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NREL's future vision: vehicle-to-grid/renewable communities

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  • Felix Kramer
    Plugging In to Renewable Communities How transportation based on renewable energy-powered communities may solve our addiction to fossil resources. By Terry
    Message 1 of 1 , May 4, 2006
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      Plugging In to Renewable Communities
      How transportation based on renewable
      energy-powered communities may solve our addiction to fossil resources.
      By Terry Penney and Jennifer Elling

      [See original for excellent graphics]

      Terry Penney is the FreedomCAR and Advanced
      Vehicle Technology manager at NREL, Golden, Colo.
      Prior to joining NREL in 1979 as an aerospace
      engineer, he worked on the space shuttle. He has
      worked on hybrid vehicle technology since 1992.
      Contact Penney at terry_penney@.... Jennifer
      Elling is a senior communicator and project lead
      for the Renewable Community at NREL. Contact
      Elling at jennifer_elling@....

      What if you could virtually eliminate your
      reliance on petroleum and the associated concerns
      about greenhouse gas emissions and national
      security — without giving up your personal car?
      Better yet, what if the infrastructure to power
      this fossil fuel-free vehicle was tied to your
      neighborhood electric grid, one that distributed
      electricity generated from renewable energy to
      your home and “plug-in” hybrid electric car? Your
      advanced plug-in vehicle would be designed to
      draw electricity from the combined renewable
      energy grid or a plug-in renewable energy system.
      Plug-in vehicles are like today’s hybrid
      vehicles, but with bigger, more costly batteries
      and a smart control strategy. Now consider that
      in this community, not only would renewable
      energy (RE) power the homes and businesses, but
      buildings would be built for maximum efficiency
      and on-site solar heating and electricity
      generation to use zero or near-zero energy from
      the grid. Most of the pollution, health and
      national security concerns of fossil fuels would be a thing of the past.

      Researchers are quickly moving toward developing
      the technologies to support just this type of
      sustainable transportation infrastructure and
      RE-based community. Many of these innovations are
      here today, and we catch the first glimpse of
      what these communities might look like as more
      builders construct developments in which most or
      all of the homes are solar and use near-zero
      energy. The paradigm-shifting difference in the
      renewable energy community to come rests in the
      single integrated, RE-based energy system for
      transportation and residential/commercial buildings.

      Driving Vehicle-to-Grid Technology
      Because this renewable community will be
      connected to a grid that operates in two
      directions — both distributing and accepting
      electricity — the next-generation hybrid electric
      vehicles will have the ability to store excess
      electricity for timely return to the grid. We
      call this “two-way” plug-in a vehicle-to-grid
      (V2G) hybrid. Utilities spend a tremendous amount
      for capacity to continuously balance supply and
      demand across the grid or provide backup
      electricity during outages and peak-demand
      periods. Because batteries are particularly
      effective for this kind of critical service,
      utilities might pay V2G owners to “borrow”
      energy-storage capacity (see sidebar, “Linking It
      All Together”). Combined with fuel savings, this
      income could pay back the more expensive battery
      cost within relatively few years.

      As federal regulators and electric utilities work
      to revamp the aging North American electricity
      transmission and distribution infrastructure,
      they have the opportunity to reduce our nation’s
      increasing reliance on imported oil by creating
      mechanisms to encourage clean distributed
      generation, including V2G. This combined power
      grid will enable utilities to tap a source of
      competitively priced backup electricity, while
      investors will have a means of profiting from the
      possible transition to renewable energy.
      Batteries, such as those used in a V2G-enabled
      car, are one of many new clean and distributed
      resources that could contribute to a smart grid
      of the future. This smart grid would communicate
      continuously with both suppliers and consumers of
      electricity to maintain the most secure,
      cost-effective system. It will require
      cost-effective advanced interconnection equipment
      that allows full functionality of a V2G plug-in
      hybrid. Consensus-based standards for these vehicles also must be developed.

      This effort is just one of the critical areas on
      which researchers are focused. At the National
      Renewable Energy Laboratory (NREL), experts are
      working to advance smart control systems in
      vehicles to make V2G technology a reality and to
      create a more efficient, reliable distribution
      system. Probably the biggest challenge to
      commercialization of plug-in hybrids is the cost
      and weight of batteries. NREL is researching
      thermal-management, modeling and systems
      solutions to improve energy-storage technology
      (see the sidebar, “Overcoming the Battery
      Technology Challenge”). Even at today's battery
      costs, however, plug-ins may be able to repay
      their costs within a few years. NREL scientists
      and engineers also research improved power
      electronics and smart control systems critical to
      hybrid efficiency and conduct sophisticated
      modeling and analysis to demonstrate the economic
      viability of plug-ins and identify key areas for improvement.

