Modifications at TECO’s Big Bend plant affect desal plant operations
Tampa Bay Water has been studying the feasibility of expanding its desalination operations to provide an additional 10-15 million gallons per day (mgd) of drinking water to the region. However, changes at Tampa Electric’s (TECO) Big Bend Power Plant in Apollo Beach, where the Tampa Bay Seawater Desalination Facility is co-located, are impacting not only expansion plans for the Tampa Bay Water’s desalination facility, but also its current water production capacity.
TECO is modernizing its Big Bend Power Plant in Apollo Beach to minimize the use of coal for electricity production. Modifications include retiring two of four cooling water tunnels. While these modifications will benefit the environment by improving land, water and air emissions at the Big Bend Power Plant, they will impair Tampa Bay Water’s desalination operations if the water utility does not also make modifications.
Tampa Bay Water uses TECO’s cooling water tunnels for the desal plant’s intake and discharge. The tunnels provide the desalination plant’s seawater supply in addition to diluting the concentrated seawater leftover from the desalination process. Concentrated saltwater must be diluted before it can be returned to the bay.
Tampa Bay Water has been working to restore a reliable supply of seawater to the plant. This $16 million project scheduled to be completed by late 2023 will create a new intake connection and extend the current intake connection to our facility and include a pump station and a pipeline. However, this project does not solve the issue of reduced blending water for diluting the concentrated discharge. Without a solution to the reduction in blending water, the desalination plant could be limited to 16 mgd on a consistent basis.
Additionally, TECO’s changes may also limit when the desalination plant can operate throughout the year. Tampa Bay Water typically relies more on water from the desal plant during the fall and spring dry seasons. TECO’s changes will result in less cooling water being available during those months, which are also when TECO has lower power demands.
Tampa Bay Water and its consultants are looking at several potential options to regain production capacity at the desalination plant by addressing the concentrate discharge limitations. Tampa Bay Water will present those options to the Board later in 2022, along with options to expand this important regional water supply facility.