Geothermal resource energetics

The theory of geothermal heat extraction is discussed on the basis of three simple idealized models, that is, (1) single fracture flow, (2) intergranular flow and (3) intergranular vaporization models. Theoretical expressions for the total available specific resource energy per unit area or unit volume are given. These results are illustrated by a number of numerical data which are useful in the assessment of the potential of individual geothermal resources.     

Geothermal resources assessment in Hawaii

The Hawaii Geothermal Resources Assessment Program was initiated in 1978. The preliminary phase of this effort identified 20 Potential Geothermal Resource Areas (PGRAs) using available geological, geochemical and geophysical data. The second phase of the Assessment Program undertook a series of field studies, utilizing a variety of geothermal exploration techniques, in an effort to confirm the presence of thermal anomalies in the identified PGRAs and, if confirmed, to more completely characterize them. A total of 15 PGRAs on four of the five major islands in the Hawaiian chain were subject to at least a preliminary field analysis. The remaining five were not considered to have sufficient resource potential to warrant study under the personnel and budget constraints of the program.The results of these studies have allowed us to attempt an estimate of the probabilities of low- to moderate-temperature (50–125°C) and of moderate- to high-temperature (125 – 360°C) geothermal resources in 12 of the survey areas; inadequate data or interpretational difficulties did not allow a valid estimate to be made for the remaining three study sites. Table 11 presents estimated probabilities for these PGRAs that are based on all currently available data.The results of these studies have also demonstrated that no single surface geothermal exploration technique is capable of providing unequivocal proof of a subsurface thermal anomaly under all field conditions; it is more frequently the case that an estimate of the geothermal potential of a given PGRA must rely on a synthesis of all geological, geophysical and geochemical data available. Experience in the Kilauea East Rift Zone, a Known Geothermal Resource Area, has also demonstrated that none of the currently available surface exploration techniques are capable of yielding definitive information regarding the production capabilities of a specific parcel of a geothermal reservoir; the only technique that has proven capable of providing this information has been the drilling and flow testing of deep exploratory wells.The island of Kauai (Figs 1 and 2) was not studied during the current phase of investigation. Geothermal field studies were not considered to be warranted due to the absence of significant geochemical or geophysical indications of a geothermal resource. The great age of volcanism on this island would further suggest that, should a thermal resource be present, it would be of low temperature.The geothermal field studies conducted on Oahu focused on the caldera complexes of the two volcanic systems which form the island: Waianae volcano and Koolau volcano. The results of these studies and the interpreted probability for a resource are presented below.Lualualei Valley: (Figs 1 and 3). Geologic mapping located the focus of the late-stage eruptive activity near the back of Lualualei Valley and tentatively identified the Waianae caldera boundaries within the valley. Soil geochemistry studies defined anomalous zones of mercury concentrations and radon emanation that appeared to be coincident with the caldera boundary faults. Groundwater chemistry and temperature measurements identified a distinctly anomalous well near the back of the valley and several others with slightly anomalous conditions on the caldera boundary faults. Geophysical soundings indicated low subsurface resistivities within the valley that were interpreted to correspond to warm fresh to saline water-saturated basalt. On the basis of the available data, the probability for a low- to moderate-temperature resource (50–125°C) within 3 km of the surface is assessed at 10–20%. The probability for a higher