter are broken down by microbiological activity in the absence of air, at slightly elevated temperatures (mostly between 30-40oC or 50-60oC) [7]. For biogas technology to benefit a country, a national policy is needed to develop and disseminate it both at the formal and the informal levels. This is true for Ghana, where the technology has been around for the past about 50 years but there is no such policy at the national level. As reported in [8], there are about 10 companies in Ghana providing biogas plant construction services and based on a survey there are about 50 biogas plants in Ghana currently and of this number, 22 were fully operational, 10 are functioning partially, 14 are not functioning, 2 are abandoned and the remaining 2 are under construction. The main reason for the small number of biogas plants in operation can be attributed to the lack of policies like tax breaks to encourage people to build such plants. The lack of maintenance can also be blamed for the breakdown of most of the plants. The lack of adequate funding for research institutions like the Kwame Nkrumah University of Science and Technology (KNUST) to do active research and train local people to build and operate such plants at the local level is also to blame. Last but not least, the lack of education on the potential benefits this technology has to offer also plays a role in why it is not widespread in the country. In a more recent paper published on the 3rd of December 2010 by Arthur et al., only about 100 biogas plants were identified [9]. There are two Non-Governmental Organizations (NGOs) in Ghana that are involved in doing research and encouraging and promoting the use of biogas technology and other renewable energy sources, namely, Centre for Energy, Environment, and Sustainable Development (CEESD, URL: www.ceesdghana.org), and the Kumasi Institute of Technology and Environment (KITE, URL:www.kiteonline.net). Currently, the government in Ghana has policies at the national level that encourages and promotes the use of solar energy and wind energy, which are relatively more expensive technologies when compared to biogas. One advantage of biogas is that it can be produced at the local level without the need to import any parts from outside, thus saving the country of its foreign exchange reserve. In a report released by Engineers without Borders (EWB)-Germany, a small scale biogas plant was developed in Karagwe, Kagera province, Northwestern Tanzania [10]. The plant was built after a prototype was designed by students at the University of Hohenheim and in BerlinLichtenberg in a greenhouse in order to simulate the conditions prevailing in Kagera. The plant in Karagwe district has been in operation since the end of December 2010 and it produces 2m3 of biogas a day, enough for four hours of lighting and cooking two meals for a family of six. No materials from outside were imported to develop the plant. With this pilot plant operating with no major problems and with people being trained locally, similar small scale plants will be built to meet the energy needs of the local population. Based on an International Energy Agency (IEA) report, about 1.3 million deaths are reported yearly worldwide from poisonous fumes partly due to burning firewood. This number is more than the worldwide deaths recorded from malaria [10]. Adopting biogas use on a large scale in such countries would therefore have enormous health benefits. Many countries in Asia have comprehensive policies encouraging the use of biogas technology. In China for example, there are over 7.5 million household biogas digesters, 750 large-to medium-scale industrial biogas plants, and a network of rural „biogas service centres“ to provide the infrastructure necessary to support dissemination, financing and maintenance. India also has a large program, with about 3 million household-scale systems installed. Countries like Nepal, Sri Lanka, Kenya and several others in Latin America have a similar 6

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program [7]. As carbon emission levels are becoming of greater concern and as people realise the benefits of developing integrated energy supply options, biogas is becoming an increasing attractive option. The biogas process is known as anaerobic (without air) digestion, and it provides a clean cooking and lighting fuel that can be produced on a scale varying from a small household system to a large commercial plant of several thousand cubic metres. Apart from its use for cooking and lighting on a small scale, it can also be used for electricity generation and powering farm equipment. 2.1

Types of Biogas Digesters

Three main types of digester designs have been used in Ghana: fixed dome, floating drum (floating dome) and the so called Puxin digester. The digesters differentiate themselves mainly through the method of gas collection. The fixed dome digester has a gas-collecting dome that is fixed. This type of digester uses the principle of displacement of slurry inside the digester for storage of biogas in the fixed ‘Gas Storage Chamber’. When gas production commences, the slurry is displaced into the compensating tank as shown in Fig. 1. As the biogas is generated it rises and accumulates in the brick dome from where it is piped to point of use. From the outlet chamber, the spent slurry overflows into the overflow tank. The main advantages of this digester are that it is inexpensive and easy to construct because no moving parts are required. It also has a relatively long life span and almost no maintenance is required. This digester also has a disadvantage due to the fluctuation of gas pressure which strongly depends on the volume of gas stored.

Fig. 1 Fixed dome digester The second type of digester used in Ghana, the so called floating dome digester is designed in such a way that it has a dome (normally made of steel) that fits in the neck of the digester and basically floats on the gas produced in the belly of the digester below as shown in Fig. 2. As gas is produced in the digester it collects in the dome, eventually creating enough pressure for the dome to in effect "float" on the gas.

