Modelling embedded technologies in energy service networks - Modelling Distributed Energy Resources in Energy Service Networks - page 83

M G phev

Motor
load

P D phev P G phev

PHEV

P D grid

Electric
supply

P D urban

Electric
load

Σ

CHP

total

chp

P Dk

P Gk

chp

G Dk

Figure 4.21 Representation of the possible power exchanges that an electric node

might have when embedded technologies are present

Thus, the total electric power injections that supply the load required in electric
node k can be categorised into:

W phev
k

P grid
Dk

P phev
Dk

P urban
Dk

= + · (4.43)

The terms on the right-hand side of (4.43) represent the elements that will draw
power from the grid, either PHEV units or domestic (static) loads. Weight factor W phev
takes binary values ( i.e. 0 or 1) and serves the purpose of enabling the time intervals
in which it is possible to charge or discharge the PHEV technology. As it can be seen,
the superscript of the variables identify the elements that compose the total demand
P grid
Dk

. Terms from CHP power injections are omitted here and covered when term P total
Dk

is explained.
Hence, the electric power obtained for G2V and V2G services in node k is a
slight variation of (4.37) and (4.38), and can be defined as:

W phev
k

P phev
Dk

· = η G 2 V · G 2 V k (4.44)

W phev
k

P phev
Gk

· = η V 2 G · V 2 G k (4.45)

The electrical power generated when cogeneration units are dispatched was
detailed before but repeated here for clarification purposes, and determined as:

= η el W chp

Dk

P chp
Gk

G chp

· (4.46)

k

where η el is the electrical efficiency of the CHP, W chp is the CHP weight factor and

k

G chp
Dk

is the gas flow consumed.