      Envisioning the RE-Powered Community
      Let’s examine what the sustainable communities
      that underpin the V2G paradigm will look like.

      Imagine living in an RE-based community in a few
      years that emphasizes low utility bills and
      reduced petroleum use. It is designed using
      sustainable practices and materials to minimize
      the environmental damage of site development and
      conventional energy and water use and to promote quality of life.

      Your zero- or near-zero-energy home is
      constructed for maximum comfort and energy
      efficiency, with appliances and heating and
      cooling systems that dramatically reduce the
      electricity demand. Rooftop photovoltaic (PV)
      power-generating systems supply most of the
      little energy the house does need. Excess PV
      generation is used to charge your V2G hybrid or
      is sold back to your electric utility company.
      The V2G in the garage operates mostly on
      $0.03-per-mile electricity rather than
      $0.10-per-mile gasoline. The hybrid vehicle’s
      batteries store extra electricity for the home as
      a backup to the PV system. In this way, the
      vehicle actually may serve as a mobile utility.
      The local utility generates energy from wind,
      solar and other renewable sources the small
      amount of grid electricity your home may need.
      What little fuel the V2G needs may also be
      generated from renewable sources, such as ethanol
      or biodiesel in the near term, or hydrogen for
      the vehicle’s fuel cell in the long-term.

      Nearby workplaces and commuter stations could
      also have two-way electrical outlet “docks” to
      enable battery charging or, when the V2G car is
      not in operation for long periods, to provide
      electricity back to the grid. Many high-tech
      companies already have auxiliary generators
      because they need more consistent power than the
      grid provides, and such companies might be
      delighted to rely on employee car batteries
      instead. As for the town, our streets will be
      clean and quiet because V2Gs would run on their
      electric motors much more than regular hybrids.
      Operating in electric-motor mode would also mean
      greatly reduced emissions from the vehicles themselves.

      Creating the V2G Reality
      Sound like a pipe dream? It isn’t.

      Energy-efficient homes, PV systems, geothermal
      heat pumps and other effective renewable energy
      technologies are offered by many homebuilders or
      suppliers. Commercially available plug-in hybrids
      are just years away. Integrating multiple energy
      systems is the key, and the technology to do so
      is available today. Yet cost, risk, consumer
      demand, and other issues cause business to pause
      at the opportunity. With the team of experts at
      NREL, we’ve begun to respond to these issues by
      analyzing a number of renewable community
      scenarios that link transportation, homes and the
      electric grid, as well as enabling the delivery
      of large quantities of renewable energy to the
      grid. Analyses show that the homeowner would gain
      a net cost advantage by integrating a
      near-zero-energy home with a plug-in or V2G
      hybrid. Although a number of variables affect
      this calculation, the economics of the integrated
      system are substantially better than an analysis of each piece would suggest.

      For example, typically a near-zero-energy home
      with PV panels and energy-efficient measures can
      be expensive, raising the initial cost of this
      home. When included in original construction cost
      — in the home mortgage — however, energy use can
      be reduced as much as 50 percent with no increase
      in total monthly bills. For instance, a U.S.
      Department of Energy handbook
      (www.buildingamerica.gov) for hot and humid
      climates posed an example of spending an
      additional $1,500 for an ENERGY STAR home
      (including various energy-efficiency features,
      but not PV or a geothermal heat pump). For an
      additional mortgage cost of only $9 per month,
      energy bills were reduced $40 per month — for net
      savings of $31 per month. As another example, for
      a 2,600- square-foot, two-story home in
      Sacramento, Calif., efficiency measures can be
      added cost-effectively to achieve 60 to 65
      percent energy savings. At an incremental cost of
      about $20,000 and assuming a $600,000 asking
      price in the California market, this investment
      represents an upfront cost increase of only 3
      percent. In addition to immediate savings in
      utility bills, added PV electricity-generation
      and other energy-savings features will also be
      “paid back” in home resale value.

      Establishing the renewable community with V2Gs,
      of course, requires much more interaction among
      disparate disciplines. It requires a fresh look
      at state and local zoning laws. This transition
      may seem like a difficult undertaking, but when
      we consider escalating housing and utility costs,
      we find that the effort and investment have the
      potential to pay off by many measures.

