Bachelor of Science Thesis
KTH School of Industrial Engineering and Management Energy Technology EGI-2018
TRITA-ITM-EX 2018:422
Membrane Distillation
When Rivers Run Dry
Frida Borin Melika Abedi
2018-06-06
Bachelor of Science Thesis EGI-2018 TRITA-ITM-EX 2018:422
Membrane Distillation - When Rivers Run Dry
Frida Borin Melika Abedi Approved
2018-06-06 Examiner
Peter Hagström Supervisor Andrew Martin
Co-Supervisor
Imtisal E-Noor Commissioner Contact person
Daniel Woldemariam
Abstract
This thesis is a techno-economic analysis of five potential energy sources that can be used to drive a water purifying system called the WaterApp. The Product will be installed for a pilot project in Balasore in Odisha, India, which is the case which this study is based on. The prime focus of the techno-economic analysis is to get a broad look on the possible energy sources to provide a basis for further investigation on the implementation of the WaterApp.
Today, the WaterApp is still under research and development at Scarab Development AB.
The future goal is to commercialize the WaterApp and a target is providing clean drinking water for communities that are suffering from inorganically contaminated well water. Many of these communities are also suffering from poverty, which poses a great challenge in finding an altogether sustainable water providing solution. This solution could possibly be the WaterApp.
The water purifying process in the WaterApp is membrane distillation (MD), which is a thermally driven process. This means that there is a need for heat source and sink, which could be a source of high costs. This in turn could threaten to obstruct further market establishments of the WaterApp. Finding a sustainable energy providing solution is thereby an important research area for the WaterApp market establishment.
The five energy sources that are investigated are solar power, wind power, waste heat from a diesel generator, biogas and electricity from the grid. The basis for the techno-economic analysis is technical properties of the equipment used for each energy source as well as the levelised cost for the specific equipment. The sizing and properties of the energy providing equipment is chosen with respect to the WaterApp. Each energy scenario is simulated separately using the computer software HOMER Energy. The results from these simulations show that the most economical solution would be to use waste heat from a diesel generator. This is largely due to the low investment costs in energy equipment.
Sammanfattning
Denna rapport är en tekno-ekonomisk analys av fem potentiella energikällor som kan användas till att driva en modul som renar vatten, The WaterApp. Produkten kommer att installeras i Balasore, Odisha, Indien genom ett pilotprojekt och analysen kommer att genomföras som en fallstudie av denna. Den tekno-ekonomiska analysens främsta fokus ligger i att få en bred överblick av möjliga energikällor, vilket kan bli ett underlag för vidare utredning inför implementering av The WaterApp. Idag är The WaterApp fortfarande i forsknings- och utvecklingsfasen hos Scarab Development AB. Det framtida målet är att produkten ska undergå kommersialisering, varvid en potentiell marknad vore att rikta sig mot att hjälpa samhällen som lider av oorganiskt förorenat vatten. Generellt sett är det vanligt att dessa samhällen också lider av fattigdom, vilket utgör en stor utmaning att i att hitta en lösning som i alla aspekter är hållbar och samtidigt kan förse dessa med tillräckligt stor mängd rent vatten. The WaterApp utgör potentiellt den lösningen.
Processen i The WaterApp som renar vattnet är membrandestillering, vilket är en termiskt driven process. Detta innebär att det krävs en stor mängd värme, vilket skulle kunna vara en källa till höga kostnader och därmed något som hindrar The WaterApp’s vidare marknadsetablering. Detta påvisar vikten av att finna en hållbar energilösning som kan driva The WaterApp.
De fem energikällor som kommer att utredas i denna rapport är solel, vindkraft, överskottsvärme från en dieselgenerator, biogas och el från elnätet. Den energiförseende utrustningens tekniska egenskaper och dess kostnadsnivå ligger till grund för den tekno- ekonomiska analysen. Dimensionering och val av prestanda för utrustningen är vald med hänsyn till The WaterApp. Varje energikälla simuleras därefter med hjälp av datorbaserade mjukvaran HOMER Energy. Resultatet från dessa simuleringar är att den mest ekonomiska lösningen skulle vara att använda överskottsvärme från en dieselgenerator. Detta är främst på grund av detta system skulle ha låga investeringskostnader.
Table of Contents
Abstract ... 3
Sammanfattning ... 4
List of Figures ... 6
List of Tables ... 7
Nomenclature ... 8
1 Introduction and Objectives ... 9
1.1 Problem Definition and Purpose ... 10
1.2 Aims ... 10
2 Background ... 11
2.1 Provision of Safe Drinking Water ... 11
2.1.1 Methods of Supplying Drinking Water ... 11
2.1.2 Well Water Related Health Issues ... 12
2.1.3 Methods for Well Water Treatment ... 14
2.2 Membrane Distillation in Depth ... 15
2.2.1 Technical Principles ... 16
2.2.2 Uses and Applications ... 16
2.2.3 WaterApp ... 16
2.2.4 Components ... 17
2.2.5 Challenges ... 18
2.3 Odisha Case Study ... 18
2.3.1 Odisha Health and Development Background... 18
2.3.2 Energy Situation in Odisha and India in general ... 20
3 Methodology ... 22
3.1 Potential Energy Solution ... 22
3.1.2 Solar Power ... 22
3.1.3 Wind Power ... 23
3.1.4 Waste Heat from a Diesel Generator... 25
3.1.5 Biogas ... 26
3.1.6 Electricity from the Grid ... 27
3.2 Additional System Equipment ... 29
3.2.1 Electricity Energy Storage (EES) system and Converter ... 29
3.2.2 Heat Pump... 30
3.3 Simulating the Energy Solutions using HOMER ... 30
3.3.1 Assumptions Made for Simulation... 31
3.3.2 Energy Demand ... 32
3.3.3 Solar Power Simulation ... 33
3.3.4 Wind Power Simulation ... 35
3.3.5 Waste Heat from a Diesel Generator Simulation ... 37
3.3.6 Biogas Simulation ... 37
3.3.7 Electricity from the Grid Simulation ... 39
3.3.8. Simulation Output ... 39
3.4 Sensitivity Analysis ... 40
4 Results and Discussion ... 41
4.1 Simulation and Calculation Results ... 41
4.2 Sensitivity Analysis Results ... 43
5 Conclusion and Future Work ... 45
References ... 47
Appendix A - Cost Summaries for each simulation ... 53
List of Figures
Figure 1: a) A healthy spine, b) A spine where fluorosis has caused abnormal bone formation
around the joints of the spine………..………..13
Figure 2: AGMD system………..……….15
Figure 3: WaterApp unit with a heat pump system………..…………..17
Figure 4: 10 cassette AGMD module………..………18
Figure 5: PV Module price (USD 2010/Wp) ………..………23
Figure 6: Wind speed variation depending on hub height………..24
