FEATURES OF RENEWABALE ENERGIES

Transcription

1 CHAPTER 6 EVALUATION OF RENEWABLE ENERGY SOURCE This chapter summarizes the features of five renewable energy resources, which can be basic information for selecting most appropriate renewable energy source in planning a rural electrification project. Each renewable resource is evaluated in terms of its present status and potential including its distribution, scale of development, and cost considerations, and then appropriate systems using renewable energy in the country are discussed. 6.1 FEATURES OF RENEWABALE ENERGIES Although renewable energy resources vary, the Guideline discusses hydro, solar, wind, biomass, and geothermal energies, which have already been used for electricity generation in Indonesia. Most of renewable energies can be converted into not only one kind of energy but also several kinds of energy such as heat, light, mechanical power, and electricity. The Guidelines, however, focus mainly on electrical use from a view of rural electrification. The followings show the outlines of these energy resources Hydro Flowing water creates energy that can be captured and turned into electricity. This is called hydropower. Hydropower is at present the largest source of renewable power, generating about 15% of the electricity used in Indonesia. There are various scales in hydropower plants. These are usually classified into three levels of size: large (or full-scale), mini and micro. Large (Full-scale) hydro These produce enough electricity for large towns and extensive grid supplies. A large-scale hydro plant produces generally more than 10MW of power. Mini-hydro These make a smaller contribution to national grid supplies, typically in the range of around 100kW to 10MW. Sometimes the higher end of this range, 10 MW, is referred to as small hydro power. Micro-hydro These are smaller still, and usually do not supply electricity to the national grid at all. They are used in remote areas where the grid does not extend. Typically they provide power to just one rural community or one rural industry. They range in size from several hundred watts, just enough to provide domestic lighting to a group of houses through a battery charging arrangement, to around 100 kw, which can be used for small factories and to supply an independent local mini-grid (off-grid) which is not part of the national grid. Sometimes the smaller end of the range, less than 10 kw, is referred to as Pico hydro. In Indonesia, while most of large and mini hydropower plants have been developed by PLN and generate electricity for the national grid, most of micro hydropower plants have been operated and maintained not by PLN but by community levels such as 6-1

2 cooperatives, NGOs and private owners for their own use with mini grids. Micro hydropower facilities have been manufactured and constructed by domestic industries and have reached commercial stage. Since, as shown in the ANNEX 1, most portion of Indonesia is abundant in rainfall, it is expected that there are a large number of promising hydro potentials Solar There are a variety of technologies that have been developed to take advantage of solar energy. Two of these technologies, which produce electricity, are photovoltaic (PV) systems and concentrating solar systems. Photovoltaic (PV) systems Photovoltaic (PV) systems convert sunlight directly into electricity. A solar or PV cell consists of semi-conducting material that absorbs the sunlight. The solar energy knocks electrons loose from their atoms, allowing the electrons to flow through the material to produce electricity. PV cells are typically combined into modules that hold about 40 cells. About 10 of these modules are mounted in PV arrays. PV arrays can be used to generate electricity for a single house or, in large numbers, for a power plant. The former is widely called solar home system (SHS), and the latter is centralized system. Sometimes, centralized system is combined with other power supply system such as diesel and hydropower to generate electricity more efficiently. This kind of system is called hybrid system. In Indonesia solar cell technology has been widely applied, particularly for SHS. SHS has been implemented in remote areas which is far from electricity grid (PLN). System used in SHS is stand alone system. Each SHS has capacity of 50 Wp. Generally a SHS consists of - 1 solar module (50 Wp) - 1 battery charge regulator (BCR) - 1 battery 70 Ah - 3 units TL type lamp, each 10 watt - 1 stop contact for radio and Black and White TV Most of SHS components have been manufactured in Indonesia. Although solar module, one of main components, is still imported from industrial countries, it can be procured easily at reasonable price in the markets in Indonesia. Concentrating solar systems Concentrating solar system uses the sun's heat to generate electricity. The sunlight is collected and focused with mirrors to create a high-intensity heat source. This heat source produces steam or mechanical power to run a generator that creates electricity. In Indonesia, however, there is no experience of introducing this system. 6-2

