LCA of Hydro Power Plant

AReportOnASSIGNMENT NO. : 1LIFE CYCLE ASSESMENTOFHYDRO POWER PLANT

For the partial fulfilment of the courseENERGY SYSTEM ENGINEERINGSubmitted ByKALYANEE AMBATKAR (2013H101024P)PRATHYUSHA NAINI (2013H101023P)SAKSHI BATRA (2013H101019P)

Submitted to:Dr. Raman SharmaDEPARTMENT OF CHEMICAL ENGINEERING

BIRLA INSTITUTE OF TECHNOLOGY AND SCIENCE, PILANI23rd September 2014Contents1. Introduction:31.1. Hydro Power Stations:31.1.1. Storage Power Stations:31.1.2. Pumped Storage Power Stations:41.1.3. Run-of-river Power Stations:41.2. Small Hydropower Stations:42. Working Mechanism Of Hydropower Plant:53. Life Cycle Analysis (LCA):73.1. Benefits of Conducting an LCA:93.2. Limitations of Conducting an LCA:103.3. Case Study:103.3.1. Methodology of LCA :103.3.2. LIFE CYCLE INVENTORY ANALYSIS113.3.2.1. Civil Works:113.3.2.2. Electro-Mechanical Equipment:123.3.2.3.Operation and Maintenance:123.3.2.4.Decommissioning133.3.3. Energy Pay Back Period:133.3.4. GHG Emissions134. CONCLUSION:135. REFERENCES:14

List of Figures:Figure 1: Mechanism of hydropower plant5Figure 2: Electricity Generator6Figure 3: Layout of Hydro Electric Power Plant7Figure 4: Life Cycle Stages8Figure 5: Phases of an LCA (Source: ISO, 1997)9

List of Tables:

Table 1: Classification of Small Hydropower in India5Table 2: Inventory of Energy Use and GHG Emissions in Civil Works11Table 3: Inventory of Energy Use and GHG Emissions in E&M Equipment12Table 4: Inventory of Energy Use and GHG Emissions in Annual O&M12Table 5: Total Life Cycle Inventory of Energy Use and GHG Emissions of Projects13

1. Introduction:Electricity is an essential requirement for all facets of our life. It has been recognized as a basic human need. It is a critical infrastructure on which the socio-economic development of the country depends. Supply of electricity at reasonable rate to rural India is essential for its overall development. Services sector has made significant contribution to the growth of our economy. Availability of quality supply of electricity is very crucial to sustained growth of this segment. As per Census 2001, about 44% of the households do not have access to electricity. Hence meeting the target of providing electricity to all is a daunting task requiring significant addition to generation capacity and expansion of the transmission and distribution network. Hydro power is generated by using electricity generators to extract energy from moving water. Historically people used the power of rivers for agriculture and wheat grinding. Today, rivers and streams are re-directed through hydro generators to produce energy, although there are pros and cons as far as local ecosystems are concerned. Run-of-river hydropower plants are generally installed in mountainous streams where the catchments are generally steep and vulnerable to high soil erosion. Seasonal heavy rains, especially in tropics and monsoon regions produce large sediment yield from these catchments and the streams experience high sediment concentrations during seasonal floods.Hydro power is a renewable economic, non-polluting and environmentally benign source of energy. Hydro power stations have inherent ability for instantaneous starting, stopping, load variations etc. and help in improving reliability of power system. Hydropower has generated a great deal of interest because it is inexhaustible source of energy & a moderate method for providing electricity to far flung areas in hilly regions. These projects have long useful life extending over 50 years and help in conserving scarce fossil fuels.

