e-Highway 2050: A methodology to define power technologies expected to impact grid architecture studies at 2050

Challenge
The main challenge relates to the identification and selection of power system technologies expected to impact grid planning studies in a pan-European context at 2050:
- How to define a portfolio of power generation, storage, demand-side and power transmission technologies at the 2050 time horizon impacting the European transmission grid?
- How these power technologies are consistent with the defined eHighway2050 scenarios?

Background and assumptions 
This knowledge article is to be read in the general context of the e-Highway2050 project. In this project, an energy-scenario approach was adopted and five energy scenario projections of likely futures are expected to grasp all likely evolutions of the power system at 2050. The methodologies to define these scenario  and their quantification are detailed in parallel knowledge articles. The five retained eHW scenarios are described in the knowledge article “Challenging energy scenarios for the pan European transmission system by 2050”.

More particularly, it is written in the particular context of the power system technology characterization. The scope of power system technologies covers the whole electricity value chain from generation and storage, transmission (passive  and active transmission technologies) to demand.

Description of the resuls
The technology component of a grid planning approach is indeed of prime importance. In e-Highway2050 project, a technology assessment has been made to provide techno-economic data to the grid simulations. It is clear that the selection of technologies to be considered will influence these simulations at various levels: the level of electricity demand and the nature of the generation mix, the grid architecture options and the types of reinforcements. It consists in the construction of a database displaying data (i.e. technical performances, costs, environmental impact, etc.) that characterizes the different technologies for the next four decades, i.e. from today to 2050.

In an energy context dominated by renewable energy sources in Europe (scenario 100% RES electricity), it is expected that renewable energy sources, since widely adopted and integrated  in the power system, will see their maturity and cost trajectories positively impacted. In terms of transmission system reinforcements, the two complementary options that are the addition of new transmission links (new lines, new cables in AC or DC) and the increase of power flow controllability will be considered at a degree depending on the energy scenario at 2050.

Not all power system technologies need to be detailed in-depth at the 2050 time horizon. Some of them might remain marginal (not mature or too costly) or simply not relevant to the scenario. To illustrate such issue of relevance of a technology to a scenario, let us take an example.  The “Large scale RES and no emissions scenario” (X5) is characterized by some key features.

Since large-scale offshore wind parks in the North Sea and Baltic Seas or implementation of transcontinental liaisons with North Africa might be needed, it is likely that generation technologies such as Off-shore wind power, PV, CSP or HVDC transmission technologies will be critical.
On the same way, since for that scenario Electrification of Transport, Heating and Industry is considered to occur both at centralized (large-scale) and decentralized (domestic) level, it is likely that demand-side technologies  such as EVs or heat pumps will be needed.
Last but not least, nuclear technology as a centralized technology is to be included in the technology portfolio as a technology in the generation mix for the same scenario “Large-scale RES and no emissions scenario” (X5). Technology selection will have to be consistent with the scenario-based approach followed by the project and considered sufficiently mature and deployed at the considered time horizon by the pool of technology experts in charge of the selection process.

The result is therefore a technology selection approach considering two series of inputs:
- all power technologies likely to impact a grid planning approach at a mid- or long-term time horizon
- the five e-Highway2050 scenarios.

1. Rationale of selection
The technology portfolio of power system technologies is defined upon selection criteria that are based on their possible impact on transmission networks with regard to planning issues by 2050.  For example, typical transmission technologies solutions include AC interconnections, DC interconnections, hybrid AC/DC interconnections, or Power Electronics to better control flows over long distances.  

More specifically the retained selection criteria include the relevance for grid planning at the considered time horizon, the validation that the technology is a contributor to the scenario (as a result of its commercial maturity).
For each technology area, a review of all technologies has been made with the support of technology experts which led to the e-Highway2050 technology portfolio.
For generation, storage and transmission area, the technology portfolio has been constructed based upon experts’ views.
For demand-side technologies, a specific methodology has been proposed on the basis of the criticality induced by the future demand-side technology changes, impacting the transmission system at 2050.

The selection and more generally the data gathering process for generation and storage technologies was mainly carried-out by a professional association, partner of the project (Eurelectric with its subcontractor VGB Power Tech) and an academic institution (University of Comillas) for electrochemical storage  technologies.
A professional association (EWEA, European Wind Energy Association) delivered the data for wind energy. 
The Institute of Power Engineering (IEN) completed the data sets for generation with specific data related to biomass-fired CHP (combined heat and power) plants.
The data gathering process for demand-side technologies (electric vehicles, heat pumps and lighting) was performed by TECHNOFI.
For transmission technologies, data was provided by T&D Europe for active transmission technologies (HVDC converters, FACTS, transformers, etc.), Europacable for cables (passive transmission technologies) and a pool of TSOs (RTE and Amprion), partners of the project, for overhead lines (passive transmission technologies).

2. The e-Highway2050 technology portfolio
As a result, the database is organized per technology, listed hereafter:
- generation and storage technologies: hydropower; PV; concentrated solar power; wind power; geothermal; gas turbines; hard coal and lignite with or without CCS (Carbon Capture and Storage); nuclear power; biomass and biogas; pumped-hydro; CAES (Compresssed Air Energy Storage); electrochemical storage;
- demand-side technologies: electric vehicles; heat pumps; lighting (Light Emitting Diodes and Organic LED);
- passive transmission technologies: high voltage (HV)AC  and DC cables (AC and DC submarine and AC and DC underground); HVAC and DC overhead lines; high temperature conductors; combination of HVAC/HVDC transmission solutions; gas insulated lines; superconductors;
- active transmission technologies: converters for HVDC (CSC and VSC); FACTS (shunt and series); phase shift transformers and transformers with tap changer; protection and control at substation and at system level.

Figure 1. Technological scope of the e-Highway2050 technology database

3. The technology portfolio and the energy- scenarios
For each scenario at 2050, the technology challenges and thus the technology portfolio are different.
Let us consider as an example the “100% electricity RES” scenario. It is indeed an extreme scenario with 100% RES penetration which presents specific technological challenges mainly in renewable electricity generation, but also in the demand side in energy efficiency, new uses and electricity storage while increased power transmission needs are expected.

Table 1. Key features of the “100% RES electricity” scenario and associated technologies

More generally, for the five considered scenarios an overview in terms of criticality is presented below.

Table 2. Criticality of challenges for the technology area for each e-Highway2050 scenario.

Criticality index can thus be used as a direct filter to get the final technology portfolio from all possible technology options displayed in Figure 1 (e.g. filtering out the technologies rated ++ or +).

Assessment of the methodology use and limitations 
Such approach could be easily reproduced on different energy scenarios when reassessing the Table 2 on the criticality of technologies per energy scenario. It could be easily reused to any other issues of technology assessment in an uncertain context for which technologies play a crucial role. The prerequisite is the availability of technology roadmap competences via experts from academic or industry.

References
Deliverable D3.1 eHighway2050