Resource Assessment Methodology Research Articles

A scalable wave resource assessment methodology: Application to U.S. waters

Waves deliver large quantities of energy to populated coastlines around the world, and wave energy technology research and development has accelerated over the last two decades. Throughout this time national and regional resource assessments have utilized disparate methodologies, which can cause confusion and skepticism. In this work, we describe a theoretical wave resource assessment methodology that addresses many of the major areas of inconsistency and debate. Applying this revised methodology to U.S. waters, we find the theoretical U.S. wave energy resource to be 3300 TWh/yr, with region totals of 2000 TWh/yr in Alaska, 510 TWh/yr along the U.S. west coast, 380 TWh/yr in Hawaii, 290 TWh/yr along the east coast, 69 TWh/yr in the Gulf of Mexico, and 17 TWh/yr in Puerto Rico and the U.S. Virgin Islands. We also find significant uncertainty in these estimates associated with the underlying model dataset, which emphasizes the importance of thorough model validation and calibration as well as quantifying uncertainty.

Wind Resource Assessment: Optimizing the Weibull Distribution Curve

Abstract: In this paper, it was analyze the wind speed characteristics and provide projections of optimal wind resources by comparing data at different hub heights using wind power law. We have acquired data from an operational project site in the western part of India using data points acquired from the site from August 2017 to February 2018.Weibull distribution probability distribution function and cumulative distribution function for wind speed and other parameters involved in an accurate wind resource assessment methodology. To predict wind regimes, the Weibull probability function is commonly used. A comparison of alternative methods for estimating Weibull parameters of a wind regime is presented in this research. For the estimation, five alternative methods are discussed and employed. The study examined wind speed time series data at two sites over the course of a year. Although all five methods produce similar results when plotting error versus wind speed, the standard deviation method produces the best results.

Assessing the variability of expert estimates in the USGS Three-part Undiscovered Mineral Resource Assessment methodology: A call for increased skill diversity and scenario-based training

Abstract Future mineral exploration will necessarily be conducted in increasingly challenging and uncertain search spaces as near-surface, high-quality ore deposits are progressively depleted. Faced with this increase in task complexity, an important consideration from an exploration management perspective is the behavioural aspect of information interpretation and decision-making. One such challenging search space is the Sandstone Greenstone Belt, Western Australia, covering an area of approximately 920 km2, that is deemed prospective for the discovery of archean orogenic gold deposits, with mined (historic production), inferred and indicated resources (JORC 2004 and 2012) totalling 54 t Au. Gold endowment estimates made by geoscience experts, during an exploration project evaluation workshop, were compared with estimates from a group of non-geoscientists, made during a separate but identical workshop. Significant differences were identified between the estimates of the expert geoscientists and the non-geoscience expert group, with the latter proving more conservative. However, a portion of the geoscience experts (N = 11) group produced conservative estimates, comparable to a non-geoscience expert group (N = 10), with both suggesting the existence of additional gold deposits of similar size and quality to known resources (with group estimates for median total endowment of 99 t and 120 t Au, respectively). The remaining geoscience experts (N = 11) presented significantly more optimistic, albeit inconsistent, estimates for the gold endowment of the project area, predicting the existence of undiscovered deposits significantly larger than those already defined in the belt (with a group estimate for median total endowment of 350 t Au). Although the true undiscovered gold endowment within the project area remains uncertain, several possible factors can explain the variations in estimates. These include the application of contrasting strategies, with participants opting to apply more empirical or conceptual methods, and to differences in background experience, resulting in distinct skillsets and varying ability to estimate uncertainty. To improve the quality of expert estimates, it is suggested that individual expertise and appropriate assessment strategies can be developed through scenario-based training courses, and that greater skill and experience diversity within exploration teams is desirable, leading to more balanced aggregate estimates. Further research is warranted to determine which, if any, of the proposed factors account for these disparities. This research could be used to adapt the composition of exploration teams and develop training programs to promote the development of expertise in predictive exploration targeting, in order to promote discovery of future mineral resources.

