Investment in ICT: With most electricity networks in mature markets having been under invested for years, making the network “smart” will require considerable investment, exactly where that spending will go depending on the character and deficiencies of each network. There are some common components, however.
First of all, it is recognised that at the very least, consumer premises must have advanced metering, providing two-way communication between the consumer and the utility. Only after the meter is installed is it possible for consumers to have the information they need to use their electricity more efficiently.
Once the meter has been installed, the consumer is able to respond to utility signals that energy should be saved. The utility may, for example, implement time-of-day pricing, charging more at peak periods as a signal to consumers to shut off unnecessary power use through load control switches. Some devices, such as thermostats, washers, dryers and refrigerators may be adapted to respond to such signals.
By this means the consumer saves money and the utility evens out its load, thus achieving a better load factor and improving asset utilisation. Evening out the load has the additional benefit of reducing transmission and distribution losses, which are highest when loadings on the wires and cables are excessive.
In the EU, directives and regulations are in place to ensure that the Smart Grid at least achieves the intelligent metering stage over the next few years. By 2020, the main Directive states that 80% of households in Europe should be equipped with smart electricity meters and that a complete roll out should be achieved by 2022. Many meters have already been installed. It is probable that more advanced ones will need to be installed to achieve the full potential of the Smart Grid. In particular, advanced communication and metering systems will be needed to incorporate the resale of electricity from small-scale self generation and plug-in electric vehicles.
Meters form only part of the information structure required to link the consumer to the electric utility. The power companies will have to invest in microprocessor based systems at the substations, and further up the chain.
The bulk of the utilities ICT investment, however, is likely to be in the internal management of their networks. This will include the use of high speed sensors (PMUs) distributed throughout the network to monitor power quality and in some cases respond automatically. Wide area networks of PMUs, fully integrated into the system, are thought to be capable of containing domino effect blackouts, thus containing any problem to a small portion of the network. Network power system automation will enables rapid diagnosis of and precise solutions to specific grid disruptions. The systems involve analytical software, control systems and operational applications.
The need to form the information infrastructure of the network itself has become more pressing with the steady integration of distributed generation, much of which is from intermittent sources and has no facility for long term storage (including wind and solar PV power). Without well structured integration of distributed generation, the new sources of electricity threaten to reduce the integrity of the grid further, at the very time that it most needs improvement.
Transmission and Distribution
Smart Grid and other developments in the electricity business have direct bearing on the physical (non-electronic) components of the transmission and distribution network. Although the main impact is on transmission, distribution may be affected too. We have seen in Section 2, for example, that the increased electricity demand created by plug-in vehicles may mean that many distribution transformers will need to be replaced.
Upgrading the Transmission Network: As far as transmission is concerned, recent developments are pulling in two directions. In theory, by achieving better loading, the Smart Grid should reduce the need for new transmission lines. On balance, however, recent developments are positive:
New transmission lines needed to link in distribution generation sources.
More long distance transport of electricity as the electricity market becomes deregulated.
More offshore power connections, in deeper water.
The three trends taken together mean greater transmission lengths at a higher voltage, the third means that much of this is offshore. The net result of these trends has been a growing interest in HVDC transmission as opposed to HVAC. Not only does DC transmission mean lower electricity losses for any given distance of transmission, it also allows transmission at ultra-high voltages, beyond the thermal limits of AC lines.
HVDC in Favour: The downside of DC transmission (from the investors’ point of view), is that AC/DC and DC/AC inverters are needed at either end of the cable. In calculating whether the DC option is appropriate, the electrical losses in the inverter as well as its cost needs to be taken into account. This makes HVDC transmission only appropriate over quite long distances.
In terrestrial applications, HVDC lines are mostly overhead aluminium conductors. The big growth area in this market, however, has been in subsea lines, mainly linking country networks but increasingly also linking up wind farms located at some distance (over 50 km) from the shore.
Subsea Interconnection: A big potential in Europe exists in the development of a North Sea and Baltic Sea super-grid, for which there are a number of proposals in place, combining inter-country connection with the linking in of offshore wind farms.
The European Commission proposed a North Sea Offshore grid in its Second Strategic Energy Review, published in November 2008. This grid was identified as one of six priority energy infrastructure actions of the EU. The North Sea Offshore Grid is envisaged by the European Commission as a building block of a greater European-super grid.
A political declaration of the North Seas Countries Offshore Grid Initiative was signed in December 2009 at the European Union Energy Council by Germany, the United Kingdom, France, Denmark, Sweden, the Netherlands, Belgium, Ireland and Luxembourg. The European Commission is due to publish a "Blueprint for a North Sea Grid" in 2010.
A Market for Copper Sheathed Cables? Aside from the interconnection issue, the shift of wind power development into deeper water creates a potential market for floating wind towers, requiring flexible links to the ocean floor rather than the existing fixed links. The Hywind turbine, undergoing a two-year trial off Norway from 2009, is one such technology. The design allows the floating wind tower to operate at depths of over 120 metres, where fixed installations would become exceptionally expensive, to around 700 metres.
The oil and gas industry already has a well-established track record in operating floating systems at great depth, requiring cable connections to the seabed. The so called FPSOs, floating production units, were generally restricted to a water depth of 1,000 metres in the 1990s, but in the past decade operation in depths of 1,500 metres become fairly commonplace, and over 2,000 metres has been achieved.
This, and the possible use of floating wind turbines, is potentially a very interesting market for copper use in the copper sheathing of power cables. The cable connecting the platform to the seabed has to withstand recurrent bending, axial and torsional forces, with frequencies induced by the currents and waves. To compensate for this a so-called “dynamic” cable is required, capable of withstanding the extreme forces imposed and remain water tight.
Figure 83: Copper Sheathed Dynamic Cable Design and Sheath Testing24
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