SERC Completes Siting Analysis for Electric Vehicle Infrastructure on the North Coast

Over half of Humboldt County’s energy-related greenhouse gas emissions come from transportation. Nationwide, the transportation sector contributes 28% of all greenhouse gas emissions. Plug-in electric vehicle (PEVs) present a compelling opportunity for communities to dramatically reduce these emissions along with air pollutants responsible for a wide range of adverse health impacts.

To support the successful introduction of PEVs to the North Coast, SERC is serving as the technical lead on the North Coast Plug-in Electric Vehicle Readiness Study. Funded by the California Energy Commission, this work is being done in partnership with the Redwood Coast Energy Authority and local engineering firm GHD.

One of the key questions we have addressed is how to deploy PEV chargers throughout the region in a cost-effective manner. This is a complex question. Where will PEV drivers live? Where will they drive? How long will they spend at their destinations? How will drivers adapt when they need a charge but no station is available?

Our approach to answering these questions was to develop an “agent-based” simulation model of PEV drivers in Humboldt County. Individual PEV drivers (or agents) are simulated as they conduct their daily travel throughout the county and interact with a hypothetical charging network. Drivers begin a day with a vehicle, an itinerary of trips, and a set of rules for how to behave. An example of a rule would be that drivers seek out a charger if their battery doesn’t have sufficient energy to make their next trip. Another example would be that some drivers elect to charge their vehicle even if it’s not necessary.

The simulation evolves over the course of the day as drivers follow their rule sets, interact with the charger network, and respond to changing circumstances. At the end of a simulation run, we can summarize the day’s events in a multitude of ways. Where, when, and how often did drivers charge? How many drivers experienced inconvenience of some kind (e.g., experienced a delay while waiting for a charger)? By repeatedly running the simulation with different charger locations, we can use the model to evaluate the impact of any hypothetical infrastructure scenario on driver inconvenience.

For a given penetration of PEVs into Humboldt County, we used optimization to find the infrastructure scenario that provided the greatest benefit to drivers for the least cost. The map of Eureka below provides an example of the recommended infrastructure for 2% penetration of PEVs, or roughly 3000 vehicles. Maps of the whole county can be downloaded at www.schatzlab.org/projects/policyanalysis/pev.html.

The recommended PEV charging infrastructure for the City of Eureka for 2% penetration of PEVs, or roughly 3000 vehicles. The estimated cost of this scenario is $130k.

The recommended PEV charging infrastructure for the City of Eureka for 2% penetration of PEVs, or roughly 3000 vehicles. The estimated cost of this scenario is $130k.

We also developed some general conclusions about the optimal siting of PEV chargers in Humboldt, which are likely transferable to other rural communities:

  • Overall, relatively few chargers are needed to support a large number of PEV drivers.  Approximately 45 public chargers were sufficient to support about 3000 drivers in the 2% penetration scenario. Drivers will be able to accomplish most of their travel needs (~90%) just by charging at home.
  • Chargers tend to be sited in and around population centers and major regional corridors.
  • Level 2 chargers (which can charge a Nissan Leaf in ~5-6 hours) provide a more cost-effective means of supporting PEV drivers than DC fast chargers (which can charge a Leaf in less than 1 hour). This is primarily because DC fast chargers are about 10 times more expensive to install and only charge batteries to 80% of full capacity.
  • Exact siting of chargers is flexible. Chargers can be sited in one zone or a neighboring one and the overall impact on PEV drivers will be about the same as long as the total need for chargers in that region is satisfied.

Our deployment guidelines wouldn’t be complete without an estimate for when the infrastructure should be in place. To answer this question, we looked at the historic adoption of the Toyota Prius and other hybrids in Humboldt. If we assume that drivers will adopt PEVs at the same rate as hybrids, then we would expect that 1% of the light duty vehicles in Humboldt will be PEVs by approximately 2018 and 2% by 2025. In other words, there’s little time to spare in rolling out PEV chargers.

Fortunately, the North Coast PEV Readiness team is already working on a near-term implementation plan. Critical to this plan is identifying specific sites where the first wave of PEV chargers might be installed. This process involves soliciting input and feedback from a variety of municipalities and local stakeholders to ensure that the final sites reflect the needs and priorities of the whole community. If you’d like more information, or want to participate in this process, contact the Redwood Coast Energy Authority.

Renewable Energy Mini-Grids

Over the past year, SERC has been collaborating on the Renewable Energy Mini-Grids for Improved Energy Access project with researchers from Lawrence Berkeley National Laboratory (LBNL), Energy and Resources Group (ERG) at University of California at Berkeley, Prayas Energy Group and Palang Thai. These efforts are in support of the Global Lighting and Energy Access Partnership (Global LEAP) initiative associated with the Clean Energy Ministerial.

Renewable energy-based mini-grids offer a significant opportunity to increase access to reliable electricity services for rural populations throughout the developing world. A mini-grid is a village-scale electrical distribution system served by an isolated generator of up to a few hundred kW in capacity. Power on these grids is often provided by diesel generators, but can be supplied by local, renewable resources such as microhydro, solar, biomass or wind. Mini-grids offer an intermediate solution between stand-alone individual home power systems and main grid connection, and often prove to be more cost-effective and beneficial to the community than either of those alternatives.

Our team recently produced three documents to help inform delegates participating in the Mini-Grid Development roundtable discussion at the fourth Clean Energy Ministerial (CEM4) in New Delhi in April. CEM4 brought together energy ministers from 23 of the world’s leading economies, along with business leaders, NGOs and academia to discuss policies, technologies, investment, and skills needed to achieve the CEM’s goal of “accelerating the transition to a global clean energy economy.” Our team’s contributions included:

A biomass mini-grid in India.

A biomass mini-grid in India.

 

SolarMiniGridJP

A solar mini-grid in India.

  • Sustainable Development of Renewable Energy Mini-Grids for Energy Access: A Framework for Policy Design, which provides a review and critique of mini-grid policies from several countries and offers recommendations for national policy design to support the development of mini-grids.
  • A Guidebook on Grid Interconnection and Islanded Operation of Mini-Grid Power Systems Up to 200 kW, which is intended to help meet the widespread need for guidance, standards, and procedures for interconnecting mini-grids with the central electric grid as rural electrification advances in developing countries.
  • Review of Strategies and Technologies for Demand-Side Management on Isolated Mini-Grids, which discusses different measures available to help with load management on isolated mini-grids.

These documents are available on the SERC website at www.schatzlab.org/projects/developingworld/minigrids.html.