To understand what you need from an independent power plant, or what you can get from your independent power plant, you need to be clear on the relationship between these two concepts.  When we use energy, we use it to do work, whether that work is heating or cooling our home, cooking on the stove, being lifted up a building in a lift, or moving around in our car.  Energy is all about being able to do work when we need to.

Energy can be stored so that it can be used to do work as we require it. Energy can be stored in many ways: as a wound-up spring, as compressed air, as pressurized steam, or as a suspended weight in an old clock.  One of the common ways that we store energy is as chemical energy.  The fuel that we use in our cars is chemical energy: it contains large molecules that are broken down into small molecules to release energy when they are burned in the engine.  The large molecules (hydrocarbons of petrol or diesel fuel) are the stored energy.

The fuel in a car’s fuel tank is its energy – it represents the amount of work that the car can do; in this example of a car, that’s the distance that it can be driven.  A certain amount of fuel means that the car can travel a certain distance.