Extract from the speech of Matteo Codazzi (CEO at CESI) at the 3rd Dii Desert Energy Conference, held in Berlin on November 7th, 2012 The Target
Europe is undoubtedly a forerunner in the actions towards a sustainable energy future. Following a debate started in 2007, in 2009 the EU Parliament and Council set binding targets on CO2 emission reduction, RES generation penetration, increase in energy efficiency and introduction of biofuels for transportations; all targets shall be achieved by 2020.
Despite the ambitious so-called 20-20-20 targets, soon after the issue of the Climate and Energy package, a new discussion has started, targeting outstanding long term objectives on the power system decarbonisation by 2050: the long-term objectives aim at a 80% reduction of CO2 emissions compared to 1990 level in the energy sector, which means basically an almost full decarbonisation of the power sector.
For the power sector the 2050 target means a whole and deep change in the generation mix: thus, are we thinking about an evolution or a revolution in the generation endowments of the EUMENA region? As a matter of fact, this path, in the form of a “revolution” in generation assets, has taken place and is currently already ongoing in the European Member States prompted by the binding 2020 targets.
The “revolution” in the generation sector
In the last decade in Italy, we have assisted to an impressive boom of RES generation, particularly from the sun which reached 16 GW of installed capacity. Similar trends have been witnessed in other EU Members States, like in Denmark for the wind, in Germany for the wind and the sun and in Czech Republic for the sun.
All that occurred as a consequence of the power market opening, entailing competition and attraction of investments from the private sector - see the booming of CCGT in Italy - and the incentives to foster RES generation, which for some technologies showed an over-remuneration with respect to the real total costs (or LCOE: Levelized Cost Of Energy), such as PV in Italy.
Both ingredients worked fairly well in Europe to rapidly change the generation mix, particularly towards green or less pollutant forms of energy. Don’t forget that also the generation from fossil fuels is now greener that it used to be 10 years ago, no need to recall the new CCGT plants with efficiency as high as 55% or even more, which replaced old and more pollutant units with efficiency below 30%.
In the power sector everything is closely interrelated. The fast evolution in the power generation, but we would better say “revolution”, is having a dramatic impact on the power system. Let’s think, for example, to the numerous and serious problems caused by a massive penetration of non-programmable RES generation, such as generation from wind and solar.
For instance, in Italy the impressive growth in PV generation is already creating a remarkable distortion in the residual load curve to be covered by the conventional generation. Particularly, in the early evening PV generation is originating high load gradients: 14 GW of load ramp in half an hour to be followed by the conventional generation and import. The load gradient may be even steeper in case of wind generation decrease in the early evening. Hence, the flexibility enhancement of the conventional generation is becoming a key priority to operate the systemassociated, when possible and necessary, to a downward modulation of RES generation. This is a classical “load following” problem caused by non-programmable RES generation.
By the way, this issue is even more critical for PV generation, which is installed in a large percentage in MV and LV networks and, as such, this form of generation is not directly controllable by the TSOs.
But, skipping the long series of potential problems caused by non-programmable RES generation, such as “risk of cascade disconnection”, “local overloads”, “risk of over-generation”, “impact on the day-ahead power market prices”, “need for higher reserve margins”, “impact on the auxiliary service markets”, the forthcoming generation revolution is calling for a much greater challenge:the redesign of the transmission grid.
The challenge of the transmission grid
In fact, it’s well known, that most of the RES generation is location dependent (wind, sun, geothermal, hydro, but also, to some extent, biomass). Hence, new corridors either on land or off-shore shall be built to convey production to the load centres.
Of course, if we shift this “revolution” in the generation assets from a country-basedperspective to a tri-continental perspective(EU-ME-NA region), the need for new e-highways (electricity highways) becomes a key factor to achieve the above mentioned targets, as already recognized, among others, by Dii. Thus, the focus is shifted to the transmission grid, which risks being a bottleneck in the power transactions if its development is not adequately addressed in due advance.
Solutions for the transmission grid of the future
It is well-known how difficult it is to build a new EHV overhead line in Europe. The bottlenecks caused by the transmission grids have been the main reason of the market fragmentation and are now a major concern in the deployment of massive RES generation.