Figure 7: Historical and Forecasted Onshore Wind LCOE and Learning Rates………….………….24
Figure 8: Biogas System………..……….26
Figure 9: Estimated future cost level of different EES technologies……….29
Figure 10: Simulation system Overview………..……….30
Figure 11: System sketch of the different energy sources………..31
Figure 12: System sketch of a solar power based system………33
Figure 13: System sketch of a wind power based system………35
Figure 14: Polar Curve - P10-2………..………..35
Figure 15: System sketch of a genset based system providing waste heat……….37
Figure 16: System sketch of a biogas based system………..………….38
Figure 17: System sketch of a system using electricity from the grid……….39
List of Tables
Table 1: Range of health risk in relation to level of contamination in drinking water………….13 Table 2: Comparison of water purification methods for arsenic removal………….………….…….14 Table 3: Installed capacity in MW of power utilities - Odisha State………….………….………….….20 Table 4: All India Power Supply Position………….………….………….………….………….………….……….28 Table 5: Emissions by Energy Source in Distributed generation………….………….………….……….28 Table 6: Cost analysis - Solar power………….………….………….………….………….………….………….….34 Table 7: Cost analysis - Wind Power………….………….………….………….………….………….………….….36 Table 8: Cost analysis - Waste Heat from Diesel Generator..…….………….………….………….……..37 Table 9: Cost analysis - Biogas………….………….………….………….………….………….………….…………..38 Table 10: Cost analysis - Electricity from the grid………….………….………….………….………….……..39 Table 11: Parameter of Change Sensitivity Analysis………….………….………….………….………….….40 Table 12: Results………….………….………….………….………….………….………….………….………….……….41 Table 13: Results from sensitivity analysis………….………….………….………….………….………….……43
Nomenclature
Symbols
Sign Denomination Unit
Yday Production target yield per day [liters/day]
Yhour WaterApp permeate flow at 80 degrees [liters/hour]
Yday, min Production minimum yield [liters/day]
mdot Mass flow rate [kg/s]
Tin Well water temperature [°C]
Tout Water app demand temperature [°C]
cp Specific heat [J/(kgK)]
Cenergy Cost for produced energy [USD/kWh]
CNPC Net present cost [USD]
Qel Supplied electricity [kWh]
Qth Thermal energy [kWh]
Abbreviations
AGMD Air Gap Membrane Distillation AC Alternating Current
c-Si Crystalline Silicon mc-Si Multi-Crystalline DC Direct Current
DCMD Direct Contact Membrane Distillation
DRDO Defence Research and Development Organisation EES Electricity Energy Storage
EPRI Electric Power Research Institute
HOMER Hybrid Optimization of Multiple Energy Resources LCOE Levelised Cost of Energy
MD Membrane Distillation NPC Net Present Cost
PP Polypropylene
PTFE Polytetrafluoroethylene PV Photovoltaic
RO Reverse Osmosis UN United Nation
VMD Vacuum Membrane Distillation WHO World Health Organization
1 Introduction and Objectives
Poisoning from minerals that are naturally occurring in the groundwater in some areas in India is a rising issue [Shah and Kumar, 2009]. Climate change has affected shallow water resources, drying up rivers and lakes. Also, populations are growing and the agricultural sector is expanding, which both increase the general demand for water. When the access to water is decreasing, people are looking for water elsewhere and often do so by establishing deeper local wells. These wells are not always safe for drinking and contamination from poisonous minerals can affect whole communities since they have no other choice of drinking water. The poisonous minerals are not found in the same high levels in the shallower water sources as in the deeper wells, which is the reason to the rising issue of diseases from mineral poisoning.
Balasore in Odisha, India, is an example of an area that is severely affected by high fluoride levels in drinking water. In India in general, over half of groundwater resources have fluoride above recommended levels [Ayoob and Gupta, 2007]. The effects from the poor access to clean drinking water are primarily diseases such as, discoloured teeth and endemic skeletal fluorosis. [Ayoob and Gupta, 2007]. Also, studies of high levels of fluoride in groundwater show that excessive dietary intake of fluoride is affecting the IQ and physical development amongst children [Wang et al., 2007]. The area of Balasore has been investigated by an Indian organisation, Fluoride Knowledge and Action Network, which declares that the situation is alarming. Some waters have been measured to contain above 5 mg of fluoride per litre water, which is highly exceeding recommended maximum levels. This is causing growth disturbances, discoloured teeth, joint contractions and pain amongst a large share of the population [Fluoride Action Network, 2016].
There is a need for a solution to provide these people with clean and safe drinking water.
The area is suffering from high levels of poverty that requires an economically sustainable solution for purifying the local water. The options are constrained, but the situation is desperate. If this problem is pursued, there are possible economic gains even if the initial investment costs might be high. This has been shown empirically in some regions that have invested in safe water supplies where the reduced health-care costs and adverse health effects where higher than the undertaken cost of water-improving actions [World Health Organization, 2017a]. Also, building a water purification system that is environmentally sustainable is of great importance in order to secure the wellbeing of future generations.
A pilot project has recently been initiated in Balasore that will provide a school with clean drinking water. The water purification unit aims to provide 200 children with 400-600 litres of water per day. The purifying technique is air gap membrane distillation (AGMD), and the equipment is provided by Scarab Development AB. During the spring of 2018, the unit is being built by HVR Water Purification AB which is a subsidiary of Scarab Development AB.
The energy source that will be used for driving the pilot unit is electricity from the grid in Balasore. A heat pump is also installed, which is connected to the grid and supplies the required heat to drive the process. This is not a sustainable solution and therefore renewable-based alternatives should be examined.
1.1 Problem Definition and Purpose
The purpose of this study is to investigate and compare potential energy solutions for the WaterApp in Odisha. The study will serve as a techno-economical basis for further development. A complete and solid product solution is improving the basis for further establishment of the technology in Odisha and potentially in other parts of the world that are suffering from contaminated drinking water.
