EWEA - The European Wind Energy Association

Introduction

A large contribution from wind energy to European power generation is technically and economically feasible. EWEA projects 230 GW in 2020 and 300 GW of total installed wind power capacity in Europe in 2030. This will result in a power generation in the same order of magnitude as the individual contributions from conventional technologies developed over the past century.

These large shares of gross annual electricity demand coming from wind – in the order of 12% in 2020 and 22% in 2030, depending on the development of the demand and the energy efficiency - can be realised, while maintaining a high degree of system security in the power systems. The constraints of increasing wind power penetration are not inherently technical problems with wind technology per se. The barriers are mainly a matter of regulatory, institutional and market modifications, and should be dealt with in a broader power market context. Moreover, a re-orientation in the European power systems to take the characteristics of large-scale wind power into account is in line with the overall European policy objectives of sustainability, security of supply and competitiveness.

In order to properly assess the scope of integration of wind power, a system-wide approach should be adopted. Wind cannot be analysed in isolation from other parts of the power system - and all systems differ. The size and inherent flexibility of the power system are crucial aspects in determining the system’s ability to accommodate a high share of wind power. The role of a variable output power source, like wind energy, needs to be considered as one aspect of a variable supply and demand electricity system. The already established system reserves and balancing methods, available for coping with variable demand and supply, are in principle adequate for dealing with the additional variable supply of wind power, at penetration levels of up to around 20% of supply, depending on the nature of the system. For larger penetration levels, power systems need more flexibility, for example in generation and demand response, to accommodate the further integration of wind energy. In addition, transmission and distribution network infrastructure needs to be upgraded and extended to accommodate the increased power flows, to better distribute the geographically diverse wind resource, and to access the offshore wind resources.

The economic impacts of wind power integration are beneficial. Studies in the United Kingdom, Germany and the Nordic area confirm that system integration costs for wind power, under the most conservative assumptions (low gas price compared to the current level, low to zero social benefit of CO2) make up only a small percentage of the actual consumer price of electricity. In addition, wind power, by virtue of its relative price stability compared to fossil fuels, reduces portfolio generation costs. Therefore, wind and other zero fuel cost technologies have a positive effect on the overall energy mix.

The major challenges of wind power integration need to be addressed in the following main areas:

• Design and operation of the power system
• Grid infrastructure
• Connection requirements for wind power plants
• System adequacy and the security of supply

Finally, institutional and legal barriers to increased wind power penetration need to be addressed and overcome. Conclusions and recommendations in these areas are discussed below. 

System operation: power and energy balancing

Like any other form of generation, wind power will have an impact on power system reserves and will also contribute to a reduction in fuel usage and emissions. The impact of wind power depends mostly on the wind power penetration level, but also on the power system size, geographical area, generation capacity mix, the degree of interconnection to neighbouring systems and load variations.

When about 10% of total electricity consumption is produced by wind power, the increase in extra reserves is estimated at 2-4% of installed wind power capacity, assuming proper use of forecasting techniques. The consensus obtained from several national system studies is that the corresponding extra cost for secondary reserves is quite low, amounting to 1-3€/MWh (wind), typically less than 5% of generating cost at such a wind power penetration level. To be meaningful, these costs have to be compared to the reserve cost of other electricity generating technologies. However, such studies have not yet been conducted.

For the purposes of balancing, the qualities of wind energy must be analysed in a directly comparable way to that adopted for conventional plants. Balancing solutions involve mostly existing conventional generation units (thermal and hydro). In future developments of European power systems, increased flexibility should be encouraged as a major design principle (flexible generation, demand side management, interconnections, storage etc.), in order to manage the increased variability induced by renewables. Long gate-closure times should be reduced for variable output technologies. The balance market rules must be adjusted to improve accuracy of forecasts and enable temporal and spatial aggregation of wind power output forecasts. Curtailment of wind power production should be managed according to least-cost principles from a complete-system point of view.

Grid connection requirements and grid codes

It is evident that clear rules are needed to ensure that the power system operates efficiently and safely. In this respect, wind energy technology is evolving to keep up with ever stricter technical requirements. There are continuous changes in grid codes, technical requirements and related regulation, often introduced at very short notice and with minimum involvement of the wind power sector.

Grid codes and other technical requirements should reflect the technical needs for system operation and should be developed cooperatively between TSOs, the wind energy sector and authorities. Costly technical requirements should only be applied if they are based on a truly technical rationale and if their introduction is required for reliable and stable power system operation.

On the short term, there is a need for a structural harmonisation of grid code requirements for wind energy in Europe in order to avoid unnecessary costs for manufacturers and developers, to increase transparency, and to facilitate the process of further technical harmonisation of the requirements.

