A hydroelectric generator small enough to be worn as a backpack weighs less than 30 lb and is designed to generate up to 500 W. The Backpack Power Plant (BPP) will operate in streams at least four feet deep where the water is running at 2.3 m/sec.
Installation of a BPP starts with the digging of two trenches on opposite sides of the stream into which a lightweight anchor is inserted. A rope is then strung between the anchors onto which the hydropower plant is hung.
Bourne Energy in Malibou, Calif., came up with the BPP and says it is based on the high-tension mooring systems that hold up floating oil rigs. Further, BPPs can be set up in arrays to generate more than 30 kW of power.
The BPP will cost a mere $3,000. Bourne plans to make a military version able to generate 600 W and weighing less than 25 lb. The military version can also be bottom-mounted to be completely invisible. More info:
http://www.bourneenergy.com/futuremain.html#SPP