In order to supply completely safe drinking water to a school in Balasore in Odisha, India that are suffering from contaminated water, a WaterApp unit will be installed. The WaterApp will need thermal energy to drive the purifying process. Based on the access to different energy sources in the specific area, which energy source is to be chosen? How will the system look like and how will the different energy sources affect the produced yield?
What will each system cost and will it be a feasible alternative for areas such as Odisha India?
1.2 Aims
The aim of the project is to identify and analyse five different energy solutions that can be used to drive the purifying process of air gap membrane distillation in Balasore, Odisha, India. The calculations will result in a cost per litre of safe drinking water for each of the energy alternatives.
2 Background
2.1 Provision of Safe Drinking Water
2.1.1 Methods of Supplying Drinking Water
Applied methods of supplying drinking water differ depending on the infrastructure, natural water resources and economy and water demand of the area in focus. The specific method of supply can give water access for a whole community, a small network of buildings or as a private water supplying system, of which different types are discussed below.
Piped Distribution and Community Supplies – is a common method in industrialized countries and cities for providing drinking water to the population. In order to establish such a system there needs to be large investment costs in infrastructure. This is the reason why developing countries usually do not have the resources to build or expand these types of water distribution systems [Lee and Schwab, 2005]. Once a system is established there is still need for large expenses in maintenance, operations and reconstruction in order to maintain a safe water quality in the whole system. Otherwise a system failure (i.e.
intermittent pressure, failure to disinfect water or maintain a proper disinfection residual, excessive network leakages, corrosion of parts, inadequate sewage disposal, inequitable pricing and usage of water, etc.) pose a serious threat to public health [Lee and Schwab, 2005].
Bulk Water Supply and Vended Water – are both a way of distributing stored water. This requires transportation to the location of distribution. Bulk water transportation can be made by ships/fleets, pipeline and rail tankers. Vended water is usually distributed with tankers or from standpipes and water kiosks. The distributor is usually an agency or private company. This method is used when there is limited or no choice of providing drinking water, often in developing countries.
Bulk water can be stored as treated or untreated. As treated water the requirements on equipment and routines are high in order to maintain a good quality. Vended water should be clean according to WHO guidelines, although there has been recorded incidents where vended water has been a source of health threat due to poor handling [World Health Organization, 2017a].
Well Water and Surface Water – are methods of collecting water from a local water source and are commonly used all across the world. In both cases the quality of the water source must be investigated regularly in order for it to be guaranteed as a safe source of drinking water. If the water quality is poor, it has to be treated before drinking.
Surface water poses a larger threat of microbial contamination, while well water is more likely than surface water to contain contaminants that are inorganic. Control of microbial quality of the water should always be prioritized, due to the potentially severe consequences of waterborne infectious diseases. But effects of inorganic contaminants are
also a large threat to public health and should be treated accordingly [World Health Organization, 2006].
Desalination – is a method that has gained more attention as climate change, expanded use of water resources and population growth are seriously threatening the world’s access to fresh water. During the process of desalination, salts from brackish or saline surface water and groundwater are removed in order to render it acceptable for human consumption or other uses. The method is used both in small and increasingly large scales and is today commonly used in eastern Mediterranean areas. Desalination can be done in several different processes, out of which membrane and distillation desalination processes are most applied [World Health Organization, 2017a].
2.1.2 Well Water Related Health Issues
“Access to clean water and sanitation” is the United Nation (UN) goal of Sustainability number 6, which clarifies that safe drinking water is an important issue in order to reach sustainability in communities. Mineral contaminated water is a growing concern [Shah and Kumar, 2009]. The minerals that are naturally occurring in well water are not all poisonous though, and some minerals are even desired at an adequate level. The World Health Organization (WHO) has investigated the upper limit of the minerals that are a healthy dietary intake in moderate levels, but a health threat if a certain level is exceeded. These minerals are iron, zinc, copper, iodine, calcium, potassium, magnesium and Fluoride [World Health Organization, 2005]. Other minerals that occur in groundwater are directly poisonous at any level, i.e. arsenic, uranium, radon [World Health Organization, 2006].
Arsenic and fluoride are the most dangerous inorganic contaminants of drinking water on a world basis [World Health Organization, 2006]. The sufferings from the contaminations are most severe in Africa, Asia and South America [Amini et al., 2008]. Finding a way to provide these affected areas with safe drinking water is crucial for retaining public health. In order to treat the problem there is need to understand where the contaminations come from and how it affects the human body.
Flouride
Fluoride is found naturally in rock formations and soils and it is spread to ground water primarily due to geogenic processes. Sea water contains levels of fluoride around 1.2-1.4 mg/litre, and most surface waters at concentrations less than 0.1 mg/litre. Fluoride also occurs naturally in food (i.e. fish and tea) and food that has been treated with water with high levels of fluoride (i.e. vegetables). [Amini et al., 2008]
As mentioned before, Fluoride is both health beneficial and detrimental depending on the level of dietary intake. According to the World Health Organization the human body’s ability to absorb fluoride can be reduced with a calcium-rich diet. If a calcium-rich breakfast is taken in relation to a standard dose of fluoride, absorption decreases from 100% and on a fasting stomach down to 60%. Solely water hardness in the range of 0-500 mg Ca Co3/litre has little effect on the fluoride absorption in the human body.
The range of health risk in relation to level of contamination in drinking water is presented in Table 1. Note that these levels are approximate since no exact figures are established.
Table 1: Range of health risk in relation to level of contamination in drinking water
0.5 - 1.0mg/litre Risk of dental fluorosis, but no adverse medical effects at this level 0.6 - 0.8 mg/litre Areas indicate that there is an increased risk of skeletal fluorosis
0.8 < mg/litre Clinically proven risk of skeletal fluorosis.
6.4 < mg/litre Empirical studies show that there might be a risk of fluoride affecting children’s intelligence and growth.
250 - 450 mg/litre Deadly
[Wang et al., 2007 and World Health Organization, 2005]
It is well known that fluoride in controlled levels is a dietary recommendation for good dental health. The fluoride strengthens the enamel, preventing cavities. Exceeded levels of fluoride causes dental fluorosis, which is a hypoplastic defect of the enamel. There are different levels of dental fluorosis. The first and mildest level is a loss of sheen in teeth, the second level is white patches showing in the enamel. The most severe level is discolouring that may be accompanied by pitting [Brickley and Ives, 2008].
