Google "energy calculator" and you'll find websites like this. It could very well be the case that something like induction is a better choice for you than propane or natural gas.

In my area, buying any electric appliance rarely ever pays if the other choice is gas...

Keep in mind that appliances of all sorts use around 25% of the total energy bill, and kitchen appliances around 10% (laundry and entertainment consume most of the rest). I know from experience (I keep written records) that I use 1-2% of my 100 gallon tank per month for cooking.

Here is a link that might be useful: Appliance energy usage

Thanks very much for the responses and ideas. Cpovey, what kind of LP gas range or cooktop do you have that takes 1-2% of your 100 gal tank per month? By the way, Happy Thanksgiving!

cpovey, great information thanks

justthebasics, no one can predict the future for you but you can calculate this yourself using your utility bills. A gallon of liquid propane contains approximately the same energy as 27 kilowatt-hour (kWH) of electricity. You didn't tell us your utility but if like me you're in Puget Sound Energy territory, you pay 8 cents per kWH. Multiply by 27 and that's $2.16. We also don't know your local price for propane but where I am, it's currently around $2.00 per gallon. So propane is slightly cheaper than electricity here. Call it a toss-up, really. You can plug in your own numbers. Of course, that's just now - there's no way to know what's going to happen to prices of either during the life of your oven. Propane will go up and down with oil, more or less, but electricity in this region is also likely to go up.

Frankly, even if there *were* a big difference, as cpovey says, for most of us, energy usage in an oven comes well down the list. That's unless you do something *really* silly, like buy a "classic" AGA. It's down the list after space heating, after water heating, after clothes drying, after the refrigerator. Really, operating costs for cooking don't amount to much - you really can choose based on other factors.