3 6.1.3 Wind Wind turbines capture the wind's energy with two or three propeller-like blades, which are mounted on a rotor, to generate electricity. The turbines sit high atop towers, taking advantage of the stronger and less turbulent wind at 24 meters or more aboveground. Wind turbines can be used as stand-alone applications, or they can be connected to a utility power grid or even combined with a photovoltaic (solar cell) system. Stand-alone turbines are typically used for water pumping or communications. However, households in windy areas can also use turbines to generate electricity just like solar home system. For utility-scale sources of wind energy, a large number of turbines are usually built close together to form a wind farm. The wind is the fuel source for wind energy. The potential areas for generating electricity are limited to the areas with average annual wind speed of over 4.0 m/s at 24 meters aboveground. Indonesia does not have many areas with abundant winds, except some islands and coastal areas. Understanding the wind resource is a crucial step in planning a wind energy project. Detailed knowledge of the wind at a site is needed to estimate the performance of a wind energy project. In Indonesia, although some components and materials for wind power such as tail Vane, Towers, foundations, storage units, cables, electric parts, monitor, etc. can be produced in locally. But main components for wind power such as generator, inverter dummy load, rotor blades and control units must be imported at present Biomass Biomass (organic matter) can be used to provide heat, make fuels, and generate electricity. This is called bio energy. Wood, the largest source of bio energy, has been used to provide heat for thousands of years. But there are many other types of biomass, such as wood, plants, residue from agriculture or forestry, and the organic component of municipal and industrial wastes, that can now be used as an energy source. Current practical technologies that produce electricity by utilizing biomass are roughly divided into two types: direct combustion system and gas burning system. Direct combustion system In direct combustion systems, biomass is directly burned in a boiler to produce steam for electricity. This system can burn biomass fuel with moisture content up to 65% and comparatively large size material such as wood blocks are the most usual type of combustion technology commonly practiced in rural industries. Wood is one of the most used biomass fuels in this system. In Indonesia, biomass combustion boilers are broadly used in plywood industries, sugar factories and palm oil industries, for meeting their own demand. Gas burning system Gas burning system can be sub-divided into two types: gasification system and biogas system. 6-3

4 Gasification systems use high temperatures to convert biomass into a gas (a mixture of hydrogen, carbon monoxide, and methane). The gas fuel reciprocating engines or gas turbines, which turn electric generators. Although some gasification technologies have been developed in Indonesia, gasification systems, however, are still not commercially in the country. In other country, small-scale gasification systems utilizing rice husks have been developed and practically used in agricultural areas. Typically these systems produce electricity of less than 100 kw in output with utilization of automobile diesel engines, and are very cheap compared to other renewable energies. In Indonesia, however, these systems have not been introduced and disseminated. Biogas is a gas that is produced from biomass by decay or fermentation. Biogas technology generally has been achieved by Indonesian experts and currently there are many systems have been installed. However the Biogas technology is applied mainly for cooking in the households not for generating electricity Geothermal Geothermal energy technologies use the heat of the earth for direct-use applications, geothermal heat pumps, and electrical power production. Wells can be drilled into underground reservoirs for the generation of electricity. Some geothermal power plants use the steam from a reservoir to power a turbine/generator, while others use the hot water to boil a working fluid that vaporizes and then turns a turbine. Indonesia is abundant in geothermal potentials and several geothermal power plants have been developed. However, these sizes are more than several 10 MW and there is no small-scale power plant suitable for rural electrification. Major equipment for mechanical and electrical component in the geothermal power plant, such as turbine, generator, can pump, control & instrument and other moving part are imported. 6-4

