The overarching objective
In response to the call ENERGY.2012.7.2.1, the overarching objective of e-Highway2050 is to develop a top-down planning methodology to provide a first version of a modular and robust expansion plan for the Pan-European Transmission Network from 2020 to 2050, in line with the pillars of European energy policy.The project is aimed at planning the Pan-European Transmission Network, including possible highways, capable of meeting European needs between 2020 and 2050.
The overarching objective has been split into nine individual objectives:
To frame the scope of a 2050 transmission infrastructure development plan including boundary conditions (WP1).
Starting with the outputs from the Ten-Year Network Development Plan (TYNDP) 2012, which have been established under a set of shared assumptions for the network in 2020, meeting this objective requires the following:
- Reviewing national policies in the mid term and long term, including recent 2050 studies such as the ECF or SUSPLAN work
- Appraising macro-economic factors which may have an impact on infrastructure development up to 2050
- Assessing the effects of potential Electricity Highway System (EHS) architectures on EU Member States and the Internal Electricity Market (IEM) affiliation
- Proposing assumptions (boundary conditions) which are accepted by the stakeholders in view of undertaking the present long-term planning studies at a pan-European level: consultations with the various stakeholders will pinpoint the grid infrastructures, technologies and electricity market assumptions which are ruled out for the present R&D activities.
To detail candidate grid architectures able to meet the challenges of electricity markets by 2050 (WP2).
Using today’s methodologies available within the TSO community, a scenario-based planning approach is being developed and implemented, using these four basic steps:
- Establishing the overall energy generation and consumption profiles:
A set of macro-economic scenarios is defined by zone and by country, for the different types of energy supply, from 2020 to 2050 involving simulated hourly time increments. Generation is based on fuel types, combining centralised and decentralised options. Consumption is based on type of business and usage.
- Geographical mapping of electricity generation capacities and consumption profiles:
Generation and consumption are localised, thus mapping the above types of generation and consumption via EU27 and IEM affiliates. The R&D challenge is to find the appropriate level of description for the pan-European grid required to support the architecture design in 2050 and evolutions from 2020 to 2050. Today's infrastructure will be considerably upgraded prior to 2050, which will require collecting the age of all lines and creating upgrading scenarios by 2050 (e.g. individual replacement, suppressed lines, new lines). The pan-European grid description is a compromise to account both for the geographical dispersion of generation and demand, and the evolution of transmission networks between 2020 and 2050. The modelling of this complex meshed network requires a generation clustering technique using each TSO’s expertise to describe the pan-European grid.
- Simulating the behaviour of the pan-European network to detect grid overloads and/or weak points by 2050:
Starting with the 2020 grid architecture, intensive scenario simulation will provide conditions under which the grid is overloaded while implementing several grid architecture options by 2050. The R&D challenge is to numerically detail 8760 hours of simulated grid behaviour per year according to 2050 electricity scenarios. The purpose of this is to detect any weak points in the grid where network capacity increases will be necessary. This detailed hourly description is needed to address correlated uncertainties introduced by a massive integration of renewable energy sources.
- Proposing grid architecture options and evolutions based on several intertwined technology route options:
The architecture options include AC interconnections, DC interconnections, hybrid AC/DC interconnections, the use of Phasor Measurement Units (PMUs), Dynamic Line Ratings or Power Electronics either to raise existing line capacities and/or to improve the control of long-distance flows. Combining the technologies available by 2050 (and the tentative performances proposed by manufacturers) allows a portfolio of candidate grid architectures to be detailed which are able to alleviate the detected overloads by 2050. Such tentative grids improvements can also lead to the use of overlay lines as exemplified in a recent study carried out in the USA where using multiple HVDC lines may prove to be a more economical choice than a full AC transmission system.
- Establishing the overall energy generation and consumption profiles:
To validate a portfolio of technologies which will have a direct or indirect impact on the grid architecture studies (WP3).
Several technological and economic factors will have an impact on the availability of power technologies for grid operators from 2020 to 2050:
- Firstly, European manufacturers who are leaders on the world market may benefit from higher growth in other parts of the world, but also from large-scale technology demonstrations already launched in Europe in parallel with the expected investment in Europe from 2012 to 2020. They propose a technology portfolio using more power electronics and more distributed information systems. This will affect the way system operators operate the power systems on a daily basis.
- Secondly, Transmission System Operators are facing public opposition to overhead lines. The response of the TSOs is often to invest in underground cables and DC technology. Moreover, the development of innovative long-distance power lines for large bulk transmission could bring technological breakthroughs such as superconducting cables with very low impedances and extremely high currents.
- Thirdly, investments in new power technologies are also being made to improve power flow control. However, this will progressively increase the complexity of the system, which in turn will change the way the electricity system is managed and keep reliability at its optimal level (using more corrective actions).
- Fourthly, the advent of storage technologies and real-time smart grid applications will provide new means of coping with feed-in fluctuations of RES-based electricity production.
A comprehensive range of technology must therefore be made available by manufacturers to TSO planners in order to cover the most probable grid architecture options: this will be based on robust technological and economic data for technology performance from 2020 to 2050, which is sourced from recently completed or ongoing EU-wide studies (REALISEGRID, IRENE40).
To detail modular development plans from 2020 to 2050, based on new grid architectures which will be able to overcome potential operational and/or non-technical barriers (WP4).