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Fig. 2 Floating dome digester The floating drum normally has a central steel pipe which facilitates its vertical up and down movement and also has metal guides built into the sides of the digester. When biogas is produced, it rises up and starts collecting in the gas holder due to its light weight. The gas holder now starts moving up. Since the gas holder cannot rise up beyond a certain level, more pressure begins to be exerted on the slurry as more and more gas starts collecting. The weight of the floating steel cylinder ensures that the gas produced is under constant pressure, which gives this type of digester its main advantage. The main disadvantage of such a digester is the high cost incurred in building and maintaining the sliding mechanism. These types of digesters generally have a shorter life span than fixeddome digesters. The third type of digester which has been used in Ghana is the so called Puxin digester. The Puxin digester is a unique patented digester sold commercially. One of the main features of the digester is the fact that it basically functions as a hydraulic system. The entire digester is flooded with water, with the water at the same level in the inlet; digester neck and outlet (see Fig. 3). As the biogas is produced in the bottom of the digester belly, it rises upwards and is eventually caught in the dome. As the volume of gas increases, it starts to replace the water in a downward direction. The resulting upward pressure of the replaced water ensures that the collected biogas in the dome is always under constant pressure (up to 8 bar). Decomposition of the material now takes place under water, creating the ideal anaerobic conditions so critical for the creation of methane gas. The added advantage of the water is that it is also responsible for creating the constant pressure under which the biogas is available in this type of digester. The fact that the gas is always available at the same constant pressure is a major advantage for the efficient running of most gas appliances. Another advantage of the Puxin design is the ease with which the digester can be emptied out.

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Fig. 3 Puxin digester From the three types of digesters that have been tested and implemented in Ghana, we selected the puxin digester for the following reasons: • • • •

It carries on all of the advantages of traditional fixed-dome or floating drum digesters while overcoming their main disadvantages. Unlike other kinds of digesters which have failed in some cases, the puxin digester has a 100% success rate in Ghana It can be emptied out with ease therefore any type of organic material can be used Last but not the least, the price is compatible to other traditional digesters that have been used making it an obvious choice due to the above mentioned advantages.

2.2 Application of Biogas In Ghana, biogas predominantly has been directed at the formal sector and very few plants are built for families in rural areas. But from the work presented in [10], it is seen that biogas has the potential to help rural dwellers overcome the difficulties that is associated with walking long distances for firewood. The health benefits too are immense in addition to women being spared the time they waste in going for firewood so they can concentrate their efforts on other issues in the home.

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Fig. 4 Picture of a large stove given to schools and restaurants in Ghana that is fueled by biogas In Ghana, there are some households that make use of biogas for cooking, heating water and lighting lamps. It enables them to overcome the difficulties that come with standing in long queues for LPG. In figure 4, a large gas stove that is common in most restaurants and schools in Ghana is shown. The stove traditionally uses LPG that is at times difficult to come by and it is expensive. The present price of it is $1.81 per kg. Biogas is also used in sanitation. In rural areas and for some schools, the pit-latrine is used and the smell and its effects like mosquitoes that lead to malaria can be avoided if the human excreta is used to produce biogas (see figure 5). The bio-slurry that comes out if treated well is without bacteria and it is odourless. On a larger scale, biogas is used to generate electrical power by fueling gas turbines or internal combustion (IC) engines generators. It can also be used as fuel for cars.

Fig. 5: A typical bio-latrine that is common in use in towns and villages in Ghana 10

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3.

CASE STUDY-DESIGN OF 20 SEATER ANAEROBIC DIGESTER BIOGAS PLANT

The case study of this project is the design of a biogas plant for the Mfantipim Boys Senior High School, Cape Coast, Central Region, Ghana. A similar plant has been built at the Pope John Senior High School, Koforidua, Ghana, but it is a 16 seater facility. After carrying out a survey at the school and based on data provided by our contacts in Ghana, it was decided to build a biogas plant for a 20 seater toilet facility with electricity generation and effluent filtrate recycling features. A 20 seater 5/2 litre double flush button squatting type water closets (WCs) facility is to be constructed at the academic site of the Mfantipim Boys Senior High School. As most students are at the academic site for classes about 8 hours in a day, we expect a maximum patronage of 1,000 people per day, with an average of 850 people per day. The effluent from the treatment anaerobic digester treatment plant would be filtered and recycled into the WCs. The wash hand basins would be serviced from the Ghana Water Company Ltd. (GWCL) or potable water source on campus. The waste from the wash hand basins would be filtered and recycled with the effluent to make up for any possible losses of water through evapotranspiration or little undetected leakages (due to possible misuse). After filtration through a rapid sand filter (with backwashing facility), the filtrate would be pumped by a submersible pump into an overhead tank for recycling. Two 1.2kW biogas generators would be run on the biogas that is produced from the biogas plant and the rest would be used for cooking and heating. Part of this power will be used to power a pump; otherwise a back-up electrical connection to the national grid would energize the pump. The pump would be operated once a day for just about thirty minutes to fill the overhead tank provided. The remaining power will be used by the school for other purposes like lighting, cooking, etc. The facility comprise of modern biolatrine with biodigesters attached to them. In Ghana, three types of biogas systems are currently in use, namely: fixed dome, floating drum and Puxin as described in details in chapter 2. For this project, the latter design is used, because of its demonstrated success rate and the advantages it offers. 3.1

