The use of renewable energy to improve the sustainability of Southeastern U.S. pond aquaculture: technical, economic, and industry evaluations of solar power options

Final Report for LS05-181

Project Type: Research and Education
Funds awarded in 2005: $14,850.00
Projected End Date: 12/31/2007
Region: Southern
State: Alabama
Principal Investigator:
Barrett Temple-Vaughan
Tuskegee University
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Project Information

Abstract:

A workshop on renewable energy use in pond aquaculture was held to bring together stakeholders to discuss current research findings, potential uses, and research needs. It featured seven notable speakers, and was attended by representatives from the academic, government, and production sectors of catfish industry from the states of Alabama, Georgia, South Carolina, Mississippi, and Arkansas. Though the workshop was a success, there was no firm collaboration formed from the workshop. In addition, there was only moderate interest in potential projects expressed from producers at industry group meetings.

Project Objectives:

1. Bring together the stakeholders to discuss the current research findings, potential uses, and research needs for renewable energy water circulator use in aquaculture

2. Coordinate the writing of the proposal(s) and facilitate collaborations between the stakeholders

3. Extend the current research at Tuskegee University for gathering preliminary data to support a full proposal

Introduction:

The purpose of this planning project is to form collaborations between the stakeholders in the pond aquaculture industry—farmers, processors, industry officials, extension agents, university and government researchers, equipment manufacturers, and electricity providers—to develop full proposals to examine the scientific and economic feasibility of using renewable energy water circulation technologies to improve the sustainability of aquacultural operations. Pond aquaculture in the Southeastern U.S., primary the catfish industry, is profitable but may not be considered sustainable because it requires large inputs of feeds, chemicals, and energy. One recommendation to improve sustainability is to control and minimize electrical aeration use, and technologies that could use renewable energy have shown a potential to be utilized towards that effort (Boyd and Tucker 1995; Tucker and Steeby 1995; Green 2004). The full proposal would leverage ongoing and completed research to develop the experimental, field, and economic studies needed to examine the potential impacts of renewable energy water circulation technology use on aquaculture sustainability.

The sustainability of pond aquaculture, primarily catfish farming, has been a significant topic of study. Boyd and Tucker (1995) assessed the sustainability of channel catfish farming by examining all aspects of production from pond construction to effluent management. They stated that, “since channel catfish farming requires large inputs of feeds, chemicals, and energy, it cannot be considered truly sustainable because it diminishes resource bases”. Ten recommendations were made for improving sustainability; one was that “aeration should be provided, but aerators should be operated only when dissolved oxygen concentrations decline”. Boyd (1999) examined aquaculture sustainability and environmental issues, relaying the results of studies that found that, overall, catfish farming was a “green industry”. Boyd concluded, however, that, “there is urgency for the assessment of environmental impacts of aquaculture so that better management practices can be developed to prevent or mitigate these impacts”.

The use of water circulators in pond aquaculture may be a strategy to address both energy use and environmental (effluent) concerns. Boyd (1998) described the greatest influence of water circulators as “the blending of surface water with subsurface water”. He stated that “water circulation prevents thermal and chemical destratification”, “helps maintain oxygenated conditions at the mud-water interface”, and “stimulates phytoplankton growth” as it establishes a uniform dissolved oxygen profile. Gross et al. (2000) examined nitrogen transformation and balance in channel catfish ponds and noted the environmental benefits of water circulation. They concluded that “water circulation can enhance the rate of nitrification and convert potentially toxic NH3 [ammonia] to NO3 [nitrate] and enhance losses of nitrogen by providing more NO3 for denitrification” as well as “favor NH3 loss from the water via diffusion”. They also conclude that water circulation “will suspend organic matter from the sediment in the water column and the more oxygenated environment in the water as compared to the bottom soil should result in faster organic matter decomposition and less accumulation of organic matter on pond bottoms” (Gross et al. 2000). This is conclusion is particularly significant because Boyd (1999) stated that the ”total suspended solids was the only water quality variable often outside of the normal concentration limits for typical National Pollution Discharge Elimination System (NPDES) permits for effluents” and that one of the three main sources was the erosion of pond bottoms.

Several researchers have evaluated water circulators in aquaculture. Most notably, Howerton et al. (1994) designed a horizontal, axial-flow water circulator for use in channel catfish ponds. Tucker and Steeby (1995) evaluated this water circulator, finding “impressive” reductions in electrical aerator use. In their comparison of aeration requirements between uncirculated control and circulated ponds, they found 456 hours and 265 hours, respectively. These results translated into an overall power use per pond of 6840 kWh for the uncirculated ponds and 3975 kWh for the circulated ponds, a reduction of 42%. The power savings, however, were “substantially offset” by the electrical costs of circulation at 2169 kWh. Howerton et al. (1994) concluded that “although several studies have shown benefits of water circulation, the value of water circulation and the best methods of applying water circulation are not known, and further testing by researchers and “on farm” evaluation by commercial producers is necessary.

