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Greg Hanssen's A Bridge to the Hydrogen Highway

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  • Felix Kramer
    This is a version of the document that Greg Hanssen, partner at EnergyCS (the creators of the lithium-ion version of PRIUS+), delivered at EVS21, the Worldwide
    Message 1 of 1 , Apr 21, 2005
      This is a version of the document that Greg Hanssen, partner at EnergyCS
      (the creators of the lithium-ion version of PRIUS+), delivered at EVS21,
      the Worldwide International Battery, Hybrid and Fuel Cell Electric Vehicle
      Symposium & Exposition), in Monaco April 5. Greg is also co-chairman of the
      Production Electric Vehicle Drivers Coalition, an early force in promoting
      EVs in California. You can find a link to the PDF version of this document
      at http://www.calcars.org/vehicles.html

      A Bridge to the Hydrogen Highway
      By Greg Hanssen, EnergyCS

      August 20, 2004 updated March 9, 2005

      California has set forth on the ambitious goal of building a network
      of hydrogen fueling stations by the year 2010. This clean fuel 'Hydrogen
      Highway' is intended to solve the familiar 'chicken and egg' problem of
      vehicles and infrastructure. While the vision of a renewably fueled zero
      emission vehicle future remains clear, there are still many hurdles to be
      overcome before affordable Fuel Cell Vehicles (FCVs) are likely to reach
      the public. This paper proposes an enhancement to the FCV platform that
      would reduce vehicle cost, increase efficiency and alleviate the consumer
      anxiety over a sparse hydrogen infrastructure.

      One of the rarely discussed issues is how the Hydrogen Highway could
      compete with a ubiquitous gasoline infrastructure. Prototype FCVs have
      only half the range of a traditional gasoline vehicle. How accepting of a
      medium-range vehicle will consumers be if the nearest refueling station is
      10 miles out of their way? A solution: give the consumer access to
      refueling capability at home.

      While home-based hydrogen generation devices may not be available in
      the near future, a hydrogen fuel cell based electric vehicle could easily
      gain additional driving range by enlarging the existing hybrid battery and
      adding a plug for home recharging. The electric energy gained from a home
      re-charge would complement the fuel cell and provide additional daily
      driving range beyond that of the hydrogen fuel cell itself. By expanding
      the existing fuel cell hybrid battery to a high-energy battery, a
      substantial portion of the daily driving could be done directly without the
      overhead of hydrogen production. The Hydrogen Highway would then allow
      such vehicles to go well beyond the traditional range of a normal battery
      electric vehicle. Renewably produced hydrogen would complement renewable
      electricity from the battery to allow unlimited range and quick refueling
      while also permitting inexpensive and convenient home refueling.

      At the moment, fuel cell power comes at a high price. Current fuel
      cells approach $3000 per kilowatt although these costs are expected to drop
      closer to $1000/kW during the next phase of prototype vehicles. High
      energy, low weight advanced lithium batteries can now be purchased for as
      little as $200/kW. As long as fuel cell costs exceed that of batteries,
      there is a clear advantage to decreasing the fuel cell size and increasing
      the onboard hybrid battery. A battery-dominant hydrogen FCV would only
      need a fuel cell large enough to keep the battery charged for average
      driving as the battery would supply the additional peak power. At $1000/kW
      for the fuel cell, reducing an 80kW fuel cell to 20kW could save
      $60,000. Adding 50 miles of battery range would add less than $10,000
      resulting in a net savings of $50,000 in the near to midterm.

      Additional battery range would not only decrease infrastructure
      anxiety and vehicle cost, but could ultimately increase FCV
      efficiency. Advanced lithium batteries can return up to 80% of the
      electricity used to charge them. Using electricity to manufacture hydrogen
      and compress it, followed by a conversion back to electricity in a fuel
      cell may return as little as 20% of the original electricity. The battery
      portion of a plug-in FCV drive cycle would therefore deliver electricity to
      the mo://gup to four times more efficiently than through hydrogen. With
      renewable electricity at such a premium, great effort should be taken to
      use it as efficiently as possible.

      Ultimately a plug on a hydrogen FCV could allow the vehicle to sell
      back hydrogen produced electricity for peak power needs or provide valuable
      voltage regulation services through the battery to further benefit the
      California electric grid. In the near term, while fuel cell costs exceed
      that of batteries, adding battery power and a plug will clearly increase
      the consumer and societal benefits of FCVs.

      If the plug-in hydrogen FCV is the keystone in a bridge from gasoline
      to the hydrogen future, how do we complete this bridge? A plug-in gasoline
      hybrid could take the existing momentum of vehicles like the Toyota Prius
      and move us further in the direction of a renewably powered zero emission
      vehicle future by replacing more of the gasoline based driving cycle with
      renewably produced electricity. While adding a plug to a fuel cell vehicle
      reduces the vehicle cost, the same cannot yet be said for a gasoline
      hybrid. But this is likely to change in the very near future with fuel
      costs rising and battery costs dropping.

      The EnergyCS/Valence Technologies plug-in hybrid Prius prototype
      demonstrates the viability of the gasoline plug-in hybrid concept. The
      ability to displace gasoline with electricity is accomplished by replacing
      the stock 1.3kWh NiMH hybrid battery with a 9kWh high-energy, lightweight
      Valence Saphion lithium-ion battery pack. The Toyota battery monitoring
      controller is also replaced with an EnergyCS lithium monitoring
      system. The EnergyCS control package consists of cell monitoring and
      balancing for the lithium batteries as well as pack voltage and current
      sensing, fan and charger control, user display and SD flash data recording.

      The Saphion lithium battery pack can be externally charged with the
      on-board 120/240V charger in under 8 hours. While the expanded battery is
      sufficiently charged, the control system takes full advantage of built-in
      modes of the Toyota hybrid system to use electrical energy from the battery
      to displace gasoline. At lower speeds or power demands, the vehicle may
      run without burning any gasoline at all. When the expanded battery is
      depleted, the control system emulates normal Prius operation and the
      vehicle behaves like a normal Prius until the battery is recharged.

      The amount of gasoline consumed over a normal daily driving cycle is
      dramatically reduced with the introduction of up to 9kWh of electricity
      from the grid. Preliminary driving tests over a variety of surface streets
      and freeways in Southern California have netted a gasoline efficiency of
      between 120mpg and 180mpg for the first 50 to 60 miles of the day. After
      50-60 miles the average gasoline consumption drops back to 50mpg under
      normal Prius emulation mode.

      The environmental as well as energy security implications of
      displacing gasoline with electricity could be tremendous. While plug-in
      hybrid gasoline vehicles like the EnergyCS/ Valence Prius could eventually
      help build a bridge to fuel cell vehicles, in the near term they could also
      dramatically reduce our reliance on imported fossil fuels.

      As California strives to increase the amount of renewable electricity
      on the grid, vehicles that can be powered by this clean energy by way of
      batteries and hydrogen must be built to realize this zero emission vehicle
      future. The convenience, low cost and high efficiency of batteries
      combined with fast hydrogen refueling on the Hydrogen Highway make for the
      ultimate zero emission vehicle solution. In order to complete this bridge
      however, consumers must first be introduced to clean and inexpensive home
      refueling by way of plug-in hybrid gasoline vehicles.
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