Feasibility of running a laptop on its battery charger

Without a battery, a Macbook will run at a much slower speed. It provides enough power for most works except heavy ones. It will consume less power since the MacBook does not have a battery to avoid crashing. You may see flickering display or heat issues as well. If the old battery is swollen, it is better to remove it immediately to avoid it from exploding. Installing a new battery will be a permanent solution.