Grid upgrades and costs are not an isolated wind power issue

The European grid infrastructure needs upgrading at national, cross-border and trans-European level, not only to accommodate increasing amounts of wind power cost-efficiently, but also in view of the rising demand for other generating technologies. A well-interconnected transmission network will enable the benefits of the continental wind resource to be reaped to the full. The fact that grid reinforcements benefit all system users also has to be taken into account. Therefore, an integrated approach to future decisions is needed, which should take the particularities of wind power technology, as well as those of other technologies, into account. In this respect, grid connection charges to cover the upgrade costs should be fair and transparent and competition should be encouraged.

The complex process of upgrading the grid systems requires short and long-term measures to enable a smooth integration of wind power. Short-term measures include the optimisation of the existing infrastructure and adaptation of management procedures. Reinforcement at critical transmission corridors, as identified within the TEN-E Guidelines, is also necessary in the short term. TradeWind - a recent study published by EWEA - identified 42 interconnectors in Europe and a corresponding time frame for their reinforcement to enable the economic integration of the foreseen wind power capacity levels of 2020 and 2030. A transnational offshore grid is proposed to accomodate large amounts of offshore wind power and to make full use of the continent-wide smoothing effects of wind power in synergy with electricity trade between Member States. This would improve the functioning of the emerging internal electricity market, similar to the way European gas pipelines have been constructed.

Adding wind power to the existing system contributes favourably to security of supply

Wind energy replaces energy produced by other power plants, which improves the energy adequacy of the power system. This is especially beneficial when wind is saving finite energy sources, such as gas, coal and oil, thus decreasing the effect of price volatility on the national economy. In addition to energy, wind power replaces conventional generating capacity. At low penetration rates, the capacity value of wind power is  in the order of its average power during times of peak load (20% of installed wind power capacity, depending on site conditions and wind power penetration in the system). The geographical aggregation of wind power at European scale has a strong positive effect on its capacity value. Finally, adding wind power to the existing system contributes favourably to the security of supply by virtue of technology diversification and indigenous production.

EWEA’s grid integration activities

In 2005, EWEA published its analysis and recommendations concerning grid integration in the comprehensive report: Large scale integration of wind power in the European power supply, 2005. In November 2006, a conference on the large-scale integration of wind power was organised in collaboration with the European Transmission System Operators (ETSO) and the European Commission. EWEA is currently working, in collaboration with its members and associated organisations, along the following main lines:

1. European Grid Code developments

In order to have a coherent influence of the wind industry on the process of development of Grid Code requirements in Europe, a Working Group (WG GCR) has been launched within EWEA. Its objective is to exchange experiences in grid connection from different countries and to work towards the harmonisation of grid code requirements. The Working Group consists of representatives from wind turbine manufacturers, wind farm developers and operators, consultants, service providers and wind power associations. In 2007, the WG prepared a first position paper with viewpoints on issues and harmonisation of Grid Code requirements for wind power. The WG recommends a structural harmonisation of Grid Code requirements on the short term, and a co-ordinated dialogue at European level with the stakeholders (TSOs, regulators, European Commission). In addition, the Working Group closely monitors technical developments and standards (for example IEC 61400-21, national codes from Germany, Spain).

2. Grid infrastructure upgrade

EWEA monitors the development of European policy (TEN-E) and provides input through based on analysis of technical and policy aspects. EWEA participates in the working group for onshore and offshore grid development of the European Coordinator. Within the TradeWind project (see below) EWEA recommended specific network upgrade measures to facilitate the integration of the wind power scenarios up to 2030. Furthermore, through participation in Technology Platform Smart Grids, EWEA monitors the communication of developments, new proposals and results, with respect to new technological developments in the area of transmission and distribution grids.

3. European Electricity Market (legislation, regulation)

EWEA closely follows development of the legislative and regulatory framework governing the functioning of the Internal Electricity Market. In 2008, the most important development is the adoption of the legislative package (3rd liberalisation package) proposed by the European Commission. Through the TradeWind project, EWEA has assessed the efficiency of the market rules and has recommended improvements to enable an efficient trade of wind power in the markets.

4. System integration studies

EWEA has coordinated a Consortium of nine partners, carrying out a European study project, TradeWind, which recommended interconnection upgrades and market measures that enable the large-scale integration of wind power in the future European supply for wind power scenarios until 2030. Detailed project deliverables, including Work Package reports, papers and proceedings of the three seminars are downloadable from the project website. EWEA keeps track of the progress and results of national and international studies on large scale wind power integration. This includes cooperation with the EWIS project and participation in the IEA task group 25.