Plant Design

The plant size will be designed to produce (10-24)m3 of biogas from biodigesters with recycling system attached to it including excavation. It would also include the following: construction of concrete digesters made of concrete cast over steel moulds. The size of the mould is 5x10m3; 10m3 Glass fibre reinforced plastic/uPVC, reinforced concrete cover slabs as well as partial backfilling/consolidation and disposal of excess excavated material (within 1 km radius) in ordinary ground condition up to 3m deep. The facility will also include biogas conditioning devices (dehydrator and desulphurizer) in addition to having a biogas flow meter. Also included will be extra-overhead items for the earth works and effluent filtration facility. Details of the list of items to be used in the design of the plant are given in Table 1. Table 1: Summary of items used in the biogas plant design ITEM A

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DESCRIPTION 50 m3 Puxin Biogas Plant including excavation • construction of concrete digestors • 10 m3 Glassfibre reinforced plastic/ uPVC reinforced concrete cover slabs, as well as partial backfilling/ consolidation and disposal of excess excavated material (within 1 km radius) in ordinary

UNIT

QTY

Amount ($)

Set

1

18,000.00

2011 NSBE Consulting Design Olympiad (CDO)-NSBE -Aachen/Morgan State University Chapters

B C

ITEM A B C D E F G H I J K L

ITEM A

B C D

E

ITEM A B

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ground condition up to 3.0m deep. Biogas conditioning devices (Dehydrator + desulphurizer) Biogas Flow meter SUB-TOTAL

Pair Nr P1

1 1

1,600.00 150.00 19,750.00

EXTRA-OVERHEAD ITEMS FOR EARTH WORKS (PROVISIONAL) Excavation in ordinary ground up to depth of 1.5m Ditto for depth exceeding 1.5m but not exceeding 3.0m Ditto for depth exceeding 3.0m but not exceeding 6.0m Extra over normal excavation for excavating in hard rock Demolition of existing incomplete masonry structures Extra over normal excavation for excavating in water logged area Extra over normal excavation for excavating in fused laterite/ soft rock Ditto but for quick/ running sand Ditto but for excavation around cables Importation of suitable fill material for backfilling Backfilling and consolidation around biogas plant Carting away of excess excavated material to a Suitable area less than 2 km away SUB-TOTAL

UNIT

QTY

AMOUNT ($)

EFFLUENT FILTRATION AND RE-USE Effluent filtration pool for effluent, 4 m3 capacity, constructed of cylindrical grade 20 mass concrete, including all necessary excavation, as well as filter medium and piping works Supply and install 0.75 kW submersible pumps (Duty and standby) Electrical and connections of pumps to source (as back-up to biogas generator) Supply and lay 100mm class ‘B’ uPVC pipes to connect existing toilet facilities to proposed Puxin biogas plant including all necessary excavation, backfilling and disposal of excess material 4m high power using concrete and masonry materials, including 5m3 (overhead) and polytank for backwashing SUB-TOTAL

UNIT

QTY

AMOUNT($)

Nr.

1

3,600.00

Set Provisional sum

1

1,500.00

m Set

12

DESCRIPTION(APPLIANCES/PIPES & FITTINGS Lamp with electronic firemeter 20 Litre rice cooker

m3

6.00

m3

8.00

m3

9.00

m3

33.00

Lot m3 m3 m3 m3 m3 m3

11.00 108

m3 P2

1,700.00 33.00 11.00 22.00 5.00 5.00 1,821.00

715.00

P3

108.00 ?

5,923.00

UNIT

QTY

AMOUNT ($)

Nr. Nr.

6

65.00 360.00

2011 NSBE Consulting Design Olympiad (CDO)-NSBE -Aachen/Morgan State University Chapters

C D E

1.2 kW biogas generator and house Double burner stove Gas pipes and fittings, including all necessary excavation & backfilling

Nr. Nr. ml

SUB-TOTAL

P4

2 70

3,600.00 54.00 450.00

4,529.00

The general summary of the items listed in table 1 is given below in table 2 for the proposed 20 seater/anaerobic biogas digester facility for the Mfantsipim Boys Senior High School in Cape Coast, Ghana. Table 2: General summary of items needed for the design of the biogas plant design ITEM Construction of 20 seater Puxin biogas digester (P1) Extra-Overhead items for earth works (Provisional) (P2) Effluent filtration and re-use (P3) Appliances/Pipes & fittings (P4) Total

Cost ($) 19,750.00 1,821.00 5,923.00 4,529.00 32,023.00

The following is the space requirement for the facility to be designed: 1. 2. 3. 4.