temperature resource is less than 5%.Mokapu Peninsula and Koolau Caldera: (Fig. 3). Geologic mapping identified three post-erosional volcanic vents on Mokapu Peninsula; the inferred ages were on the order of 300,000 years. Geochemical studies on Mokapu were unable to identify a self-consistent pattern of soil geochemical anomalies or significant groundwater chemical anomalies that would suggest a geothermal resource. Resistivity soundings determined subsurface resistivities that were consistent with cold seawater-saturated sediment. The probability for even a low-temperature geothermal source at depths of 3 km or less beneath Mokapu is considered to be less than 5%.Results of preliminary soil geochemical studies and interpretation of available groundwater data to the south of Mokapu, within the Koolau caldera, suggest that some thermally induced alterations may be present. Interpretation of geophysical data indicates that the temperatures within the ancient Koolau magma chamber are less than 540°C and that the shallow subsurface resistivities show no evidence of thermal effects. On the basis of the rather sparse data currently available, the probability for a low- to moderate-temperature resource associated with the Koolau magma chamber is considered to be 10% or less.Due to the anticipated small demand for geothermal power on the island of Molokai in the foreseeable future, only preliminary efforts were made to assess the potential for a resource on this island. An abandoned well reported to have produced warm water when it was first drilled during the 1930s was located, but temperature measurements were unable to detect anomalies within the open portion of the hole; collapse of the lower third of the bore did not permit access to the water table, however. Soil geochemical analysis did not indicate significant mercury concentrations or unusual alteration minerals in the vicinity of the well. In the absence of detectable anomalies from the preliminary investigation, further studies were not considered to be warranted. The probability for a resource on West Molokai is not considered to be high; however, sufficient data are not available to offer an estimated probability for a resource.Geothermal assessment activities on Maui included an evaluation of the major rift zones and post-erosional volcanic vents on both West Maui volcano and Haleakala volcano. Field surveys conducted on West Maui yielded the following results (Fig. 19).Olowalu and Ukumehame Canyons: extensive geologic mapping characterized the southwest and southeast rift zones of West Maui volcano and interpreted these structures to suggest a migration of the rift zone activity late in the formation of West Maui. Numerous late-stage alkalic and trachitic dikes and plugs were also identified in the survey area. Ground-water geochemical and temperature measurements identified distinctly anomalous water chemistry and temperatures. Resistivity sounding data for the area was interpreted to indicate a thick layer of warm, fresh to saline water beneath the Olowalu and Ukumehame Canyons. The probability of a thermal resource having a temperature greater than or equal to 50°C is estimated to be 50–60%, whereas a temperature greater than or equal to 125°C has an estimated probability of 10% or less.Lahaina-Kaanapali: soil geochemical surveys were unable to identify a self-consistent pattern of soil mercury concentrations or radon emanation rates that would suggest a thermal resource. Groundwater temperature measurements and chemical analyses were similarly unable to detect significant thermal alterations. Geophysical soundings detected subsurface resistivities consistent with cold water-saturated alluvium and basalt. The probability of a thermal resource existing in this area is less than 5%.Honokowai: groundwater chemistry and temperature data for this area were unable to confirm the existence of any thermal impacts and geophysical soundings indicated normal subsurface resistivities. Hence the probability for a resource in this location is believed to be less than 5%.Field surveys on Haleakala were confined to the lower portions of the three major rift zones and yielded the following analyses:

• Haleakala Northwest Rift: soil geochemical and groundwater chemical studies in this area both indicate potential anomalies. The interpretation of the anomalies with regard to thermal alterations was not, however, unequivocal. Geophysical soundings were unable to identify significantly anomalous subsurface resistivities or self-potential variations. The probability of a low- to moderate-temperature resource is placed at 10–20%, whereas that for a high-temperature resource is less than 5%.
• Haleakala Southwest Rift: geologic mapping has determined that several flows on this rift are less than 10,000 years of age and that a few are less than 1000 years old. Preliminary geochemical studies were unable to identify unequivocal evidence of thermal effects on the lower rift zone area, whereas geophysical soundings indicated that thermal groundwaters may be present at depths of less than 3 km. The probability for a low- to moderate-temperature resource is estimated to be 30–40%, whereas that for a high-temperature resource is placed at 15–25%.
• Haleakala East Rift Zone: preliminary geochemical and geophysical surveys were performed in this area. The results of these efforts did not identify significant anomalies; however, difficulties in interpretation and the small amount of data available do not allow an assessment of geothermal potential to be made.

The island of Hawaii, being the youngest and most volcanically active island in the Hawaiian chain, was found to have the largest number of PGRAs (Fig. 34). The current assessment program performed field surveys in six of the most promising PGRAs on Hawaii, which yielded the following results:

• Kawaihae: geophysical surveys performed over this area indicate a set of magnetic and resistivity anomalies that suggest that an intrusive body, associated with the Puu Loa cinder cone, may be heating local groundwaters. Groundwater chemistry and temperature anomalies confirm the existence of a heat source in the vicinity; however, the temperatures are not indicated to be very high. The probability of a low- to moderate-temperature resource in the survey area is indicated to be 35 to 45% and a moderate- to high-temperature resource to be 15% or less.
• Hualalai: geologic mapping on the western flank of Hualalai suggests that frequent eruptive activity has occurred during the last 5000 years. Geophysical surveys have identified distinct magnetic, resistivity and self-potential anomalies near the summit of Hualalai, whereas the lower western flank has not shown significant thermal effects. Geochemical data on the lower flanks were similarly unable to identify any obvious thermally induced anomalies. These data suggest that there is a 35–45% probability of a low- to moderate-temperature thermal resource near the summit of Hualalai and a 20–30% probability of a high-temperature resource in this area. Probabilities for comparable resources existing on the lower flanks are estimated at 15–25 and 5% or less, respectively.
• Mauna Loa Southwest Rift: limited geophysical surveys performed on the lower southwest rift were unable to detect significant resistivity anomalies to depths equivalent to the local water table, and a self-potential traverse detected only one anomalous gradient that was interpreted to be the result of a downgoing streaming potential. No strong geothermal anomalies were identified; however, the limitations of the available data set do not allow a probability estimate to be made of the resource potential in this area.
• Mauna Loa Northeast Rift: geophysical and geochemical field studies performed in this PGRA were unable to detect any evidence of a geothermal anomaly in this location. The probability for even a low temperature resource is estimated to be less than 5%.
• Kilauea Southwest Rift: geologic mapping has indicated several areas of steaming ground and warm coastal springs adjacent to the rift systems. A re-analysis of available geophysical data for this area concluded that warm groundwater was present within the rift zone. Magnetic anomalies observed over the rift indicate that subsurface temperatures may exceed the Curie temperature. The probability for a low- to moderate-temperature resource on this rift is considered to be 100%, whereas that for a high-temperature resource on the upper rift is estimated at 70–80%.
• Kilauea East Rift Zone: an extensive body of geological, geophysical and geochemical data concerning the East Rift Zone is available and virtually all of this data indicates that a high-temperature thermal system is associated with the entire rift. Deep exploratory geothermal wells drilled into the rift zone have identified temperatures in excess of 350°C and continuous production from one of these wells for a period of more than two years indicates that sufficient recharge is available for production of geothermal electrical power. The probability for both a low- and high-temperature resource on this rift zone is 100%.

     

Geothermal resource development in agriculture in Kebili region, Southern Tunisia

Geothermal energy in the Kebili region, south of Tunisia, is used in a number of applications, but mainly in agriculture. Approximately 95% of the thermal water is used for irrigation of oases and heating greenhouses. Generally, when the water temperature is less than 40–45 °C it is used directly for irrigation, but when it exceeds 45 °C it is cooled by means of atmospheric towers before being used to irrigate 16,000 hectares of oases (half of the total area of the oases in Tunisia). Geothermal energy is also used for heating and irrigating greenhouses, which are considered promising and economically feasible applications. The total area of heated greenhouses in the country has increased considerably and is today at 103 ha, 44% of which are located in the Kebili area. Utilization of the geothermal resources will, without a doubt, increase in the near future once we have implemented the last phase of the greenhouse project. By the end of 2003, 13 ha will be added in the region, representing an increase of 29%.     

Wind resource assessment software

As wind farms increasingly spring up all over the world, the complexities of wind farm placement become ever more demanding. Choosing suitable and appropriate sites, minimising their environmental impact and optimising their output become increasingly sophisticated juggling acts. The process can be made easier and lead to significant increases in output with the aid of computer aided design packages. There are various wind resource assessment software packages available on the market. Here, we highlight some of benefits that such software can offer, packages that are available at the moment and look at likely future developments and demands in the computer aided construction of windparks.     

