Plug in the car

One of latest “must-have” home appliances in Cayman is a “green” charging station for electric cars.

These eco-friendly vehicles have been legal on Cayman’s roads since late 2012, following several years of campaigning.

Sara Chung of Newlands Savannah in Grand Cayman is understood to be the first motorist in the Caribbean to have a charging station installed at her home, after swapping her conventional Hyundai Matrix for a Chevy Volt plug-in electric hybrid car in June.

Sara, who works in George Town, charges her car when she gets home from work at night.

The Level II charging station, which is located on the wall outside Sara’s home is 220-volts and it takes just four hours for the car’s battery to be fully replenished, allowing it to drive for up to 50 miles.

The Chevy Volt drives initially on electricity, gas-free and tail pipe emission-free.

Alternately, when needed, the car uses a quiet, onboard gas generator to provide electric power for a total range of up to 375 miles, meaning that Sara won’t come to a standstill on her way home, if the battery power runs out.

“I liked the idea of going green, and the gas prices were just killing me,” says Sara, who spent around $55 per week on gas for her previous car. “Now it takes me a whole month before my gas tank runs out so I spend about $35 on fuel (per month).”

Sara also has plans to switch to other environmentally-friendly measures around the house, including solar panels.

There are plans to install charging stations in various public locations across Grand Cayman, with three already operational at Camana Bay, Governors Square, and Cayman Motor Museum in West Bay.

Cayman Automotive Leasing and Sales has also signed an agreement with the Laguna condo complex on Seven Mile Beach to install Level II charging stations free of charge for apartment owners who purchase an electric vehicle.

John Felder, president and chief executive officer of Cayman Automotive, was behind the campaign to have Cayman’s law changed to allow electric cars to drive on the islands’ roads.




  1. I would be interested to know what the impact of the daily battery charging is on Sara’s CUC bill. I think one would have to take that into account to have a meaningful cost comparison against the 55 per week it used to cost to fuel her old petrol car.

    If the Chevy Volt is charged using electricity generated from CUC, is it not using power derived from burning oil in CUC’s generation plant? The car itself may not produce emissions when running on battery power but charging it every day contributes to the emissions from CUC’s power plant. It would be interesting to know how the marginal increase in emissions from the plant due to running an electric car like the Chevy Volt compares with the emissions from a standard modern petrol powered car.

    In other words, how green and how cost effective are these vehicles assuming they are not charged using a solar powered charging station?

  2. Again, nothing is said about solar power. Is this Level II charging station solar powered or not? This is the key piece of information – otherwise the article is useless.

    If it is solar powered – than it’s cool, well done Sara!

    If it is connected to grid – (and assuming that car is being charged overnight, it is more likely that it is Power transformator, which allows to charge car from CUC grid.) – then – thanks Sara, for burning double the amount of diesel (at CUC), modern gas car would burn. Including additional damage to environment.

    Also in this case, article lacks information about change in CUC bill (we were told about drop in gas expenses, but what about electricity?).

    Another thing which I am curious about – Does Cayman Automotive have any specific agreements concerning electric vehicle and any kind of additional bonuses / motivational payments from Chevy for increasing sales of specifically electric cars?

  3. Stanislav Zholnin, do you have facts or calculations to back up your statement on power consumption on the grid versus a gas burner?

    My research shows a Chevy Volt stores about 13.2 Kwh in its battery on a full charge and can go 38 miles average on that. So a full charge would cost approximately CI4.75 based on .36/kwh which is the average on my last CUC statement. That’s less than one gallon of diesel fuel at the pump, so it would be making the equivalent of more than 38 mpg on a fuel to electricity cost basis. Using figures from CUCs most recent annual report, one gallon of fuel can produce about 18.55 Kwh, so a full charge on the Volt costs CUC approximately .71 gallons of diesel to generate.

    These figures don’t seem to support your statement, but please share if you have other facts to back it up as this affects us all. I do agree that solar generation would be ideal and the article states she is looking into that, but to refuel the vehicle at night it wouldn’t be very helpful.

