Modeling Solar Farm Hydrology using EPA SWMM
Open Access
- Author:
- Nair, Adira
- Area of Honors:
- Biological Engineering
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Ali Demirci, Thesis Honors Advisor
Cibin Raj, Thesis Supervisor - Keywords:
- Solar Farm Hydrology SWMM EPA
- Abstract:
- With the demand for green energy rapidly increasing, solar energy as a renewable energy source is expanding across the world. Implementing solar energy on a large scale requires solar farms installation on land covering hundreds of acres of area. Solar farms also change the existing land use and affect the hydrological response of the catchment. However, the impact of solar farms on catchment hydrology is rarely studied due to the lack of established methods to model and difficulty in modelling their unique land cover. The areas over which solar panels are installed are impervious on the panel and pervious underneath it, making it challenging to model. In this study, a framework is proposed to model the hydrological response of a solar farm using EPA SWMM. The framework split each row of the solar farm into four sections, the impervious solar panel, a wet section that captures the majority of runoff from the panel, a spacer section that encompasses the space between the solar panel rows, and an underpanel section which represents the space under the solar panel. The runoff from one section is routed to the next section in the order of natural water flow. All these sections represent one row of the solar farm, so the runoff from each row is then routed to the next row until the limiting length of sheet flow is reached. Then, all the sheet flow runoff from the solar panel rows is routed to an open channel conduit that represents shallow concentrated flow. This pattern is followed for the rest of the solar farm area, and the conduits are then connected to an outfall. With this general setup, many variables such as the slope of land, slope direction of the solar panels, and rainfall events can be easily modified to understand the effect on hydrology for specific scenarios. In this study, a solar farm in State College, PA is used as a case study to develop the SWMM model. Then, a pre-construction and a post construction solar farm model is developed on SWMM based on the properties of the case study site. Using these models, several simulations were conducted for various design storms to calculate the additional runoff created by the construction of the solar farm. The post construction solar farm model had a higher total runoff volume and a higher max flow than the preconstruction model for all the simulated storm events. The original solar farm SWMM model is then modified to study the hydrology under different solar farm orientations such as varying site slopes and solar panel direction. The framework can serve as an easy tool to study the hydrological response of the catchment before and after the installation of solar farms and to help study runoff and erosion mitigation strategies.