Accuracy quantification of a CFD model in complex site by cross-checking wind measurements

In the present study it is discussed a sensitivity analysis on input parameters of a CFD resource assessment methodology built on top of OpenFOAM 4.1, a well-known open source library for numerical fluid dynamics. RANS are solved for dry uncompressible air, the Atmospheric Boundary Layer is calculated without thermal effects (neutral conditions). It is highlighted how the control of a metric based upon a weighted root mean square error (wRMSE) of the local accelerations (speed ups) can guide the wind analyst in the design of the computational mesh and further numerical settings. Moreover, it will be quantified the wRMSE as a function of the distance to the measurement points. The parameters analysed are the horizontal extension of the model, the horizontal resolution within the refined area, which is covering the layout of the wind farm, three different versions of k-ε turbulence closure and the number of directional sectors considered.

Assessment of the Malaysian tidal stream energy resource using an upper bound approach

In this paper, an upper bound approach is used to determine the maximum power available to tidal stream turbines placed at five sites along the west coast of Peninsular Malaysia. A depth-averaged hydrodynamic model of the Malacca Strait is built and validated against field measurements. Actuator disc theory is then used to introduce rows of tidal stream turbines as line sinks of momentum and to determine the maximum time-averaged power available to rows of both moderately sized and very large turbines, placed strategically at the locations of highest naturally occurring kinetic energy flux. Results suggest that although the Malaysian tidal stream energy resource is not large enough to make a significant contribution to the country’s energy mix, there may yet be opportunities to use low-speed tidal turbines in small-scale and off-grid electricity generation schemes. Methods are described in detail and links to source codes and results are provided to encourage the application of this simple, yet effective resource assessment methodology to other promising tidal energy sites.

Development in exploration risk and resource assessment methodology

Development in exploration risk and resource assessment methodology

Invasion of alien plant species and their impact on different ecosystems of Panchase Area, Nepal

The aggressiveness of invasive alien plant species has been amidst the changing climate, which has necessitated further research in this area. The impact of invasive alien plant species in the Panchase area of Nepal was assessed through the forest resource assessment and other methodologies such as, household survey, group discussion, direct field observation, participatory cluster mapping, quadrat sampling, laboratory analysis, and GIS mapping. A total of nine major invasive species, in which Ageratum houstonianum and Ageratina adenophora were found spread throughout the ecosystem. The invasion was fueled by anthropogenic disturbances such as leaving the agricultural lands, fallow and degradation of habitat. As a consequence, native species such as Artemisia indica and Urtica dioica were outcompeted mostly in the fringes of fallow lands, agricultural lands and in the disturbed sites. The intrusion was, however, less in the forest area, implying that community-managed dense canopy forests are less susceptible to invasion and routine management can offset the negative effects of invasion. Even though many negative consequences of the invasion were observed in the study sites, the possibility of the economically exploiting the biomass of invasive alien plant species for generating income locally was noticed.Banko Janakari, Vol. 27, No. 1, page: 31-42

Performance measures in geothermal power developements

Geothermal resource assessment requires several input parameters at a time when field information is normally very limited. The power plant efficiency is an important parameter as it affects investment cost and profit. However, there is significant debate in the geothermal industry on the appropriate performance measure to implement. In this paper we attempt to determine the best performance measures for financial decision making during the exploration stage of geothermal power developments. We compare and contrast current performance measures commonly used by the geothermal industry. This includes thermal efficiency, geothermal brine effectiveness, utilisation efficiency and enthalpy efficiency.We show that enthalpy efficiency, categorised by the geothermal reservoir enthalpy, is the best financial performance measure because it is similar to other measures on most criteria, but superior in terms of comparability across different geothermal sites, while satisfying homoscedasticity. Utilisation efficiency, on the other hand, was demonstrated to have the least reliability while requiring additional input parameters.We recommend using the modified enthalpy efficiency developed in this work for resource assessment of new geothermal fields, benchmarking with existing development and for comparison with conventional fossil-fuel thermal plants. This should also affect the choice of resource assessment methodology.

Influence of wave resource assessment methodology on wave energy production estimates

Renewable energy resource inventories show that ocean waves are one of the most energy dense untapped resources in the world, and present an opportunity to generate significant quantities of electricity. To accurately assess the levels of usable energy over long periods, a parametric representation of the raw wave resource is required. This study investigates the variability across four wave energy assessment methods, and two input data sources, to quantify the uncertainties in WEC power production assessments. Two conventional methods were tested: a time-series method and a standard spectral method with a generic spectral shape. Two higher fidelity techniques were additionally studied; an aggregate spectral and a partitioned spectral method.Annual WEC energy production assessments varied between 472 MWh and 543 MWh, a difference of 15%. The partitioned spectral method is shown to minimize prediction uncertainties, yet results in a 14% reduction in annual WEC energy production and increasing power variability. Spectral shape has limited impact on power estimates and energy production assessments, while the numerical wave model data can underestimate annual energy estimates by up to 13%. These uncertainties significantly impact the feasibility of wave energy developments and need to be accounted for as the industry matures.