  4. Christoph,

    Valid question. I already made such calculation ones, several months ago in comments, but I can repeat applying specifically to Chevy Volt:

    a) battery capacity is 16.5 kWh for 2013 model. (wikipedia)
    b) CUC price per kWh – 0.36 cents approximately, I agree
    c) One gallon produces 18.55 kWh at CUC – agreed.
    d) Distance travelled on one battery charge – 38 miles, agreed.

    First major problem is that charging the battery is not an efficient process. It is not like putting gas in a tank. General guideline (you can google that) is that charging looses 20-30 percent. Let’s go at bottom of estimate, so we need 16.5 * 1.2 = 19.8 kWh out of the wall to fully charge the battery. This will cost CI 7.13 to the user.

    Transmission of electricity over distance is not free. You can guess it by difference between Output and Electricity sold in CUC financials, which is respectively (for 2012) – 587.1 and 547.8 millions kWh. 7 percent is reasonable loss estimate. So we need CUC to produce 21.19 kWh, so CUC will spend 21.19 / 18.55 = 1.15 gallons. Please also remember that here we are always talking about imperial gallons.

    1.15 IG = 1.44 US Gallons (those used in MPG measurements).

    So, we ended up with the following:
    Distance – 38 miles.
    Cost to user – CI7.13 which is approx. 1.22 IG at the pump or 1.47 US Gallons at the pump.
    Diesel burnt by CUC – 1.44 US Gallons

    So effective fuel efficiency:
    based on cost to user – 25.8 MPG
    based on actual fuel burnt – 26.3 MPG.

    Let’s say it is just 26 MPG. Is it efficient? Car is priced in US at 38,000

    Toyota Prius (the one which is fuel powered recuperation of breaking energy) – 50 MPG, price in US at 25,000-29,000

    So this is my analysis. I welcome any commentaries. I don’t say that my analysis is perfect, but I would really like (and I think it is to the benefit of Cayman) if some independent party (not CUC and not Cayman Automotive) would do analysis like this.

  5. Actually the use/charging capacity of the battery is only 10.8 kwh due to a buffering system not allowing full charge and depletion. Chevy’s own figure of 13.2 kwh per charge take into account the 22% charging loss, so your first calc isn’t relevant. I agree with 7% transmission loss though, so let’s say it takes 14.12 kwh for a charge.

    This equates to around .76 IG or .91 USG, so still above 38 MPUSG, and around CI5.08 in electricity cost to go 38 miles.

    I can’t determine whether the vehicle is worth the cost. That’s not my place to answer anyway as I’m not spending the money on it. My only point was that your statement that she’s burning double the diesel by having CUC generate it instead of her vehicle isn’t accurate.

    This makes intuitive sense if you think about it, as propelling a vehicle by an internal combustion engine is quite inefficient in the first place. Producing the power on a large scale and storing in a battery should be a more efficient process, even with charging losses. If this weren’t true, then we would all be just as well off by dumping CUC and buying our own diesel generators to power our homes.

  6. Christoph,

    It would be nice to have actual measurements in Cayman environment. I will not be challenging your calculation. Still, some thing worth noting:

    1) I don’t agree with your point on intuitive sense. Intuitive sense tells me, that the more transformations energy goes through, the less efficient it becomes. On the generators, diesel generation on a large scale is marginally more effective. The reasons why we don’t all just use personal electricity generators, I think is mostly because of other reasons – like convenience, grid load balancing, noise levels and such.

    When comparing using internal combustion engine to directly propel vehicle with using internal combustion engine to create electricity, transport electricity, charge battery, run electric engine, and propel vehicle – intuitively it makes much less sense to me.

    But people can have different opinions.

    2) above 38 MPG is very shy claim compared to what they claim in US (with different electricity production breakdown). In US-based comparisons these cars are often north of 100 MPG. Which makes a lot of sense to use.

    Let’s see how it works out, but I still insist on charging this cars with solar energy.

  7. It’s good to see some sensible debate and discussion in the comments section to this article about the costs and benefits of using electric vehicles here in Cayman.

    Much of the reporting in the Compass and its related publications seems to take a very simplistic view and focuses only on the benefits of using electric vehicles. In fact, much of the reporting reads like an outright advertisement for Cayman Automotive! I think it would benefit Cayman’s consumers to see a more balanced picture presented.