Space (net) requirement for the Puxin biogas plant Glass fibre reinforced plastic gasholders Effluent storage pool/filter 1 Nr. 20 seater WC facility

10m x 7m 4m x 2m 6m x 2m 18m x 6m

The project period for the completion of the project is six (6) months. The items listed in table 3 are the basis for the design of this biogas plant. Table 3: Summary of the parameters and their values used in the design of the biogas plant DESIGN BASIS Current student population Current teaching staff strength Straight school hours per day Shift school hours per day No. of shifts per day Design population (Average daily patronage) Existing no. of 5 litre WCs Existing no. of wash hand basins 5/2 litre double flushing water closets to be installed

13

QUANTITY 2000 N/A 8 N/A N/A 1000 N/A N/A

2011 NSBE Consulting Design Olympiad (CDO)-NSBE -Aachen/Morgan State University Chapters

3.2

Expected Biogas Yield

Based on human excreta only from the design population, the expected biogas yield will be in the range (10-24) m3 a day. It has to be noted that 2m3 of biogas is equivalent to 1kg of LPG in energy content (thermal) [11]. To compare biogas to LPG, it is done in terms of the energy content (Heat). Assuming standard conditions, that is, 1 kwh = 3.6MJ; biogas density = 0.8kg/m3. The caloric value of biogas is 6kwh/m3. Using these figures, the caloric value of biogas is 27MJ/kg [12]. We can therefore conclude that 1kg = 46.6MJ (LPG) and 1kg= 27MJ (biogas). 3.3

Twenty (20) Seater Sanitation Facility

One of the advantages of this system is sanitation. In this project, the school has agreed to provide the 20 seater sanitation together with the cost that is associated with it. The breakdown of the items included in this facility is listed below: • • • • • • • • •

20 seater water closet facility using 5-litre squatting water closets 4 no. wash hand basins on pedestals Floor furnished with unpolished porcelain tiles PVCT & G ceiling Honey comb windows with mosquito proof netting Long span Aluminium roofing sheets, Interior white wall tiles and External wall painting of emulsion. Also included is 5m3 overhead storage polytank and roof stand.

A line diagram of the biogas plant is shown in figure 6 below showing the latrine, the digester (a total of 5 of them each with a capacity of 10m3), a pump, a sedimentation tank, a sand filter, a carbon filter and a UV treatment unit.

Fig. 6: Line diagram of the biogas plant with sanitation facility at the Mfantipim Senior High School, Cape Coast, Ghana.

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3.4 CO2 Emissions Reduction through the use of biogas as fuel The importance of biogas use as fuel is critical for the environment because it will help to reduce the amount of CO2 that is emitted into the atmosphere. On a large scale, the impact is high and on a small scale, it also makes a difference if the effect is considered over a long period of time. To make reducing CO2 emissions attractive, the clean development mechanism (CDM) was introduced under which countries and companies that met their CO2 requirements can trade any savings they get in CO2 emissions reductions. Other countries and companies that are emitting above their limits are also to buy Carbon credits. This market is expected to grow as concern for the global temperature increase grows across countries in the world. In this work, the CO2 offset to be accumulated over the life of the biogas plant is computed. For this purpose, a baseline scenario must be defined. To do this, we will consider where the 3kW equivalent power to be generated by the biogas would have been generated from in the absence of the biogas plant. In Ghana, power is predominantly generated from the Akosombo hydropower plant, but a thermal plant in Takoradi uses crude oil to produce electric power. We will assume that the power supply to the Mfantipim Senior High School is produced at this thermal plant. The Takoradi thermal plant uses diesel, light crude oil and natural gas. Assuming a plant efficiency of 40 %, this would lead to the production of CO2 that can be calculated as follows: & Hη Power output, p = m

& = mass flow rate of the fuel. Assuming the plant is run on natural H is the Calorific value, m gas and for H = 43 MJ/kg and for η, which is the plant efficiency = 40%, we get:

(

)

m& = p (η H ) = 3000 W 0.4 × 43000000 Jkg −1 = 1.744186 ×10 −4 kgs −1 We are assuming that the natural gas here is pure methane and so the quantity of methane consumed in 1 year = 5,425.12 kg. Now, number of moles of CH4 in 1 year = mass of CH4/(Molar mass of CH4) = 5,425.12 x 103 g/(16 gmol-1) = 339,069.76 mol. The balanced equation for the combustion of CH4 is: CH4+2O2 = CO2+2H20. Therefore, moles of CO2 generated in 1 year = 339,069.76 mol. And hence, the mass of CO2 generated in 1 year = 339,069.76 mol x 44 gmol-1 = 14,919.10 kg = 14.92tCO2. For a plant life of 40 years, we will get a total of 596.8 tCO2 reduction. Using the baseline scenario, it means that 14.92tCO2 p.a. would be offset by producing biogas at the school in Cape Coast. Assuming that the CO2 emissions reduction is sold on the international market under the CDM at a rate of 50$/t CO2, an additional income of $745.95 p.a for the considered plant will be obtained. For a plant life of 40 years revenue of $29,838.00 will be generated.