1.1. Hydro Power Stations:1.1.1. Storage Power Stations:

Storage power stations are power plants with an appreciable reservoir. Depending on the drop height it is distinguished between low, medium and high pressure power stations. The pumped storage power stations are a special type of storage power stations. While conventional storage power stations use water that comes from natural catchment areas higher up, the pumped storage power stations pump water up to reuse it. The share of pumped water to turbined water can reach up to 100 % (basic water flow plants). In this case the power plant has no natural supply of water. Often, storage hydropower stations are a mix of both, storage hydropower plants and pumped storage hydropower plants. Generally the different kinds of power plants differ more in the way they are operated than in the way they are built. Therefore the construction and deconstruction of storage hydropower stations and pumped storage hydropower stations are modelled identically, while the operation of storage and pumped storage hydropower plants is modelled separately.The pumped storage hydropower stations modelled may include basic water flow plants though. These are plants with no natural water supply.The capacity of the reservoirs differs between the storage power stations: It can range fromthe storage capacity of water for a whole year down to only one day. Strictly speaking, even the run-of-river power stations have a small reservoir where the water is hold back. 1.1.2. Pumped Storage Power Stations:Pumped storage describes the circulation of water between a lower and an upper reservoir. Itcan run in a closed circuit where the water is pumped up in the hours with low electricitycosts and turbined again when the demand and the costs for electricity are high. Pumped storage is also on hand, if the water is pumped up to a hydropower station to increase the inflow or for seasonal storage. In this study, only the hydropower stations with a closed circuit are considered as pumped storage hydropower stations. The others are included in the storage hydropower stations due to their similarities.Depending on the altitude ratio of the pumping and the turbination of the water, there is eitherno net electricity generation (altitude ratio > 0.7) or the amount of net produced electricitycorresponds to the difference between the electricity needed for pumping and the total electricity produced (altitude ratio < 0.7)

1.1.3. Run-of-river Power Stations:Run-off-the-river hydroelectricity is a type of hydroelectric generation whereby the natural flow and elevation drop of a river are used to generate electricity. Power stations of this type are built on rivers or canals with a consistent and steady flow, either natural or through the use of a large reservoir at the head of the river which then can provide a regulated steady flow for stations down-river. Run-off-River projects are dramatically different in design, appearance and impact from conventional hydroelectric projects. Power stations on rivers with great seasonal fluctuations require a large reservoir in order to operate during the dry season, resulting in the necessity to impound and flood large tracts of land. In contrast, run- off- river projects do not require a large impoundment of water. Instead, some of the water is diverted from a river and sent into a pipe called a penstock. The penstock feeds the water downhill to the power station's turbines. Because of the difference in relief, potential energy from the water up river is transformed into kinetic energy while it flows downriver through the penstock, giving it the speed required to spin the turbines that in turn transform this kinetic energy into electrical energy. Additionally, there is no alteration of downstream flows, since all diverted water is returned to the stream below the powerhouse. Most run-off-river power plants consist of a dam across the full width of the river to provide the head needed forrunning the turbines. Whatever water is not needed for generating electricity spills over the dam at a spillway. Such installations have a reservoir behind the dam but flooding is minimal and it is not used to store water for later generation. The run-of-river power stations can also be divided into high, medium and low pressure powerstations. As already mentioned above, some high pressure run-of-river hydropower stations are already taken into account in the list of the storage hydropower stations.

1.2. Small Hydropower Stations:The category of small hydropower stations includes all the hydropower stations with capacity below 300 kW. In other definitions hydropower stations with a capacity up to 1 MW are included. They have been constructed during the industrialisation. First they were used as mechanical driving mechanism later they were converted to generate electricity. When the larger power stations were built and the production cost fell, the small hydropower stations were abandoned. They are situated in rivers and ravines but also in infrastructures such as drinking water supply systems, waste water treatment facilities, tunnels and the infrastructure for the production of artificial snow.In recent years small hydro electrical power has received great deal of attention from many points of view (i) as a sizeable and easily utilizable source of renewable energy and (ii) as a moderate investment method for providing electricity to under developed areas. Minimising the environmental impacts is one of the most significant technical and political challenges, energy sector is facing today. In India, rising electricity demands and rural development schemes has been continuously advocated for the development of Small Hydropower for the electricity generation as well as rural electrification. The general practice all over the world is to define SHP by power output. Different countries follow different norms keeping the upper limit ranging from 5 to 50 MW.In India, SHP schemes are classified by Central Electricity Authority (CEA).Table 2 shows the classification of SHP.Table 1: Classification of Small Hydropower in IndiaSr. No.TypeStation CapacityUnit Rating(kW)

