PRT small system energy consumption calculations, for Palo Alto 18 station, 5 mile system

Calculate: worst case peak hourly electric load for 300 vehicles.  Worst case is the basis for purchasing electricity.

 

 

 

kW per accelerating vehicle

11

Assumes 15 hp vehicle @ 0.746E3 Watts/hp

% of accel. kW used by coasting vehicles

40

 

kW per coasting vehicle

4.4

 

# vehicles in system @ peak

300

 

% of vehicles accelerating

25

Includes vehicles leaving stations and climbing hills

% of vehicles coasting

75

 

kW per 300 vehicle fleet @ peak hour

1815

kW accelerating * # accelerating + kW coasting * # coasting

 

 

 

Calculate: worst case 24 hour electric load.  Each of 24 hours uses a % of peak.

Hour of the day

% of peak

 

1AM

10.0%

 

2AM

10.0%

 

3AM

10.0%

 

4AM

10.0%

 

5AM

16.7%

 

6AM

16.7%

 

7AM

58.3%

 

8AM

100.0%

 

9AM

66.7%

 

10AM

33.3%

 

11AM

75.0%

 

12 noon

83.3%

 

1PM

83.3%

 

2PM

33.3%

 

3PM

33.3%

 

4PM

33.3%

 

5PM

66.7%

 

6PM

100.0%

 

7PM

58.3%

 

8PM

16.7%

 

9PM

16.7%

 

10PM

10.0%

 

11PM

10.0%

 

12 midnite

10.0%

 

TOTAL

961.7%

 

kWh per Palo Alto per 250 weekdays

17,454

 

kWh for 250 weekdays

4,363,563

 

% of electricity used in 115 "off days"

40

 

kWh for 114 off days

795,914

 

Total annual kWh used

5,159,476

 

 

 

 

Calculate: Electricity cost

 

 

Electricity cost per kWh

$0.12

Could range from $0.02 to $0.16

Electricity cost per year

$619,137.16

 

 

 

 

Check calcs against Ed Anderson's paper, “What Determines Transit Energy Use?”

First loop avg trip distance (in miles)

1

 

Second loop avg distance

2

 

avg trip distance (first & second loops)

1.5

Assumes 50% of trips use 1 loop, 50% use two loops

trips per day

26,000

 

passenger miles per day

39,000

 

456 watt-hours per passenger mile

456

40% empty vehicle miles (deadheading) is accounted for.

Total daily kWh

17,784

 

Annual kWh for 314 days

5,584,176

Taxi 2000's rule of thumb is 314 days per year

Electricity cost per kWh

$0.12

Could range from $0.02 to $0.16

Electricity cost per year

$670,101.12

 

 

 

 

What Determines Transit Energy Use? J. Edward Anderson.  Journal of Advanced Transportation, Vol 22 No 2, 1988.  pp 108-133.