價格高 充電站數少 電動車銷路不如預期
President Barack Obama set a goal in his 2011 State of the Union speech – put one million electric vehicles on the road by 2015. But auto analysts and executives doubted that was possible. Turns out the doubters were right. U.S. car dealers have sold just over 250,000 electric vehicles since they were introduced in 2010.
U.S. car dealers sold more than 13 million petrol-powered passenger cars, light pickup trucks, SUVs and vans in 2013 and more than 14 million in 2014, according tomotorintelligence.com, a site provided by Autodata Corp.
The U.S. Department of Energy says the high purchase price of EVs is partly to blame. Electric vehicles range in price from about US$15,000 to more than $70,000. At the upper end of that scale, the purchase price can be prohibitive.
EVs are cheaper to operate than petrol-powered cars and trucks in the long run and they produce no air pollution. Nor to they contribute to climate change. But American drivers have been slow to switch.
Trying to solve the riddle of Americans’ sluggish acceptance of electric vehicles, Lang Tong and Shanjun Li, researchers at Cornell University, frame the issue as a traditional chicken and egg riddle – which came first, the chicken or the egg?
The chicken is the limited number of EV charging stations in U.S. cities and along highways.
Tong and Li contend this poses a major roadblock to greater acceptance because recharging EVs can be inconvenient, if not impossible, in many places.
The egg is that investors are reluctant to build more charging stations, when there are so few electric vehicles on the road.
Through their research Tong and Li found that cities with more charging stations also have more electric cars.
In their analysis, a 10 percent increase in the number of charging stations per million people in a city would result in a 10.8 percent increase in the market share of electric vehicles in that city.
They say more charging stations are needed in parking garages in urban centers, parking lots in shopping malls, apartment complexes and business sites.
After analyzing a data set of quarterly EV sales in 353 metro areas from 2011 to 2013, Tong, a professor of engineering at Cornell, said, “As one might expect, there is a strong dependency between the growth of electric vehicle market share and the available charging options.”
One goal of Tong’s and Li’s INSPIRE project, entitled “An Engineering and Economic Pathway to Electric Vehicle-Based Transportation,” is to consider how to engineer transformative technologies for large scale charging of electric vehicles that can work with existing electric grids in a cost-effective way.
Currently, most EV owners plug in to a standard 120-volt home outlet and charge their batteries overnight. Others pay to install a 240-volt charging station at home, cutting charging times roughly in half.
A third alternative is to purchase an electric vehicle equipped with electrical connections for high, direct-current charging. This can recharge an electric vehicle four to six times faster than an alternating current charger; but the cost typically runs $15,000 to $25,000.
Tong and Li believe more efficient charging options that lower electricity costs would speed up electric vehicle adoption.
They are investigating vehicle charging with solar panels on garages, examining possibilities for local energy storage and studying how to better utilize price differentials in the electricity market.
They also are designing efficient, large-scale charging facilities using an Intelligent Energy Management System that optimizes the cost of vehicle charging at malls or parking garages where many cars could draw energy from the power grid all at once.