Comparison of numerical weather prediction based deterministic and probabilistic wind resource assessment methods

Numerical weather prediction (NWP) models have been widely used for wind resource assessment. Model runs with higher spatial resolution are generally more accurate, yet extremely computational expensive. An alternative approach is to use data generated by a low resolution NWP model, in conjunction with statistical methods. In order to analyze the accuracy and computational efficiency of different types of NWP-based wind resource assessment methods, this paper performs a comparison of three deterministic and probabilistic NWP-based wind resource assessment methodologies: (i) a coarse resolution (0.5°×0.67°) global reanalysis data set, the Modern-Era Retrospective Analysis for Research and Applications (MERRA); (ii) an analog ensemble methodology based on the MERRA, which provides both deterministic and probabilistic predictions; and (iii) a fine resolution (2-km) NWP data set, the Wind Integration National Dataset (WIND) Toolkit, based on the Weather Research and Forecasting model. Results show that: (i) as expected, the analog ensemble and WIND Toolkit perform significantly better than MERRA confirming their ability to downscale coarse estimates; (ii) the analog ensemble provides the best estimate of the multi-year wind distribution at seven of the nine sites, while the WIND Toolkit is the best at one site; (iii) the WIND Toolkit is more accurate in estimating the distribution of hourly wind speed differences, which characterizes the wind variability, at five of the available sites, with the analog ensemble being best at the remaining four locations; and (iv) the analog ensemble computational cost is negligible, whereas the WIND Toolkit requires large computational resources. Future efforts could focus on the combination of the analog ensemble with intermediate resolution (e.g., 10–15km) NWP estimates, to considerably reduce the computational burden, while providing accurate deterministic estimates and reliable probabilistic assessments.

Wind Resource Assessment Method for Floating Deep Offshore Wind Turbines

This study presents a new methodology for the assessment of the wind energy resource at deep offshore locations where the use of floating wind turbines is foreseen. The wind resource assessment methodology developed follows the principles used by IEC 61400-12-1 standard in general and proposes the use of experimental data from a floating light detection and ranging (LIDAR) system on a deep offshore region – that assumes the role of the ‘temporary mast’ – and a coastal meteorological mast installed onshore acting as the ‘permanent met mast’. The methodology takes into consideration the time shift between the locations of the two measurement points and the wind direction associated with different atmospheric phenomena. The results obtained conclude that the methodology increases the accuracy of the wind resource assessment campaign while reducing the involved costs and technical risks. An added advantage is the possibility of extending this methodology for the evaluation of the power performance of floating wind turbines during the operational phase of the power plant.

A wave energy resource assessment case study: Review, analysis and lessons learnt

A case study of the development of an overall resource assessment for the Wave Hub site in the southwest UK is presented. Wave Hub is one of the earliest large-scale wave farms planned. Several resource assessment studies have been performed for the site, but the published results are high-level and predicted power availability varies significantly. This paper provides a detailed overview and re-analysis of the multiple datasets used in the original studies, which consisted of a combination of physical measurement and numerical modelling. The quality of the datasets is assessed, and reasons for the discrepancies between predicted resource levels investigated. Results from a SWAN model for the region illustrate significant levels of spatial variability in the resource due to the complexity of the local bathymetry, and examination of long-term global model datasets shows notable inter-annual variability. It is thus concluded that a resource assessment methodology utilising datasets from multiple locations and of short duration significantly reduces the accuracy of the predicted levels of resource. From these results, key learnings for future developments are discussed.