5 6.2 REQUIREMENTS FOR EVALUATION OF RENEWABLE ENERGY RESOURCES In order to evaluate renewable energies for choice of an optimal energy source in a rural electrification project, this section discusses requirements for evaluation of renewable energy resources. These requirements may be divided into two groups taking into account two different project stages, namely, development stage and operating stage Constraints of renewable energies in development stage The requirements in development stage may be considered as constraints of renewable energy to be evaluated rater than requirements. The followings are such constraints to be evaluated. Geographical and regional constraints - Distribution of potential - Restriction of location (What is basic condition of feasibility) Influence of weather condition Supply availability - Characteristic in scale - Voltage, supply capacity (Watts) per household, and service hours - Influence of distribution of households Necessary Survey Plan/Design Construction/Installation Environmental load Requirements of renewable energies in operating stage Electricity business, regardless of its scale, may be composed of three basic components: Management, System, and Consumers. These components are closely correlated to each other with a direction in a circle, and function to each other. (Refer to Figure.6.2-1) Functions that these components offer to other components are Operation and Maintenance (O&M) from Management to System, Service from System to Consumers, and Payments from Consumers to Management respectively. If even one of these three components fails to function properly, sound cycle of the business, as a whole, will not go well, and eventually the business itself will be suspended. For example, when some consumers fail to pay their electricity charges, Management will not get all the necessary funds for O&M, and it will be unable to sufficiently operate and maintain System. Due to insufficient O&M, System will be unable to supply Consumers with sufficient electricity. In response 6-5

6 to inappropriate electricity supply by System, Consumers who will have complaints about the inappropriate electricity supply and have no longer willingness to pay may increase. Due to increase of delinquents, financial difficulty of Management will become worse than ever. Thus the electricity business will fall into a vicious spiral and eventually will be suspended. Meeting the requirements of these three components is crucial for sustainability of electricity business and these requirements are also very important factors for evaluation of renewable energy sources to choice the optimal renewable energy for individual rural electrification projects. 6-6

7 Correlation of Project Components Management Payments O&M Consumers System Service Affordable Payments Good Electricity Supply Easy O & M Low Capital Cost/ low kw cost Low Running Cost/ low kwh cost (O&M and Repair Cost) Good Awareness Supply satisfied with Consumersf demand (Sufficient kw, kwh, and service time, Low fluctuation) Reliability (Stable supply, Not easy to be broken) Available by local population Easy to repair (easy and immediate to procure equipment for maintenance, including spare parts) Requirements for Sustainability Figure Composition of Requirements for Sustainability 6-7

8 (1) Affordable Payments Since it certainly needs some expense to operate and maintain facilities of any Systems and sometimes expense for recovering a part or all of the capital cost of Systems is also necessary, Management must always secure funds for these expenses. These funds are normally secured by electricity tariffs consumers pay in return for enjoying electricity Service. If electricity tariff is too expensive for consumers to pay, Management cannot secure enough funds for the above-mentioned expenses. Therefore Payments as a major function from Consumers to Management should be made appropriately, and the Payments must be affordable for Consumers. Thus, Affordable Payment is one of key factors for sustainability. To realize Affordable Payment, the followings are required. Low capital cost/ low kw cost Normally, the lower capital cost for installation of electricity facilities is, the lower electricity tariff is set up and the easier it is for consumers to pay the tariff. Low capital cost (fixed cost) is, therefore, one of requirements of optimal renewable energy that should be selected. When actually compared with alternative energies, it is necessary to take into account differences of benefits that consumers will receive from their systems, namely, electricity supply capacities of the alternative energies. KW (construction unit) cost, that is, a construction/installation cost per installed capacity of a system. Although this cost does not reflect all the differences mentioned above exactly, roughly it presents a cost that are taken into such differences because there is no great difference in consumers using hours of electricity in rural areas whatever energy resources is. Low running cost/ low kwh cost Like capital cost, low running cost is also one of requirements of optimal renewable energy that should be selected. The significance of running cost being low in a rural electrification project is much larger than that of capital cost being low, because a lack of running cost directly affects the operation and maintenance of the system. Although appropriate uses of grants and subsidies can help the implementation of rural electrification project, the use of grants or subsidies to cover running cost is dangerous and could undermine the long-term sustainability of a rural electrification project. Consumers are, therefore, required at least covering full running cost of the systems. Awareness of consumers Even though a tariff is low enough for consumers to pay, some consumers may have no willingness to pay for the electricity unless they become aware of the value of the electricity and their obligation to use of electricity. Consumers are often willing to pay the tariff only for valued services. The valued services greatly depend on electricity supply by the System. Consumers willingness to pay also depends on their sense of values to electricity. Although degree of consumers awareness to electricity seems to 6-8