Skeletal fluorosis is a disease that is affecting the bone structure. Fluoride harms the bone formation and resorption, which results in a bone structure that has a higher density resulting in abnormal bone formations. The high density bone structure is less elastic, and often leads to bone fractures. The abnormal bone formations cause bone pain, reduction in mobility of joints and stiffness. Figure 1 compares a section of a normal spine to the same one where fluorosis has caused abnormal bone formation around the joints of the spine and bone density is increased [Brickley and Ives, 2008].
Figure 1. a) A healthy spine, b) A spine where fluorosis has caused abnormal bone formation around the joints of the spine [Brickley and Ives, 2008]
Arsenic
Arsenic is a chemical component found naturally in the earth’s crust. In its inorganic form, it is highly toxic and poisonous. Arsenic is naturally present in the environment and is comes in contact with humans through contaminated water, industrial processes, eating contaminated food as well as smoking tobacco. Inorganic arsenic is one of the most substantial chemical contaminants in drinking water and groundwater globally. According to the World Health Organisation, at least 140 million people in 50 countries drink arsenic contaminated containing arsenic more than 10 μg/L, which is above the WHO provisional guideline value.
According to World Health Organization, long term exposure to inorganic arsenic through drinking water can cause severe health issues having both short term and long term effect.
It can result in symptoms such as vomiting, abdominal pain and diarrhoea. Long term effects can lead to chronic arsenic poisoning where symptoms usually appear on the skin.
Pigmentation changes, skin lesions and hyperkeratosis are common and can in severe cases lead to skin cancer. [World Health Organization, 2017b]
2.1.3 Methods for Well Water Treatment
There are several methods of removing high levels of inorganic contaminants in well water in order to provide safe drinking water, these are shown in Table 2. Finding a solution that can meet adequate product performance at a reasonable cost is a major challenge. A number of options to produce clean drinking water has been reviewed as an alternative to air gap membrane distillation, which is the method of focus in this study.
Table 2: Comparison of water purification methods for arsenic removal
Method As Separation Efficiency Cost Comment
Filtration Low Low Uncertatin/incomplete as removal
Adsorption Medium Low Uncertatin/incomplete as removal
RO High High High electicity demand
MD High High High thermal energy consumption
[Khan and Martin 2014]
Filtration
Filtration is a common way to remove a wide variety of contaminants from drinking water.
There are different methods of filtration. Mechanical filters can remove suspended contaminants such as sand. Activated carbon filters absorb chlorine and organic compounds. Other methods include oxidizing filters and neutralizing filters. Although a simple and relatively cheap method, most filtration methods do not completely remove
chemical and mineral contaminants. The method is more efficient when used in combination with other water treatment methods [Dana, 2016].
Adsorption
Adsorption is another low cost solution. It can be highly effective for flour removal and arsenic up to certain contamination levels. But once those levels are exceeded, clean drinking water cannot be fully guaranteed [Onyango and Matsuda, 2006].
Reverse Osmosis
Reverse osmosis, RO, is a pressure- driven process where water is passed through a semipermeable material. Only the water molecules are let through the material whereby the contaminations are separated from the water, leaving it purified and safe for drinking.
RO requires a lot of electricity and is merely providing clean water when the contamination is below a certain level. Also, fouling is a problem that lowers the performance of the equipment over time [Malaeb and Ayoub, 2011].
Membrane Distillation
There are different types of membrane distillation, e.g. direct contact membrane distillation (DCMD), Small scale vacuum membrane distillation (VMD) and air gap membrane distillation (AGMD). In this study, the specific type of membrane distillation is AGMD [Khan and Martin 2014].
AGMD share some of the complications that come with reverse osmosis (such as high energy demand), but provide clean water up to a higher performance level even at extremely high contamination levels. Apart from the process of reverse osmosis, membrane distillation needs heat for the process to run, not electricity (even if electricity can be converted to the heat that is required for the process). This method of removing contaminations is further investigated in the following chapter.
2.2 Membrane Distillation in Depth
Membrane Distillation separates aqueous feed by transferring the vapour molecules of water using a microporous hydrophobic membrane, in this case resulting in distilled water.
The process is thermally driven where the temperature difference across the membrane cause a vapour pressure difference [Alkhudhiri et al., 2012].
Figure 2. AGMD system [Alkhudhiri et al., 2012]
Membrane distillation can occur in different ways and this thesis will be focusing on air gap membrane distillation (AGMD) which is shown in Figure 2. The AGMD is a thermally driven process, which means that there is need for a large amount of heat. The source of the required heat can either be a direct heat source or through an electrically driven heat pump.
The challenge of providing heat is to find an energy source at a reasonable cost and that is sufficiently accessible in the specific area.
2.2.1 Technical Principles
The feed solution, which is the contaminated water, is heated up on one side of the membrane. The membrane then transfers the vapour molecules through the air gap and finally the permeate is condensed on the cold side of the membrane. For an effective process, the membrane needs to have good thermal stability as it will be exposed to high and low temperatures. In addition, it should have a low resistance to mass transfer to be able to separate the contaminated particles, as well as high resistance to chemicals that it might be exposed to. Furthermore, it should also have low thermal conductivity to reduce heat loss, which will potentially occur but can be used as waste heat [Alkhudhiri et al., 2012].
2.2.2 Uses and Applications
Membrane distillation is used in different aspects such as desalination, wastewater treatment and in the food industry. The benefits of membrane distillation are that is a cost- effective process. The membrane itself is made of plastic which is considered a cheap material that also prevents corrosion problems. It is also considered one of the most effective separation processes where almost complete separation occurs. [Alkhudhiri et al., 2012] Other benefits include low operating temperatures, low hydrostatic pressures and Less susceptibility to fouling. Furthermore, it can use renewable energy sources or waste heat for the heating process, is what we will be focusing on throughout our thesis [Sterlitech, 2017].
