Introducing the Energy System

Now we’ve looked at your learning objectives  for the course let’s get into the content.   We are starting with an overview of the  energy system by doing this we hope to   provide you with a foundational understanding  of the wider system in which your V2G operates.   This will be important when understanding the  use cases and value propositions which we will   come to later in the course. By the energy  system we mean the system of generation,   transmission, distribution and  consumption of electricity,   normally at a national scale. In this video  I’ll show you how is happens, what are the key   roles within an energy system and some of the key  challenges.

Typically in large energy systems,   electricity is generated by a mixture of fossil  fuel and renewable generation assets. The output   from these is stepped up to a very high voltage  by transformers before entering the transmission   network that carries the electricity over long  distances to the region where it is needed.   Once close to where it is needed the voltage  is stepped down again by transformers and the   electricity enters the distribution network.  The distribution network takes the electricity   over shorter distances to all the homes  and businesses that need that electricity.   Interestingly or increasingly we are  seeing more distributed generation   such as solar panels that can be connected  directly to the distribution network.   These can be on standalone sites or in roofs  of buildings already connected to the network.   Within the energy system V2G can act as  both demand - consuming electricity - and   generation - producing electricity - and  is connected to the distribution network.  

So what are the key roles in the energy  system? First we’ve got the generators   they’re the owners of the large generation  assets on the system and sell the output   from them into the wholesale electricity market.  Next we have the transmission system operator,   they own and manage the high voltage  long distance transmission network,   then the distribution system operator they only  manage the lower voltage distribution network,   then the consumers these are  the users of the electricity   however as the energy system evolves they can  also be small-scale generators of electricity too.   Suppliers are responsible for buying the  right amount of electricity from generators   and selling it to consumers.

Another key role is  the energy system operator they are responsible   for the operation of the energy system as a  whole ensuring supply and demand always balance.   The final role is that of aggregators they  aggregate smaller flexible generation and   demand assets selling flexibility from  them to the ESO or potentially the DSO.  

Now when operating the energy system as you can  imagine there are many challenges that need to be   overcome to ensure safe reliable and efficient  operation however there are two specific ones  

that I’d like to draw your attention to: firstly  that at every moment the supply of energy into   the system and the demand of energy out from the  system must match. Unlike gas or water electricity   cannot easily be stored and the electricity  network has no inherent storage in it. Ensuring   supply and demand is in each moment is the same is  primarily this responsibility of the ESO. Secondly   that the lines and the transformers of both  transmission and distribution level cannot be   overloaded. This responsibility falls on the TSO  DSO and ESO.

One thing that can help with both of   these challenges is something called flexibility  in this context flexibility is the ability of   either demand or generation assets to adjust  their behaviour as a result of an external signal   so this could be a power station increasing its  output or perhaps an EV chargepoint reducing its   charging demand. Flexibility has become  an increasingly important consideration   in modern energy systems and as you will see  later in the course is an important aspect of V2G