Whilst there are a myriad of easy ways to pay for fuel, and if individuals can be as motivated as my daughter, lots of opportunities to snare fuel discounts, whether you wait for the 10 cent a litre off days or use the supermarket vouchers or Smart Fuel discounts, that is not really helpful in a fleet situation if you have more than one or two cars.
For a fleet, it is more about simplicity, visibility and control. This means that being able to make one payment a month for all the fuel and easy ability to apportion costs to cost centres greatly simplifies the accounts department's job, and having comprehensive reporting, and especially exception reporting, eases the fleet manager's job. If you also get a discount then that is almost the icing on the cake these days.
Fuel cards do all this and more. By committing to one fuel brand (they all offer a dedicated card system) such as Mobil Card, all your drivers pay for fuel with the same mechanism, resulting in a single monthly invoice. Via an online system you can order and delete cards, set purchase limits by product type (usually down to specific fuel types), fuel only, fuel and oil only, etc. Cards can be cost centred for reporting and drivers enter odo readings when fuelling to allow you to monitor consumption and look for exceptions (for instance very high consumption might be a result of filling the boat at the same time as the car). A standard fuel discount per litre can be negotiated, varying with the size of your fleet, which avoids the need to shop for the day’s best deal. The additional costs are usually a card fee (often annual) and a transaction fee which is significantly less than the equivalent credit card fee. Again, larger fleets can negotiate on some of these costs.
For smaller fleets you can often access one of the Oil company cards via an affiliate scheme through a business organisation such as the local EMA or Chamber of Commerce which will get a better deal in terms of fees and discounts, but still your own account and all the other card benefits.