Given solar panels usually last for 25 to 30 years before losing efficiency, you would still have 17 to 22 years of savings on energy costs. What Can a 300 Watt Solar Panel Run? A solar panel delivering around 300 watts of power would be able to run things like ceiling fans, lights, rice cookers, phone and laptop chargers, a television or computer, and even electric fences. However, you'll need more energy storage batteries if you want to run heavier loads during grid outages, like an air conditioner, hot tub, or electric heating system.