      Developing Transportation-Wise Suburbs Today
      Your home and car probably represent your biggest
      personal impact on our nation’s increasing energy
      demand, and therefore on national security, trade
      deficits, global warming and air quality. The
      renewable communities concept presented in this
      article marries energy-responsible homes and cars
      for a sustainable lifestyle. By leveraging new
      technologies and sustainable building practices,
      RE-based communities can demonstrate that it is
      possible to minimize the detrimental effects of
      fossil energy, while addressing the greatest
      energy challenges of the American suburban lifestyle.

      Our team at NREL views renewable communities
      using V2G technology as an ideal way to
      demonstrate the effectiveness of the wide range
      of energy-efficiency and renewable energy
      technologies the laboratory is helping to
      develop. Rooftop photovoltaic and utility-scale
      solar thermal systems are a prime option.
      Depending on location, the community can also
      rely on wind, solar thermal or biomass energy.
      Our analysts can model the near-zero-energy
      buildings to identify the most cost-effective
      efficiency measures, model the V2G vehicles to
      identify optimal battery and other component
      sizes and matches, and design systems to most
      effectively use the communities' mix of
      distributed and central electrical generation.
      Ethanol from cellulosic biomass can supply what
      liquid fuel the vehicles must use. We see
      renewable communities as a path to minimizing
      energy import, fossil-fuel use and greenhouse gas
      emissions, while providing the highest-quality lifestyle.

      What will it take to start building these
      renewable communities? Any new venture involves
      risk, but we believe Americans are eager to live
      in communities that minimize their contribution
      to greenhouse gases and reduce national
      dependence on imported oil. Several organizations
      and business entities have contacted us about
      this vision, and we see elements of it around the
      world. It is only a matter of time before we see
      integration of all the pieces of advanced
      technology, putting us on a path to
      sustainability based on renewable energy. It’s
      not a question of “if,” but of “when, who and
      where” this vision will become a reality.

      3 Sidebars:
      A Glimpse of the V2G Future Today?
      How soon could we have vehicle-to-grid (V2G)
      plug-in hybrid communities? None exist yet, but
      Global Electric Motorcars (GEM) gives us a
      glimpse of what they might look like. The leading
      maker of neighborhood electric vehicles, or NEVs,
      and a DaimlerChrysler company since 2000, GEM has
      sold its vehicles to entire communities that
      feature NEVs as part of their basic
      infrastructure. In Bay Harbor, Mich.;
      Celebration, Fla.; and Playa Vista and Otay
      Ranch, Calif., entire neighborhoods use NEVs for nearly all local travel.

      Linking It All Together
      What makes the renewable energy-based community
      of the future unique is the integration of the
      electric utility system with a system to power our personal vehicles.
      [GREAT GRAPHIC] Source: Dean Armstrong, NREL
      The interconnected energy system can flow two
      ways, as shown by the arrows in this graphic. A
      “two-way” plug-in hybrid vehicle (also known as a
      vehicle-to-grid, or V2G, vehicle) is plugged into
      an electric outlet in the garage of the home or
      workplace, allowing electricity to flow from the
      energy-management system (traditionally the grid)
      to the vehicle and vice versa. An
      energy-management operator can broadcast a
      control signal to any number of V2Gs (including
      fleets) to give or request electricity. Each
      vehicle’s smart control system monitors its
      ability to give and receive electricity and
      communicates this information with the operator.

      Overcoming the Battery Technology Challenge
      If battery technology is the key to realizing the
      benefits of plug-in hybrid vehicles, then the
      thermal management of these batteries is
      essential for their longevity and performance.
      During the past 10 years, the National Renewable
      Energy Laboratory (NREL) has developed a
      world-class laboratory for energy-storage thermal
      management. The lab uses the latest modeling
      software, hardware and thermal-imaging techniques
      to improve the performance and design of advanced
      batteries such as nickel-metal hydride (NiMH),
      lithium-ion and lithium polymer batteries.
      2001 Panasonic NiMH module
      Redesigned 2004 Panasonic NiMH module
      These infrared images taken at NREL show how
      Panasonic improved the thermal performance of its
      NiMH module. The 2004 module has a lower maximum
      temperature and is much more uniform. The U.S.
      Department of Energysponsored work at national
      labs and industry is aimed at overcoming the
      barriers to implementing advanced batteries in
      vehicles such as cost, calendar life, abuse
      tolerance and low-temperature performance. Access www.nrel.gov.
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