Small hydropower projects are normally run-off-the-river schemes with no provision for storage of water. For a project to be economically viable it is essential to know whether there will be sufficient discharge available at the potential site. As a normal practice, flow duration curves are used to determine the dependable flows. Long series of discharge data is required to develop flow duration curve. However, such flow data are invariably not available at such potential sites which may be in hundreds or even thousands. To determine the flow duration curve at such ungauged sites, flow simulation methodology using hydrological modelling was deployed.
The potential of new technologies for assessing the flow through indirect method of hydrological modelling was showcased for small hydro schemes. Streams of Beas basin in Himachal Pradesh were considered in this study.
The GIS tool was used for extraction of profiles along the identified streams with hydropower potential to locate the ideal drops along the streams. These locations were translated into outlet points to be used in the hydrological model (SWAT) to assess the flow series using precipitation and basin characteristics and thus the flow duration curve at these locations.
A standalone application (Small Hydro Power Potential Calculator (SHP2C) has been developed. Salient features of the application include modules for Profile Extraction; User defined site selection and Power potential calculation. This alternate technology for siting the potential small hydropower sites is highly economical especially for inaccessible areas where conventional surveys are not possible.
To demonstrate the application of GIS and modelling technology for identifying potential sites for small hydro projects. The following specific objectives were identified for the study:
- Assessment of long series of flow data using the long series of the past historical precipitation data with the hydrological model.
- Extraction of longitudinal profiles along the identified streams using GIS tools to locate the drops along the streams. Criteria for identifying appropriate locations were based on the optimum drop in a reasonable distance along the stream.
- Translate these locations into outlet points where flow assessment is required using hydrological model. Compute the flow duration curves at these locations by using the generated flow series.
- Development of a standalone application “Small Hydro Power Potential Calculator (SHP2C)” to automate the process of Profile Extraction; User defined site selection and flow generation to evaluate the Power potential of each site.
Figure: The flow duration curve for the 7 year simulated record of Palachan
Figure: The dimensionless flow duration curve for the 7 year simulated record of Palachan
Findings & Outcomes
It was successfully demonstrated that it is possible to use the geo-informatics and the hydrological simulation tools to identify the potential sites for small hydropower. A highly user friendly application was developed to automate the process that made the whole process of identifying the potential small hydropower sites highly efficient and cost effective.
Figure: The SHP2C (Small Hydro Power Potential Calculator) application, Map View
Figure: The SHP2C (Small Hydro Power Potential Calculator) application, Chart View
Linkage to the SDGs
Goal 6: Clean Water and Sanitation
Ensure availability and sustainable management of water and sanitation for all.
Goal 7: Affordable and Clean Energy
Ensure access to affordable, reliable, sustainable and modern energy for all.
Goal 11: Sustainable Cities and Communities
Make cities and human settlements inclusive, safe, resilient and sustainable.
Provision of water and electricity to the remote settlements can plug the migration of the rural people to the cities. Thus proper identification of small hydro sites with sustained availability of flow is very important.