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Japan

Japan Wants To Boost the Use of Electric Vehicles as a Power Source During Natural Disasters (qz.com) 74

Japan, a country which frequently suffers natural calamities such as tsunamis, typhoons, and earthquakes is looking to further harness the power of batteries used in electric vehicles (EVs) during such disasters, local media reports. From a report: Nissan, which produces the Leaf, the world's best-selling EV model, plans to hold an event in March to let people stay overnight in their cars and try using the electricity stored in their car batteries to simulate the experience of being in an emergency, according to Japanese newswire Jiji. A fully charged electric vehicle can supply power to a standard home for up to four days, a Nissan official told the news outlet. The company last year came to an agreement with Tokyo's Nerima Ward and the city of Yokosuka to provide EVs for free in emergency situations. Nerima also last year (link in Japanese) implemented a system whereby owners of EVs would be able to loan their vehicles out for free to those in need during a disaster, and also started using EVs for its fleet of police patrol cars.
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Japan Wants To Boost the Use of Electric Vehicles as a Power Source During Natural Disasters

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  • by psergiu ( 67614 ) on Thursday February 21, 2019 @01:54PM (#58159176)

    ... implemented a system whereby owners of EVs would be able to loan their vehicles out for free ...

    Mandatory or voluntary ?

    • Considering the statistics on natural disasters, you might get actually paid in lower energy prices. It's all a matter of averages. Get an X % discount for being ready to help someone once every few years? Kind of makes sense.
    • Re: (Score:1, Troll)

      by AmiMoJo ( 196126 )

      In Japan everyone pulls together in the event of a natural disaster. Some of it is legal requirements, such as being required to leave the keys in your car if you abandon it so that emergency services can move it, and some of it is just people doing the right thing.

      For example many vending machines switch to free vend in the event of an emergency, and some even offer charging for mobile phones. I'm sure many drivers would be happy to loan their battery to where it is needed, e.g. evacuation centres or medic

      • by rtb61 ( 674572 )

        It would still make more sense to subsidise solar panels on house roofs and fit them with batteries. They can keep generating electricity and all you need is an extension lead from any house, whose home power system is still running.

      • by AmiMoJo ( 196126 )

        Okay, this is weird. Who was triggered by this post? I mean how can someone be upset enough by it to label it "troll"?

        Is this just straight up abuse, a stalking systematically hitting all my posts, or have we found some new species of snowflake?

  • by foxalopex ( 522681 ) on Thursday February 21, 2019 @02:18PM (#58159328)

    Not many people realize how much power EVs are capable of. I own a Chevy Volt which is a mixed battery / gas generator type vehicle and so I have a view of exactly what KWatt's I use when I drive around on my dashboard. Your average house rarely exceeds 10 KWatts at peak power use. Travelling on a straight highway uses about 21 Kwatts of power while slow speed urban driving can be as low as 7 Kwatts. Volt's peak battery output is around 107 Kwatts which could easily cover several houses all at once, it's amazing to think that's how much power is used when a car is accelerating. The Volt's gas engine / generator is about 80hp which is way above any of your camping portable generators which are probably a measly 1-4 hp. The issue is how to hook up the house power safely. Volt's primary power line off the battery is about 360v DC with enough amperage to more than put you in the grave. Unless the car maker safely designed a way to tap the system, it's difficult to do.

    • by Solandri ( 704621 ) on Thursday February 21, 2019 @02:56PM (#58159592)
      Every time I point this out, the EV advocates mod me down. The Nissan Leaf comes with a 40 kWh battery, approximately 80% of which is usable (32 kWh). Charging efficiency happens to be about 80%, so you need to use about 40 kWh of electricity to top the battery off with 32 kWh.

      The average American home uses 10,399 kWh in a year [eia.gov], or about 28.5 kWh per day. (Apparently a typical Japanese home uses a lot less.) So half-charging a Leaf every day (roughly 50 miles/day use) increases household electricity consumption by (20 kWh / 28.5 kWh) = 0.7 = 70%. Since all that additional electricity consumption happens overnight, if every house has an EV then suddenly the peak electricity consumption period switches from mid-day to overnight. And the lower electricity prices people are expecting to pay to recharge their EV evaporates. Moreso if there's significant solar power generation in the grid. Since solar provides electricity only during the day, the electricity during night to charge all these EVs will have to come from generators the power companies can spool up to meet the overnight demand spike. (Storing solar power in batteries for overnight use is not cost-effective unless solar generation exceeds 100% of daytime consumption. It makes no sense to run other power generators during the day just so you can store solar power in batteries for use during the night, when you can just use the solar power directly during the day (avoiding battery losses) and run the other power generators during the night.)

