Almost every time I hear a discussion of energy production and costs, I hear the term “grid”. It always conjures up th eimage of some giant scaffolding in the sky for me. What is this grid and where is it? How does it work? It seems that the “grid” is intimately tied into the possibilities of utilizing energy sources such as solar power or wind power to reduce dependence on fossil fuels.
To understand what the “grid” is, you have to understand how the energy we use every day gets to us. At its simplest, the energy we receive gets to us in a two-step process – it is first “transmitted” and then it is “distributed”. It seems to work like this. Somewhere there is an electrical power-generation source. This source could be a plant that burns fossil fuels, a nuclear reactor, or a hydro (water) station (i.e. Niagara Falls). The electric power that is generated this way is sent to substations over very high transmission wires. This is what is known as the electric-power transmission system. Substations are located closer to the end user. High voltage power received at substations has its voltage stepped down to a lower voltage and it is then “distributed” to customers - us.
A hitch in this process is that there has to be a perfect balance between the electrical energy produced and the electrical energy being used. If there is less electrical energy available than needed, then we can experience brown outs and even blackouts. On the other hand, if there is more electrical power produced than needed, where does it go? Hence the “grid”.
Electrical energy is not easily stored. The critical balance between production and
usage is not an easy one to maintain. To make electrical energy available where needed, the grid concept was developed whereby transmission lines are
interconnected so that excess production in one area can be solved by sending
that excess to another area that is experiencing more demand. The “grid” consists of transmission lines interconnected on a regional, national and international level so that electrical power can be reduced or expanded as needed.
The ‘grid”, however, is kind of a one-way street. It sends power from the production source to the user. When it comes to solar power or wind power, these power sources are typically operating at the low voltage end of the power spectrum and, in order for it to get into the “grid”, the power produced at these sites has to move in the opposition direction to get to the transmission lines. This is a problem waiting for a solution on a regional and national level and is why the term "grid" comes up in discussions on who to utilize these intermittent power sources.