this is from my fluid mechanics class! fyi

A remarkable amount of energy is available from the salinity-gradient energy between sea water and fresh water. It is estimated about 2 terawatts available globally from rivers flowing into the sea. Several approaches to capture salinity-gradient energy are being developed, one of the most promising one is the pressure-retarded osmosis (PRO). A conceptional diagram is illustrated in Figure 6 , the diluted seawater flows with a flow rate of 40ft3/s from an elevated reservoir through a conduit to a turbine at a lower level and out of the turbine through a similar conduit. From this conceptional estimation. the pressure difference between seawater side and fresh water side in a PRO system is converted to liquid level difference. The seawater level is 400ft above the fresh water level. The friction loss in the line is 50ft1bf/1bm. If the efficiency of the turbine in converting the mechanical energy given up by the fluid to the turbine shaft is 70%(1=0.7). Assume the density difference between seawater and fresh water can be neglected. Estimate the power in Mega Watt (MW) to be generated from this PRO system throus