These findings have prompted several studies on renewable energy water circulators. Green (2004) at the USDA-ARS Aquaculture Systems Research Unit is evaluating pond-level mechanical methodologies to manage phytoplankton in catfish production ponds. The study will examine several circulators, including a solar powered propeller circulator manufactured by Pump Systems Inc. that is a smaller version of models normally used for lake destratification and wastewater treatment. The unit can circulate up to 2 hectares (5 acres) of water, however, the unit at a cost of $13,000 may not be economically sustainable. Similarly, the principal investigators at Tuskegee University are currently evaluating several solar powered diffused-air circulators at the pilot scale for water circulation and flow rate capabilities. Though the use of diffused air may be the least efficient at aeration (Boyd 1998), it is very capable at moving water. Diffused-air aerators have been proven to be effective for thermal and chemical destratification in large bodies of water (Mackay et al 2003). These units, manufactured by Kelln Solar for livestock-watering dugout aeration, may have lesser capabilities, but cost less than $5,000.

The project generated from this planning project would have the overall goal of finding cost and technically efficient ways of incorporating water circulation technologies into pond aquaculture production. The goal of this planning proposal focuses on moving existing pond aquaculture systems toward sustainable aquaculture. The planning grant will result in the development of a full proposal that is research-based with an educational outreach component to extend the project findings to the public. The full proposal will include pilot, experimental, field scale, and economic evaluations of the capabilities of several solar-powered circulation systems. The field scale evaluations will act as demonstrations of the technologies at actual operating farms, and the ecological and economic benefits to the farmer will be assessed, documented, and shared with our extension collaborators. This project is complementary to other SARE-funded projects in improving of the sustainability of aquaculture, such as those that have examined the management of effluents (OS04-018, SW01-062, FNE00-330, FW00-104, etc.). A Planning Grant is applied for because we wish to plan for the submission of a Research & Education proposal, gain commitments from cooperating institutions and the participation of end-users.

Cooperators

Click linked name(s) to expand
  • Ntam Baharanyi

Research

Materials and methods:

The objectives for achieving the goal of preparing the full proposal(s) entail an approach of (a) developing a technically and economically sound concept and partnerships, (b) generating sufficient supporting work, and (c) guiding the composition of the proposal document.

Objective 1 Bring together the stakeholders to discuss the current research findings, potential uses, and research needs for renewable energy water circulator use in aquaculture

Approach Hold stakeholder gatherings and investigator/collaborator planning meetings in December 2005, February and April 2006 (September, if preproposal is selected)

December 2005 – Mini-symposium at Professional Agricultural Workers Conference (Tuskegee)

A mini-symposium will be held for researchers and industry officials to present their work on sustainable energy options and share ideals. The invitees to the mini-symposium will include our colleagues and representatives from the following stakeholder institutions, agencies, and organizations: Tuskegee University Agricultural and Resource Economics and Cooperative Extension; Auburn University Fisheries and Allied Aquacultures and Agricultural Economics and Rural Sociology; Alabama A & M University Agribusiness; Mississippi State University Agricultural Economics and Agricultural and Biological Engineering; Fort Valley State University College of Agriculture; University of Arkansas at Pine Bluff Aquaculture; Alcorn State University School of Agriculture; USDA-Agricultural Research Service Aquaculture Systems Research Unit (AR) and Stuttgart National Aquaculture Research Center (AR); Alabama Cooperative Extension Service; Mississippi State University Extension Service; Alabama Fish Farming Center; Alabama Farmers Federation; Alabama Catfish Producers; Catfish Farmers of Mississippi; Catfish Farmers of Arkansas; Simply Solar, Inc. (FL); Pump Systems, Inc. (ND); Kelln Solar, Ltd. (Sask., Canada); Vinyard Technology Co. (AL); Southern Pride Catfish LLC; Harvest Select Catfish, Inc.; SouthFresh Farms; Black Warrior Electric Membership Corp.; and Southern Company (MS, AL, GA, Gulf (FL), and Southern Power).

Presentations of current renewable energy research and technologies would ideally be given by: Tuskegee University; Auburn University Fisheries and Allied Aquacultures and Agricultural Economics and Rural Sociology; USDA-Agricultural Research Service Aquaculture Systems Research Unit; Pump Systems, Inc.; Kelln Solar, Ltd.; and Simply Solar, Inc.

Following the presentations, a meeting will be held to initiate the planning of the full (pre)proposal. Possible collaborations will be discussed and the feedback and comments of the attendees will be considered. Possible projects and principal investigators will be identified.

