Belgium, as a member state of the European Union, has to set ambitious targets towards carbon-neutrality by 2050; this ambition in turn requires a carbon-neutral energy supply to all end use sectors in Belgium on their respective pathways towards a net-zero carbon future. However, how much renewable electricity from wind and solar can be generated within the Belgian borders?
EnergyVille/VITO has estimated the technical potential for renewable energy generation from PV on roofs and onshore wind installations in Belgium to be 118 GW. The assessment is based on a spatial explicit approach to account for the roof area and land requirement of decentralized electricity generation in a country where space is scarce. To this end, it builds on recent collaborations with local and regional authorities and their policy frameworks and ambitions.
In collaboration with imec and the Royal Meteorological Institute (RMI), EnergyVille/VITO maps how the current availability of wind and solar irradiation is distributed over Belgium, and where and how much renewable wind and solar energy generation is (technically) feasible in Belgium. The strength of the method used is that (i) it calculates hourly renewable generation profiles at high spatial resolution and (ii) that it contains a spatial optimization that allows optimal localization of wind and PV over Belgium. The high geographic and temporal resolution of the derived dataset serves as valuable input for long-term energy system, grid capacity and market models.
The study is part of the BREGILAB project (Balancing the Belgian electricity system for maximal use of Renewable Energy generation by a Grid Injection Limit Algorithm and optimal Battery deployment) which investigates how a balanced electricity system can be established in Belgium at minimal cost.
The derived dataset supports the assessment and analysis that focus on:
- How realistic is it to achieve the regional, national and international renewable energy ambitions given the technical potential of renewable energy sources?
- How to safeguard 1) sufficient space to increase renewable energy generation and 2) a transition to a second generation of wind turbines through a process of decommissioning/commissioning?
- How to better account for grid flexibility to cope with a higher penetration of the energy market by intermittent energy sources, and supporting the national energy requirements?
The outcome is equally relevant to policy makers, businesses and knowledge institutes, and therefore, the approach and our main findings are reported here.
The Dynamic Energy Atlas
The Dynamic Energy Atlas (DEA, Figure 1) is used to map and analyze both current and potential solar and wind electricity generation. The software tool combines spatial data and spatial modelling with technology and meteorological data to produce results on the spatial resolution of 100x100 meters for the entire Belgian territory – including offshore.
We focus on electric energy generation from wind turbines and solar on roofs. The spatially explicit inventories of currently installed wind and PV technologies are used to calculate hourly electricity generation. The technical potential for additional installations is modelled by delineating the available space for representative and available PV modules and wind turbines in the market today (for onshore wind VESTAS V112 - 3.3MW; and PV SPR-MAX3-400 with 226 Wp per m² capacity). RMI delivers spatially explicit hourly data on wind speed (ALARO ERA5) and solar irradiation (Meteosat second generation and ALARO ERA5) which is used to calculate the potential production at each location.
Figure 1 The Dynamic Energy Atlas (DEA) is a VITO/EnergyVille tool to map and analyze electric energy generation and demand in a spatial and temporal explicit way.
Policy scenario for onshore wind capacities and generation
Construction permits for wind turbines are subject to safety and policy guidelines that aim to keep the risk for accidents, nuisance or impact on the environment as low as possible. Therefore, a list of distance limiting criteria (e.g. distance to housing, transport infrastructure) and no-go zones (e.g. nature reserves) are to be taken into account when modelling the available space for additional wind turbines. Not all aspects of this potential impact can be grasped with one single distance rule for each turbine type or boundary condition.
A scenario allows flexibility with respect to which boundary conditions to consider and how strict distance rules are set when modelling the available space for additional wind turbines (Figure 2). The BREGILAB policy scenario combines relevant boundary conditions and corresponding distance rules for the selected wind technology (VESTAS V112 – 3.3MW) as determined by policy frameworks and regulations at the level of regions in Belgium. Therefore, it reflects current technological opportunities with respect to onshore wind development. The output of this scenario is reported and used to run a national scale energy system model (TIMES Belgium).
Figure 2 Schematic overview representing boundary conditions for the policy and an alternative scenario to construct onshore wind turbines. Negative advice limits allow no wind turbines, inside the positive advice limit wind turbines are usually licensed, and in between (orange zone) additional impact studies are required before licensing. The BREGILAB policy scenario only excludes the negative advice limit as the minimal distance between wind turbines and other infrastructure, buildings, and designated areas.
Technology assumptions to assess solar capacities and generation
Solar technology is a rapidly developing field with continuously improving efficiencies of PV modules . For the assessment of additional potential on residential and commercial roofs the SPR-MAX3-400 premium market module (226 Wp per m²) is selected which is expected to be common in the next 5 to 10 years. It remains a conservative estimate because according to the ITRPV projections PV technology is expected to evolve to efficiencies far beyond that figure as new technologies will become mainstream (e.g. tandem cell technology).
