I would like to start a discussion about prioritization of different energy sources and sinks in the grid.
Independent of the protocol we use or the details of DC bus signaling, we need to define how we manage demand and supply if energy availability is not abundant.
As an abstract concept, the energy system can be treated as a market, even if a cost doesn't necessarily mean monetary cost. A draft concept could look like this:
The cost of energy is measured on a scale from 1 to 10 (with 10 being highest cost and lowest availability). The current energy cost in the system is communicated to each participant. It can be determined by a master controller or automatically, e.g. in a system with DC bus signaling, where a higher system voltage means lower cost.
Each load is assigned a priority level (switch-off cost threshold) from 1 to 10, which signifies the importance of the load or the willingness to pay. 10 means it's the most critical load which should be switched off last. 1 is used for dump loads which could e.g. use electricity for heating if it is abundant.
Each energy source is assigned a priority (switch-on cost threshold) which defines at which system level cost the source should start to supply power to the grid. Renewable sources should always supply power if needed, backup power like diesel generators should be switched on only to supply most critical loads.
An energy storage system can have a flexible priority setting, depending on how efficient it can store the energy (including all conversion steps) how much it costs to store the energy (e.g. cycle life). A battery for example might have a charging threshold set to quite low cost and a discharging threshold set to higher cost, so that the margin can pay for the degradation of the battery.
Below image tries to summarize the concept with some arbitrary voltages of a 48V nominal system for better understanding.
I would like to start a discussion about prioritization of different energy sources and sinks in the grid.
Independent of the protocol we use or the details of DC bus signaling, we need to define how we manage demand and supply if energy availability is not abundant.
As an abstract concept, the energy system can be treated as a market, even if a cost doesn't necessarily mean monetary cost. A draft concept could look like this:
The cost of energy is measured on a scale from 1 to 10 (with 10 being highest cost and lowest availability). The current energy cost in the system is communicated to each participant. It can be determined by a master controller or automatically, e.g. in a system with DC bus signaling, where a higher system voltage means lower cost.
Each load is assigned a priority level (switch-off cost threshold) from 1 to 10, which signifies the importance of the load or the willingness to pay. 10 means it's the most critical load which should be switched off last. 1 is used for dump loads which could e.g. use electricity for heating if it is abundant.
Each energy source is assigned a priority (switch-on cost threshold) which defines at which system level cost the source should start to supply power to the grid. Renewable sources should always supply power if needed, backup power like diesel generators should be switched on only to supply most critical loads.
An energy storage system can have a flexible priority setting, depending on how efficient it can store the energy (including all conversion steps) how much it costs to store the energy (e.g. cycle life). A battery for example might have a charging threshold set to quite low cost and a discharging threshold set to higher cost, so that the margin can pay for the degradation of the battery.
Below image tries to summarize the concept with some arbitrary voltages of a 48V nominal system for better understanding.
Let me know your thoughts.