The electric energy sector is undergoing a major transformation. The established model, of traditional thermal power plants providing most of the ‘firm’ power to match variable levels of demand, is being challenged by the steadily increasing share of power supply from temporally-variable renewable energy sources, such as wind and solar power (e.g. REN21 2018 ). Demand variability is also increasing as a result of the widespread use of embedded smallscale generation (e.g., rooftop solar PV) and air conditioning, and can further change in response to price signals. This transformation in the energy sector is taking place against a variable and changing climate. Given the weather- and climate-dependency of both renewable energy and demand it is important to develop robust climate-based tools that can assist energy planners, market operators and policymakers.
'The established model is being challenged by the steadily increasing share of power supply from temporally variable renewable energy sources'
Source: ©imaginima - istockphoto.com
In order to assist the energy sector in understanding the role of climate on energy systems, and uptaking this climate information, the EU Copernicus Climate Change Service (C3S)  has taken as one of its foci the development of climate services for the energy industry, such as through the European Climatic Energy Mixes (ECEM) project. The C3S ECEM’s aim has been to produce a proof-of-concept climate service, or Demonstrator, to enable the energy industry and policymakers to assess how well different energy supply mixes in Europe could meet demand, over different time horizons (from seasonal to long-term decadal planning), focusing on the role climate has on the mixes. This objective has been tackled through a close interaction with stakeholders, in a framework that allows for co-design of the service.
The C3S ECEM project  started in November 2015, and represents a collaboration between teams from the University of East Anglia (UEA, UK), Electricité De France (EDF, France), the Met Office (UK), MINES ParisTech/Armines (France), the University of Reading (UK) and the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA, Italy). The project had a duration of 29 months.
The specific underlying challenges motivating C3S ECEM are:
- To describe the ways in which energy supply and demand over Europe are affected by the spatial and temporal variations of their climate drivers
- To produce scenarios that demonstrate how different energy supply mixes can meet demand at the European scale, particularly given the projected high level of highly climate-sensitive renewable energies.
The C3S ECEM had a strong programme of stakeholder engagement activities. Input collected via workshops, one-to-one meetings with experts, advisory committee interaction, email surveys, webinars and interactions at key conferences and seminars has been key in developing the Demonstrator . This is the tool that collects the output produced by C3S ECEM and presents it in a user-friendly and interactive format, and it therefore constitutes the essence of the C3S ECEM proof-of-concept climate service. For instance, the approach taken in each workshop has considered the expected audience and, especially, the level of progress of the project, starting from a simple wireframe of the Demonstrator presented during the first workshop.
To provide the key ingredients to the Demonstrator, the C3S ECEM project produced reference data sets for climate variables based on the ERA-Interim reanalysis. Subsequently, energy variables were created by transforming the bias-adjusted climate variables using a combination of statistical and physically-based models. These energy variables include: electricity demand, and generation from wind power, solar power and hydropower. A comprehensive set of measured energy supply and demand data was also collected from various sources including ENTSO-E , e-Highway 2050 , EUROSTAT , World Bank, national Transmission System Operators (TSOs) data not contained in the ENTSO-e dataset , the WindPower database  and data from EMHIRES  and other projects. These data have been critical in providing a reference to assess the robustness of the model used to convert climate into lectric energy variables. The main elements of C3S ECEM are shown in Figure 1 .
Climate and energy data have been produced both for the historical period (1979-2016) and for future projections (from 1981 to 2100, to also include a past reference period, but focusing on the 30-year period 2035-2065). The skill of current seasonal forecast systems for climate and energy variables has also been assessed. Data are provided for the European domain, in a multi-variable, multi-timescale view of the climate and energy systems. It can therefore help in anticipating important climate-driven changes in the energy sector, through either long-term planning or medium-term operational activities. For instance, it can be used to investigate the role of temperature on electricity demand across Europe, as well as its interaction with the variability of renewable energies generation. Figure 2 shows an example of how solar power scenarios for the next decades are represented within the C3S ECEM Demonstrator .
The C3S ECEM Demonstrator is constituted of a visual tool to display and investigate climate and energy data, along with a comprehensive set of documentation such as fact-sheets, methods and assumptions, key messages, event case studies  and frequently asked questions. It also has the option to enter feedback for the developers of the
Demonstrator to take on board. However, response to users’ queries, data updates or fixes are not acted upon within set time frames. In this sense, this is a proof-of-concept climate service, rather than a fullyfledged (operational and/or commercial) climate service. The C3S ECEM Demonstrator is viewed as a building block for the C3S operational service for the energy sector which is currently being developed.
Article based on: https://www.adv-sci-res.net/15/191/2018/
 Renewables 2018 Global Status Report (Paris: REN21 Secretariat).
 e-Highway 2050 was an EU project (2012-2015), participated in by a large number of Transmission System Operators (TSOs), energy companies and research institutions, that investigated a number of scenarios for power production across Europe: http://www.e-highway2050.eu
 European Meteorological derived high-resolution renewable energy source generation time series: https://ec.europa.eu/jrc/en/scientific-tool/emhires
 Climate data of relevance to the energy sector (top left) are first bias -adjusted and then converted into energy variables through statistical modelling or transfer functions. Climate and energy variables (var.) produced by the C3S ECEM are presented via the Demonstrator (inset Figure expanded as Figure 2) together with a wide range of documentation. For more information, see: http://ecem.climate.copernicus.eu/ (from Troccoli et al. 2018, Advanced in Science and Research, to appear).
 It shows solar power for France for the projection period (RCP8.5) for the five e-Highway2050 scenarios described in the text (time series plot) and for Europe (underlying map) for year 2050 for the first e-Highway2050 scenario (purple line in the time series). Comprehensive documentation about the Demonstrator is available at the bottom left hand side of the Demonstrator (http://ecem.wemcouncil.org/, this figure has been produced from the Demonstrator).
 Silva, V. and A. Burtin (2015) Technical and Economic Analysis of the European System with 60% RES, EDF Technical Report.