． Small or medium scales power generation plant operated by amateur users
． Power generator close to loading for self-supply or power supplemental.
． Both PV and SWT are of distributed power generation

．Global market size of PV is 10% more than LWT and 100 times more than SWT.
．SWT market is confined to use in rural area.
．Power generation cost of PV is 15 times of LWT and 3 times of SWT.

	Installed cost (US$/W)	Electricity Cost (US$/kWh)	Pay back Yrs	Potential Cost Yr 2010 (US$/W)	Typical Site	Global Market Size(Billion US$)
LWT	0.9~1	0.035			Remote Area	>8
PV	8	0.61	25	3.0	Suburban	>9
SWT	4	0.22	15	1.5	Rural	<0.1