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 watthours 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 108133. 