3.5 Costing the Project The cost of the project can be divided into capital cost, owner’s cost and site preparation and operation and maintenance (O&M) cost. The above listed cost is given in tables 1 and 2 with the exception of the owner’s cost and the O&M. The owner’s cost includes the following: - Insurance at 1% 15

2011 NSBE Consulting Design Olympiad (CDO)-NSBE -Aachen/Morgan State University Chapters

- Inflation during construction at 9.08% - Transportation and training of personnel The O&M is broken into labour costs and non-labour fixed O&M costs, which is estimated as $1500.00/p.a (See appendix A) If O&M is added, together with the interest on capital at 8% p.a taking into account as the capital recovery factor we get a total annual running cost of $12,994.63 if the cost of fuel is not considered and an annual running cost of $13,549.43, if the fuel cost is considered. The life of the biogas plant is taken as 40 years. The details of the costing of the project are shown in Appendix A. 3.5.1 Cost-Benefit Analysis The cost to produce biogas is a function of the capital; owner’s and site preparation cost and the efficiency or output of the biogas plant. Facility revenue includes sales of biogas and sales of bio-slurry as fertilizer plus the accrued revenue from avoiding CO2 emission. The latter revenue from the sale of CO2 is computed considering the baseline scenario that looks at the equivalent energy that the biogas plant will produce being generated from the Takoradi Thermal Plant that uses crude oil as fuel (See section 3.4). The details of the capital cost are given in tables 1 and 2; owner’s and O&M are shown in Appendix A. The revenue from the sales of biogas is also given in the cost benefit analysis in appendix A. Four scenarios are considered. In the first scenario, only biogas is sold and no additional revenues from CO2 sale and bio-slurry sale are considered. In the second, revenue generated from CO2 sale is considered in addition to the sale of biogas. In the third scenario, additional revenue from the sale of bio-slurry is considered in addition to the sale of biogas but no sale of CO2. In the fourth and final scenario, the sale of both CO2 and bio-slurry are considered in addition to the sale of biogas. Each time bio-slurry is sold, the cost of the fuel is added and when this revenue is not considered, the fuel cost is not added. The summary of the outcome is as shown in table 4 below. Table 4: Summary of ROI for biogas plant built at a school in Cape Coast, Ghana

Scenario Biogas gen. Cost

I.1 2.094219763

I.2 2.094219763

I.3 2.183631527

I.4 2.183631527

Revenue from sales of biogas $/a @

10858.75

10858.75

10858.75

10858.75

Revenue from sales of bio-slurry $/a @

0

0

12,264.00

12,264.00

Revenue from Carbon Exchange $/a @ $30/t CO2

0

745.95

0.00

745.95

ROI (yr)

-

10.64

-

14.05

4.32

3.95

To sell bio-slurry (waste from the digester), it is assumed that due to extensive education the population will accept its use as fertilizer. Assuming that 30m3 of bio-slurry is produced a day 16

2011 NSBE Consulting Design Olympiad (CDO)-NSBE -Aachen/Morgan State University Chapters

and at a price of $1.12/m3, it will generate an annual income of $12,264.00. For the fuel consumption on a daily basis, 40m3 of human excreta is assumed in the cost-benefit analysis. The above table shows the return on investment (ROI) for various scenarios. It is clear that there would be no ROI if the bio-slurry and the CO2 emissions reductions are not sold. When these are taken into accounts, the project will pay for itself in less than 5 years. It must be noted that the cost of the bio-slurry is taken in comparison with that of imported fertilizer, which might not be the case. This is because in Ghana, people are not comfortable with using it for this purpose. With education, it could become common thus increasing its demand and consequently its price. The excel sheets showing detail calculations are shown in appendix A. The various scenarios that are considered are shown in details in this table.

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2011 NSBE Consulting Design Olympiad (CDO)-NSBE -Aachen/Morgan State University Chapters

4. PROJECT FINANCING The financing of this project will be basically through loan, equity and grant that will constitute 65, 25 and 10 percent, respectively. The loan will be raised from a consortium of financial institutions, namely the African Development Bank (ADB) and the World Bank (WB) under the Development Market Place (DM). The equity will be raised by Mfantipim Boys Senior High School while the grant will be offered by some international agencies. The interest rates shall not exceed 10% and the loan will be payable in 5 years which is within the break even point of this project. Some international funds that have been set up to provide grants or interest-free loans to developers of energy efficiency and renewable energy projects will be used. These include the Global Environmental Facility (GEF), and the Renewable Energy and Energy Efficiency Partnership (REEEP). The purpose of these facilities is to provide financing that addresses the environmental and developmental value not included in the conventional financing of these projects, and also to demonstrate innovative approaches that can be replicated. The proposed project clearly falls under this category. The RWTH Aachen University and the Morgan State University NSBE Chapters will supervise the construction of the plant and will continue to offer technical support to ensure the proper running of the plant. 4.1 Detail Description of the Participating Agencies In the following, the various participating companies are discussed in details.

