Power Connections
■ AC/DC converter stations. ■ Transmission components based on power electronics, commonly known as FACTS (Flexible AC Transmission Systems) devices.
■ Energy Storage. ■ ‘Smart transmission grids’, protection, control and ICT.
Energy Storage At present there are very few technically and economically
feasible solutions for storage of electricity. Otherwise, it would have been much easier and far less expensive to integrate a significant share of intermittent renewables into the electricity system. Electricity storage can be used for a wide range of applications on small and large networks. Some existing power systems use limited amounts of energy storage in their networks, mainly pumped hydroelectricity storage. In interconnected systems the energy storage facilities,
located in one area, will play a substantial role in balancing non-dispatchable and intermittent power, mostly from RES, located in another area where the conventional generation does not offer sufficient flexibility. In order to keep a power system stable, various ancillary services are required. The frequency of the system must be kept constant (or at least within very narrow limits) and this requires the ability to inject or absorb real and reactive power, often within very short timescale. Conventional fossil-fired generation can be used to provide regulating power and short and longer-term reserve power. As the proportion of renewable generation increases, the requirement for reserve power increases, too.
The development of interconnection
capacity between two separate countries (or areas) allows greater flexibility in the generation mix
Interconnections Around the World All regional markets have passed through an initial phase
where the participating countries were interconnected gradually. For instance, the regional market in Central America developed stepwise from the connections of El Salvador- Guatemala, Panama-Costa Rica, Costa Rica-Nicaragua, etc. Finally, in 2004 the interconnection between Honduras and El Salvador allowed the integration of all Central American countries in a common electricity market. In the current climate, interconnections between different countries are strongly recommended as they can help achieve global energy goals. The development of interconnection capacity between
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two separate countries (or areas) allows greater flexibility in the generation mix. In particular, the availability of cross-border transmission capacity may help select power from cheaper units located in another area or country.
Market Integration Issues Greater integration between different transmission systems
increases the overall benefits, but it also requires a greater degree of harmonisation. The development of cross-border energy trading may increase dependence on the import. This may have an impact on security of supply, unless a robust and credible common policy and strategy exist. This is a critical issue that affects the development of numerous large-scale projects. Some of countries are reluctant to become dependent on supplies from outside their borders. On the other hand, there are good examples of opposite policy approaches. Thailand, for instance, is exploring possibilities of long-term contracts with IPPs located in Laos. The hydro project Nam Theum 2 in Laos, with the installed capacity of 1,088 MW, is close to commissioning and nearly 90% of its electricity production will be exported to Thailand based on a long-term PPA. The peak demand of Laos was 415 MW in 2007, and it would have been impossible to develop the project only for the internal market. In a liberalised environment, decisions on transmission
network expansion/reinforcement, as well as on investment in generation, are made by different entities and may have a different impact on each type of market participants – consumers, suppliers and electricity producers. It is important to analyse the different incentives and interests
that the system operator (SO), responsible for system planning, may have in defining and developing the transmission
worldPower 2010
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