Wind energy resource assessment in Madrid region

The “Comunidad Autónoma de Madrid” (Autonomous Community of Madrid, in the following Madrid Region), is a region located at the geographical centre of the Iberian Peninsula. Its area is 8.028 km², and its population about five million people. The Department of Economy and Technological Innovation of the Madrid Region, together with some organizations dealing on energy saving and other research institutions have elaborated an Energy Plan for the 2004–12 period. As a part of this work, the Fluid Mechanics Laboratory of the Superior Technical School of Industrial Engineers of the Polytechnic University of Madrid has carried out the assessment of the wind energy resources [Crespo A, Migoya E, Gómez Elvira R. La energía eólica en Madrid. Potencialidad y prospectiva. Plan energético de la Comunidad de Madrid, 2004–2012. Madrid: Comunidad Autónoma de Madrid; 2004]; using for this task the WAsP program (Wind Atlas Analysis and Application Program), and the own codes, UPMORO (code to study orography effects) and UPMPARK (code to study wake effects in wind parks). Different kinds of data have been collected about climate, topography, roughness of the land, environmentally protected areas, town and village distribution, population density, main facilities and electric power supply. The Spanish National Meteorological Institute has nine wind measurement stations in the region, but only four of them have good and reliable temporary wind data, with time measurement periods that are long enough to provide representative correlations among stations. The Observed Wind Climates of the valid meteorological stations have been made. The Wind Atlas and the resource grid have been calculated, especially in the high wind resource areas, selecting appropriate measurements stations and using criteria based on proximity, similarity and ruggedness index. Some areas cannot be used as a wind energy resource mainly because they have environmental regulation or, in some cases, are very close to densely populated towns. In the finally selected areas, it is assumed that there are hypothetical wind farms, consisting of 2 MW turbines in appropriate configurations, in which the turbines are about 11 diameters apart. Its energy production will give an estimation of the wind energy potential of the Madrid Region.     

Wind resource assessment in Hormozgan province in Iran

In this study, statistical analysing is performed of wind data measured over a 10 min period based on the Weibull distribution function during one year at three heights carried out to determine the potential of wind in two locations in the Hormozgan province. According to the results, wind speed at 40 m height in Kish city ranged from 4.47 m/s in October to 6.69 m/s in March with average value of 5.32 m/s. However, for Jask city wind speed ranged from 3.4 m/s in January to 5.16 m/s in June with average value of 4.22 m/s. According to world classification of wind power, the wind power density is in class 2 for Kish site while for Jask site it is in class 1. Energy production of different wind turbines at different heights is determined. At the end, an economic evaluation was carried out to determine whether studied sites are suitable for development of small-scale wind turbines.     

Wind resource assessment and comparative economic analysis using AMOS data on a 30 MW wind farm at Yulchon district in Korea

Detailed feasibility studies are necessary for wind farm development projects because the profitability changes greatly according to wind resource, wind turbine, CAPEX (capital expenduture), OPEX (operation expenditure), SMP (system marginal price), and REC (renewable energy certificate) price. Although measuring wind data over one year in the proposed site is essential, it is a cost-intensive and time-consuming process; hence, in the early stages of development, pre-feasibility studies are conducted using reference wind data from the neighboring areas. In the present study, a pre-feasibility study was conducted in Yulchon district of South Korea to develop a 30-MW wind farm. A wind resource map of Yulchon district was predicted using the AMOS (Aerodome Meteorological Observation System) wind data measured at Yeosu Airport. Three cases of wind farms each with different wind turbines were designed, and comparative economic analysis was carried out. The wind farm designed with SL3000/113 wind turbine recorded the highest profitability with project NPV of 33.62 billion KRW(33.29 million USD, 24.33 million EUR) and project IRR of 9.81%.     