9 have no relation with the choice of renewable energy resources, it is very important for sustainable operation that consumers feel friendly to the system and are aware that the system is their own. People often do not feel friendly to something so large, complicated and sophisticated. Simpler and smaller system is desirable for rural electrification, if possible. Their sense of values to electricity and awareness of the obligation to use of electricity could be improved by education or training on use of electricity that are given to them. In this respect, renewable energies that allow many consumers to participate in many project stages such as construction, operation and maintenance stages may be desirable. Thus, being friendly to the system and possibility of consumers participation could also be one of requirements of optimal renewable energy that should be selected. (2) Easy O&M Many of renewable energy generating systems are generally recognized to need a few maintenance jobs because they, except biomass, do not need any fuel to generate electricity. None of them, however, is maintenance free, and necessity of appropriate operation and maintenance is common to all generating systems including conventional systems. It is very significant especially for rural electrification projects that operation and maintenance is easy. Rural electrification projects should be operated and maintained mainly by local population who have limited capacities in finance and technical skills. Therefore, Easy O&M (operation & maintenance) is one of important requirements of optimal renewable energy that should be selected. Requirements of Easy O&M are discussed in two items as follows; Available by local population As mentioned above, electricity business in rural areas should be done mainly by local population because of difficulties in economic, social, natural and geographical conditions. O&M by local population do not always give negative impacts or constraints on their electricity business. O&M by local population lead to many good influences to the business and it is desirable for as many local population/ consumers as possible to participate in projects from the viewpoint of Consumers awareness mentioned in the previous section. Easy repair It is quite natural that a system which is not easily broken should be chosen. There is, however, no system that never be broken during long-term operation, and most of systems require replacements of parts or materials even in daily use. Since the burden to cope with such repairs and replacements in rural electrification projects is relatively very large under many constraints such as human resources and geographical conditions, the importance of easy repair in terms of period, financial and human resources, should be highly evaluated. (3) Good Electricity Supply Ensuring that consumer expectations are in line with the energy services to be provided is essential factor to have consumers keep their willingness to pay for electricity service. To realize Good Electricity Supply to consumers, the followings are required. Supply satisfied with consumers demand 6-9

10 Although most of generating systems utilizing renewable energies can supply consumers with limited electricity, electricity supply systems should provide at least a modest level of electricity people need. Therefore it is basic requirements to meet consumers basic demand without fail. Quality and quantity of electricity, service hours of electricity, degree of fluctuation of supplied electricity, and so forth, can be factors to evaluate renewable energies. Regarding consumers basic demands for electricity, it is estimated that to provide basic electric services for household, community (hospital and schools) and commercial activity, people need about 50 kwh per person per year (see Table for a list of electricity demand per month per house hold, assuming on 5 persons per household) 1. Table Typical Energy Service Requirements in the Form of Electricity for Off-Grid Populations in Developing Countries Development TYPICAL ENERGY SERVICES FOR OFF-GRID HOUSEHOLDS Electricity Demand. NEED kwh /month, per household House-hold Lighting 5 hours / day at 20W for a household 2-6 energy Radio/Music 5 hours per day at 5W per household need Communication 2 hours per day at 10W per household Potable water Electric pump providing the community with 5 litres per day per capita Medical services 2.5 kwh / day for basic services in a rural clinic for 100 households Education 2.5 kwh /day for lighting, water pumping, copying, computer, copier, TV, Video, radio etc in a school for 100 households Productive (income generating 5 kwh / day for equipment used by workers from 10 households 0-20 uses) TOTAL 3-30 Reliability The long-term sustainability of a rural electrification depends on well-designed Systems (including proper construction, assembly and installation procedures) that meet consumers expectations and capacity to pay. A system that is the first system to be introduced in the country needs to be demonstrated for an appropriate period, and until its reliability is proven, it must not be adopted to any normal electrification project. Only systems that have been proven to be reliable for long-term use should be used in a 1 G8 Renewable Task Force, Chairman s report, July

11 rural electrification project. This is a very important requirement for choice of optimal renewable energy. 6.3 EVALUATION OF RENEWABLE ENERGIES IN RURAL ELECTRIFICATION Features of Renewable Energies The features of targeted five renewable energies (Micro hydro, solar, wind, biomass and geothermal) based on the requirements as discussed in a previous section (6.2) are summarized in Table Table shows advantages and disadvantages of five renewable energies excerpted from Table

