Earlier this year I wrote a series of posts about my quest for a new, more fuel-efficient car. I was skeptical about the environmental benefits of plug-in electric vehicles when they are driven in Alberta, where a significant amount of our electricity comes form coal-fired generation.
A friend who is on the cutting edge of green technology suggested that I was being short-sighted. Why rely on Alberta’s grid? Why not install a PV array and generate my own electricity?
Mea Culpa. I love solar PV. I can’t help myself. Those mono- and poly-crystaline panels are just so darn cool. So, the idea of buying a plug-in electric vehicle and charging the on-board batteries with solar PV is intriguing. (For those of you recoiling on the potential price tag, read on.)
Over the past year, my PV obsession has taken me to Springbank, Phoenix, Denver and Regina. Last week it took me to Raleigh, North Carolina for the American Solar Energy Society (ASES) Conference.
In a sparsely attended session at 8:30 in the evening, Dan Davids, president of Plug-In America, Rob Threlkeld, an environmental services manager with General Motors, and Dr. Vincenzo Marano, a researcher from Ohio State University’s Center for Automotive Research, tackled questions about electric vehicles and their compatibility with solar PV. The Mac versus PCesque ad Gasoline isn’t right for cell phones (pictured above) is courtesy of Plug-In America.
Recall that there are two types of electric vehicles – ones like the Chevy Volt, that have to be plugged in, and gasoline-electric like the Honda Insight, that do not. The information below relates to plug-in electric vehicles, so called PEVs.
A typical estimate for electric vehicle fuel efficiency is 0.2 kilowatt-hours of electricity per mile (0.124 kilowatt hours per kilometre). If you drive 40 kilometres a day, that is 5 kilowatt-hours.
Some car companies are integrating PV panels into vehicle design, but these panels are used to power interior accessories and aren’t big enough to keep the car’s batteries charged and re-charged, no matter where you live.
In Calgary, where I live, we average about 3.6 average daily peak sun hours. This number varies greatly over the year. In December, we only get one hour of peak sun a day. In June, just less than six.
With 3.6 prime sun hours, you would need 1.4 kilowatts of PV, or six panels at 240 watts each, to cover your 40-kilometre road trip. (This does not take into account losses due to temperature variability and other design factors.) With panel areas at about 18 square feet (1.7 square metres), that’s a roof size of 108 square feet (10 square metres).
So, to run my car on PV, I would need to put PV panels on a south-facing roof on my garage or house. Luckily, this isn’t as difficult as it used to be. In 2008, the Alberta government passed regulations that allow people to install grid-tied micro-generation facilities (including solar PV) on their roofs. In this way, and with a little planning, it would be possible to use PV to power a PEV.
PEVs are plugged into 120 or 240 volt outlets. These kinds of outlets are typical in a residential setting. The former feeds your big screen TV. The latter your stove. That being said, you usually won’t find a 240 volt outlet in your garage, so if you want to go that way, you will need an electrician to install one.
Next comes the design and installation of your PV array. PV panels often have a maximum power point voltage of around 30 volts. Therefore, a six panel system is more than adequate to get you to the 120 volts required for Level 1 charging, but not quite enough to reach the 240 volts for Level 2. The lower voltage means a longer wait to get to full charge – likely between 8 and 15 hours, depending upon how low the battery is.
The bottom line is that it is technically feasible to buy a plug-in hybrid in Alberta and run it on grid-tied PV.
Now let’s compare the costs.
Assume that, on average, I drive 40-kilometres every day. In one year, I will drive 14,600 kilometres.
The operating costs of a gasoline vehicle include gas costs and maintenance. According to Statistics Canada, average unleaded gasoline prices in Calgary have varied between 97.5 and 117.2 cents per litre over the last five months. Gas prices are usually more expensive in the summer than the winter, so I’ll assume an average gasoline price of 117.2 cents. A new gasoline-powered VW Beetle has fuel efficiency ratings of 11.8 litres per 100 kilometers in the city and 8.1 litres per 100 kilometres highway. Assuming 55% highway driving and 45% city driving, the fuel cost for 1 year is $1750. Add about $500 a year for regular maintenance, and the total annual cost is $2250. (Fuel economy numbers and calculations of weighted fuel costs are estimated using www.fueleconomy.gov)
The operating cost of the PEV would be the electricity cost. If I don’t install a grid-tied PV system, I will need to buy grid electricity to charge my PEV. The cost of electricity (excluding fixed charges) in Calgary is about 8 cents per kilowatt-hour. Assuming a Chevy Volt uses on average 0.2 kilowatt-hours of electricity per mile (0.124 kilowatt hours per kilometre), the fuel cost for 1 year is $1820. According to Plug-In America, maintenance costs are very low. In the absence of a number I will assume $200, then the total annual cost for the electric vehicle is $2020.
The cost to install a six-panel, 1.4 kilowatt l PV system is likely between $8,000 and $10,000. Given the assumed cost of electricity, the simple payback of this system would be between 5 and 6 years. (I could also sign up for Enmax’s forthcoming solar PV program. This would eliminate the upfront cost, but also the payback.)
But here is the kicker. The price of a 2010 VW Beetle (no word on what the new model will cost in 2011) is between $18,000 ad $26,000. A 2011 Chevy Volt starts at $40,000. So even though I may be able to make the annual operating costs go around, the upfront capital cost of the PEV is a killer.
Plug-In America is right that gasoline isn’t right for cell phones. And they may well be right that some day it won’t be right for cars. But for the moment, the winners are still Big Oil and Big Automakers.
Enough about PV. How about a discussion about wind?
