Environmental Engineering and Earth Sciences

Falta Receives Major Research Projects from ESTCP and SERDP

Subsurface thermal energy storage using boreholes could allow solar thermal power plants to generate electricity at night and on cloudy days

EEES Professor Ron Falta was recently awarded $2M by the Environmental Security Technology Certification Program (ESTCP) for a research project entitled High Temperature Subsurface Borehole Thermal Energy Storage.  One of the main challenges facing the transition to a low carbon economy is finding ways to economically store surplus energy so that it is available when energy demand exceeds supply.  Falta and his team, including EEES Professor Dr. Larry Murdoch, will be developing and field testing an innovative technology for storing practically unlimited amounts of thermal energy safely in the ground using closed-loop borehole heat exchangers.  The heat exchangers transfer heat to the subsurface when energy supply exceeds demand and then extract that heat when demand exceeds supply.  The ultimate goal of this project is to develop a storage system that allows solar thermal power plants to operate for long periods when the sun is not shining.  A small experimental system will be constructed near the Clemson campus to test heat exchanger designs.  Then a large-scale pilot storage system will be built and tested at a military base.  The project will be the first application of borehole heat exchangers at high temperatures (150-250oC).

ESTCP is an environmental technology demonstration and validation program funded by the Department of Defense. The Program was established in 1995 to promote the transfer of innovative technologies that have successfully established proof of concept to field or production use. ESTCP demonstrations collect cost and performance data to overcome the barriers to employ an innovative technology.

Professor Falta recently received a second grant ($840k).  This one is funded by the US Navy through Strategic Environmental Research and Development Program (SERDP) for a project entitled Development of a Practical Modeling Platform for Assessing Saltwater Intrusion Impacts under Future Sea-Level Change Scenarios.  Climate change is resulting in rising sea levels, which is threatening freshwater aquifers located close to coastal areas.  This is a major concern for the Department of Defense, which has over 1,800 coastal installations worldwide. Many of these bases rely on groundwater as a source of drinking water and other uses.  Falta, with his co-investigators at the Navy, the Technical University of Delft, GSI Environmental, and Aquaveo will be developing computer models to predict the extent of this problem as sea levels rise.  A better understanding of saltwater intrusion is a critical first step in developing strategies to mitigate the impacts.

SERDP is Department of Defense’s environmental science and technology program, planned and executed in full partnership with the Department of Energy and the Environmental Protection Agency, with participation by numerous other federal and non-federal organizations.

Dr. Falta is the principal investigator of an ongoing $860k ESTCP project titled Incorporating Matrix Diffusion in the New MODFLOW Flow and Transport Model for Unstructured Grids.  Matrix diffusion is a groundwater contaminant transport process that occurs in fractured rocks and other heterogeneous systems.  Dissolved contaminants diffuse from fractures into the rock matrix where they serve as long term sources of contamination.  Falta developed a new mathematical technique for approximating this process in numerical models, and this project focuses on implementing that method in the popular MODFLOW groundwater modeling software. This work is a collaboration with the companies GSI Environmental and Aquaveo.

Professor Falta is also a co-principal investigator on a $360k ESTCP project in collaboration with the consulting firm Arcadis.  The project, entitled Thermal In Situ Sustainable Remediation (TISR) To Enhanced Biotic and Abiotic Reactions and Accelerate Remediation, seeks to demonstrate the low-temperature solar-powered thermal technology known as Thermal In Situ Sustainable Remediation (TISR).  The goal of TISR is to accelerate treatment of groundwater pollutants by enhancing biotic and abiotic contaminant degradation rates by modest increases in subsurface temperatures.  Dr. Falta and his team are developing computer models to predict the profile of subsurface heating that will occur in response to circulation of warm water through borehole heat exchangers.  Dr. David Freedman is contributing to this project by measuring the impact of temperature on biotic and abiotic degradation rate constants using laboratory microcosms.