12 Table Comparison of Renewable Energy Sources (1/4) Micro hydro Solar Wind Biomass Geothermal Few None (excluding private use) None Many (SHS: about 48,000 units, Centralized system/hybrid system: more than 6 units) Off-grid-based Many (more than 100 sites) US$ 2,000 7,000 /kw SHS : US$ 8,000 9,000 /Wp N/A N/A N/A Capital Cost per kw None None One site (broken at present) Many (7 sites with 769.5MW of total capacity) Water pump, communication Water pump Factory use for their own steam None equipment, etc. and electric needs Solar heat use (Total capacity300mw) The average value of solar Potential areas are limited to Potential areas are limited to More than 200 indicative areas radiation in the country is 4.7 the areas with average annual the areas producing large have been identified for kwh/m 2. There is no negative wind speed over 4.0 m/s at 24 quantities of biomass fuel such geothermal potential areas area for PV system installation. meters above ground level. as agricultural and wood industry residue Grid-based Many (more than 100 kw in installed capacity) Others Mechanical-power-driven use Existing Applications for traditional device such as water mill Possible only in certain areas in agricultural Possible areas Possible only in certain areas Applicable all over the country 1. Potential areas More than 90% of the country receives average annual rainfall of more than 1500 mm, and most of the country abounds hydro-potential. Possible in large part of the country 6-12 Locations where geothermal potential is identified Locations where biomass fuel such as agricultural and wood industry residue is available. Agricultural areas Locations where wind potential is identified There is no negative area for solar power in the country. Locations where hydro potential is identified 2. Suitable locations (natural conditions for development) Geothermal potential areas Windy locations Anywhere all over the country Mountain villages No influence on its generation. Possible to generate stable electricity continuously. Practically nothing to influence on its generation Wind power depends on wind velocity that varies greatly according to climate and day-to day weather conditions Solar power depends on solar radiation that varies greatly according to climate and day-to day weather conditions Hydro power depends on river flow, which is closely related to 3. Influence of weather conditions (stability) No influence of weather condition No influence of weather condition amount of rainfall and fluctuates in volume seasonally (in longer-term than solar and wind) Wide fluctuation Wide fluctuation Seasonal influence Not suitable for small/micro scale with less than several MW. Plant capacities in the country rage from several hundred W to Ranging from several ten Watts in scale, and larger in scale, more economical. Applicable for electrification Cost per output is not related to scale in output. Applicable for electrification Ranging from several kw in capacity, and larger in scale, more economical. Applicable for electrification 4. Characteristic in scale MW, and larger in several scale, more economical. only for Applicable grid-connection. Applicable as mini and normal grid-connected power resources. of ranging from individual households to several hundred households. of ranging from individual households (SHS) to several hundred households (Centralized system) 6-12 of more than several ten households. Not suitable for individual households. 6-12