National-scale wave energy resource assessment for Australia

A nationally consistent wave resource assessment is presented for Australian shelf (<300 m) waters. Wave energy and power were derived from significant wave height and period, and wave direction hindcast using the AusWAM model for the period 1 March 1997 to 29 February 2008 inclusive. The spatial distribution of wave energy and power is available on a 0.1° grid covering 110–156° longitude and 7–46° latitude. Total instantaneous wave energy on the entire Australian shelf is on average 3.47 PJ. Wave power is greatest on the 3000 km-long southern Australian shelf (Tasmania/Victoria, southern Western Australia and South Australia), where it widely attains a time-average value of 25–35 kW m^?1 (90th percentile of 60–78 kW m^?1), delivering 800–1100 GJ m^?1 of energy in an average year. New South Wales and southern Queensland shelves, with moderate levels of wave power (time-average: 10–20 kW m^?1; 90th percentile: 20–30 kW m^?1), are also potential sites for electricity generation due to them having a similar reliability in resource delivery to the southern margin. Time-average wave power for most of the northern Australian shelf is <10 kW m^?1. Seasonal variations in wave power are consistent with regional weather patterns, which are characterised by winter SE trade winds/summer monsoon in the north and winter temperate storms/summer sea breezes in the south. The nationally consistent wave resource assessment for Australian shelf waters can be used to inform policy development and site-selection decisions by industry.     

The state of solar energy resource assessment in Chile

The Chilean government has determined that a renewable energy quota of up to 10% of the electrical energy generated must be met by 2024. This plan has already sparked interest in wind, geothermal, hydro and biomass power plants in order to introduce renewable energy systems to the country. Solar energy is being considered only for demonstration, small-scale CSP plants and for domestic water heating applications. This apparent lack of interest in solar energy is partly due to the absence of a valid solar energy database, adequate for energy system simulation and planning activities. One of the available solar radiation databases is 20–40 years old, with measurements taken by pyranographs and Campbell–Stokes devices. A second database from the Chilean Meteorological Service is composed by pyranometer readings, sparsely distributed along the country and available from 1988, with a number of these stations operating intermittently. The Chilean government through its National Energy Commission (CNE) has contracted the formulation of a simulation model and also the deployment of network of measurement stations in northern Chile. Recent efforts by the authors have resulted in a preliminary assessment by satellite image processing. Here, we compare the existing databases of solar radiation in Chile. Monthly mean solar energy maps are created from ground measurements and satellite estimations and compared. It is found that significant deviation exists between sources, and that all ground-station measurements display unknown uncertainty levels, thus highlighting the need for a proper, country-wide long-term resource assessment initiative. However, the solar energy levels throughout the country can be considered as high, and it is thought that they are adequate for energy planning activities – although not yet for proper power plant design and dimensioning.     

Offshore wave energy resource assessment in the East China Sea

The offshore wave energy resource in the East China Sea (ECS) off the coast of the southern East China is assessed using wave buoy data covering the period of 2011−2013. It is found that the averaged offshore wave power was approximately 13 kW m⁻¹ in the region of interest. Most of the offshore wave energy in the ECS is contributed by the sea states with significant wave heights between 1.5 m and 3.5 m and with wave energy periods between 6 s and 8 s. Seasonal variations are detected in the wave characteristics of significant wave height and wave power. The predominant wave directions are mainly from the II quadrant and the IV quadrant, respectively, in winter and summer, in accordance with the monsoon characteristics in the ECS. Wave heights, periods and power are generally higher in winter and autumn, and weaker in spring and summer; however, extreme values occur in some summer and autumn months due to the extreme conditions caused by typhoons passing over this region. These extreme sea states do not contribute much to the total annual energy, mainly because of their low occurrence, but may bring risks to the wave energy converters.     

Wind energy resource assessment for five locations in Saudi Arabia

The analysis of recently collected wind data at five sites in Saudi Arabia namely, Dhulum, Arar, Yanbu, Gassim and Dhahran is presented. The five sites represent different geographically and climatologically conditions. The data collected over a period spanned between 1995 and 2002 with different collection periods for each site. Daily, monthly and frequency profiles of the wind speed at the sites showed that Dhulum and Arar sites have higher wind energy potential with annual wind speed average of 5.7 and 5.4 m/s and speeds higher than 5 m/s for 60 and 47% of the time, respectively. The two sites are candidates for remote area wind energy applications. The costal site's, i.e. Yanbu and Dhahran wind speed data indicated that the two sites have lower annual wind speed averages and wind blows at speed higher than 5 m/s during afternoon hours. That makes the two sites candidates for grid connected wind systems for electrical load peak shaving. The data of Gassim site showed that the site has the lowest wind energy potential compared to the others. The annual energy produced by a Nordex N43 wind machine is estimated to be 1080, 990, 730, 454 and 833 MWh for Dhulum, Arar, Yanbu, Gassim and Dhahran, respectively. The analysis showed that the estimated annual energy produced by the machine based on 10 min averaged data is 2.5% higher than the estimated energy based on 30 min averaged data.     