February 2006 – Presentation to Alabama Catfish Producers and Planning Meeting (Alabama)

A presentation on the proposed renewable energy research and work will be given at the Alabama Catfish Producers meeting at the ALFA Alabama Farmers Federation Annual Commodity Group Conference. The purpose will be to inform the producers of the effort and to solicit producer partners for the field evaluations. The second planning meeting of the principal investigators and any prospective producer partners will follow the producers meeting.

April 2006 – Tour of Mississippi and Alabama Pond Aquaculture Farms (East MS and West AL)
A two-day tour of pond aquaculture farms located in eastern Mississippi and western Alabama will be taken by the principal investigators and collaborators. The primary purpose will be to finalize the producer-researcher collaborations.

Objective 2 Coordinate the writing of the proposal(s) and facilitate collaborations between the stakeholders

Approach Host monthly telephone conferences between the principal investigators and collaborators and coordinate the writing and reviews of proposal drafts.

Following the initial meeting in December 2005, monthly telephone conferences will be held beginning in January 2006 until June 2006. Several requests for proposals will be considered, but the primary focus will be the Southern SARE Research and Education Preproposal due in June 2006. The writing and bi-monthly document reviews will be coordinated through electronic word processor drafts, which will be submitted and reviewed by all the investigators and collaborators through electronic mail. If we are selected to submit a full proposal to Southern SARE, the telephone conferences will continue from August 2006 until the submission in November 2006. Other programs such as the USDA CSREES 1890 Institution Research Capacity Building Grant and the USDA Rural Development Renewable Energy Systems and Energy Efficiency Improvements Grant, both due in 2007, will also be considered.

Objective 3 Extend the current research at Tuskegee University for gathering preliminary data to support a full proposal

Approach Evaluate capabilities of a modified solar power diffused-air aerator/circulator

The current research at Tuskegee University evaluating the capabilities of solar powered diffused-air aerator/circulators is funded by the Alabama Department of Economic and Community Affairs. However, this agency limits evaluations to those technologies that are currently commercially available in order to permit the immediate adoption of technologies by the end users—farmers. This objective would allow the extension of the research toward evaluating minor, farmer-accomplishable design modifications of the equipment. The planned modification would be similar to that devised by Boyd (1995) for operating a diffused-air aerator which was placement in a bore hole to control the flow. The modification proposed for this study will be operation of the diffuser within a short, large diameter pipe through which the movement of water from the bubbles will be controlled and concentrated. The modification will be evaluated in an existing 47 m2 tank, and the circulation and flow rate will be measured. These and the unmodified aerator findings will be presented and used to support the full proposal.

Research results and discussion:

Objective 1 Bring together the stakeholders to discuss the current research findings, potential uses, and research needs for renewable energy water circulator use in aquaculture

December 2005 – Mini-symposium at Professional Agricultural Workers Conference (Tuskegee)

The mini-symposium was held for researchers and industry officials to present their work on sustainable energy options and share ideals. The invitees and presenters to the mini-symposium did include colleagues and representatives from a variety of stakeholder institutions, agencies, and organizations. Represented were Tuskegee University, Auburn University, Mississippi State University, Fort Valley State University, Clemson University, USDA-Agricultural Research Service, World Wildlife Fund, Alabama Fish Farming Center, Alabama Farmers Federation, and the Alabama Catfish Producers.

Following the presentations, a meeting was held to discuss the presentations and initiate the planning of possible collaborations

February 2006 – Presentation to Alabama Catfish Producers and Planning Meeting (Alabama)

A presentation on proposed renewable energy research and work was be given at the Alabama Catfish Producers meeting at the ALFA Alabama Farmers Federation Annual Commodity Group Conference. The purpose was to inform the producers of the effort from the mini-symposium and to solicit producer partners for the field evaluations. There was only moderate interest among the producers at that meeting.

Objective 2 Coordinate the writing of the proposal(s) and facilitate collaborations between the stakeholders

Following the initial meeting in December 2005, there was no firm collaborations formed between the stakeholders that attended and presented.

Objective 3 Extend the current research at Tuskegee University for gathering preliminary data to support a full proposal

This objective would have allowed the extension of the research toward evaluating minor, farmer-accomplishable design modifications of the equipment. However, the ADECA funded research project was extensively delayed to do purchasing issues. This objective was not accomplished.

Participation Summary

Project Outcomes

Project outcomes:

To date, the project has had few demonstrable impacts. The workshop was successful at bringing together the stakeholders, but little was catalyzed. At the time of this writing, September 2009, Tuskegee University is working with one farmer in using renewable energy for circulation with caged culture. We expect that by gathering preliminary data first and releasing our results that we may be able to gather collaborator and producer interest for future proposal submissions.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.