13 Table Comparison of Renewable Energy Sources (2/4) Micro hydro Solar Wind Biomass Geothermal 5. Supply to households (in case of off-grid base) 6. Necessary survey for technical feasibility Voltage: AC220V Capacity: more than 100W/household Service hours: available for 24 hours Almost the same service as grid-based electricity. Off-grid type: discharge observation (Obtaining minimum discharge) Grid-connected type: discharge observation for several years) SHS: DC12V Capacity: Module output: 50Wp, Battery: 70Ah(4 5 hours available per day with demand of W) Limited service No need for observation (since sufficient solar radiation is already identified over the country) Refer to SHS Limited service Wind speed site measurement for at least one year. N/A N/A Estimation of accumulation of biomass fuel Long- term and large-scale survey necessary for verifying the presence of promising geothermal reservoirs. 7. Plan/Design Individual designs by experts taking site condition into account are necessary. A standardized design for cross-flow turbine has been introduced and applied. (T-type cross-flow turbine with capacity of less than 100 W) Available for local consultants /trained NGOs 8. Procurement of All micro hydro components equipment have been manufactured in Indonesia and are easy to procure. SHS: Component configuration is almost standardized, and there is no need for individual design. Centralized system: necessary for experts to design for individual plant. All SHS components have been manufactured in Indonesia except solar module which is still imported from industrial countries and are easy to procure. Individual household type: Necessary for experts to design for individual location. (but, component configuration is almost standardized like SHS) Centralized system: Necessary for experts to design for individual plant. Main components including wind turbine for practical use must be imported, and it takes long time to procure them. Individual household/ off-grid type (assuming bio-gas engine in other countries): no need for individual design. MW class: Necessary for experts to design for individual plant. It is necessary for engineers with high technical knowledge carefully and skills to design facilities based on data and information obtained through site survey/observation. Mainly imported. Mainly imported. 9. Construction/ Installation Need for civil works. Required automobile-accessibility to location. Period: Several months one year Villagers participation in civil works is possible. Available for local contractors/ NGOs 6-13 SHS: Transportable by manpower. Easy to install. Possible to install for a day. Villagers participation in installation is possible. Available for local contractors/ NGOs Centralized system: Required automobile-accessibility to location Period: Several months one year Required automobile-accessibility to location. Individual household/ off-grid type (assuming biogas engine in other countries): Required automobile-accessibility to location. MW class: Required automobile-accessibility to location Period: Several months one year, No possibility of villagers participation It takes several years or much more from verifying the existence of a geothermal reservoir to commissioning. Scale of construction is relatively larger. No possibility of villagers participation

14 10. Operation and Maintenance Table Comparison of Renewable Energy Sources (3/4) Micro hydro Solar Wind Biomass Geothermal Aspects of human resources Daily operation and maintenance by local operators trained properly is possible. Easy repair works of civil facilities is possible by villagers Possible to operate and maintain the system by only local population. Aspects of human resources Daily operation and maintenance by consumers trained properly is possible. Technicians who have taken technical training course is necessary at each location. Possible to operate and maintain the system by only local population. Aspects of human resources Daily operation and maintenance by consumers trained properly is possible. Technicians who have taken technical training course is necessary at each location. Possible to operate and maintain the system by only local population. Individual household/ off-grid type (assuming bio-gas engine in other countries): Possible to operate and maintain the system by only local population MW class: Technicians with high mechanical knowledge and skills Operation and maintenance by only professionals MW class: Technicians with high technical knowledge and skills Operation and maintenance by only professionals Physical aspects (lifetime) Well-designed micro hydro power plants may be able to generate for at least ten years without replacement of major equipment. Running costs are relatively very low because there is no need for major replacement during lifetime of the system. Physical aspects (lifetime) Lifetime of PV module is more than ten years. SHS: (Automobile) Batteries can last for only 2 3 years, and need small maintenance such as keeping the acid level monthly. Centralized system: In addition to daily maintenance such as keeping the acid level, it is necessary to replace all the deep-cycle batteries which is expensive within ten years. Running costs are relatively high because one of major components, batteries need replacement at intervals during lifetime of the system Physical aspects (lifetime) As for storage batteries, it is almost the same conditions as PV systems. Wind turbines and generators are generally designed to retain their functions for at least ten years, but they are often broken in much shorter lifetime as designed due to severe mounting condition that they are directly exposed to the weather at high position. Running costs are relatively high because one of major components, batteries need replacement at intervals during lifetime of the system and wind turbines and generators are relatively easier to be broken due to their severe mounting conditions. Physical aspects (lifetime) Since this is only a renewable energy that needs fuel, it is necessary to always keep appropriate fuel supply. Major equipment is reciprocating engines, steam boilers and turbines, and they need periodical inspections and replacements of parts or material such as lubricating oil. (same as diesel generators and thermal power plants) Running costs are relatively high because their systems are composed of mechanical equipment which need inspection and replacement at intervals, and they need fuel collection and storage. Physical aspects (lifetime) Since steam or hot water exploited from the geothermal reservoirs normally contains substances that damage plant equipment, frequent replacement of equipment such as plumbing and/or additional well may be necessary for keeping their output level. Running costs are relatively high because their systems are composed of equipment that need frequent replacements due to utilization of steam or hot water that contains harmful substances for equipment