2.2.3 WaterApp
HVR Water Purification AB is a Swedish company that has developed a specific technology for water purification called the WaterApp. The WaterApp is an independent unit that is scalable and uses air gap membrane distillation to purify water. It is designed to be placed in areas with limited access to clean drinking water. The technology requires a heat source to work and the idea is to use waste heat in order to minimize investment and operational costs. However, any heat source could support the system, such as heat pumps or solar thermal power. The WaterApp requires a temperature between 60°C and 90°C in order to deliver necessary production yields and the system can be seen in Figure 3. Although, the quality of the purified water does not depend on the temperature but on the following parameters:
a) complete rejection of pollutants from water
b) capital cost of equipment is 4000-5000 € per m3/day capacity c) the largest O&M cost is <1kWh/m3 of electricity
Figure 3. WaterApp unit with a heat pump system [HVR Water Purifications AB., 2008]
Together with Scarab Development AB and researchers from the KTH Royal Institute of Technology in Stockholm, there is an ongoing project in Odisha, India looking at installing the WaterApp to supply a school in Balasore with clean drinking water. In this thesis, we are looking to see what energy sources could drive the WaterApp to be able to obtain the production yield intended for the school. After this project, as well as a few others, performance analyses will be done to modify the technology for future commercialization of the equipment [HVR Water Purifications AB., 2008].
2.2.4 Components
The AGMD considered in this thesis is shown in Figure 4. The membrane in the AGMD is made up of hydrophobic (non-wetting) micro pores made from polytetrafluoroethylene (PTFE) with polypropylene (PP) support. It has a porosity of 80% and thickness of 0.2 mm.
The size of the whole module is 63 cm wide and 73 cm high and has a stack thickness of 17.5 cm. It is made up of ten cassettes containing two membranes each. The total active membrane area is 2.3 m2, with a total membrane area of 2.6 m2. The feed water runs through the bottom of the cassettes and the permeate flows out from the top, with a maximum flow rate of 1200 l/h. [Woldemariam, 2017].
Figure 4. 10 cassette AGMD module [Woldemariam, (2017)
2.2.5 Challenges
Although Air Gap Membrane Distillation is one of the most effective methods of removing contaminants from water, there are some challenges with the method that prevent it from being a feasible option for commercial implementation. The main challenge is membrane wetting, which means that contaminated feed water could leak through the membrane and thus contaminating the permeate. Other barriers include membrane pollution and water loss due to various reasons including pore wetting. In addition, membrane distillation modules are highly costly as well as require a high thermal energy consumption in order to be efficient. Furthermore, although the module itself has a long life span, the membranes can vary due to the challenges stated above. Depending on how contaminated the feed is, the membrane itself might be worn down faster and in need of replacement more often [EMIS, 2010].
2.3 Odisha Case Study
As this thesis is about Balasore, a city in the state Odisha, the background is primarely investigating Odisha in general and not only Balasore.
2.3.1 Odisha Health and Development Background
India is severely affected from inorganic contaminated drinking water. Out of all domestic need for water, 80% in rural areas and 50% in urban areas is met by groundwater that is under threat of excess levels of fluoride, arsenic, iron, nitrate and salinity [Ayoob and Gupta, 2007]. Out of these, fluoride and arsenic are the two most severe sources of public distress.
India has 36,988 habitations that are prevailed by Fluoride contaminations, and Odisha is severely affected [Tushaar and Kumar, 2009].
The problems of fluoride contaminated water is shown in the highly common disease fluorosis, which affects 66 million people including 6 million children under 14 years age [Ayoob and Gupta, 2007]. The disease is often not diagnosed, which leaves the victims untreated or mistreated for a long time. In India there are many people with stained teeth, paralyzing bone diseases, stooped backs, crooked hands and legs, blindness and other handicaps. This is looked down upon and is a source of marginalization since skeletal miss growth limits the ability to move and is aesthetical.
There are indicators that malnutrition due to poverty is worsening the effects of contaminated water [Ayoob and Gupta, 2007]. Poverty is more extensive in Odisha than in the rest of India (33% compared to national average of 22% 2012). The poverty is most severe in the south and west regions where it reaches up to 58-71% (2012) [World Bank, 2016b].
Odisha’s economy has grown rapidly the past 12 years, which has led to a vast decrease in poverty both in rural and in urban areas. Compared to some of the other low income states the economic growth of Odisha has been higher, and between 2007-2009 it was even higher than the national average [World Bank, 2016b]. Empirical studies of interventions in improving access to safe drinking water has proven to favour the poor in particular, and can be an effective part of poverty alleviation strategies. This is due to reduced healthcare costs and adverse health effects [World Health Organization, 2017a].
Odisha has an opulent nature and today most jobs are in the agricultural sector [World Bank, 2016b.] Even so, the recent economic strengthening in Odisha is due to a vastly growing industrial sector, which has been driven by political initiatives that have created a beneficial environment for new businesses in terms of tax, land use and financing [Government of Odisha, 2015]. The industrial growth has been seen in many different sectors; mining and metal, paper manufacturing, automotive manufacturing and aluminium production [Department of steel and mines and Department of industries].
There are signs of an improved health sector in India, but still health care is expensive and many do not have health expenditure support. [Ghoshal, 2016] The extension of malnutrition in Odisha is close to the national average, stunting is affecting 38% of the children below five years of age (2014 data), and most occur amongst the poor population.
During 2012 only 27% of the Odishan households had access to drinking water on the premises [World Bank, 2016a]. Most households get water from a local well or shallow water source and carry the water to the premises [Sääsk A., 2018].
Due to lack of infrastructure and building techniques, most houses are not equipped with plumbing systems or latrines. This leads to a widespread practice of open defecation (73%
of all households used open defecation 2012). Even amongst the richer population, open defecation is common [World Bank, 2016a].
2.3.2 Energy Situation in Odisha and India in general
Table 3: Installed capacity in MW of power utilities - Odisha State
Ownership/Sector
Modewise Breakup
Grand Total Thermal
Nuclear Hydro (Renewable)
RES (MNRE) Coal Gas Diesel Total
State 420 0.00 0.00 420 0.00 2062 6.30 2488
Private 2939 0.00 0.00 2939 0.00 0.00 188 3127
Central 1634 0.00 0.00 1634 0.00 89.0 0.00 1723
Sub-Total 4993 0.00 0.00 4993 0.00 2151 194 7338
[Ministry of power, 2017-2018]
Initiatives that has been made towards increasing future Installed capacity in Odisha is the construction of two new mega power plants Darlipalli (1600 MW capacity, coal) and Rourkela JV with SAIL (250 MW capacity). In addition, there is one plant in bidding phase, Talcher thermal III (1320 MW capacity, coal) [Ministry of power, 2017-2018].
