You might want to get an HVAC opinion on this to get an idea how removing this heat source will affect the overall climate of the space, especially cold Edmonton winters (based on your username). In some places a fireplace like that is purely decorative. In others, however, the appliance might be functioning as an extension to your central heating system.

Looks like a very large space to heat, considering the high ceilings. Make sure whatever else is heating that space has the capacity to do so without also putting extra stress on the rest of the house. Where is the thermostat in relation to this room? If there is a thermostat in the room is it wired to the central air system? Or is it wired to the fireplace?

I don't see any electric baseboard heaters under the window. Check whether that register ("vent") under the window is supplying heat or if it's an air return. How many total windows and registers are there around the room?