崇明岛风力资源分析与评价

根据风能密度、风能频率分布、风向频率等气象参数,对上海崇明岛风力资源状况和风力发电前景进行了分析与评价.结果显示,崇明岛50m高度处的年平均风速为7.0m/s.年平均风能密度为339.1W/m2,年有效风速小时数为8418h,年可利用风能小时数为2208h,主风向较为稳定,风能分布较为集中.分析表明,崇明岛风力资源丰富,达到开发标准,适宜发展风力发电.文章为开发崇明风力资源提供了有价值的参考.     

Solar energy resource assessment — Brazil

Appropriate information on solar resources is very important for a variety of technological areas, such as: agriculture, meteorology, forestry engineering, water resources and particularly for an innovating technology such as solar energy. In the market entry process of an innovating technology such as solar energy, the enlarged and sustained reproduction of this energy strongly depends on the economy and reliability of the demonstrative solar systems installed (within a restricted or wide scale). The economy and reliability of a system are the consequence of a well-prepared project, resulting from an accurate knowledge of the solar resource available. Therefore, knowing the potential of the solar resource accurately is not only a need, it is also an imperative for a larger diffusion and use of the solar energy.The existing sources of information on radiation in Brazil are quite varied, both at the institutional level and in different types of publications. At the institutional level these sources are: the National Institute of Meteorology, secretary of agriculture, research centers, universities, and electric power generating and distributing companies, among others. The publications with this information are project reports, internal reports of institutions or several magazines. Thus, the quality of the data varies considerably, the information presents spatial and temporal discontinuity and the instruments as well as the measurement units are not standardized.The general objective of this paper is to recover, qualify, standardize and make available the best information from the current existing solar resource in Brazil, either in the form of isoline charts of solar radiation, insolation, numeric tables or analytic summaries of a great part of the publications on the theme over the last forty years.     

The United Nations' approach to geothermal resource assessment

Although the emphasis of United Nations' assisted geothermal projects has been on demonstrating the feasibility of producing geothermal fluids, the potential capacity of individual fields has been estimated by both the energy in place and decline curve methods. The energy in place method has been applied to three geothermal fields resulting in total resource estimates ranging from 380 to 16,800 MW-yr. The results of these studies must be considered highly tentative, however, due to inadequate reservoir data and a poor knowledge of producing mechanisms. The decline curve method has not given quantitative results concerning ultimate field potential because of the relatively short duration of well tests (several weeks to a maximum of 11 months). In all cases, however, the decline of flowing wellhead pressure, field pressure, and flow rate has continued to decrease with time.A new method for making regional assessment of geothermal potential is described, which is based, in part, on an assessment of the probable range of the power potential of geothermal fields as inferred from a frequency distribution analysis of fields already under development throughout the world. Depending on the reservoir containing dry steam or water, and its location in a region of groundwater recharge or discharge, average power potentials can be expected to range from 36 to 3360 MW.     

