MN DNR Letters

Soon after returning from San Diego, Ted Christopher began consulting with key officials at the Minnesota Department of Natural Resources. 


Charles Anderson, PhD | Fisheries Research Program Supervisor

Mr. Ted Christopher,


            Your vertical axis hydroelectric turbine design remarkably minimizes risk to fish and wildlife. It appears completely free of risk from pinch points and grinding, or sudden or large pressure changes, and the upstream moving fins would move relatively slowly and are curved so as to pose very little risk of striking. Those are the major sources of mortality in conventional hydroelectric turbines.


I hope you have good luck moving to prototype and production.




Dr. Luther Aadland, PhD | River Ecologist in the DNR Division of Ecological Services and Waters

Comments on Ted Christopher’s Turbine:


            I was very impressed with the design of the vertical shaft turbine. I also believe it could be implemented with minimal environmental impact. While any structure in a river displaces habitat, the design eliminates the most damaging aspects of traditional hydropower. Without the need for dams, the turbine would not affect fish passage, inundate habitat, alter temperature or nutrient regimes, or adversely affect channel stability as do dams and reservoirs.


The only apparent affect would be direct occupation of space. Avoidance of critical habitat areas or installation of high densities of turbines in a reach would help to minimize adverse effects. Placement slightly above the stream bed would allow benthic invertebrates to colonize under the turbine and would avoid problems with sediment transport and mobile stream beds.


I think the potential for this design is substantial, especially if it can replace existing or proposed conventional hydropower associated with dams. Even greater is its potential to harness tidal flow. With the caveat of proper application, this may be one of the most environmentally friendly means of power production I’ve seen.


Luther Aadland, PhD

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