1MicroUpto 100Upto 100

2Mini101-2000101-1000

3Small2001-250001001 -5000

2. Working Mechanism Of Hydropower Plant:A dam is built where there is a natural source of water in a valley and it is used to hold the water and create pressure so that the water can produce more electrical power. The gravitational potential energy stored in the water is used to turn generators and create electricity. Electrical generators are turned by massive turbines, which are within tunnels in the dam wallwater flows through the tunnels with great pressure due to the great height, at which is kept in the dam. If there is a greater volume of water or there is a very large difference between the water level and where it flows out, then more power comes out of the water as it has greater potential energy. For example: Hydro power generation works well in mountainous countries as the water can be stored at very high pressures. The dam wall increases with width as you go down towards the base this is because the water pressure gets greater as depth increases. This difference in height of the water is called the head.

Figure 1: Mechanism of hydropower plant

The generator contains two main parts: the rotor and the stator. The rotator is the part which rotates and the wire has a huge magnet inside of it; and the stator is the part which is covered in copper. A hydroelectric generator converts this mechanical energy into electricity. The operation of a generator is based on the principles discovered by Faraday. He found that when a magnet is moved past a conductor, it causes electricity to flow. In a large generator, electromagnets are made by circulating direct current through loops of wire wound around stacks of magnetic steel laminations. These are called field poles, and are mounted on the perimeter of the rotor. The rotor is attached to the turbine shaft, and rotates at a fixed speed. When the rotor turns, it causes the field poles (the electromagnets) to move past the conductors mounted in the stator. This, in turn, causes electricity to flow and a voltage to develop at the generator output terminals.

Figure 2: Electricity Generator

Some countries that use hydroelectric power:China is the largest producer of hydroelectricity depending on the Yangtze River., followed by Canada, Brazil, and the United States.Egypt also uses hydroelectricity depending on the River Nile, which the longest river in the world (6695 km). The Nile River is often associated with Egypt; it actually touches Ethiopia, Zaire, Kenya, Uganda, Tanzania, Rwanda, Burundi and Sudan, as well as Egypt. President Gamal Abdel Nasser decided to make use of it and built High Dam in Aswan, Egypt in 1954 to produce hydroelectric power.Advantages: Renewable energy source: hydroelectricity uses the energy of running water, without reducing its quantity, to produce electricity. Hydroelectricity makes it feasible to utilize other renewable sources Hydroelectric enterprises that are developed and operated in a manner that is economically viable, environmentally sensible and socially responsible represent the best concept of sustainable development. Increases the stability and reliability of electricity systemsFigure 3: Layout of Hydro Electric Power Plant3. Life Cycle Analysis (LCA): It is a tool for evaluating the environment impacts of a product or system through out its entire life span, usually from raw material extraction to final disposal. The LCA can be applied to assess the impact of electricity generation on the environment and will allow producers to make better decisions pertaining to environmental protection. The two primary approaches for LCA are commonly used, one is based on Process Chain Analysis (PCA) and the second approach is based on Economic Input- Output (EIO) model.Although only few references on hydropower are available yet, previous LCA studies and comparisons of various energy options have reported superior environmental performancefor hydropower projects in terms of energy consumption and Global Warming Potential (GWP) These study reports give an overall life cycle results only which makes it difficult to distinguish exactly what is included and what assumptions are made in the study. Several studies have explicitly mentioned that emissions from the reservoir were considered.Life cycle assessment is a cradle-to-grave approach for assessing industrial systems. Cradle-to-grave begins with the gathering of raw materials from the earth to create the product and ends at the point when all materials are returned to the earth. LCA evaluates all stages of a products life from the perspective that they are interdependent, meaning that one operation leads to the next. LCA enables the estimation of the cumulative environmental impacts resulting from all stages in the product life cycle, often including impacts not considered in more traditional analyses (e.g., raw material extraction, material transportation, ultimate product disposal, etc.). LCA is a tool which helps in selecting the most feasible process or service from available options.The term life cycle refers to the major activities in the course of the products life-span from its manufacture, use, and maintenance, to its final disposal, including the raw material acquisition required to manufacture the product.LCA is a technique to assess the environmental aspects and potential impacts associated with a product, process, or service, by: Compiling an inventory of relevant energy and material inputs and environmental releases Evaluating the potential environmental impacts associated with identified inputs and releases Interpreting the results to help you make a more informed decision

