Harnessing Ocean Energy from Coastal and Offshore Pakistan

There is potential for harnessing renewable energy from coastal waves and tides, from the coastal and offshore areas of Pakistan. The Sindh coast is a complex creek network located in the 170 km of the Indus deltaic area. The flood and ebb of tides in and out of these creeks have a high velocity of 0.2–0.5 m/s. NIO Pakistan has conducted preliminary feasibility surveys for energy extraction from the Indus deltaic creek system. The 17 major creeks have the capacity to produce estimated energy of approximately 1100 MW. The seawater ingresses inland at some places up to 80 km due to the tidal fluctuation, which is favorable for energy extraction from tidal currents in coastal Sindh. In total, 71% of our Planet Earth is covered by the oceans. The oceans are massive collectors of solar radiation received from the sun. The oceans store the potential energy that is received in the form of incident radiation from the sun that generates thermal energy. A 10 °C temperature difference can be harnessed between the surface and bottom water, using a working fluid. The thermal difference absorbed by the oceans can be converted into electricity through ocean thermal energy conversion (OTEC). The ocean tidal and wave energy has advantages over energy produced using different fossil fuels; there are also several benefits of using renewable sources of ocean energy. Viability of ocean energy in Pakistan is discussed in this paper.

Blandford-Znajek mechanism in the general stationary axially-symmetric black-hole spacetime

We consider the Blandford-Znajek process of electromagnetic extraction of energy from a general axially symmetric asymptotically flat slowly rotating black hole. Using the general parametrization of the black-hole spacetime we construct formulas for the flux of the magnetic field and the rate of energy extraction, which are valid not only for the Kerr spacetime, but also for its arbitrary axially symmetric deformations. We show that in the dominant order these quantities depend only on a single deformation parameter, which relates the spin frequency of a black hole with its rotation parameter.