Energy Demand
The power demand in India almost doubled between the years 2000 and 2015, and is expected to have quadrupled by the year 2040 [International Energy Agency, 2015].
Odisha’s industry sector is increasing fast. The producing industries are a high-power- demand-business. In addition, economic growth and urbanization are reasons behind increasing power demand. This puts high pressure on the power distribution system, an issue that is being solved with increased installed capacity. These initiatives are presented in the previous section. The demand for grid extension is also increasing as poverty is decreasing. Despite the fast development of the energy sector, many people in India don’t have access to electricity. Out of the whole Odishan population, 27% did not have access to electricity in 2013 (32% rural population, 4% urban population).
Power outages in India are common, due to insufficient distribution and generation. In order to guarantee the access to consistent power, many private and municipal companies have invested in generators. [Timmons H., 2012]
Electricity for the Poor and in Rural Areas
Electricity is subsidised in India. The population below the poverty line pay only a specific share (50-80%) of the average cost of supply. This is a policy which has been established by the Indian Central Government, and there are no signs that the policy is about to be phased out. The gap between production cost and revenues is covered by the government [International Energy Agency, 2015].
The subsidy system has been discussed to be an obstacle towards further electrification of rural areas. It threatens project profitability as tariffs are below cost-recovery levels, which
puts off private investors. There are many initiatives towards electrifying India, and over 50% of the electrification is expected to be through mini-grid and off-grid solutions.
Especially in areas distant from existing transmission lines or of lower population density [International Energy Agency, 2015].
Indian Energy Potential and Future Development
India has set up ambitious targets towards developing the energy sector. For instance, a pledge to build up a 40% share of non-fossil fuel capacity in the power sector by 2030 [Pandey, 2017]. This would mean a development in nuclear power and renewable energy production but since the development of nuclear and hydro sector is limited, the enforcement will have to rely largely on solar and wind power. A high level of renewable resource based electricity production puts pressure on the system, and in order to reach the target, India requires a development of the transmission infrastructure and distribution.
Solar – The installed on-grid capacity of solar energy in India today is around 8.5 GW (end of September 2016) [Pandey, 2017]. India has high potentials in developing the solar energy sector. It has an average of 300 days of sunshine every year and thereby has among the best solar potentials in the developing world to harness solar energy. [Pandey, 2017] The target for 2022 is to have 100 GW of solar energy, which both will be as on-grid and off-grid power.
Wind – The wind power generation potential in India is estimated at over 100 GW, and current installed capacity is almost 28 GW. These installations are primarily land based and utility scale. A milestone towards reaching the target of expanding the wind power sector is to have 60 GW installed capacity by 2022 [Pandey, 2017].
3 Methodology
This study will identify and investigate different potential energy solutions that can supply the required amount of energy for the WaterApp. The method of this study is divided in to three different sections. Firstly, the potential energy sources are selected and reviewed (see section 3.1). Secondly the additional equipment is identified based on the information gathered in the first part of the method (see section 3.2). The first and second parts make up the knowledge base for the third part of the method, which is to make simulations of each energy source (see section 3.3). The simulations are made based on a situation where a WaterApp would be installed in Balasore, using each one of the selected energy sources.
3.1 Potential Energy Solution
The first part of the method is to select and review potential energy solutions. This selection is based on the analysis of the general situation and energy situation in Odisha (see section 1.4 in this report). The selection was made with regard to five different factors:
1. Is it an environmentally friendly source of energy?
2. Is the resource sufficiently accessible in the area of study?
3. How much land area is needed?
4. Is the system simple enough in terms of components and required equipment?
5. Is the system simple enough to operate and maintain?
Based on the study of Odisha and these factors, the selected potential energy solutions are solar power, wind power, waste heat from a diesel generator, biogas, and electricity from the grid.
Rising climate issues put pressure on the world’s energy technology. This, along with the moral responsibility to give aid to communities suffering from social injustices, calls for a solution like the WaterApp when powered by an environmentally friendly energy source.
Solar, wind, waste heat and biogas directly fall within this category. Depending on the energy mix in the distributed generation, electricity from the grid could also be an environmentally friendly energy alternative.
3.1.2 Solar Power
As discussed in section 1.4.2 the solar power development potential in India in general is high. Solar power is a way of converting solar radiation into electricity using a photovoltaic (PV) module or system. The process of producing electricity works in a way that the PV cells, that make up the PV module, are semi-conductors. When the solar radiation hits the surface of the semi-conductor, electrons are “knocked” out of a molecular lattice. This leaves freed electrons and their vacant positions, which diffuse in an electric field to separate contacts.
As this process generates a flow of electrons, direct current (DC) electricity is produced.
Most applications therefore need a converter in order to make use of the electricity, as most applications are built for an alternating electrical current (AC) [International Energy Agency, 2011]. The converter is a part of the “balance of system” that consist of accessory equipment that is not a part of the electricity generation process, but is necessary for operation and monitoring. This also includes transformers, electrical protection devices, wiring, and monitoring equipment [International Energy Agency, 2011].
There are two different types of PV technologies available on the market today. These are silicon wafer-based crystalline silicon (c-Si) and thin films. The most common one is the crystalline silicon technology. The performance level of the crystalline silicon is given at standard conditions, i.e. air mass 1.5 and 25°C temperature. The two product groups of c-Si PVs are single crystalline (sc-Si) and multi-crystalline (mc-Si) and have an efficiency level of 14-22% and 12-19% respectively. The lifetime guarantee of a c-Si PV is usually 25-30 years with at 80% of the rated output.
The establishment of solar power has vastly increased after the development of thin film PVs 1986 [International Energy Agency, 2011]. As the knowledge development has been continually strong since then, the cost reduction has been immense. The major factors that has driven the cost reduction has been identified as manufacturing plant size, module efficiency and purified silicon cost. The PV learning curve has been on average 19.7%
between 1986 and 2010, which is shown in Figure 5.
Figure 5. PV Module price (USD 2010/Wp) [International Energy Agency, 2011]
The amount of electricity production during one day depends on how many solar hours (seasonal variation), the length that the rays must travel through the atmosphere before reaching the PV, the level of dust particles and water vapour they meet (including cloud formations that block sunlight) and also the temperature and angle of the PV. The performance level is higher at lower temperatures and the PV should preferably be directly aimed so that it is facing the incoming solar rays.