Figure 4: Life Cycle StagesThe LCA process is a systematic, phased approach and consists of four components: goal definition and scoping, inventory analysis, impact assessment, and interpretation as illustrated in Figure 2:

1. Goal Definition and Scoping - Define and describe the product, process or activity. Establish the context in which the assessment is to be made and identify the boundaries and environmental effects to be reviewed for the assessment. 1. Inventory Analysis - Identify and quantify energy, water and materials usage and environmental releases (e.g., air emissions, solid waste disposal, waste water discharges). 1. Impact Assessment - Assess the potential human and ecological effects of energy, water, and material usage and the environmental releases identified in the inventory analysis. 1. Interpretation - Evaluate the results of the inventory analysis and impact assessment to select the preferred product, process or service with a clear understanding of the uncertainty and the assumptions used to generate the results.

Figure 5: Phases of an LCA (Source: ISO, 1997)

3.1. Benefits of Conducting an LCA:An LCA can help decision-makers select the product or process that results in the least impact to the environment. This information can be used with other factors, such as cost and performance data to select a product or process. LCA data identifies the transfer of environmental impacts from one media to another (e.g., eliminating air emissions by creating a wastewater effluent instead) and/or from one life cycle stage to another (e.g., from use and reuse of the product to the raw material acquisition phase). If an LCA were not performed, the transfer might not be recognized and properly included in the analysis because it is outside of the typical scope or focus of product selection processes.By performing an LCA, analysts can:

Develop a systematic evaluation of the environmental consequences associated with a given product. Analyse the environmental trade-offs associated with one or more specific products/processes to help gain stakeholder (state, community, etc.) acceptance for a planned action. Quantify environmental releases to air, water, and land in relation to each life cycle stage and/or major contributing process. Assist in identifying significant shifts in environmental impacts between life cycle stages and environmental media. Assess the human and ecological effects of material consumption and environmental releases to the local community, region, and world. Compare the health and ecological impacts between two or more rival products/processes or identify the impacts of a specific product or process. Identify impacts to one or more specific environmental areas of concern.

3.2. Limitations of Conducting an LCA:Performing an LCA can be resource and time intensive. Depending upon how thorough an LCA the user wishes to conduct, gathering the data can be problematic, and the availability of data can greatly impact the accuracy of the final results. Therefore, it is important to weigh the availability of data, the time necessary to conduct the study, and the financial resources required against the projected benefits of the LCA. LCA will not determine which product or process is the most cost effective or works the best. Therefore, the information developed in an LCA study should be used as one component of a more comprehensive decision process assessing the trade-offs with cost and performance, e.g., Life Cycle Management.3.3. Case Study:Karmi-III micro hydro power project is located 36 km from Bageshwar town in district of Bageshwar Uttarakhand (India) by road upto Godiyadhar village and followed 8 km by foot track. This project envisages diversion of water from KARM GAD which is tributary of river Saryu through a semi permanent weir by 93 m long, 0.275 m diameter steel pipe and utilizing 55.0 m of net head. Two hydraulic turbines of 25 kW each with synchronous generators are installed and power is transmitted through 11 kV lines to 5 villages (Dobar, Topania, Munar, Thalidar and Khalidar). The area falls in the humid temperate zone of higher Himalaya.The maximum temperature is in the range of 30C to 0C during summer and winter respectively. Karmi micro hydro plant is located in zone (V) of the seismic zone map of India, accordingly the basic seismic coefficient for the site is to be selected.This project was constructed in the year of 2005 with a capacity of 50KW and of Net head 55.0 m3.3.1. Methodology of LCA :Among the earlier mentioned approaches, EIO based LCA approach has been adopted in the present study. The EIO-LCA approach consists of a matrix of economic data (representing the inputs from all sectors of the economy into all other sectors and the distribution of each sectors output throughout the economy) and a matrix of sector level environmental coefficients. EIO based software of the U.S. economy is developed by the Green Design Institute at Carnegie Mellon University. In this study EIO-LCA model is used to account for the energy input and GHG emissions associated with the manufacturing of major materials and equipment used in these projects. The Carnegie Mellon EIO-LCA software (US Deptt of Commerce 1997 Industry Benchmark) is used in the present study. The cost estimates of these projects pertain to different years. These costs have been inflated using inflation table of India to bring all the costs as per the level of year 2004-05 in Indian currency. Further the costs are converted into equivalent U.S. dollars by using the purchase power parity (PPP) in that year (2004). Further U.S. dollar has been adjusted for the year 1997 by using the U.S. Consumer price index (CPI).In this study, a functional unit is taken as 1kWh of net electricity produced by small hydro power. GHG emissions are normalised to an equivalent of CO2 (gm) emissions per kWh of net electricity production based on IPCC 100 year Global Warming Potentials (GWP).The material input and monetary costs are extracted from detailed project report (DPRs) of the projects and visiting the site. Fig (1) shows a schematic diagram of run-of river small hydropower layout. Life cycle of a small hydro project is divided into four stages:

