How Solar Energy Helps Fleets Get the Most Out of Electric Vehicles
October 10, 2017
October 10, 2017
As Alameda county works to replace hundreds of gas-powered cars in its municipal fleet with plug-ins, building out the requisite charging infrastructure to power them has been a challenge. Electricity use at the fleet’s main facility in Oakland regularly incurs overage charges thanks to utility PG&E’s tiered commercial pricing system—which places rate tariffs on high electricity consumers—costing the county an additional $60k per year in energy costs. What’s more, the building itself is already at maximum electrical capacity, so adding new charge stations would require $100k or more in upgrades to expand service from PG&E.
“We’ve installed charging stations at about a dozen of our sites but we have about 150 offices,” says Phillip Kobernick, Sustainability Project Manager for the County of Alameda. “Now we’re looking into more complicated sites where we would need to trench through maybe 100 feet of asphalt or go underneath a ditch to run power from a building to where the cars are parked.” Kobernick says he would also like to integrate more plug-ins at law enforcement sites like county jails, where heightened security complicates installations and further interferes with trenching power to parking areas.
While these impediments might dissuade other fleets from electric vehicle adoption entirely, Alameda is looking to one of plug-in mobility’s natural allies in the fight to reduce greenhouse gas emissions: solar energy.
With solar-powered charging setups, fleets can reduce their dependence on the grid, cut energy costs, and even avoid complex and expensive upgrades to utility infrastructure. What’s more, fueling electric vehicles with a renewable energy source like solar further reduces emissions compared to gasoline—which can be helpful in meeting GHG reduction targets.
Reducing Grid Dependency (And Cutting Energy Costs)
On the whole, the modest numbers of electric vehicles in use today don’t pose much of a threat browning out the grid during peak electrical demand hours. For individual facilities like Oakland’s main municipal fleet parking hub though, servicing the added electricity needs of just a few more EVs may not always be an option. Alameda plans to add as many as 500 new plug-in vehicles in the near future.
“We’re basically switching from gasoline to electricity and our facilities are not equipped to handle that electrical load,” says Kobernick. “So adding new power generation is going to be an important part of the mix.” Even with the comparatively small number of plug-in vehicles Alameda already uses, the county is saddled with massive tariffs under tiered commercial pricing.
Few utilities are as extreme as PG&E in punishing commercial customers for high monthly electricity use. Time-of-Use rate pricing—which adjusts the price of electricity based on what time of day it’s used—is becoming increasingly widespread. Both pricing structures effectively exist to serve a similar purpose: de-incentivize customers from overtaxing the grid with excessive energy demand. Under either price structure, plug-in vehicles will add a lot of extra kilowatt-hours to your monthly bill, which can become severely detrimental to ROI outlooks for fleet EV adoption.
Solar-EV Infrastructure Options
Home solar-EV setups usually consist of rooftop panels, an AC converter, and a common Level 2 charging station, all hooked up to the same electrical meter. Any excess electricity production not being used by the home or to charge a plug-in vehicle is sent out to the grid, where it contributes to meet the power needs other nearby houses. The meter zeroes out the electricity that is sent out against what comes in from the grid, so you don’t have to have your car plugged in or be running home appliances while the sun is out in order to benefit from creating your own electricity.
Chances are, a fleet setup that pairs rooftop solar panels at the parking garage with EVSE works about the same. Not all solar-powered electric vehicle charging setups interact with the electrical grid that way though. In fact, some aren’t hooked up to it at all.
Integrated products like Envision’s EV ARC bring solar PV panels, level 2 EV charging and energy storage together into a single, self-contained unit. During daylight hours, these EVSE can either directly charge a vehicle plugged into them or charge a large internal lithium-ion battery pack. This allows vehicles to go out during the day and charge later at night without pulling any energy from the public grid.
New York City recently finalized an agreement to purchase 30 EV ARC units from Envision in support of its pledge to add 2,000 plug-in vehicles to its fleet by 2025. An added benefit is that these units come with minimal installation cost and can be moved from site to site as needed using Envision’s ARC Mobility transportation system. The system provides fleets with flexibility in planning for electric vehicle adoption because the placement of solar charging stations doesn’t have to be permanent. Or, a city can relocate the charge station if special conditions (like hosting major international events or a natural disaster) present themselves.
Not only can these setups bypass outsized installation costs from trenching power lines to difficult locations, Koberneck says they can bring other benefits for public fleets. “If we have things like grid failures or attacks where the power is down and EVs are becoming a part of our fleets, having solar-based vehicle generators fits in really well to our emergency planning.”
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