Wind resource assessment of the Jordanian southern region

Wind data in terms of annual, seasonal and diurnal variations at Queira, which is located in the southern part of Jordan was studied and analyzed. For this purpose, long-term wind speed data for a period of 12 years (1990–2001) was used. The analysis showed that the seasonal and diurnal pattern of wind speed matches the electricity load pattern of the location. Higher winds of the order of 6 m/s and more were observed during both the summer months of the year (May–August) and peak hours (1100–1500) of the day. The wind duration availability is discussed as the number of hours during which the wind remained in certain wind speed intervals. The possibility of electricity generation from wind power at Queira was carried out using three different wind energy systems of sizes 100, 22 kW rated power, and a wind farm consisting of 25 small wind turbines; each of 4 kW rated power with hub heights of 20, 30, and 40 m. The energy production analysis showed higher production from the wind farm with a 20 m hub height than the production from the other two wind turbines. Similarly, the cost analysis showed that the lowest generation costs of 1 kWh were obtained for the wind farm compared to the other two wind turbines. The possibility of water pumping using the wind farm was also investigated. The results showed that water pumping using wind turbines is an appropriate alternative for the photovoltaic water pumping in the region.     

A new methodology for urban wind resource assessment

In the latest years the wind energy sector experienced an exponential growth all over the world. What started as a deployment of onshore projects, soon moved to offshore and, more recently to the urban environment within the context of smart cities and renewable micro-generation. However, urban wind projects using micro turbines do not have enough profit margins to enable the setup of comprehensive and expensive measurement campaigns, a standard procedure for the deployment of large wind parks. To respond to the wind assessment needs of the future smart cities a new and simple methodology for urban wind resource assessment was developed. This methodology is based on the construction of a surface involving a built area in order to estimate the wind potential by treating it as very complex orography. This is a straightforward methodology that allows estimating the sustainable urban wind potential, being suitable to map the urban wind resource in large areas. The methodology was applied to a case study and the results enabled the wind potential assessment of a large urban area being consistent with experimental data obtained in the case study area, with maximum deviations of the order of 10% (mean wind speed) and 20% (power density).     

Development of assessment model for demand-side management investment programs in Korea

The goal of this study is the development of the assessment model for demand-side management investment programs (DSMIPs) in the areas of natural gas and district heating. Demand-side management (DSM) is the process of managing the consumption of energy to optimize available and planned generation resources and DSMIPs are the actions conducted by energy suppliers to promote investment in the DSM. In this research, the analytic hierarchy process (AHP) method was used to develop a scientific and rational assessment model for DSMIPs. To apply the AHP method, assessment indicators for the assessment have been identified by using the concept of ‘plan, do, see’ and the decision-making hierarchy was established. Then AHP model was developed to set up the priorities of assessment indicators and a survey of experts from government and energy suppliers was carried out. Finally, the priorities of assessment indicators were calculated based on the result of survey using the AHP method. The assessment model developed from this research will actually be used to assess the results of DSMIPs, which is being carried out by Korea gas corporation (KOGAS) and Korea district heating corporation (KDHC). The use of the assessment model developed by this research is expected to contribute to enhance efficiency in planning, execution, and assessment of DSMIPs.     

Quantitative risk assessment of a mobile hydrogen refueling station in Korea

Hydrogen infrastructure is expanding. Mobile hydrogen refueling stations are advantageous because they can be moved between locations to provide refueling. However, there are serious concerns over the risk of various accident scenarios as the refueling stations are transported. In this study, we conduct a quantitative risk assessment of a mobile hydrogen refueling station. Risks that may occur at two refueling locations and the transport path between them are analyzed. Our evaluation reveals that risks are mostly in an acceptable zone and to a lesser degree in a conditionally acceptable zone. The greatest single risk factor is an accident resulting from the rupture of the tube trailer at the refueling site. At sites with no tube trailer and during the transport, the risk is greatest from large leaks from the dispenser or compressed gas facility. The mobile hydrogen refueling station can be safely built within acceptable risk levels.     

Some of the design and methodology considerations in wind resource assessment

Owing to the increasing power demand and the environmental concerns of the conventional power sources, power generation from wind is receiving due attention from majority of power planners. Since wind is an intermittent energy source and to find the economic viability of wind project, a proper wind resource assessment (WRA) and analysis of the data collected is very important. An extensive literature survey on WRA is carried out and the different techniques of WRA are discussed. The methodology includes discussions on preliminary wind survey to choose the best site for installing wind data instruments, selecting the optimum wind turbine suitable for a site and the uncertainties involved in estimating the wind speed using the different WRA techniques.