15 10. Procurement of expendables and spare parts 11. Proven Reliability (in case of off-grid base) 12. Environmental load Table Comparison of Renewable Energy Sources (4/4) Micro hydro Solar Wind Biomass Geothermal Necessary expendables are only grease, bearings, drive-belts, etc. at the moving parts of turbines and generators. It is possible to procure them in the country. Locally available (inexpensive) Already proven by abundant records of use. No proven reliability Reduction of river flow, change of land caused by constructing facilities, and noise from turbines and generators are inevitable. Relatively small SHS: Procurement of major components including batteries that need replacement at intervals is available at local markets. Locally available (inexpensive) SHS: Already proven by abundant records of use. Proven reliability As long as disposal of batteries that contain toxic substance is conducted in an appropriate manner, there is few negative impact. Very small Procurement of major components need much cost and time due to import. Procurement from overseas (expensive and taking longer time) Although large-scale systems have been used for practical use in foreign countries, systems that have been introduced in Indonesia, cannot be said reliable judging from the present status of them. No proven reliability Impact to natural view and noise caused by wind turbine rotation are inevitable. As for the battery disposal, it is the same as solar power. Small Procurement of major components need much cost and time due to import. Procurement from overseas (expensive and taking longer time) Although large-scale systems have been used for practical use in foreign countries, none of systems for rural electrification level in Indonesia has been succeeded in operation. No proven reliability Noise, vibration and bad smelling may occur in operation like diesel engines or thermal power plants. Not small Procurement of major components need much cost and time due to import. Procurement from overseas (expensive and taking longer time) Although large-scale systems have been used for practical use in foreign countries, none of systems for rural electrification level in Indonesia has been succeeded in operation. No proven reliability Relatively large change of land takes place. Geothermal power may emit noxious fumes such as hydrogen sulfide. Relatively large

16 Table Advantages and Disadvantages of Renewable Energies Advantages Disadvantages Micro hydro Abundant records of applications with utilization of Indonesia s own technologies and skills. 24 hours service Inexpensive capital cost per kilo watts Almost the same service as grid-based supply and possible to be used for income generation in the daytime. Cheapest running cost (few expensive parts that need periodical replacement) Easy O&M, possible by only local populations. Solar Abundant records of applications (SHS) with utilization of Indonesia s own technologies and skills. Possible anywhere over the country Individual household installation Easy installation and O&M possible by only local populations. Possible to procure all the components in the country Wind Individual household installation More economic than solar power Biomass Regardless of geographical and weather conditions, possible to generate, as long as there are agricultural residues. Easier to get higher power because of utilization of internal combustion engines or steam turbines Micro hydros are applicable at only locations where its potential is identified. Need of qualified engineers for planning and design. Micro hydros may be unable to fully meet demand of all the households in the target area depending on hydro potential on the site. Lower density of households is, higher construction (distribution) cost is. Most expensive cost per unit output Unstable output varying greatly according to climate and day-to-day weather conditions Limited service (capacity and energy of supply, serve time) Limited productive use Need of replacement at 2 3 years interval of storage batteries that account for nearly 10 % of total cost. Need of appropriate battery disposal Applicable locations are limited to only windy parts of coastal areas and islands. Unstable output varying greatly according to climate and day-to-day weather conditions. Limited service (capacity and energy of supply, serve time) Limited productive use Need of replacement at 2 3 years interval of storage batteries Procurement of major components relies on import. (Indonesia s own technology for practical use has not been established) Few records of applications in the country As for bio-gas engines, Indonesia s own technology for practical use has not been established. Need of appropriate arrangement for biomass fuel such as agricultural and wood industry residues Geothermal Possible to generate stable electricity continuously not depending on climate and weather conditions. Same inexpensive generating cost as that of thermal power plants depending the conditions. Need of long-term and large-scale surveys for verifying the presence of promising geothermal reservoirs. Few existing small-scale plants for village level electrification Need of O&M by professionals