3.1.3 Wind Power
The Indian wind power potential is high, which is discussed in section 1.4.2. A wind turbine uses the kinetic energy of the wind to create electrical energy. The wind initiates a motion
of the rotor that drives a generator producing an electrical alternating current. There are different types of electricity producing wind turbines; on-grid, off-grid and small private. On- grid solutions are large in scale and produce high voltage and large amounts of electricity.
Different on-grid solutions are onshore, fixed bottom offshore and floating bottom offshore.
Off-grid solutions are in general smaller than the on-grid turbines since they are sized for a lower energy demand.
The location of a wind turbine is crucial for the amount of produced electricity. The explanation to this is found when studying the properties of the wind. The best energy producing wind is the one with a smooth laminar flow, because it is most effectively being translated into a rotating movement in the rotor. Turbulence and reduced wind speed is caused from objects such as buildings, vegetation and hills or mountains. The hub-height affects the performance since the wind speed is increasing with altitude, a model presented in Figure 6 [Lee et al., 2014].
Figure 6. Wind speed variation depending on hub height [Lee et al., 2014]
Wind is an energy source that is related to a mature technology but is still developing. The levelised cost of energy (LCOE) of wind power is expected to decrease in the future due to technical, policy and market developments [International Energy Agency, 2017]. The levelised cost of energy during 2014 was 100 USD/MWh and is expected to decrease by 14- 18% annually until 2030 as seen in Figure 7.
Figure 7. Historical and Forecasted Onshore Wind LCOE and Learning Rates [Wiser et al., 2016]
The cost reduction is due to a number of factors, for example increased rotor diameter so that specific power declines, rotor design advantages, reduced financing costs and project contingencies and improved component durability and reliability [Wiser et al., 2016].
3.1.4 Waste Heat from a Diesel Generator
An electric generator is a device that converts mechanical energy to electrical energy. The mechanical energy converted comes from an external source. The process of creating electrical energy through a generator is called electromagnetic induction. A source, such as a prime mover forces the movement of electric charges in the wire of its windings through a circuit. The flow of the electric charges results in the electric current supplied by the generator.
There are different types of generator sets, such as a diesel generator. A diesel generator is a combination of a diesel engine, an electrical generator, fuel and other components.
Together, they create an alternating electrical current (AC). The different generator sets also have different applications such as for a continuous load where there is no access to the power grid, backup generator, peak shaving and portable use. Thus, depending on its size and purpose, a diesel generator can produce between 8 kW to 2000 kW of electrical energy.
Lower demands are suitable for home usage, while the higher demands are found in industrial complexes.
There are many advantages to specifically a diesel generator. Diesel fuel is safer to store and less prone to accidental ignitions. The diesel engines can burn around 30-50% less fuel per kW compared to a gasoline engine. They also have about double the lifespan of a gaseous
generator set, where an engine running at 1800 RPM can operate between 12 000 to 30 000 hours before requiring major maintenance [Minnesota State University Mankato].
In addition to producing electrical energy, generator sets always produce a huge amount of heat that is often wasted. This waste heat can be recovered and used for other purposes.
The heat recovery requires a heat exchanger and the heat recovery ratio depends on the size of the engine and the amount of powered produced, as well as the heat recovery method. In a report studying the waste heat recovery from the exhaust of a specific diesel generator set using a shell and tube heat exchanger with organic fluids, shows results that around 50% of the engines power is wasted but could be recoverable [Hossain and Bari, 2014].
The cost of operating a diesel generator is highly related to the cost of diesel. The diesel market is in turn depending on supply and demand of crude oil. The future of crude oil is under debate but there is a risk of oil reserves being over exploited, leading to them being dried up and increasing prices. The development of price for diesel is therefore uncertain but is expected to be continuously rising in the future [U.S. Energy information administration, 2017].
3.1.5 Biogas
Biogas is the process of decomposition through anaerobic digestion. Organic matter such as animal manure, food waste, sewage and even human waste are broken down by the process of fermentation. The decomposition occurs in a biogas digester and methane gas is converted to carbon dioxide. The anaerobic, or oxygen-free environment in the digester allows for microorganisms to break down the organic material, and convert it into biogas.
An example of the system using animal manure can be seen in Figure 8 [Benzaken, 2017].
Figure 8. Biogas System [Dairy Energy, 2018]
Biogas generation creates energy from organic waste by utilizing nature’s natural tendency to recycle organic matter into productive resources. By doing so, it prevents waste materials from polluting landfills as well as eliminates the use of toxic chemicals in sewage treatment
plants. It is also a cost efficient process that saves that saves energy and material by treating the waste on-site.
There are many different types of biogas systems differing based on input, output, size and type. Biogas digesters are the system in which biogas is produced from waste materials. The organic matter is put in the digester where it decomposes in the digestion chamber. The digestion chamber is an oxygen-free environment that is fully submerged in water, allowing the microorganisms to break down the organic matter converting it into biogas. As mentioned, there are different types of organic matter that can be converted into biogas, which in turn means that there are different types of models for biogas digesters. The different models are designed for different purposes, such as treating municipal wastewater, industrial wastewater, municipal solid waste and agricultural waste.
India began developing small-scale biogas digesters in the 1960’s and today the main model is known as the floating drum digester. Biogas digesters are necessary in order to energy poverty in rural areas, and make cleaner cooking fuels more accessible in remote areas.
[Benzaken, 2017] It has already been implemented in numerous areas such as public toilets.
“A government’s mandate for energy generation from public toilets shall be notable towards meeting our needs and contributing for sustainability; in the form of waste treatment and renewable energy production” [Clarke Energy, 2014].
An existing model called the Bio-digester toilet technology, created by the Defence Research and Development Organisation (DRDO) already exists and is being implemented in rural areas such as Rajasthan and Uttarakhand in schools and households. It is an eco-friendly and maintenance-free system to manage human waste [Swachh Bharat Mission, 2017].
3.1.6 Electricity from the Grid
Many rural areas in developing countries don’t have access to distributed generation electricity. As discussed in section 1.4.2, this is also the case in India and Odisha. Only 70% of the state’s households had access to electricity during 2012. The electrification rate has been high though, the share of households with access to electrical power has nearly doubled since 2005 when only 39% had access [World Bank. 2016a]. In order to be able to supply safe and continuous grid electricity investments are needed. Power outages are relatively common in India, which is displayed when looking at numbers from 2014 of the power demand/power production shown in Table 4.
