System integration of renewables

Variable renewable energy (VRE), such as wind and solar photovoltaic (PV) generation, are essential for meeting future energy needs while decarbonising the power sector. VRE deployment has seen a dramatic expansion in recent years thanks to sharply falling costs and supportive policies. However, the inherent variability of wind power and PV power raises new challenges for power systems operators and regulators.

Integrating the first few percentage points of VRE share in the generation mix poses few challenges for most power systems. This is because all power systems have technical requirements due to the variability and uncertainty of power demand.

Beyond these levels, as VRE penetration increases, power systems can be seen to progress through different stages requiring increasing adaptations. VRE integration levels of more than 50% have been achieved.

country	Wind share	PV share
Denmark	48.57	2.59
Ireland	24.26	0.02
Spain	18.02	3.12
Germany	16.43	6.15
UK	14.90	3.45
Italy	6.02	8.59
Belgium	7.82	3.58
Sweden	10.93	0.14
Australia	4.80	3.10
USA	6.07	1.62
Japan	0.59	5.69
China	4.63	2.01
Chile	4.46	4.94
Mexico	3.24	0.11
South Africa	1.99	1.31
Thailand	0.57	2.29
Indonesia	0.00	0.01
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This integration of higher shares of VRE involves technical, economic and institutional factors, related to not only the particular attributes of VRE generation, but also to the complex nature of the energy sector in general.

The key to integrating VRE is power system flexibility. Flexibility describes the capability of a power system to maintain continuous service in the face of rapid and large swings in supply or demand, whatever the cause. VRE also has impacts on the economics within energy markets and the required institutional arrangements.

The IEA has successfully established itself as a global reference for analysis of system integration of renewables, assisting policymakers and operators in adapting power systems in different local contexts to enhance system flexibility and to integrate larger shares of VRE.

China Power System Transformation

Published: 18 March 2019

”China Power System Transformation" provides a summary of the state of play of Power System Transformation (PST) in China as well as a comprehensive discussion of PST internationally. The report presents findings from a detailed power sector modelling for China in 2035, building on the 2018 World Energy Outlook Scenarios. The modelling identifies the establishment of spot markets and regional trade as two of the main elements to improve system operation efficiency in China. Activating the demand side – especially electric vehicles – and electricity storage are found to be crucial for an accelerated transformation of the Chinese power system.

See also the Chinese version.


Thailand Renewable Grid Integration Assessment

Published: 12 October 2018

''Thailand Renewable Grid Integration Assessment'' undertakes a comprehensive analysis covering the technical, economic, policy and regulatory frameworks. The analysis comprises the following important areas: 1) the existing VRE penetration context in Thailand, 2) grid integration of VRE in Thailand’s future power system, 3) the technical potential and economic impact of distributed solar PV on stakeholders, and 4) the power sector planning process and system costs. The study provides recommendations to guide decision making in power sector operation and planning, investment, and policy to support the uptake of VRE in a reliable and cost-effective manner in order to achieve the objectives of Thailand’s power sector policies.  

Status of Power System Transformation 2018

Published: 23 May 2018

Power plants play a critical role in enhancing system flexibility. Based on a wealth of real-life case studies and data, this report provides a comprehensive overview of how power plants can contribute to making power systems more flexible, while enhancing electricity security. It summarises the findings of the Advanced Power Plant Flexibility (APPF) campaign of the Clean Energy Ministerial (CEM).

The solutions presented in this study have been collected in close collaboration with industry stakeholders, including manufacturers, expert consultancies, system operators and plant operators.

See also the Summary for Policy Makers.

Technical annexes to the report are available here.

Status of Power System Transformation 2017

Published: 2 June 2017

The Status of Power System Transformation 2017 report provides an overview of current trends that are ongoing across the globe, with a focus on the integration of renewables and local grid development. The report examines a broad set of recent concrete power system interventions. A framework for assessing the status of power system transformation is also introduced, and is applied to selected countries: Indonesia, South Africa, Mexico and Australia.

This report can inform stakeholders of the dynamic changes that are occurring in power systems around the world and provide insight into measures that can help to overcome new challenges.

