Environmental Engineering Reference
In-Depth Information
Table 6.9
Economic results of the natural gas network
TCOPF
Fuel
Energy
Minimum LMC
Maximum LMC
case
cost (£)
cost (£)
at node 4 (£/MWh)
at node 4 (£/MWh)
1
1693.53
5728.60
5.06
7.72
2
1727.45
5824.34
5.05
7.73
3
1724.77
5817.78
5.05
7.73
4
1696.36
5786.56
5.10
7.56
5
1746.45
5963.61
5.25
7.57
6
1785.57
6063.21
5.16
7.66
7
1783.50
6060.99
5.17
7.64
The incursion of micro-CHP units increases the natural gas provided by the slack
node, although for cases 6 and 7 this difference is more palpable since their
ability to produce electrical power is fully exploited;
●
Values of energy losses vary according to the formulation proposed; however,
it is clear that the minimum value is obtained when the whole energy system is
operated to minimise losses (
i.e.
case 5);
●
For all the scenarios the pressure values do not decrease sufficiently to require
the use of the compressor unit; nevertheless, the compressor is only constantly
active for case 5 since the trade-off of reducing losses offsets the load the
mechanism will consume;
●
If this was solely a common natural gas engineering exercise and due to its tech-
nical benefits, case 5 could make stakeholders think of it as the most efficient
strategy.
●
The following conclusions can be drawn from the economic results:
The fuel costs for running the natural gas network are less expensive in cases 2-4
(when compared to cases 5-7); this is because of the reduced operating patterns
of micro-CHP units. Yet since case 4 aims at reducing operating costs, its result
shows the effectiveness of the solver by reaching the closest value to the reference
case cost (
i.e.
case 1);
●
The energy cost results for providing the natural gas at spot market prices follow
proportionally the same trends as seen for fuel costs; thus, case 4 is the most
attractive for gas DNOs; this condition is due to the fact (as Figure 6.4 shows)
that gas prices remain constant throughout the day being assessed;
●
Taking the node furthest away from the slack as an example, the minimum LMC
increases slightly in most cases as a result of a higher base demand, while the
maximum LMC value tends to decrease as the thermal storage facilities are used
to reduce peak demand.
●
Figures 6.8 and 6.9 illustrate, according to the TCOPF operation strategy imple-
mented, the natural gas demand variations seen from the supply point. As depicted
by the figures, cogeneration devices will mostly affect the status-quo demand from
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