381
Power and Energy Directly from Water
turbine blade can be designed to accommodate flow rate; it could be long and
broad for slow-moving deep currents or it could be short and thin for fast-moving
shallow currents.
The turbine is horizontally mounted on a barge and partially submerged into the
water flowing beneath the barge. The barge on which turbines are mounted is able
to cope with fluctuations in water levels, substantial velocity increases, and direct
impact from large and fast-moving debris. The power output from the turbine would
decrease only when the water flow rate underneath the barge goes down. The barge
generates 1 MW and produces 8760 MWh electricity annually at a maximum rating
through a synchronous AC induction generator.
The power barge has very low maintenance cost and downtime and life span of
about 20 years. These barges can be deployed in rivers such as Mississippi, Amazon,
and Nile. Different designs of the barges from different countries (the United
Kingdom, Belgium, and Australia) are illustrated by alternative energy website news
publication [52].
13.3.3.6 Criteria for Choice of a device and its location
Generally, the following criteria and considerations are used to decide on the choice
and size of a device and its location [34–65] (Bertsch, 2012, pers. comm.; Dixon
et al., 2008, pers. comm.) *,† :
1. The use of hydrokinetic energy devices needs to carefully consider local
environmental implications, economics, and competing users of the site
chosen. The needs of users such as fishermen, shipping vessel operators,
recreational boaters, and coastal citizen groups need to be factored in
choosing the appropriate site for the recovery of hydrokinetic energy.
2. The device may affect the habitats of benthic animals and plants like oysters, clams, and sea grass; the potential for fish strikes or impingement on
device; and the effect of noise on movement and migration of aquatic animals or even alteration of hydrologic and sediment regimes. With careful
selection of location, these impacts can, however, be minimized.
3. The cost of electricity produced by these devices depend on the power density of stream (kW/m 2 ) or wave crest (kW/m crest height), the distance that
electricity must be transmitted to reach consumers, access of the site for
maintenance and monitoring and availability of the site for federal subsidy,
project financing, or guarantee market for the produced electricity.
4. In general, stronger currents and large wave heights will reduce the cost
of the hydrokinetic electricity. The hydrokinetic devices require minimum
* Hydrokinetic energy was included as an eligible renewable energy resource by the Energy Policy Act
of 2005. Various funding authorizations for research and development were also included in this Act as
well as the Energy Independence and Security Act of 2007.
† Bertsch, D.J., Juris Doctoral candidate, The University of South Dakota School of Law, 2011; Congress
defined hydrokinetic energy as “electrical energy from waves, tides, and currents in oceans, estuaries, and tidal areas; free flowing water in rivers, lakes, and streams, or man-made channels; and differentials in ocean temperature (ocean thermal energy conversion),” The Energy Independence and
Security Act of 2007, 42 USC §17211 (2006).
Power and Energy Directly from Water
turbine blade can be designed to accommodate flow rate; it could be long and
broad for slow-moving deep currents or it could be short and thin for fast-moving
shallow currents.
The turbine is horizontally mounted on a barge and partially submerged into the
water flowing beneath the barge. The barge on which turbines are mounted is able
to cope with fluctuations in water levels, substantial velocity increases, and direct
impact from large and fast-moving debris. The power output from the turbine would
decrease only when the water flow rate underneath the barge goes down. The barge
generates 1 MW and produces 8760 MWh electricity annually at a maximum rating
through a synchronous AC induction generator.
The power barge has very low maintenance cost and downtime and life span of
about 20 years. These barges can be deployed in rivers such as Mississippi, Amazon,
and Nile. Different designs of the barges from different countries (the United
Kingdom, Belgium, and Australia) are illustrated by alternative energy website news
publication [52].
13.3.3.6 Criteria for Choice of a device and its location
Generally, the following criteria and considerations are used to decide on the choice
and size of a device and its location [34–65] (Bertsch, 2012, pers. comm.; Dixon
et al., 2008, pers. comm.) *,† :
1. The use of hydrokinetic energy devices needs to carefully consider local
environmental implications, economics, and competing users of the site
chosen. The needs of users such as fishermen, shipping vessel operators,
recreational boaters, and coastal citizen groups need to be factored in
choosing the appropriate site for the recovery of hydrokinetic energy.
2. The device may affect the habitats of benthic animals and plants like oysters, clams, and sea grass; the potential for fish strikes or impingement on
device; and the effect of noise on movement and migration of aquatic animals or even alteration of hydrologic and sediment regimes. With careful
selection of location, these impacts can, however, be minimized.
3. The cost of electricity produced by these devices depend on the power density of stream (kW/m 2 ) or wave crest (kW/m crest height), the distance that
electricity must be transmitted to reach consumers, access of the site for
maintenance and monitoring and availability of the site for federal subsidy,
project financing, or guarantee market for the produced electricity.
4. In general, stronger currents and large wave heights will reduce the cost
of the hydrokinetic electricity. The hydrokinetic devices require minimum
* Hydrokinetic energy was included as an eligible renewable energy resource by the Energy Policy Act
of 2005. Various funding authorizations for research and development were also included in this Act as
well as the Energy Independence and Security Act of 2007.
† Bertsch, D.J., Juris Doctoral candidate, The University of South Dakota School of Law, 2011; Congress
defined hydrokinetic energy as “electrical energy from waves, tides, and currents in oceans, estuaries, and tidal areas; free flowing water in rivers, lakes, and streams, or man-made channels; and differentials in ocean temperature (ocean thermal energy conversion),” The Energy Independence and
Security Act of 2007, 42 USC §17211 (2006).