The simple answer is yes. You take out the internal combustion engine and everything associated with it. In its place you fit an electric motor and some sort of power storage system – usually batteries.
So on paper it’s a doddle… but there are two problems – finding someone smart enough to do it for you, and the cost. As an example, Liberty Electric, based in Oxford, will turn a Range Rover into a zero emissions SUV for between £95,000 and £120,000 (includes price of car).
It’s sold out for 2008, but the fee is based on the firm doing multiple vehicles. Converting only one car to run on batteries would push the price so high as to make it unfeasible.