Getting Wind and Solar onto the Grid

Published: 16 March 2017

To help policy makers understand what challenges to expect, when to expect them and how policies can set the right pace of change in power systems, the IEA has released the Insights Paper on Getting Wind and Sun onto the Grid.

The report identifies four phases of variable renewable energy (VRE) integration, each with certain characteristics and operational priorities. Building on existing cases, the study identifies solutions that different countries have pursued as they decarbonise their energy supply.

Next Generation Wind and Solar Power

Published: 14 December 2016

Systematic measures for integrating variable renewables will be a priority for countries such as Brazil, China, Mexico and South Africa, where the share of renewable power is growing rapdily. In countries such as Denmark, where variable renewables have become the main source of power, a full transformation of the power system is necessary, including infrastructure, policies and markets.

This report includes a series of country-specific case studies that show how emerging countries can achieve integration. These possible solutions include long-term strategic planning, upgrades to power systems, more advanced variable renewable technology, additional distributed resources and policies that encourage projects with greater system value.

Download a summary of the report >

The Power of Transformation - Wind, Sun and the Economics of Flexible Power Systems

Published: 26 February 2014

Based on a thorough review of the integration challenge, this publication gauges the economic significance of VRE integration impacts; highlights the need for a system-wide approach to integrating high shares of VRE; and recommends how to achieve a cost-effective transformation of the power system.

Using detailed modelling, the report analyses the impact of high shares of VRE on total system costs. In addition, the four flexible resources which are available to facilitate VRE integration – generation, grid infrastructure, storage and demand side integration – are assessed in terms of their technical performance and cost-effectiveness.

GIVAR Advisory Group

The IEA Grid Integration of Variable Renewables (GIVAR) programme aims to build understanding of the characteristics of energy systems and markets that hinder or enable the reliable, economic integration of large shares of variable renewables (VRE), and to use this knowledge to inform and further enhance IEA analysis.

The programme has an advisory group composed of external experts. Members of the advisory group can find minutes and presentations from the meetings here (password protected).

Technology Collaboration Programmes (TCPs)


Renewable Energy Technology Deployment TCP

Established in 2005, the RETD TCP was a cross-cutting and policy-focused platform which aimed to accelerate the deployment of renewables; enhance international co-operation on policies, best practicesand market instruments; and support deployment of renewable energy technologies. The RETD TCP collaboration resulted in a number of valuable publications for policy makers. While the RETD TCP closed as of 1 July 2017, the full list of RETD TCP publications may be downloaded here.

IEA Smart Grids TCP logo

Smart Grids (ISGAN) TCP

The ISGAN TCP aims to advance policy, technology and related standards for smart grids by raising awareness of their benefits, developing tools for implementation, and co-ordinating joint projects. The annual ISGAN TCP Award of Excellence has become a global mark for outstanding projects and best practices on smart grids development and deployment. 

Learn more about the Smart Grids TCP >

IEA Energy Storage TCP logo

Energy Storage TCP

The Energy Storage (ECES) TCP develops and demonstrates advanced thermal and electrical energy storage technologies and encourages their use as standard engineering design options. Innovative energy storage materials were found to increase energy efficiency and reduce CO2 emissions in a wide range of applications.

Learn more about the ECES TCP >

IEA Demand-Side Management TCP logo

Demand-Side Management TCP

The Demand-Side Management TCP focuses on strategies for modifying the demand of energy from end-users using technological solutions, regulatory or financial incentives, and other means of encouraging behavioral change. By reducing or shifting demand according to a power system's needs, investment in power generation and grid capacity can be deferred or avoided, with benefits in both fast-growing economies where much power infrastructure is yet to be built, and in established systems where ageing infrastructure needs to be replaced.

Learn more about the Demand-Side Management TCP >

About Technology Collaboration Programmes

The breadth and coverage of analytical expertise in the IEA Technology Collaboration Programmes (TCPs) are unique assets that underpin IEA efforts to support innovation for energy security, economic growth and environmental protection. The 38 TCPs operating today involve about 6 000 experts from government, industry and research organisations in more than 50 countries.

Learn more about IEA TCPs >

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