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PRT small system energy consumption calculations, for Palo Alto 18 station, 5 mile system |
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Calculate: worst case peak hourly electric load for 300 vehicles. Worst case is the basis for purchasing electricity. |
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kW per accelerating vehicle |
11 |
Assumes 15 hp vehicle @ 0.746E3 Watts/hp |
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% of accel. kW used by coasting vehicles |
40 |
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kW per coasting vehicle |
4.4 |
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# vehicles in system @ peak |
300 |
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% of vehicles accelerating |
25 |
Includes vehicles leaving stations and climbing hills |
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% of vehicles coasting |
75 |
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kW per 300 vehicle fleet @ peak hour |
1815 |
kW accelerating * # accelerating + kW coasting * # coasting |
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Calculate: worst case 24 hour electric load. Each of 24 hours uses a % of peak. |
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Hour of the day |
% of peak |
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1AM |
10.0% |
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2AM |
10.0% |
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3AM |
10.0% |
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4AM |
10.0% |
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5AM |
16.7% |
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6AM |
16.7% |
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7AM |
58.3% |
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8AM |
100.0% |
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9AM |
66.7% |
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10AM |
33.3% |
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11AM |
75.0% |
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12 noon |
83.3% |
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1PM |
83.3% |
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2PM |
33.3% |
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3PM |
33.3% |
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4PM |
33.3% |
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5PM |
66.7% |
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6PM |
100.0% |
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7PM |
58.3% |
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8PM |
16.7% |
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9PM |
16.7% |
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10PM |
10.0% |
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11PM |
10.0% |
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12 midnite |
10.0% |
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TOTAL |
961.7% |
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kWh per Palo Alto per 250 weekdays |
17,454 |
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kWh for 250 weekdays |
4,363,563 |
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% of electricity used in 115 "off days" |
40 |
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kWh for 114 off days |
795,914 |
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Total annual kWh used |
5,159,476 |
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Calculate: Electricity cost |
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Electricity cost per kWh |
$0.12 |
Could range from $0.02 to $0.16 |
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Electricity cost per year |
$619,137.16 |
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Check calcs against Ed Anderson's paper, “What Determines Transit Energy Use?” |
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First loop avg trip distance (in miles) |
1 |
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Second loop avg distance |
2 |
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avg trip distance (first & second loops) |
1.5 |
Assumes 50% of trips use 1 loop, 50% use two loops |
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trips per day |
26,000 |
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passenger miles per day |
39,000 |
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456 watt-hours per passenger mile |
456 |
40% empty vehicle miles (deadheading) is accounted for. |
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Total daily kWh |
17,784 |
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Annual kWh for 314 days |
5,584,176 |
Taxi 2000's rule of thumb is 314 days per year |
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Electricity cost per kWh |
$0.12 |
Could range from $0.02 to $0.16 |
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Electricity cost per year |
$670,101.12 |
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What Determines Transit Energy Use? J. Edward Anderson. Journal of Advanced Transportation, Vol 22 No 2, 1988. pp 108-133. |
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