IEEE Power & Energy Magazine - November/December 2014 - 47

november/december 2014

1,600
1,400

(GWh)

1,200
1,000
800
600
400

Nov.

Dec.

Oct.

Aug.

Sept.

July

June

Apr.

May

Mar.

Jan.

Feb.

200

Underground Storage and Gas Fields
LNG

International Interconnection

TUY
LARRAU

ALMERÍA
EUSKADOUR

Dec.

Nov.

Oct.

Sept.

Aug.

July

June

May

Apr.

Mar.

Feb.

800
700
600
500
400
300
200
100
0

Jan.

(GWh)

figure 14. Gas transmission system inflows in Spain in
2013, by source.

BADAJOZ
TARIFA

Mugardos

Sagunto

Bilbao

Huelva

Cartagena

Barcelona

Dec.

Nov.

Oct.

Sept.

Aug.

July

June

May

Apr.

Mar.

Jan.

800
700
600
500
400
300
200
100
0

Feb.

figure 15. Natural gas supply through pipelines in 2013:
procurement per international interconnection.

(GWh)

The coordination of the reinforcement and expansion of
both the gas transmission system and the electricity transmission system is therefore crucial to achieving the economical
and secure operation of both systems, particularly the electrical one. Transmission planning is coordinated by Spain's
Ministry of Industry and revised every four years. As a result
of the current economic stagnation, the 2008-2016 plan has
not been implemented; it was transformed into a new plan for
the period 2014-2020.
These studies by the Ministry of Industry, which are made
available to all market agents, include future projections of
demand, future projections of supply, and environmental impact
studies. They are used by different administrative bodies and
by the market agents. The outcomes of such studies are indicative only (i.e., they are not binding on producers, consumers,
or retailers), but they constitute the basis for the expansion and
reinforcement of the electricity and gas networks. They are
binding, however, for the transmission system operator.
Regarding electricity, these studies involve:
✔✔ a reference generation expansion plan
✔✔ the actual transmission expansion plan
✔✔ a reference renewable generation expansion plan
✔✔ a reference plan regarding energy efficiency and
demand-side management.
Distribution systems are not subject to strict planning
guidelines. Distribution owners must expand and reinforce
their networks to ensure adequate supply quality, however.
The objective of the Ministry of Industry's planning exercise is to reinforce and expand the transmission system of
mainland Spain in the best possible manner, reinforcing international tie lines and facilitating renewable integration. The
specific details of the transmission expansion and reinforcement studies have been described in detail by de Dios et al.,
among others. They include static and dynamic studies, feasibility analyses, and environmental impact analyses.
Regarding natural gas, these studies define new gas
pipelines and the upgrades needed for old ones (including
international interconnections), as well as the building and
upgrading of storage and regasification facilities. The gas
network design is performed so as to ensure that enough gas
enters the system to guarantee:
✔✔ the supply of the demand for direct consumption and
for electricity production via CCGTs
✔✔ the supply of 100% of direct consumption and 90%
of the demand for electricity production should any
of the international interconnections fail under peak
demand conditions
✔✔ a reasonable overcapacity of around 10%.
LNG plants are planned according to the following criteria:
✔✔ The storage capacity of each plant should allow operation at nominal capacity for at least three days.
✔✔ At 50% of storage capacity, each plant should be able
to supply its expected demand for at least three days
if located on the Mediterranean coast and four days if
located elsewhere.

figure 16. Natural gas supply through LNG plants in 2013:
procurement per LNG facility location.
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Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - November/December 2014