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Japan Power Transportation

Six Electric Cars Can Power an Office Building 296

Posted by timothy
from the sinks-and-sources dept.
cartechboy writes "How many Nissan Leafs does it take to power an office building? The answer, it turns out, is six. Nissan is the latest Japanese automaker to explore electric "vehicle-to-building" setups, this time with impressive results. The company started testing its latest system at the Nissan Advanced Technology Center in Atsugi City, Japan, during the summer. It found that just six Leafs plugged in to the building's power supply allowed it to cut peak-hour electricity use by 2 percent. Annualized, that's a savings of half a million yen (about $4,800 US) in electricity costs. How it works: The building pulls electricity from the plugged-in vehicles during peak-use hours, when power is most expensive, and then sends the power back to recharge the cars when grid prices fall. Nissan says the system is set up to ensure the cars are fully charged by the end of the workday. (Is this a devious secret way to make sure workers stay until a certain time?) Next up: Why not just do this using batteries--never mind the cars?"
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Six Electric Cars Can Power an Office Building

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  • by ZorinLynx (31751) on Thursday December 12, 2013 @01:22PM (#45671911) Homepage

    A Tesla Model S sitting in a garage has enough energy onboard to run a typical single family home for many days. It's pretty impressive just how much energy our automobiles use when we're driving them; they put the power consumption of homes and small buildings completely to shame.

  • by Saethan (2725367) on Thursday December 12, 2013 @01:24PM (#45671931)

    How many Nissan Leafs does it take to power an office building? The answer, it turns out, is six.

    cut peak-hour electricity use by 2 percent

    So the answer, it turns out, is actually 300.

  • Re:Check that title (Score:5, Informative)

    by pla (258480) on Thursday December 12, 2013 @01:32PM (#45672053) Journal
    Looks like 6 cars can offset about 2% of this office's power usage. Hardly 'powering' the whole office.

    You misunderstand - Businesses don't pay for electricity like residential users. They pay by usage per demand timeslot. So they may pay a rate of $0.05/KWH for 80% of the day, $0.12/KWH for another 18%, then for the remaining 2% (around 15 minutes) that shoots up to $0.45/KWH.

    This study found that you can run the entire building for those 15 peak demand minutes on six cars. Those 15 minutes amounts to way more than 2% of the business' electric bill (more like 10-15%), however, thus the huge net savings.
  • by LoRdTAW (99712) on Thursday December 12, 2013 @02:40PM (#45672801)

    During Sandy we needed a temporary backup generator at work. We have multiple electron beam welding machines, electric heat treating oven, laser welding machines etc. Our building service is 1200A 120/208 three phase which works out to roughly 432kW. We pull about half of the panel rated load, or 600 amps on average and close to 800 peak. A towed 500kW CAT genset was hooked up and had a 15 liter engine, same as a the average semi truck. Ran the whole building without breaking a sweat. So a semi truck can run a small factory.

    1HP is roughly 746 electrical watts. the Nissan Leaf has a 110HP motor which uses ~80,000 watts at peak output. The average American home has a 100 or 200 amp 120/240 electrical service. 240V * 200A = 48,000 Watts, which isn't used constantly but with enough creature comforts, consumption can run pretty high (AC, electronics, lights, appliances, pool filters etc.). So when you put your foot down in the Leaf, you are pulling 2x - 3x+ more current than a household can provide. Gives you some perspective.

  • by Obfuscant (592200) on Thursday December 12, 2013 @04:01PM (#45673785)

    I haven't read TFA, but someone else posted that 6 ran the entire building for 2% of the peak day.

    Then THEY didn't RTFA either. Quoting from it:

    The benefits may only be slight--Nissan says it cuts peak-hour electricity use by about 2.5 percent--

    "Cut electricity use by 2.5%" is NOT "provided all electricity for 2.5% of the day". Pick a number for peak use. Take 97.5% of that. That's how much you're still using from the grid.

    So 6 can run the entire building, but not for long.

    For those six cars to be able to provide full service to the building for ANY part of the day, the use at that time would have to be 0.025 times the peak use. One fortieth of the peak. I don't know the ratios between peak use and minimum use for normal office buildings, but I'm guessing with data centers that run 24/7 the ratio doesn't make it to 1/40.

    One poster went into a long discussion about how businesses pay for electricity to try to support the numbers, but since the article uses the 2.5% number referring to quantity and not total cost, that explanation falls flat.

    You don't even need to RTFA to see what the actual claim was. Simply RTFS.

  • Re:Why not batteries (Score:2, Informative)

    by Anonymous Coward on Thursday December 12, 2013 @05:19PM (#45674543)

    This is completely incorrect. In the US there is not a single state where commercial is more expensive than residential. Facts located here: http://www.eia.gov/electricity/monthly/epm_table_grapher.cfm?t=epmt_5_6_a

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