Table 4: All India Power Supply Position
State/Region
Energy Peak
Requirement Availability Surplus (+)
/Deficit (-) Demand Met Surplus (+) /Deficit (-)
[MU] [MU] [MU] [%] [MW] [MW] [MW] [%]
Northern 320 000 301 000 -18 500 -5.8 47 500 46 900 -621 -1.3 Western 287 000 283 000 -3 360 -1.2 43 500 46 400 2 930 6.8 Southern 310 000 250 000 -59 300 -19.1 44 700 33 001 -11 700 -26.1
Eastern 1 200 000 132 000 12 200 10.2 18 300 19 700 1 440 7.9 North-Eastern 12 400 11 000 -1 400 -11.3 2 250 2 025 -226 -10.0
All India 1 049 000 978 000 -70 200 -6.7 144 000 15 000 -3 260 -2.3*
*Considering transmission constraints, anticipated all India peak shortage works out to 6.2 [Central Electricity Authority, 2013-2014]
In section 1.4.2. the energy composition is displayed for Odisha in detail. It shows that a lot of the energy is generated from coal, which is an energy source with large emissions.
Emission factors of the main energy sources in Odisha today and target energy sources of India in the future are displayed in Table 5.
Table 5: Emissions by Energy Source in Distributed generation
Technology
Energy payback time
in months
SO2 in
kg/GWh NOx in
kg/GWh CO2 in
t/GWh CO2 and CO2equivalent for methane in t/GWh
Coal fired (pit) 1.0–1.1 630–1370 630–1560 830–920 1240
Large hydro 5–6 18–21 34–40 7–8 5
Renewable distributed generation technologies
Wind turbine
4.5 m/s 6–20 18–32 26–43 19–34 N.A.
5.5 m/s 4–13 13–20 18–27 13–22 N.A.
6.5 m/s 2–8 10–16 14–22 10–17 11
Photovoltaic
Mono-cystalline 72–93 230–295 270–340 200–260 N.A.
Multi–cystalline 58–74 260–330 250–310 190–250 228
[Ackerman et al., 2001]
3.2 Additional System Equipment
3.2.1 Electricity Energy Storage (EES) system and Converter
When renewable energy, such as solar and wind, is the sole energy source in an electrical off-grid system, there are some challenges. The system only supplies energy based on access to solar radiation or wind speed, which are uncontrollable variables resulting in a high risk of energy shortage.
A solution to the problem is to store excess energy from hours with excess production and use these at hours of need, which is made with an electricity energy storage unit. The most mature and applied technology today for off-grid storage solutions is in the form of battery storage with a combination of lead acid battery and inverters. [Pandey, 2017]
The development of the battery sector has been high during recent years as more attention has been directed towards Li-Ion batteries. The learning curve of the Li-ion batteries has been 0.06, and potential future learning curve could be up to 0,15 if policies, R&D activities and market demand are favourable to the development. [Baumgartner, 2016] This has significantly reduced the price of Li-Ion batteries, and the price is expected to be reduced even further as it is a young technology with high cost-reducing potential. The Li-ion technology is well suited for off-grid solutions due to the technical properties [Electric Power Research Institute (EPRI), Inc., 2015]:
• long lifetimes
• flexible size-to-power ratio
• high storage capacities per size unit
• high round-trip efficiencies, typically 90-95% (without AC-DC conversion)
• high depth of discharge levels (typically 80%)
The cost reduction of Li-ion has been estimated to 12% year on year for installed cost, but this number could be even higher if conditions are favourable. The estimated future cost level of different EES technologies are presented in Figure 9.
Figure 9. Estimated future cost level of different EES technologies [Electric Power Research Institute (EPRI), Inc., 2015]
As the connected equipment requires AC-electricity and the battery and PV are storing and producing DC electricity, there is a need for a converter. In the case of storing wind power, the converter transforms AC electricity from the generator to DC electricity into the battery, and then back again where the energy is used in the AC-load. The equipment is generally a source of energy loss and depending on which product type is investigated, the efficiency level is 70-98% [Muthuramalingam and Himavathi, 2009]. The cost is increasing with the performance level and is approximately USD800/kW, but is expected to decrease in the future. [Electric Power Research Institute (EPRI), Inc., 2015]
3.2.2 Heat Pump
The principle of a heat pump is that heat is extracted from a low temperature heat source, and with an electrically driven process, a higher temperature is provided as output. A heat pump always has four stages that make up the thermodynamic process; compressing, condensing, expanding and evaporating.
3.3 Simulating the Energy Solutions using HOMER
The simulations will be made using HOMER Energy. HOMER Energy is a computer software tool for designing and simulating micro grids. It takes in data for levelised costs, equipment performance, weather by hour, fuel, demand by hour, system constraints to simulate economic outcome and energy performance in relation to demand. The output from the simulations is a levelised cost of energy for each of the five different energy sources and also information about expected average unmet load. The conceptual model is illustrated in Figure 10. Based on the performance of the WaterApp, the cost of produced energy can be translated into an energy cost per litre of clean drinking water.
Figure 10. Simulation system Overview
The reviewed system in this study is built up around the WaterApp. This means that technical properties of the WaterApp is the basis for evaluating the heat demand, and amount of permeate water (clean water) which is produced at a given temperature and energy input. But the cost of the WaterApp itself will be excluded in the techno-economic evaluation.
For each of the different energy sources the system design will differ, as the energy sources vary in whether they produce heat or electricity. The system sketch in Figure 11 gives an overview of the system design of the different energy solutions. The energy sources that produce energy in electricity are solar power, wind power and power from the grid. The energy sources that produce energy in heat are waste heat from genset and biogas. The levelised cost model accounts for costs generated in energy producing equipment in terms of capital costs and operations and maintenance costs.
Figure 11. System sketch of the different energy sources
Specification and System Requirements
• The module must be supplied with enough energy for water production to be able to produce 400-600 litres per day
• The energy source must be renewable or in a way have an environmentally friendly approach
3.3.1 Assumptions Made for Simulation
(A1) Prices that are found on the internet for system components are according to market price and are therefore a representative basis for the levelized cost model.
(A2) Costs that are generated from small components in the system (such as cables and maintenance material) will not be included in calculations. This is assumed to be small and to be about as expensive in every case of energy source, and therefore should not affect the comparison between the energy sources.