(i) Civil works (ii) Electro-mechanical equipment (E&M) (iii) Operation and Maintenance (O&M) (iv) Decommissioning

3.3.2. LIFE CYCLE INVENTORY ANALYSIS3.3.2.1. Civil Works:The inventory of civil works estimated in these projects are summarized in Table 4, which accounts for major construction material in the components such as diversion, channel, forebay tank, penstock and transportation, erection etc. The total energy use and Greenhouse gas (GHG) emissions for each item is obtained from the EIO-LCA software. The inputs associated with the extraction of raw materials through the manufacturing of the material and equipment has been included in the EIO-LCA software. Table 2 summarizes the inventory of Energy Use and GHG Emissions in Civil Works

Table 2: Inventory of Energy Use and GHG Emissions in Civil WorksSr. No.ComponentsCost in Rs. 2004-05 (106)Cost in US $ (1997) (106)Energy use (TJ)GHG emissions (MgCO2eq)

1Construction2.8910.2669952.087902160.7311

2Erection0.3130.0289070.22605117.40188

3Penstock0.4180.0386040.57905952.11531

Total3.6220.33452.893230.248

3.3.2.2. Electro-Mechanical Equipment:The inventory of E&M equipment used in these projects are summarized in Table 5, which accounts for the major electro-mechanical equipments, control structures, transformer and switchyard and station auxiliaries (valves, battery, PVC cables etc). The total energy use and GHG emissions for each item is obtained from the EIO-LCA software. The inputs associated with all processes from extraction of raw materials to manufacturing of the materials and equipments are included in the EIO-LCA software. Table 3 summarizes the inventory of Energy Use and GHG Emissions in E&M Equipment

Table 3: Inventory of Energy Use and GHG Emissions in E&M EquipmentSr.NoComponentsCost in Rs 2004-05 (106)Cost in US $ (1997) (106)Energy use (TJ)GHG S. emissions (MgCO2eq)

1Turbine and generator1.750.1616191.04890985.49653

2Control panel0.50.0461770.19255815.88487

3Station auxiliary0.440.04060.294724.457

4Transfer and switch yard0.30.02770.27522.359

Total2990.27611.812148.197

3.3.2.3.Operation and Maintenance: The general estimates for the energy use and GHG emissions are based on the annual maintenance cost and use of machine tools etc. Based on the project scale, the annual maintenance cost is taken as 3% of the total civil works and 3% of electro-mechanical equipment. Annual plant electricity usage is estimated as 5% of the annual electricity output. The amount of flooded biomass per unit of reservoir area can vary from 500 Mg/ha for tropical forest to 100 Mg/ha for a boreal climate [16], whereas the carbon content of different ecosystems varies from 18.8 kg of CO2eq/m2 for tropical forests to 0.3 kg of CO2eq/m2 for desert shrub. In the SHP scheme studied, there is no storage of water, hence no change in terrestrial ecosystem is considered. Table 4 shows annual energy use and annual GHG emissions in the operation and maintenance stage.