4.1.1 African Development Bank The African Development Bank (ADB) is Africa’s premier development finance institution which is dedicated to combating poverty and improving living conditions across the continent. It is a conglomeration of the African Development Bank (ADB), the African Development Fund (ADF), and the Nigeria Trust Fund (NTF). The terms of repayment for Bank loans are as follows: a repayment period of 20 years, including a five year grace period for publicly guaranteed loans; a repayment period of 14 years, including a four year grace period for publicly guaranteed lines of credit; and a repayment period of five to 12 years, including a one to three year grace period for private sector loans. The procurement policy of the Bank is generally guided by four basic considerations: a) The need for economy and efficiency in the implementation of projects including the provision of related goods and services; b) The Bank’s interest as a cooperative institution in giving all eligible contractors and suppliers from developed and developing countries equal opportunity to compete in the supply of goods and works financed by the Bank; c) The Bank’s interest, as a development institution in encouraging the development and participation of contractors and suppliers from regional member countries of the bank; and d) The importance of transparency in the procurement process. Procurement of goods, works and related services under the Bank’s loans shall be made through international competitive bidding. However, subject to the Bank’s prior approval, other forms of procurement could be agreed upon by the Borrower and the Bank, whenever it can be established that this is done with due regard for transparency, economy and efficiency in the implementation of the project. The implementation of the proposed project will be governed by the Rules of Procedure for Procurement of Goods and Works of the ADB. 4.1.2 Development Marketplace (DM) Development Marketplace (DM) is a competitive grant program administered by the World Bank and supported by various partners that identifies and funds innovative, early stage

18

2011 NSBE Consulting Design Olympiad (CDO)-NSBE -Aachen/Morgan State University Chapters

projects with high potential for development impact. DM competitions held at the global, regional and country level attract ideas from a range of innovators, including civil society groups, social entrepreneurs, academia and businesses. DM has awarded more than $46 million in grants, supporting projects through their proof of concept phase. Using DM funding as a launching pad, projects often go on to scale up or replicate elsewhere, winning prestigious awards within the sphere of social entrepreneurship. DM competitions attract ideas from a range of innovators including civil society groups, social entrepreneurs, foundations, academia, local governments and private sector corporations. Individuals are not eligible to apply without a partnership with one of the above listed entities. Competitions are held at the global, regional and country level. While at each level competitions have specific characteristics, all loosely follow the same structure: 1. A call for proposals is open; 2. Applications undergo rigorous scrutiny by development experts from inside and outside the World Bank who select finalists; 3. Finalists are brought together at the Marketplace to present their ideas to the public and participate in networking and knowledge sharing events; and 4. A jury comprised of seasoned development professionals from inside and outside the World Bank interview the finalists during the Marketplace and then selects the projects for DM funding. The winners are announced at the close of the Marketplace. Almost every time, there is a hand full of winners with projects related to renewable energy in the developing countries which is a big priority for the World Bank. For example, in 2006 the project ‘establishing a decentralized supply of renewable energy throughout Rwanda’ was among the winners. 4.1.3 The Global Environment Facility (GEF) Established in 1991, helps developing countries fund projects and programs that protect the global environment. GEF grants support projects related to biodiversity, climate change, international waters, land degradation, the ozone layer, and persistent organic pollutants. GEF is an independent financial organization that provides grants to developing countries for projects that benefit the global environment and promote sustainable livelihoods in local communities. Types of Projects GEF projects address six complex global environmental issues: • Biodiversity • Climate Change • International Waters • Land Degradation • The Ozone Layer • Persistent Organic Pollutants (POPs) Since 1991, GEF has provided grants for more than 1,300 projects in 140 countries. 4.1.4 Swedish Energy Agency (STEM) The Swedish Energy Agency is the central administrative authority in Sweden for matters concerning the supply and use of energy. The main purpose is to implement the energy policy program set out by the Swedish Parliament in the spring of 1997, with the objective of creating an ecologically sustainable and economically viable energy system. The work of STEM is aimed at establishing a safe, efficient and environmentally benign and use of energy. This is being done in a number of ways, such as supporting research into renewable energy sources, technology procurement of energy efficient products and investment grants intended to encourage the development of renewable energy processes. In addition, the agency’s duties aims at ensuring that the Swedish grid, that is, the system for long distance transmission 19

2011 NSBE Consulting Design Olympiad (CDO)-NSBE -Aachen/Morgan State University Chapters

electrical energy is operated efficiently in order to ensure competition within the electricity supply industry. They are also the central government authority for matters concerned with strategic energy planning and local authority energy planning. They analyze the relationships between energy, the environment and economic growth. They also participate in international cooperation in the energy sector, including matters concerned with climate. STEM cooperates with other international agencies and institutions like the European Union, The United Nations among others.