Residential roofs are typically tilted while commercial and certainly industrial roofs are commonly flat. Consequently, optimal configuration of PV modules will differ in orientation and tilt between building types. For residential roofs, a rule of thumb produced by the International Energy Agency is that only 40% of the total roof area that is technically available is used. PV modules are assumed to have a 35° tilt and spread proportionally over south, west, and east to obtain realistic daily profiles and to support the Belgian ambition to optimize self-consumption. On commercial and industrial buildings, PV modules are installed with a 10° tilt and spread symmetrically west -east oriented to maximize the available surface area and to reduce operational losses. Such configuration allows 80% of the roof area to be covered with PV modules.
The potential for ground-mounted PV, floating PV and building integrated PV (BIPV) offer an important additional opportunity to increase the use of PV in Belgium. Unfortunately, no clear policy guidelines exist to prioritize ground-mounted PV over other land uses (waterbodies, agriculture or industrial complexes) nor to evaluate in a spatially explicit manner the technical potential for BIPV in a reliable way and therefore are not yet assessed in this study.
To assess the total additional capacity that can technically be installed and the respective hourly electric energy that could be generated, the identified locations for wind and PV solar are combined with technical parameters and meteorological data from the year 2017. This results in a dataset of additional renewable capacity and the corresponding hourly energy generation for each location in Belgium. Figure 3 and Table 1 report for the regions the installed capacity and technical potential considering future technology options for the different regions in Belgium.
Figure 3 Installed capacity (1/1/2018) and technical potential per technology and regions in Belgium.
Table 1 Overview of installed (1/1/2018) and potential onshore wind and roof solar capacity (GW) at the level of regions.
1 Vestas V112 – 3.3MW is used as representative market model for an onshore wind turbine
2 Trina Solar TSM-250-PC/PA05A PV module with 152.7 Wp per m² capacity is used as representative for current installed base for both residential as commercial and industrial roofs.
3 SPR-MAX3-400 PV module with 226 Wp per m² capacity is used as representative market model for PV technology for both residential as commercial and industrial roofs.
Attention: The information contained within this table is based on the assumptions specific to the BREGILAB project, information provided by third parties and sensitive to progressive insight over the course of the research project (end date 2022).
Belgium has an additional technical capacity of 18.3 GW for onshore wind. Together with the existing capacity, it leads to overall values of Flanders 9.1 GW, Brussels 0.02 GW and Wallonia 11.4 GW (Table 1). Compared to installations anno 1/2018, wind generation capacity can increase 8-fold from 2.3 GW. Reported capacities assume the installation of 3.3 MW wind turbines (VESTAS V112) within the remaining available space. Depending on its geographical location the availability varies between 1000 and 3500 full load hours or a potential additional energy generation of approximately 33 TWh per year for Belgium.
The resulting map (Figure 4) indicates that the Antwerp harbor region, northern part of East-Flanders and the southern parts of Luxembourg, Limburg and Hainaut have a high potential for additional onshore wind generation. Brussels, both Brabant provinces, the coastal region and the northern parts of Liège, Limburg and Hainaut have a low technical potential.
Figure 4 Additional potential for onshore wind energy production (MWh per ha, based on VESTAS V112 3.3MW) at the level of statistical sector. The surface area of the statistical sector is taken into account.
The BREGILAB project limited its offshore scope to the existing concessions that were permitted and already constructed (1.01 GW) or planned (1.24 GW) on 1/1/2018 (Table 1). Belgium has the ambition to increase the existing capacity to 5.8 GW with a maximal additional 3.5 GW by 2030 in the western part of the North Sea. In combination with the 2017 meteorological data, the existing and planned offshore wind parks will have an availability that exceeds 3500 full load hours per year or a potential energy production of approximately 20.3 TWh.
Belgium has an additional technical capacity of 99.6 GW on roofs with a 50/50 split between residential and commercial/industrial roofs. Flanders has the highest additional potential with 65 GW followed by Wallonia with 30 GW and Brussels with 4.2 GW (Table 1). Compared to the installations anno 1/2018 PV capacity can increase on roofs alone 26-fold from 3.8 GW, and is currently at 4.8 GW. Reported new capacities in the study assume covering the available roof space with a 226 Wp per m² PV module (SPR-MAX3-400) at specified tilt and orientation per building type. The availability of PV varies between 930 till 1060 full load hours in Belgium or a potential additional energy production of approximately 99.3 TWh per year.
For residential roofs the spatial potential clearly follows the urbanization degree of the different regions in Belgium (Figure 5). The potential on commercial and industrial roofs is highest in Flanders, but geographical concentrated around large industrial complexes situated along highways, navigable waterways like southern West-Flanders and the Meuse-Sambre axis rather than in urban centers.