      Meaning you're going to be paying the highest electricity rates to charge your EV, not the lowest. Modding me down doesn't change this truth. The same truth that lets your EV battery power your home for more than a day, also means the power pricing peak will invert when every home has an EV charging overnight.
      • The average American home uses 10,399 kWh in a year

        That's because an average American home is crap when it comes to efficiency. [shrinkthatfootprint.com]

        Since all that additional electricity consumption happens overnight, if every house has an EV then suddenly the peak electricity consumption period switches from mid-day to overnight. And the lower electricity prices people are expecting to pay to recharge their EV evaporates. Moreso if there's significant solar power generation in the grid. Since solar provides electricity only during the day, the electricity during night to charge all these EVs will have to come from generators the power companies can spool up to meet the overnight demand spike.

        Have you considered the possibility of charging *during the day*? It almost makes too much sense to store the surpluses, doesn't it? And consequently it makes too little sense to charge overnight. Thus no "overnight demand spike" is necessarily bound to happen.

        Storing solar power in batteries for overnight use is not cost-effective unless solar generation exceeds 100% of daytime consumption.

        Sooner or later, this excess generation is going to happen if the cost of solar generators becomes so low that using them pays off even despite not using their full output.

      • You make several valid points, but you miss one of the biggest issues: residential energy consumption is much less than all other uses.

        As a simple example, peak electrical demand late at night is about 20GW in California, divided by approximately 12 million households = 1.7kW/household. At that same time, the average household is consuming less than 0.5kW. You can do a similar calculation at different times of day, but residential energy consumption is really only about 1/3 of the total, even in a state

      • Since all that additional electricity consumption happens overnight, if every house has an EV then suddenly the peak electricity consumption period switches from mid-day to overnight.

        So charge some of those EVs during the day instead and even out the load. Problem solved. Why do you assume EVs can only be charged overnight? They'll be charged whenever power is cheapest.

      • by jrumney ( 197329 )
        Peak electricity consumption at mid-day comes from industrial use, not houses. The peak for housing areas is evening. Household usage is dwarfed by industrial usage, so even a 70% household increase overnight (when spare capacity is at its highest, as no electrical grid is all solar, and all other forms of generation do not disappear overnight) is easily absorbed by current generating capacity.
      • by AmiMoJo ( 196126 )

        The 40kWh Leaf has 38kWh usable. 20% is a ridiculous buffer, no car has anything like that.

        Charging efficiency depends on the charge rate. For 6.6kW (typical home/work/destination charger) it's around 90% for the Leaf. 80% is more typical of rapid chargers (40kW+).

        Overnight charging will remain the cheapest option because during the day consumption by industry and business is high. Also we have had remotely controlled off-peak energy for decades now. The power company sends a signal to turn it on when deman

  • Fukushima (Score:4, Interesting)

    by sims 2 ( 994794 ) on Thursday February 21, 2019 @02:18PM (#58159330)

    Back with the fukushima disaster in japan they were raiding the batteries from the cars in the company parking lot to keep the controls and monitor equipment running.

    Also 4 days?! I know a EV holds a lot of juice but if it can really run a home with lights and HVAC for days it should already be being sold as a home backup option.

    • 4 Days admittedly might be pushing it. A Nissan Leaf has about a 24 KwH battery. It means it can run a 1000 watt microwave non-stop for 24 hours. If you're not excessively using power it should last at least 1-2 days thou.

      • Two days in Spain, three days in Italy, five days in Brazil or Mexico [shrinkthatfootprint.com]...that's assuming all would be covered from the vehicle. With a residential solar installation, it probably wouldn't.
      • by jrumney ( 197329 )
        Presumably 4 days during an emergency situation, you are not going to be using as much electricity as a normal day. If electricity is out, there's a good chance that water supply is also affected, so hot water isn't going to be needed. And you're probably not going to be spending your time streaming Netflix on your 65" TV. That 4 days is just for minimal LED lighting and basic cooking and maybe keeping the refrigerator running.
    • Four days is probably based on the average Japanese electricity consumption, not the energy-wasting lifestyle of USAmericans.