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2011 NSBE Consulting Design Olympiad (CDO)-NSBE -Aachen/Morgan State University Chapters

5. PROJECT IMPACT The impact of the project on school and the community at large can be divided as follows: Energy Production: Being a boarding school, which currently accommodates roughly 850 people (students and staff) daily, the amount of human excreta available per day would be enormous and “free of charge”, even though one of the scenarios in the cost-benefit analysis put a cost on it. The energy produced shall be used for heating water and cooking. This will replace the more expensive, highly unreliable, and widely used LPG gas, electricity and firewood. Financial and economic benefits: Other than just saving money by producing biogas at the school, the excess of the biogas production can be bottled and sold to the local community at affordable prices. The money obtained from the sale of the biogas and from the sale of CO2 emissions under the clean development mechanism (CDM) will serve as a source of finance for future repairs and maintenance on the plant, to pay back loans and also to buy out the shares of NSBE Aachen/Morgan State University NSBE Chapter. After paying back the loans, the school could further consider a possibility of opening dairy farm. The cow dung could then be used in large scale production. The bio-slurry can then be sold at low prices as manure to the local farmers. For repairs and maintenance some local people have to be trained. This will also serve as an employment opportunity for some local individuals, who will benefit financially from the project. Should the school consider the possibility of dairy farm, some local individuals will also get employment openings through this. The project will thus, greatly improve the economy and also enhance the living standards of the community at large. Environmental benefits: Using sustainably produced biomass (human excreta) will greatly reduce the net flow of CO2 emissions in the atmosphere, than using fossil fuels in electricity generation, which have very high CO2 emission rates. The CO2 released during biogas combustion originally was organic plant material and so is just completing a cycle from atmosphere to plant to animal and back to the atmosphere. Replacing cooking and heating of water using firewood will help in the preservation of the rain forest, which also plays a great role in reducing the CO2 level in the atmosphere, thereby contributing greatly to reduction of global warming. Other than just preserving forestation, calls have been made to examine impact of the billowing smoke from burning wood. It is generally presumed that the smoke could likely be another cause of cancer.

Studies in China have shown that when it is used to heat and light greenhouses it boosts carbon dioxide levels, boosting photosynthesis by increasing the carbondioxide concentration, which boosts photosynthesis in the greenhouse plants and increase yields []. Experiments in Shanxi Province have shown that increasing carbon dioxide four-fold between 6 am and 8 am boosts yields by nearly 70 percent. A biogas lamp gives both light and warmth to silkworm eggs, increasing their rate of hatching as well as cocooning over the usual coal heating. At industrial level, the methane and carbon dioxide mix in biogas can be used to inhibit picked fruit from ripening too early as it inhibits metabolism, thereby reducing the formation of ethylene in fruits and grains. It also kills harmful insects, mould, and bacteria that cause diseases 21

2011 NSBE Consulting Design Olympiad (CDO)-NSBE -Aachen/Morgan State University Chapters

6.

CONCLUSIONS

This report discusses the potential of biogas as fuel for use in the developing world. In this work, a specific case study was considered to provide biogas for the Mfantipim Senior High School, which is a boarding school in Cape Coast, Ghana. The project begins with the discussion of the various types of renewable energy and narrowed the discussion to biogas. The justification of selecting biogas over other expensive renewable energy technologies like Solar and wind are given. In chapter two, the literature review is presented that looks at how biogas is being used in developing countries around the world to help the poor. The potential it has to offer in terms of benefits are considered. Chapter three looks at the case study. A brief introduction of the school where the project is taking place is given followed by a detailed description of the plant. The sizing of the biogas plant is also presented. This is followed by listing the various items and their associated cost that will go into the construction of the biogas plant. The cost-benefit analysis is presented together with the return on investment. It is concluded that for the project to be viable, the bio-slurry from the biogas plant must be sold as fertilizer. If this is done, the project will be able to pay for itself in less than five years. Because it is not common to sell bio-slurry as fertilizer, it is suggested that education should be used to inform people about the potential benefits of using bio-slurry as fertilizer, if it is well treated so that it does not become harmful to the population. In chapter four, the funding of the project is discussed in details followed by the discussion of the social and environmental benefits of biogas. Especially discussed is the impact on poverty reduction in the developing world in general and in Ghana in particular. The potential of biogas to provide fuel for small households in the developing world is high. For this reason, NSBE Aachen in conjunction with engineers without borders Germany are looking into the possibility of increasing the use of biogas in small households in the rural areas of Ghana. Because no national policy exists in Ghana encouraging the use and dissemination of biogas technology, it is recommended that the government of Ghana should create a national policy that will encourage the use of biogas in the country. Tax incentives and massive education are some of the tools that are at the disposal of the government to use for promoting this technology.

