hydroMinds - Small Hydropower Potential Assessment

Technical Report and Model Presentation.
1. Background and Data Requirements
2. Methodology
3. Estimating the Technical Hydropower Potential
4. Estimating the Economically Viable Hydropower Potential
5. Results and Post-Processing

Water courses suitable for hydropower generation have sustainable and ideally high flow rates as well as steep gradients between intake and powerhouse creating the necessary head. Hydropower facilities require a diversion dam to direct water from a stream into the hydraulic system that conveys the water to a powerhouse. Turbines and generators convert potential energy into electricity before the water returns to the stream.

To locate hydropower opportunities, reliable elevation data, information on land-use and land-cover as well as precipitation data is required. Remote sensing data products can be used to derive a digital elevation model (DEM) of the study area and to classify vegetation structures. Information about precipitation may be obtained from global climate databases, if local precipitation data is not available. Local discharge measurements and high accurate elevation data will increase the accuracy of the outputs.

Several data products with different accuracy levels can be used when applying the hydroMinds model. Even minimum standard data provide a good overview and allow comparing river sections as of their estimated hydropower potential. More accurate data products along with local data and expertise may lead to first capacity appraisals of identified sites.


Fig. 1: Flowchart of the main Components and Processes of the hydroMinds-Model

Fig. 2: Scematic Illustration of the Grid Point-Raster Analysis


The potential energy of downhill flowing water of a stream regardless of any physical, technical or economic limitation is defined as the gross theoretical hydropower potential. According to physical and technical reasons hydropower plants aren’t able to fully use the gross theoretical hydropower potential. The technical potential of hydropower describes the energy capacity that is actually useable when technical, infrastructural, ecological and other conditions are taken into consideration [3].

Applying the hydroMinds model, the technical hydropower potential is calculated for each grid point representing a river. Thus, each assessed river point forms a virtual powerhouse location. The virtual intake for the respective virtual project is defined being 1,000 m upstream. This assumption creates a series of virtual hydropower projects along the considered river to ensure compatibility.

The technical hydropower potential for every possible virtual project combination is calculated according to the following equation:

The following technical, physical and ecological influences reducing the gross theoretical hydropower potential are:


With extending the penstock of a virtual project a higher elevation difference may be utilized resulting in a higher hydroelectric production capacity, but also increasing investment costs. Thus, a filter routine has been implemented, taking into account economic parameters such as investment costs of a virtual hydropower generation plant, average annual power production, project lifetime expectancy as well as the feed-in tariff for selling electricity, calculating the net value of the virtual project. The virtual projects that have a negative net value are excluded from further analysis. The Internal Rate of Return (IRR)- method is applied to identify the top economically viable hydropower projects.

As all economically related parameters are very sensitive and may lead to skew results of the analysis, the parameters and assumptions need to be modified and determined carefully according to local pricing conditions. For every analysis, government agencies, local experts, manufactures and suppliers are consulted to provide input data. Based on the received information mean values for the calculations of the computer based decision-making tool can be calculated.

For every virtual project combination the net value is calculated applying the following formula and assumptions as used for a study on small tropical islands in the Caribbean:

For all virtual projects with a positive net value the Internal Rate of Return (IRR) is calculated to determine the interest rate that is equivalent to the returns expected from the project. The IRR is computed using an iterative calculation process, using different discount rates to get the discount rate that refers to a Net Present Value (NPV) = 0. The NPV of a virtual project is equal to the present value of future returns, discounted at the marginal cost of capital, minus the present value of the cost of the investment.

It is assumed that every single virtual project will be developed and built in four years. In the first year expenses for the feasibility study, project design and management are incurred which is assumed to be 1/60 of the total project development costs. Costs for civil works and all electro-mechanical equipment are spread almost evenly over the remaining three years. At the end of the fourth year the whole development is finished and all funds disbursed. Full operation time of every project is assumed to be 25 years.

The computer-based decision-making tool identifies the virtual project with the highest IRR of all possible virtual project combinations. This river section is blocked from further screening in order to avoid double selection of the same section when selecting further virtual projects from the remaining river sections according to the next highest IRR value.


The data outputs of the hydroMinds model can be used to produce topographic and thematic maps of the study area using Geographic Information Systems (GIS). Additional diagrams, charts as well as 3D-views and other types of geographic visualization provide a good realistic overview of the study area and the identified locations. The rivers and individual river sections are classified according to their suitability for hydropower, identifying and pointing out the sites with the highest potential.

For a more detailed micro-level assessment of identified locations, the hydroMinds tool, a stand-alone and web-based software, allows modifying all parameters to analyze their impacts on-site. No sophisticated software or high-performance computer systems are required for the post-processing as all calculations are webserver-based and results can be viewed, saved and printed using a web-browser.

With local knowledge and the use of the hydroMinds tool, catchments may be examined individually with customized parameters to enhance the overall accuracy of the outputs. Even without local expertise, the tool allows data exploration to identify the sensitivity of the results to modifications of parameters.


Hydroelectric power opportunities can be identified following the approach of the hydroMinds model using remote sensing and hydrological data. The results are preliminary however, but help concentrating required in-depth studies to pre-identified sites proving the economic viability of the planned hydropower project.

The use of satellite data even allows investigating study areas where local data is not sufficient. Although the accuracy of the recommended remote sensing data products can be considered to be good, local measurements may be required to validate the hydroMinds model.

For hydrological modeling the widely-used SCS-CN method was modified according to the climate of tropical regions and was approved by local measurements, expertise and re-assessing the energy potential of existing hydropower plants in the Caribbean.

To explore the data or to analyze identified locations in more detail, the hydroMinds Tool provides an indication of the estimated range of hydropower plant design capacities according to different input parameters. Both, the hydroMinds model and software-tool can improve the implementation process of new hydropower projects and help establishing a sustainable and climate-friendly energy use.




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