Direct heat resource assessment and subsurface information systems for geothermal aquifers; the Dutch perspective

AbstractA resource assessment methodology has been developed to designate prospective high permeable clastic aquifers and to assess the amount of potential geothermal energy in the Netherlands. It builds from the wealth of deep subsurface data from oil and gas exploration and production which is publicly and digitally available. In the resource assessment various performance indicator maps have been produced for direct heat applications (greenhouse and spatial heating). These maps are based on detailed mapping of depth, thickness, porosity, permeability, temperature and transmissivity (methodology presented in other papers in this NJG issue). In the resource assessment analysis 14 lithostratigraphic units (clastic aquifers) have been considered, ranging in age from the Permian to the Cenozoic. Performance maps have been made which include a) the expected doublet power (MWth) to be retrieved; b) the number of houses or hectares that can be heated from one doublet; and c) a potential indicator map, which provides insight in subsurface suitability for specific applications from a techno-economic perspective. To obtain a nationwide overview of the resource potential in terms of recoverable geothermal energy, a progressive filtering approach was used from total heat content of the reservoirs (Heat In Place – HIP) via the heat that can potentially be recovered (Potential Recovery Heat – PRH) to energy maps taking into account a techno-economic performance evaluation (Recoverable Heat – RH). Results show that the HIP is approximately 820,000 PJ which is significantly more than previous estimates of around 90,000 PJ. This considerable increase in geothermal energy potential is the result of accurate geological mapping of key reservoir properties and the development of state-of-the-art techno-economic performance assessment tools that performs Monte Carlo simulation. Moreover, for the previous estimates boundary conditions were set with the aim to compare the geothermal potential between different EU countries (Rijkers & Van Doorn, 1997). Taking into account techno-economic aspects, the RH is in the order of 85,000 PJ. This is equivalent to ~70% of the ultimate recoverable gas of the Slochteren Gas field. In total over 400 maps have been created or used as input for the resource assessment. Together, they provide comprehensive information for geothermal energy development from various stakeholder perspectives. The maps can be interactively assessed in the web-based portal ThermoGIS (www.thermogis.nl). This application complements existing subsurface information systems available in the Netherlands and supports the geothermal community in assessing the feasibility of a geothermal system on a regional scale.

Introduction to a Special Issue on Petroleum Resource Assessment Methods and Case Studies

This Special Issue of the Bulletin of Canadian Petroleum Geology contains thematic research articles based on presentations first made to the Third Resource Assessment Methodology Symposium, held September 15–17, 2010, in Canmore, Alberta. These ad hoc symposiums gather investigators to focus on petroleum resource assessment methods and case studies in conventional and unconventional reservoirs. The Canadian Gas Potential Committee (CGPC) initiated these symposiums beginning in Calgary, in 2000, with nine scientific articles published in a special issue of Natural Resource Research (Logan, 2005). The United States Geological Survey (USGS) hosted the second symposium in Denver, Colorado, in 2004, with emphasis on special problems associated with the appraisal of conventional petroleum resources. The 2010 symposium was the third of a similar theme. The Canadian Society for Unconventional Gas (CSUG), now the Canadian Society for Unconventional Resources (CSUR), the Geological Survey of Canada (GSC) and the National Energy Board (NEB) were co-organizers of this symposium. The meeting attracted sixty-six participants, including fifteen participants from outside North America. The delegates made twenty-three oral and seven poster presentations, the details of which will appear elsewhere (i.e. Canadian Society of Petroleum Geologists website and Reservoir ). The focus and content of the three symposiums follow and illustrate a number of significant changes in the nature of the petroleum resource-base and the focus of industrial, policy, and regulatory assessment needs to both describe and infer petroleum resources. In the last decade, or so, petroleum exploration and exploitation have made significant advances on two fronts. Advances in drilling and completion technologies have changed not only the supply-demand dynamics in global petroleum markets, but also the petroleum reservoir concept. Almost every rock type is now a potential reservoir. Petroleum is now produced commercially from fine-grained and organic-rich successions that were previously regarded as both top seals and source …

Comparative analysis of carbon dioxide storage resource assessment methodologies

Today, an increased emphasis on the distribution, potential volume, and cost to develop CO2 geologic sequestration resources exists. In the presence of climate change, the need to make accurate and clearly understandable assessments of carbon sequestration potential, which can be used by the government and industry to plan for technology deployment, has never been greater. We compare three CO2 storage assessment methodologies: the approach applied by the U.S. Department of Energy in its Carbon Atlas III, the modified U.S. Geological Survey methodology, and the CO2 Geological Storage Solutions methodology. All three methodologies address storage resources in porous geologic media in sedimentary basins, namely oil and gas reservoirs and saline formations. Based on our analyses, these methodologies are similar in terms of computational formulation. We find that each of the proposed methodologies is science and engineering based. As such, they are important in identifying the geographical distribution of CO2 storage resource and regional carbon sequestration potential at the national and basin-scale levels for use in energy-related government policy and business decisions. Policy makers need these high-level estimates to evaluate the prospective function that carbon capture and sequestration technologies can play in reducing CO2 emissions over the long term. The value of these high-level assessments of CO2 storage resource is to help inform decision makers in governments and industry as to whether carbon capture and sequestration is a climate mitigation option worth pursuing in particular regions.