Sometimes, the authorization process might take decades, especially in case of cross-border lines, such as in the case of Spain-France or France-Italy. And in many cases, the deadlock is overcome only adopting non-conventional solutions. For instance the new interconnector France-Spain could finally be decided in 2008 thanks to the intervention of the European Coordinator, prof. Monti, who promoted a non-conventional solution consisting of a double HVDC link fully undergrounded in the cross-border section. Similar solutions have been adopted for the new Italy-France link and for the South-Western corridor between Sweden and Norway and in other cases.
In general, it is clear that when heading for a Sustainable Energy Future, we shall focusnot only on a greener power generation, but also on a transmission grid having a much lower environmental footprint. This process is indeed already ongoing in some EU Member States: the “10 projects plan for a sustainable development”, launched by the Italian TSO (Terna) in 2007. The investment plan, which worth 1 billion euros, allows a dismantlement of 1200 km of old Overhead Lines (with 4800 electric towers) facing the construction of only 450 km of new lines, adopting state-of-the-art technologies (e.g. low sag high temperature conductors, monotubolar steel poles), which also means some 4000 hectares of land freed from the right-of-ways of the old lines, the possibility of recycling more than 60.000 tons of material (equal to the weight of about 60 Tour Eiffel), the loss reduction of about 300 GWh/yr (equivalent to the annual consumption of about 100.000 families).
Reinforcing the transmission grid capacity at a national or regional scale is possible adopting the newest technologies, which have in many cases a positive impact on the territory. In other words, in mature systems like the European one, enhancing transmission capacity and construction of new corridors entail in many cases the dismantling of many old overhead lines built 50-60 years ago. This is the concept of “network rationalization”.
On a wider scale, when thinking about a massive power transfer from the MENA region to the EU, new high capacity corridors shall be constructed: the e-highways system. To smooth the environmental impact, our vision, already shared with Dii, is to create a new layer consisting of UHV links, mostly in DC, overlapped to the existing AC EHV networks in the MENA region and the EU.
The crossing of the Mediterranean basin will be achieved through three corridors, two of them submarine (the Western and the Central corridor), whilst the Eastern one would be terrestrial (see Figure 1).
In the EU, a number of interchange substations is foreseen to exchange power between the e-highways and the underlying national/regional AC grids. In other words, the massive transfer of power between the MENA region and the EU will be made possible resorting to new generation power links composing altogether an e-highways system, which allows conveying power up to the Centre of Europe. The EU-MENA region power transfer will be achieved through the construction of a limited number of high capacity power corridors (or e-highways), the environmental impact of them may be more than compensated by the streamlining / rationalization of the existing AC grids, particularly the sections at 220 kV level.
Figure1 - EUMENA transmission corridors.
For the terrestrial links, current technology already allows the construction of links having capacities exceeding 6 GW (already applied in China); much more challenging is the crossing of the Mediterranean basin through submarine cables, the capacity of which is now limited to 1 GW and with constraints on the laying down technology related to the maximum sea depth (at present, power cables are laid down up to 1600 m of sea depth, and some solutions put forward by manufacturers allow to attain up to 2000 m, which is however still a limitation considering the morphology of the Mediterranean basin).
Finally, we shall not forget that the heading towards an integration of the EU and MENA region calls for an almost complete redesign of the grids in North Africa and the Middle East.
Firstly, the grids have up to now been developed along the coastline to transfer power in a limited amount (few 100 MW) from fossil fuelled power plants. The change in the generation asset resorting to RES will shift substantially the location of the new generating plants.
Secondly, the Arab countries are currently facing an increasing demand growth (like in Europe in the 60s), with growth rates around 5% or even more. Thus, this further driver shall be considered when optimizing the structure of the new national/regional grids and the sections of the e-highways located in the MENA region.
The design of the network of the future calls for accurate and thorough analysis to identify the best options from the technical and environmental point of view. CESI is ready to take this challenge and, as recalled, is already in the arena, working actively with Dii and other national and international organisations to bring forward the most viable transmission grid solutions.