Economic of power generation 10

 Question= Compare the annual cost of supplying a factory load having a maximum demand of 1 megawatt and a load factor of 50% by energy obtained from (1) a private oil engine generating plant ? and (2) public supply ? 

(1) detail of private oil engine generating unit =capital cost=RS 12×10⁵ , cost of repair and maintenance = RS 0.005 per kwh generated , cost of fule = RS 1600 per 1000 kg , interest and depreciation = 10% per annum, fule consumption = 0.3 kg/kwh generated, wages = RS 50,000 per annum,, (365days×24 hours = 8760 hours)

 (2) public supply company , RS 150 per kw of maximum demand plus 15 paise per kwh. 

Solution= 1 st compare = total annual running charges = annual cost of fuel + annual cost of repair and maintenance + annual wages +  annual interest and depreciation .

• annual cost of fuel = annual fule consumption × RS 1600 per 1000 kg , 

» annual fule consumption = unit generated per annum  × fuel consumption (0.3 kg/kwh) ,  

» so, units generator per annum = M D. × L. F. × Hours in a year.= 1 mw × 50% × 8760 , = 438× 10⁴ , kwh , 

» annual fule consumption = 438× 10⁴ × 0.3 kg , = 13.14× 10⁵ kg, 

» annual cost of fuel = 13.14×10⁵  kg× 1600/1000 = 21,02400 RS , (add) .

• annual cost of repair and maintenance= unit generated per annum × cost of repair and maintenance (RS 0.005 per kwh generated) , 

» so, annual cost of repair and maintenance= 438×10⁴ ×0.005 = 21,900 RS , (add)

• annual wages = 50,000 RS (add) , 

• annual interest and depreciation = capital cost × interest and depreciation (10%) , 

» annual interest and depreciation =capital cost ×interest and depreciation (10% per annum) , =12×10⁵ × 0.1 = 1,20,000 RS (add) .

•So, total annual charges=  21,02400+21,900+50,000+1,20,000 = 22,94,300 RS, answer ✓

(2) public supply =

• total annual charges = Annual fixed charges+ annual running changes , 

» annual fixed charges= M.D. × RS 150 per kw of maximum demand = 1 mw × 150 RS , = 1,50,000 RS , (add)

» annual running charges= 15 paise per kwh. × unit generated per annum , = 0.15 × 438×10⁴ = 6,57,000 RS, (add)

» So , total annual charges = 1,50,000 + 6,57,000 = 8,07000 RS , answer ✓