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REFERECES [1] Hui, S. C. M., 2000. Solar Hong Kong - present applications and future prospects, Renewable Energy World,3 (1): 76-78 [2] Renewable Energy- Current Status and Market Development (IEA), June 1999 [3] Renewable energy into the mainstream. IAE Renewable Energy Working Party http://www.iea.org/textbase/nppdf/free/2000/Renew_main2003.pdf [4] http://www.apricus.com/html/solar_start_here.htm [5] http://en.wikipedia.org/wiki/solar_hot_water [6] Sasse L. Biogas plants. Eschborn, Germany: GTZ publication, 1988 [7] Practical Action-Technology Challenging Poverty: URL: http://www.Praticalaction.org. [8] Edem Cudjoe Bensah, Abeeku Brew-Hammond. „Biogas technology dissemination in Ghana: history, current status, future prospects, and policy significance”. International Journal of Energy and Environment, Vol. 1. Issue 2, pp. 277-294, 2010. [9] Richard Arthur, Martina Francisca Baidoo, Edward Antwi. “Biogas as a potential renewable energy source: A Ghanaian case study”. Renewable Energy, Vol. 36, pp. 1510-1516, 2011. [10] Denis Dilba. “In der Entwicklungshilfe scheitern viele Projekte, weil sie zu wenig Rücksicht auf die Umstände vor Ort nehmen. Ein Verein ehrenamtlich tätiger Technik-Profis hat daraus Lehren gezogen”.Technology Review, Feb. 2011, Ingenieure ohne Grenzen-Deutschland URL:www.ingenieure-ohne-grenzen.org. [11] http://en.wikipedia.org/wiki/Liquefied_petroleum_gas#cite_note-0 [12] P.A. Scherer, (Stand der Technik zur Vergärung fester Abfallstoffe: Umweltaspekte, Prinzipien und Varianten“, Abfallwirtschaftsjournal 6, 1994, pp. 85 – 410. [13] Li Kangmin, Mae-Wan Ho. Biogas China, ISIS Report.

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Appendix A: Budget Pricing, Biogas plant, Mfantipim Senior High School, Cape Coast, Ghana. Scenario 20 seater puxin biogas digester $ Effluent filtration and re-use $ Appliances/pipes and fittings $ Cap. Cost w/o Oc & Sp $ Specific inv. w/o Oc & Sp ($/cubic metre biogas)

I.1

I.2

I.3

I.4

19,750.00 5,923.00 4,529.00 30,202.00 604.04

19,750.00 5,923.00 4,529.00 30,202.00 604.04

19,750.00 5,923.00 4,529.00 30,202.00 604.04

19,750.00 5,923.00 4,529.00 30,202.00 604.04

Owner's Costs Insurance @ 1% Interest During Con. @ 5% Extra overhead items for earth works $

302.02 1,510.10 1,821.00

302.02 1,510.10 1,821.00

302.02 1,510.10 1,821.00

302.02 1,510.10 1,821.00

Total Installed Cost Specific Inv. ($/kW)

33,835.12 676.70

33,835.12 676.70

33,835.12 676.70

33,835.12 676.70

Fuel cost $/a @ 0.038 $/cubic metre Non-Fuel O&M Labour costs $/a @ $10,000/Pers/a Non-Labour fixed O&M costs 0.5% Cap. Cost $/a Variable O&M costs @ $0.001/cubic metre biogas

0.00E+00 10,157.22 10,000.00 151.01 6.21

0.00E+00 10,157.22 10,000.00 151.01 6.21

5.55E+02 10,157.22 10,000.00 151.01 6.21

5.55E+02 10,157.22 10,000.00 151.01 6.21

6,205.00

6,205.00

6,205.00

6,205.00

2,837.42 40 8% 8.39%

2,837.42 40 8% 8.39%

2,837.42 40 8% 8.39%

2,837.42 40 8% 8.39%

Net Biogas output (cubic metre/a)

Cost of Capital $/a Life of the Plant Interest of capital Capital Recovery Factor

24

2011 NSBE Consulting Design Olympiad (CDO)-NSBE -Aachen/Morgan State University Chapters

Total annual costs

12,994.63

Biogas generation cost $/cubic metre Fuel consumption (cubic metre/a)

Revenue from sales of Biogas $/a @ 1.75$/cubic metre Revenue from sales of bio-slurry $/a @ Revenue from Carbon Exchange $/a @ $50/t CO2 Total Annual Revenue $/a

12,994.63

13,549.43

13,549.43

2.094219763

2.094219763

2.183631527

2.183631527

10858.75

10858.75

10858.75

10858.75

0

0

12,264.00

12,264.00

0 10858.75

745.95 11604.7

0.00 23,122.75

745.95 23,868.70

Annual Benefit

-

2,135.88

-

1,389.93

9,573.32

10,319.27

ROI (yr)

-

10.64

-

14.05

4.32

3.95

25