Figure 5 Additional potential energy generation (MWh) for residential, commercial and industrial rooftop PV per 100 by 100m pixel.
Achieving the energy and climate action goals
At the start of 2020 Belgium released its integrated national energy and climate action plan (NECP), which inter alia reports on renewable energy ambitions for 2030. The 2030 ‘with additional measures’ (WAM) scenario aims at 9.6 TWh electricity generation from onshore wind, and 9.75 TWh from PV. This 2030 NECP ambition can be covered by utilizing approximately 6% of the technical potential calculated by this study for PV on roofs, and 17% of the available total potential for onshore wind turbines. An energy system model with a spatially explicit technology representation will allow to provide additional insights into the most cost-efficient use of available roofs and wind turbines by taking regional differences in availability factors into account. In such way, we aim to progress in subsequent steps from a technical potential analysis towards an estimate of the energetic and economic potential of renewable energy sources in Belgium.
Towards a spatial explicit approach for energy system modelling
Decentralized energy generation requires space which is already sparse and fragmented in Belgium and therefore may compete, depending on technology choice, with high spatial demand to support housing, economic activities, transport infrastructure, agriculture and nature areas. The energy system modelling approach within BREGILAB takes into account current policy constraints on available space, and optimizes the generation potential with the demand, and grid capacity and flexibility. A unique feature of our approach is that through spatial modelling, expected shifts in the spatial criteria, as further loss of open space, increased urbanization in specific locations, can be taken into account during long-term planning. For example, the Flemish land-use change scenario that assumes a continuation of current growth trends of build-up land shows a decrease in open space of 9% by 2050 compared to 2013. Assuming a realization of the Flemish policy target of ‘no more net land take’ by 2040, on the other hand, results in a loss of open space of only 2.5% by 2050. Similarly, land use change dynamics will impact the expected de- and recommission potential of aged onshore wind turbines. The decisions made today will impact how much of the technical potential will be available in 30 years from now.
Our spatial assessment attempts to give an objective picture of the potential role of renewable energy on the future electricity system in Belgium, and is a stepping stone to investigate how to achieve a balanced system taken into account spatial limitations and opportunities. With this quantitative analysis, VITO/EnergyVille aims to support industry, investors, administration and policy makers by providing the latest objective data.
DISCLAIMER: The information reported is based on the assumptions specific to the BREGILAB project mentioned and information provided by third parties. The outcome is regularly revised as part of progressive insights over the course of the research project. Although we encourage the use of the results for other purposes then BREGILAB research, we stress that it should always be done with the necessary diligence with respect to its original purpose and by informing the authors of this study and official funding agency (FOD economy) of the BREGILAB project.
- Belgium has a technical potential for renewable energy generation capacity of 118 GW from PV on roofs and onshore wind installations, corresponding to a maximum theoretical electricity generation of approximately 132 TWh per year, exceeding the current demand of approximately 85 TWh per year of Belgium today.
- The national and regional renewable energy ambitions for 2030 as spelled out in the National Energy and Climate Plan (NECP) for PV and onshore wind can be covered by utilizing approximately 6% of the technical potential calculated for PV on roofs, and 17% of the technical potential for onshore wind turbines.
- The Dynamic Energy Atlas is a flexible software tool that combines high resolution spatial, technological and meteorological data with spatial modelling to assess potential renewable energy generation.
- A spatially explicit approach gives an objective picture of the potential role of renewable energy on the future electricity system in Belgium, and is a stepping stone to investigate how to achieve a balanced system taking into account spatial limitations and opportunities.
 Verband Deutscher Maschinen und Anlagenbau (VDMA), 2020. International Technology Roadmap for Photovoltaic (ITRPV) Ed.12, April 2021.
 International Energy Agency, 2002. Potential for Building Integrated Photovoltaics. IEA Report: PVPS T7-4, Paris
 The most common split in orientation of PV was chosen. North orientation is not included in this study since it is only observed for a very small percentage of installations.
 Based on Ministerraad van 15 oktober 2021 - Energie: productiecapaciteit van de Prinses Elisabeth-zone in de Noordzee published by FOD Kanselarij van de Eerste Minister - algemene directie Externe Communicatie
Written by Wim Clymans, Karolien Vermeiren and Frank Meinke-Hubeny.
- Wim is researcher within the spatial modelling team at VITO. He focuses on modelling land use dynamics, renewable energy transition and environmental management processes.
- Karolien is business developer within the spatial modelling team at VITO. She guides the team project focus with respect to sustainable urbanization, energy transition and circular economy.
- Frank is project manager and senior researcher in the field of Energy and Climate Strategy. He focuses on long-term energy system modelling and scenario analysis at EnergyVille/VITO.