26. The total energy stored in the capacitor bank is

U =

1

2

C

total

V

2

=

1

2

(2000)(5.00

× 10

−6

F)(50000 V)

2

= 1.3

× 10

7

J .

Thus, the cost is

(1.3

× 10

7

J)(3.0 cent/ kW

·h)

3.6

× 10

6

J/ kW

·h

= 10 cents .