Any of the candidate transmission architectures which appear promising when considered from the perspective of a cost/benefit analysis may encounter technical and non-technical barriers before they are physically deployed:
- The secure operation of the grid and the resulting reliability requires that the new network configuration can be monitored and controlled. For instance, the increasing use of High Voltage Direct Current (HVDC) transmission lines leads to a new challenge in power systems: the interaction of High Voltage Alternating Current (HVAC) and High Voltage Direct Current (HVDC) transmission systems with respect to power system stability. The ability of a power system, for a given initial operating condition, to achieve a new acceptable equilibrium state after a fault, must be ensured. These disturbances range from minor disturbances such as small and continuous changes in the generator electrical output and loads to larger disturbances such as the outage of transmission lines and generators; three-phase AC faults, DC faults, etc…
- The capacity increase usually requires new lines for which permission requirements must be met, environmental impact assessments and public consultations must be undertaken before acceptance is reached.
The network modular development plan must therefore implement 2050 architectures which not only have a promising cost/benefit profile, but which can also be integrated without compromising network reliability and for which permits and public acceptance are based on favourable environmental impact assessments (backed by possible technical countermeasures to overcome such barriers which must then be identified in conjunction with manufacturers and/or regulatory authorities). A modular network development plan can then be proposed which details the retained grid architecture options, by 2030, 2040 and 2050, assuming that grid capacity is in line with the projected generation and consumption profiles derived from the scenarios agreed to by stakeholders.
To study the governance issues raised by the candidate grid architectures and establishing a target governance model (WP5).
Recent years have seen the establishment of new coordination bodies such as TSC or CORESO within Europe to facilitate transmission system operations. These legal entities have been given rights and duties to facilitate network management on a daily basis. It is expected that new grid architectures will give rise to even more complex issues relating to the transnational aspects of electricity highways such as financing and ownership, cost allocation, roles of supranational organisations, etc. For instance, the voltage-source converters (VSC) which control algorithms on cross-border High Voltage Direct Current (HVDC) lines require coordination on both sides of the border in order to achieve two goals: maintaining the agreed power transfer and avoiding cascading failures caused by AC lines tripping. This is just one example which illustrates that existing regulations at European and national levels need to be adapted, also in order to achieve a high level of social welfare. It is therefore of paramount importance to address governance model issues before establishing a target governance model for implementing the best performing grid architectures resulting from the analysis performed in WP2 and WP6.
To perform socio-economic analyses of the candidate grid architectures based on multi-criteria cost benefit analysis (WP6).
The socio-economic value of different network expansion options requires implementation of the proper framework in order to highlight the investment priorities based on multi-criteria cost benefit analysis.
Using the planning results available, indicators need to be defined which involve background methodologies such as the one developed in REALISEGRID, and which allow the measuring of benefits deriving from aspects which are quantitatively hard to grasp such as environmental constraints, level of public consensus, operational flexibility of the network, etc.
To establish a stakeholder framework and involve stakeholder groups at all stages of the scenario-based planning process (WP7).
The project deals with long-term time horizons, with high levels of uncertainty on possible visions for the European Energy System. It delivers results that will have impacts on a pan-European level. This therefore requires the continuous and structured involvement of all stakeholder groups, using clear messages on assumptions and findings, in order to achieve the necessary credibility and acceptance of the final recommendations and results (open communication processes). Stakeholder involvement will ensure the gathering and exchange of opinions; it will test and consult on proposals regarding boundary conditions, scenarios, barrier assessments and the governance models with key stakeholders.
To validate an enhanced long-term planning methodology able to circumvent the limitations of existing approaches (WP8).
For a given 2050 energy scenario, the challenge is to find an optimal long-term expansion plan for the pan-European grid. Assuming perfect foresight, this objective seems achievable. But the complexity of this work is further increased by the increasingly high level of uncertainty within this long time frame. Various difficulties must be taken into account when ensuring the relevance and robustness of a scenario-based European planning approach:
- The expansion planning is split into generation expansion and transmission network expansion planning to make computational issues easy to handle. The objective is to find an optimal design of a very large grid including its modular development plan over a very long time horizon. The different possible generation mixes and their evolutions over the time horizon are defined through scenarios. In traditional probabilistic approaches to transmission planning, uncertainties affecting generation are mainly the availability of generating units without any correlation. The advent of wind and solar generation makes this assumption obsolete. Spatial correlations affecting wind and solar generation are critical design variables. Generation feed-ins could change substantially from one day to the other, even from one hour to the next: the potential to generate energy depends on where generators are built and the distance involved in connecting power sources to existing systems, which brings relative costs of transmission and generation closer to each other. Architecture optimisation becomes more stochastic and it should therefore be implemented as such.
- New pieces of equipment involving power electronics (AC/DC converters, electronic interfaces of wind turbines, etc…) will change the dynamic behaviour of the Pan-European Network. Secure grid architectures must be chosen to ensure its dynamic behaviour. This implies the concurrent design of grid expansion and its related defence plans to ensure an acceptable level of reliability for the pan-European system.
- Proposing routes for transmission expansion is a dynamic planning issue that typically aims at identifying a schedule for transmission expansion along an extended planning horizon. It considers operations, investment costs and a reliability index to measure the ability of the system to transfer electricity from generation sites to consumers. New research results are now available for envisaging the improvement of approaches which better formalise modular development grid for architecture options at EU level.
A novel planning methodology must be designed to address, in a sufficiently detailed manner, the formal handling of uncertainties in the long term and the optimising of modular planning aspects.
To support the work flow between the single work packages and evaluate and disseminate the project results (WP9).
The dissemination activities will focus on the delivery of structured knowledge about the results from the R&D work. They will cover both planning methodology and the proposed network expansion roadmaps encompassing grid architecture scenarios, optimisation results, barriers and drivers as well as the resulting modular development plan from 2020 to 2050.
Grid design options are detailed along with technology bottlenecks, technical planning, operations and governance, and potential supply chain gaps, with the emphasis on environmental and public acceptance issues. Governance and regulatory aspects are detailed as well as the standardisation efforts required to optimise future investments and the support of the manufacturing industry.