    • A Nissan Leaf has a 24kWh battery. A refrigerator uses about 2kWh per day. LED bulbs are about 0.015KWh (each) for every hour they are on. A TV is about 0.1kWh for every hours it's on. Central AC uses about 36kWh per day in the summer. So yes to a fridge, some lights, a little TV and keeping your phones/tablets/laptops charged; no to air conditioning (or electric heat, oven, clothes dryer, etc).
      • by Ogive17 ( 691899 )
        Central air is very uncommon in Japan. They typically have small units in a few key rooms and then only use sparingly.
      • Air conditioning could plausibly use phase change heat (cold) storage so that you wouldn't have to feed it with electricity all the time (except for heat exchanger pumps).
    • by AmiMoJo ( 196126 )

      Average per house consumption in Japan is about 3500kWh/year IIRC, or about 9.5kWh/day. Even the first gen Nissan Leaf can supply that for a couple of days, and the new 62kWh one could easily do 4-5 days. Presumably in an emergency you would try to minimize energy consumption too, so it may actually last a lot longer.

      I know, conversion losses blah blah, it's about right.

    • HVAC? I'm sure if there's a natural disaster you have better things to worry about than your home chilled to 20C.

      In the meantime my home uses ~7kWh / day on average across a given week, more on the weekends for obvious reasons. I can easily run my house for 10 days on a Model 3 battery. My girlfriend wouldn't even need to cut back her binge watching of Netflix.

  • by Solandri ( 704621 ) on Thursday February 21, 2019 @02:24PM (#58159366)
    Most Japanese do not live in single family residences with dedicated garage space. Most live in apartments with shared parking, where is no way to get electricity from "your" EV to "your" home. The buildings are simply not wired up that way. Maybe newer apartments can be wired so an EV charger in your assigned parking slot gets tied in to the meter (and wiring) of your apartment. But that seems like it'd be excessively complicated - I imagine most such chargers will simply tap into the building's main power line, and its dedicated meter is added up with the apartment unit's meter to calculate the monthly power bill.

    Unfortunately, this 1:1 transference of electricity from your EV to your home is necessary if you want people to conserve the power to stretch it out through a multi-day power outage. If you turn the electricity into a shared resource, the tragedy of the commons [wikipedia.org] kicks in. And people start using all the electricity they can giving little thought to conserving it. Japanese culture might help counter that (they place a high emphasis on responsibility to society). But one bad apple in the apartment drawing lots of wattage for an AC, water heater, and playing games on his high-end PC could put a significant dent in the available power across all EVs powering the building.
    • by ColaMan ( 37550 )

      If they have the real-time metering you could simply shut off apartments that are over the allocated amount.

      eg. all the charge (+ discharge) bays are connected to the building grid. There's an issue with outside power, and building management checks the charge on all the vehicles and decides to allocate 10% of the available EV power sources that are above 80% to the building supply.

      They then notify the apartment owners that each apartment has X amount of kWh available for the duration of the outage and to l

    • by AmiMoJo ( 196126 )

      Most Japanese people behave responsibly in the event of an emergency. For example some vending machines automatically switch to free vend and offer a wifi hotspot using their cellular connection (normally used for stock level monitoring and card payments). Obviously in many countries such a machine would be immediately raided, but in Japan it works.

      Having said that, in the event of an earthquake it's usual to evacuate apartment blocks and move to a designated safe area. The risk of collapse is always there

  • The Prius battery is right at about 200V and most electronic things in your house (your TV, your computer and such) work on DC just fine. Those things that don't include electric motors or things that use old power transformer based power supplies instead of switching versions.

    An ham radio operator published his experiences in using his daughter's Prius as a backup power source. He was able to power pretty much everything in his house that used a switching mode power supply without any issues directly

  • This idea is interesting, but worrisome to me. In a disaster there's a good chance you might need to get the heck out of dodge after a couple days. I'd hate to see what happens when 1000's of people need to travel away from the emergency but can't because their car's battery is drained from powering their house's appliances.
    • by quenda ( 644621 )

      The roads are still impassable to cars, so you get on your petrol-powered scooter or mountain bike.

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