17 6.3.2 Evaluation of Renewable Energies Based on the features discussed in the previous section, 6.3.1, the applicability of each renewable energy is summarized in Table In conclusion, at present and in the near future, only micro hydro and solar (SHS) are recommendable as renewable energies that are applicable to rural electrification (off-grid base) in Indonesia. This does not mean that other energies, namely, wind, biomass, and geothermal, can or should not be used for rural electrification at all, or that there is no possibility of being a promising energy in the future. These energies, however, lack at present some features that are crucial for sustainable rural electrification project as discussed in 6.2.2, and they cannot be treated in the same way of micro hydro or SHS Choice of Renewable Energies In selecting one energy among several energies for a specific location, generally there is need for the following two steps. 1. Feasibility Check 2. Economic Evaluation As mentioned above, only the two energies, micro hydro and solar (SHS) are applicable, and the selection is just to choose either micro hydro or SHS (solar). First step is to judge their feasibility under conditions at a specific location. SHS could be implemented everywhere because solar radiation is high enough over the country, while hydropower depends greatly on natural conditions and it is a prerequisite that hydro potential is near to the location. If there is no hydro potential near the location, a remaining alternative, SHS, is automatically selected as the optimal renewable energy source at this step without going to the next step, Economic Evaluation. In the case that both the energies are feasible at the first step, the selection could be conducted based on their economic evaluation. There is need for the comparison of only hydro and SHS, and it is widely believed that solar energy is the most expensive. As mentioned in (1) Affordable payment, it can be made a rough comparison by using KW costs (capital costs per kw). Micro hydro: US$ 2,000 7,000 per kw SHS : US$ 8,000 9,000 per kwp Since the above cost of SHS is not kw cost but kwpeak, it cannot be directly compared, but, because actual output must be smaller than kwpeak, economic viability is worsen than capital costs per kwp and it is clear that Micro hydro is cheaper than SHS as believed widely. If there is need for a close comparison, the economic comparison could be made by calculating the following unit energy costs. 6-17

18 Table Summary of Applicability to Rural Electrification Renewable Energies Solar Grid base Applicability by scale Rural electrification (off-grid) Mini grid Hydro AA AA (US$ 2,000-7,000 / kw)* 1 SHS C C Centralized Individual Households A AA (US$ 8,000-9,00 0 / kwp)* 2 A A C Conclusions on Applicability to Rural Electrification Most applicable energy where available potential exits Applicable as the next best energy where micro hydro is not applicable. (Remarkable restriction: Impossible full time service) Wind B B B Biomass B B C Not applicable because it is fatal disadvantage as rural energy that should provide reliable electricity to consumers that at present procurement of major components relies on import. Not applicable because it is fatal disadvantage as rural energy that should provide reliable electricity to consumers that Indonesia s own technology for practical use has not been established Very little possibility of its application because of few Geothermal AA B C existing small-scale plants for village level electrification Legend AA: Preferable and proven as practical use A : Applicable, but costly B : Not applicable at present (necessary for tests, demonstration step, establishment of domestic equipment supply system, etc.) C : Not applicable even in the future (from technical point of view) Note *1:Capital cost per kw *2:Capital cost per PV Module Peak Output (kwp)

19 To ascertain which technology option produces energy most cheaply, the cost of producing one unit of energy from each option should be estimated. The unit costs are equal to the total costs divided by the annual units supplied. Unit energy costs = Total annual costs Energy supplied per year The annual costs will include the operation and maintenance costs plus the annual cost of the capital spent on the plant/system. When this method is used, it is necessary to pay attention to figures of Energy supplied per year. Since, in off-grid operation, generating energy is greatly different from actual supplied energy (in other words, consumption energy) due to using dummy load control, (possible) generating energy must not used as Energy supplied per year. 6.4 CONCLUSIONS AND RECOMMENDATIONS In conclusion, at present and in the near future, only micro hydro and solar (SHS) are recommendable as renewable energies that are applicable to rural electrification (off-grid base) in Indonesia. Where a micro hydro potential is identified, normally micro hydro is the most suitable energy option. Note: These do not mean that other energies, namely, wind, biomass, and geothermal, can or should not be used for rural electrification at all, or that there is no possibility of being a promising energy in the future. These energies, however, lack at present some features that are crucial for sustainable rural electrification project, and they cannot be treated in the same way of micro hydro or SHS. In order to adopt these energies for rural electrification for the time being, it is necessary for some firm intuitions such as governmental organizations to look after those projects to the very end of the projects. For treating with these energies in the same way of micro hydro or SHS, it is necessary for adequate tests, demonstration step, establishment of domestic equipment supply system, etc. 6-19