Table 4: Inventory of Energy Use and GHG Emissions in Annual O&MSr.NoComponentsCost in Rs 2004-05 (106)Cost in US $ (1997) (106)Energy use (TJ)GHG S. emissions (MgCO2eq)

1Civil works0.18660.0100350.086796.90744

2E&M works0.08970.0082830.054364.44591

3Others0.020.0018470.0111930.957027

Total0.218360.0201650.15234312.31038

3.3.2.4.DecommissioningThe major components used in the power house are expected to last for 20-35 years. The energy consumption and GHG emissions for replacement and maintenance have been averaged and included in the operation and maintenance stage. Ideally decommissioning stage is also very important in accounting the total inventory of energy use and GHG emissions. However, the practice of demolition of small hydro power structures and components are very uncommon for the reason of renovation, modernization and uprating of the existing power house. As a power house completes its life, it goes for renovation, modernization and uprating. So there is no need to demolish the existing power house, but only to modify as per the condition of project site at that particular time. Table 5 summarizes the total Life Cycle Inventory of Energy Use and GHG Emissions of Projects

Table 5: Total Life Cycle Inventory of Energy Use and GHG Emissions of ProjectsSr No.ComponentCost in Rs 2004-05 (106)Cost in US $ (1997) (106S. )Energy use (TJ)

GHG emissions (MgCO2eq)

1Civil works3.6220.33452.893230.248

2E and M works2.990.27611.812148.197

3O&M*6.55080.604954.57029369.3114

Total13.16281.215559.27529369.3114

3.3.3. Energy Pay Back Period:Project costs are not directly proportional to the energyuse or environmental loads. For this project, civil works share is 31.19%. E&M equipment share is 19.54% and O&M work share is 49.27%. The annual net energy generation for this power plant at 80% load factor after deducting 5% energy a auxiliary consumption is 3.3288 lac units. The average life of the power plant is assumed to be 30 years. The EPBT for this power plant have been worked out as 2.71years.

3.3.4. GHG EmissionsThe contribution of GHG emissions from each life cycle stages for Karmi-III micro hydro power plant has been evaluated. The GHG emissions shared by civil works are of 30.79%, E&M equipment shares are of 19.82% and O&M shares are of 49.39%. The total GHG emissions are 747.7564 MgCO2eq respectively. The GHG emission for power house is estimated 74.88 gCO2eq/KWhe for the Karmi-III power plants.4. CONCLUSION:

Hydroelectricity is a very unique way of generating energy. It is one of the most used systems around the world. Also, it is a renewable energy source which is very helpful to our planet and it is something that will never end unlike natural gas and fossil fuels. Therefore, many of the countries and many more in the future will choose it over a lot of the other ways to generate electricity. All in all, it is a very cost efficient and green way to generate something that us human beings need in our daily lives!

In this study, the LCA of run-of river Karmi-III micro hydro power plant has been studied. The EPBT of this power house varies from 1.28 to 2.71 years and GHG emissions vary from 35.29 to 74.88 gCO2eq/kWhe. The variation in the EPBT and GHG emissions shows that as the capacity of the power house increases EPBT and GHG emissions decreases. The EPBT and GHG emissions from small hydro power generation system are less as compared to the conventional type of electricity generation systems.

5. REFERENCES:1. Baidya, G. In Development of Small Hydro, Proceedings of the International Himalayan Small Hydropower Summit (HSHS), Dehradun, India, Oct 12-13, 2006; Sharma, J. D.; Sinvhal, H.; Saraf, A. K.; Saini, R.P.; Singal, S.K.; Ahmad, Z., Eds: Alternate Hydro Energy Center: Roorkee, India, 2006; pp. 30-38.2. Anonymous (2004). Environmental Impact Assessment Report of Tidong Hydroelectric power project Himachal Pradesh, Unpub. Report, pp 1-14.3. Hardman &co (2008) Run-of-River Energy Sector Report An Early Stage Industry in Western Canada. Leaders in Corporate Research, pp: 1-32.4. Singh T.P., Chandrashekhar. J. and Agrawal. A.K. (2007) Analysis of Water and Sediment Flow in Desilting5. Basin of a Run-of-River Hydroelectric Project. International Conference on Small Hydropower - Hydro Sri Lanka, 22-24 October pp: 1-6.