An Assessment of the Hydrokinetic Energy Resource of the Florida Current

Available ocean model and physically measured data from the Florida Current are analyzed to provide a detailed assessment of the hydrokinetic energy resource of the Florida Current, in support of harnessing a portion of it using ocean energy conversion devices. It has been estimated that approximately 25 GW of hydrokinetic power is available in the Florida Current. Fluctuations in this energy resource are described. Based on the analysis, realistic parameters governing where hydrokinetic energy extraction devices-turbines-may be ideally installed are discussed. An energy resource assessment methodology that has been developed is described. It can be used as a design tool for implementation of arrays of ocean energy extraction devices.

Tools for Small Hydropower Plant Resource Planning and Development: A Review of Technology and Applications

This paper reviews and compares software tools for the planning and design of small hydropower (SHP) plants. The main emphasis is on small scale hydropower resource assessment computer tools and methodologies for the development of SHP plants corresponding to a preliminary or prefeasibility study level. The paper presents a brief evaluation of the historic software tools and the current tools used in the small hydro industry. The reviewed tools vary from simple initial estimates to quite sophisticated software. The integration of assessment tools into Geographic Information System (GIS) environments has led to a leap forward in the strengthening of the evaluation of the power potential of water streams in the case of the spatial variability of different factors affecting stream power. A number of countries (e.g., Canada, Italy, Norway, Scotland and the US) have re-assessed their hydropower capacities based on spatial information of their water stream catchments, developing tools for automated hydro-site identification and deploying GIS-based tools, so-called Atlases, of small-scale hydropower resources on the Internet. However, a reliable assessment of real SHP site feasibility implies some “on the ground” surveying, but this traditional assessment can be greatly facilitated using GIS techniques that involve the spatial variability of catchment characteristics.

Regulatory, design and methodological impacts in determining tidal-in-stream power resource potential

Tidal-in-Stream energy has been heralded by many as a significant potential source for clean power, a scheme where kinetic energy is extracted from tidal currents. A number of estimates have suggested that tidal power may become a sizeable fraction of overall electricity generation, however these estimates have been largely based on a resource assessment methodology that dramatically oversimplifies the physical phenomenon at play. This paper develops a model that considers the effect of energy extraction on the bulk flow, showing that tidal energy inventories that assess solely kinetic energy flux may represent both an order-of-magnitude overestimation of the resource and a significant oversimplification of regulatory impacts.The interplay between the characteristics of a flow and the regulatory and economic issues will likely limit tidal power generation to levels significantly below the physical maximums. Permitted flow reduction, turbine design and staging of development all have significant and predictable impacts on the extractible resource. Energy planners must therefore understand these relationships in order to appropriately assess the magnitude of generation that can be realistically be produced from tidal energy.

Assessment of Product Engineering Creativity

One important element of a company's capability to innovate is the creativity of each individual employee – especially in the context of product engineering. Employee recruitment or promotion to improve the creativity of one's workforce needs assessment of individual creativity. This paper proposes a human resource assessment methodology suitable to assess creative ability of product engineers on an individual level. This methodology is composed of pre‐existing instruments to measure prerequisites (including cognitive abilities, expertise, personality and motivation), and outputs of general creativity. The specifics of product engineering creativity and recruitment or promotion decisions are taken into account.

Assessing the Relative Importance of Tangible and Intangible Resources: Empirical Results from the Forest Industry

Abstract The importance of a diverse resource base to competitiveness of firms has been emphasized in resource-based view (RBV) literature and empirical studies done on various industries. Despite this emphasis, resource assessment methodologies within the RBV framework have been seldom approached, and the relative importance of different resources for business operations is not well understood. The data of the study were collected among large- and medium-sized sawmills within the Finnish forest industry. The objective of this study was to assess within the RBV framework the importance of tangible and intangible resources in business operations of sawmills. This was accomplished by introducing a multicriteria decision analysis (MCDA) method suitable for practical resource assessment. According to the results, personnel, managerial, raw material, and financial resources were the most crucial for sawmills. In the future, applying the MCDA to resource assessments could be combined, e.g., with a financial statement analysis to evaluate the effects of resource usage decisions on business performance.