First Float Column
An history of past editorials from the homepage of the IEA-PVPS website.
27th October 2016
Welcome to the 21st edition of the international survey report on Trends in Photovoltaic (PV) Applications up to 2015, provided to you by the IEA PVPS Programme.
The “Trends Report” is one of our flagship publications and a worldwide reference regarding the global photovoltaic market development. The unique series of “Trends Reports” has covered the transition of PV technology from its early and expensive niche market developments in the 1990s to the recent large scale global deployment and increased competitiveness. In contrast to 2014, 2015 has seen an impressive growth and acceleration of the global market deployment with about 50,7 GW of additional installed capacity, 26,5% above 2014, of which about 40 GW were installed in IEA PVPS member countries (2014: 34 GW). As in 2014, China, Japan and the USA lead this important growth, accounting for 33 GW of installed capacity in these 3 countries alone. 8 countries have installed more than 1 GW while another 7 countries have markets above 300 MW. The globally installed total PV capacity is estimated at roughly 228 GW at the end of 2015. Although the price reduction for PV systems has continued its trend for a slower decline in 2015, this year (2016) shows evidence of a more rapid cost reduction, in parallel with a trend towards higher overcapacities in the industry. Concerning PV generation costs and more precisely recently contracted power purchase agreements (PPAs), new record values of below 3 USDcents/kWh have been announced, confirming what is achievable today under very good market and solar resource conditions. The other side of the coin is the observation that large parts of the global PV market (78%) are still driven by financial incentives, accompanied by an increasing share of selfconsumption or net-metering (15%) and about 6% of the market coming from competitive tenders.
Yet, in many regions of the world, PV is one of the least cost options for electricity generation from new renewable energy technologies. New business models such as third-party investments and similar PV-as-a-service proposals are being developed by different stakeholders. While PV markets continue their impressive growth, technology progresses rapidly as well with thin film technologies approaching efficiencies similar to those of crystalline silicon. In parallel, emerging PV cell concepts and novel designs lead the way where PV technology might be heading to in the future. The increasing variety of technologies, designs and appearances of PV modules open up new applications and opportunities. Grid and energy system integration issues are becoming important in countries with a high share of PV, making PV a growing player in the energy field as a whole. In summary, PV continues its impressive and dynamic development in technology, industry, applications, installed capacity, price and business models, providing great opportunities for many stakeholders along the value chain. Learn all about the details of this exciting development by reading through our 21st edition of the Trends Report!
25th August 2016
2015 seems to be far behind us in terms of market development but official statistics are just starting to be released now in many sectors. PV doesn’t escape this and our IEA-PVPS National Survey Reports are coming in. After more than 20 years, each year they contribute to a better understanding of PV development in key IEA-PVPS countries with reliable information about the market, the industry, the policies and the economic context in which PV develops. These reports browse a variety of PV markets which allows the reader to understand and compare the specifics of a country with a level of detail that is not provided anywhere else. While the PV market continues to boom globally, these national reports offer a synthetic view on the policies that allowed the market to develop or not.
14th June 2016
This year’s EU-PVSEC conference, co-located with the Intersolar fair, will be the occasion for the IEA-PVPS experts to present new reports and findings on multiple subjects related to PV development globally. After reports on Hybrid PV-diesel-storage systems, self-consumption, preliminary data about the 2015 global PV market and two reports on methodological guidelines on LCA and net-energy analysis, IEA-PVPS will present a brand new report, co-signed with IRENA on “End-of-Life management for PV Panels”. This report will highlight once more that the sustainable aspects of PV development represent an important subject for the PV community.
Next to these reports, IEA-PVPS with be present with a booth and will organize or take part to three side events during the EU-PVSEC conference. These workshop will look at the question of PV quality, end-of-life of PV modules and the question of PV competitiveness, with or without storage. Organized jointly with the EU-PVSEC, these events are organized with the collaboration of several organisations such as IEA-SHC, IRENA or Solar United.
28th April 2016
The IEA Photovoltaic Power Systems Programme IEA PVPS is pleased to present its 2015 annual report. A further strong global market growth and a continued increase in competitiveness of solar photovoltaic (PV) power systems make PV one of the most vibrant developments in the present energy technology landscape. Achieving levelized costs of electricity from PV as low as below 5 USDcents/kWh, establishing Gigawatt (GW) scale markets in an increasing number of countries around the world and a continuous evolution of the market framework set the scene for our collaborative efforts focussed on a further sustainable development of PV technology, industry, applications and markets.
2015 has seen close to 50 GW of additional installed PV capacity worldwide, 25 % above 2014 and raising the cumulative installed capacity close to 230 GW. As in 2014, China, Japan and the USA represented the largest markets in 2015, accounting for two-thirds of the additional installed capacity. Meanwhile, more than 50 % of the global PV capacity is being installed in the Asia-Pacific region. Nevertheless, Europe also saw a growth in absolute terms.
23 countries have now reached cumulative installed capacities above 1 GW and in at least 20 countries, PV contributes with 1 % or more to the annual electricity supply, reaching between 7 and 8 % in some European countries.
Dynamic developments in PV technology, industry and market deployment form the framework for the activities of the IEA PVPS Programme. As a leading and unique network of expertise, our mission is to cooperate on a global level in this rapidly evolving technology area. Working on both technical and non-technical issues, IEA PVPS undertakes key collaborative projects related to technology and performance assessment, cost reduction, best practice in various applications, rapid deployment of photovoltaics and key issues such as grid integration and environmental aspects. Anticipating future needs, IEA PVPS increasingly focusses on recent policy and market issues, new business models, sustainable policy frameworks as well as technical and market related integration of photovoltaics in the electricity and energy system at large. These issues relate to the latest developments and insights regarding e.g. self consumption or working more closely with utilities.
In a world where PV is becoming more and more a mainstream technology and where increasingly more stakeholders and organizations are active, providing well targeted, high-quality information about relevant developments in the photovoltaic sector as well as policy advice to our key stakeholders remain our highest priorities. Indeed, due to the increasing recognition of photovoltaics as an important future energy technology, the interest in the work performed within IEA PVPS is constantly expanding and the outreach of our efforts becomes more and more relevant. Besides the continuous exchange and cooperation within the IEA technology network, stronger ties are being built with organizations such as IRENA and the IEC.
Interest and outreach for new membership within IEA PVPS continued in 2015. After being absent from IEA PVPS for more than 10 years, Finland has rejoined our programme in 2015. We very much welcome Finland back as partner in our network. Due to the UK which has left the programme, our membership has remained at 29, keeping IEA PVPS as one of the largest IEA technology collaboration programmes (TCPs). Exploration for membership continued with Chile, Greece, India, Morocco, New Zealand, Singapore and South Africa as well as with EPRI (Electric Power Research Institute USA) and ECREEE (ECOWAS Regional Centre for Renewable Energy and Energy Efficiency). IEA PVPS continues to cover the majority of countries active in development, production and installation of photovoltaic power systems. We thereby strive to respond as much as possible to the increasing role that the new IEA Executive Director Fatih Birol has called for by the IEA TCPs.
Our overall communication and dissemination efforts were continued through systematic distribution of PVPS results through publications, conferences and workshops. Communication was further supported by the PVPS website www.iea-pvps.org and targeted press work. Moreover, the IEA PVPS booth and the workshops at the 31st European Photovoltaic Solar Energy Conference in Hamburg (Germany) attracted a large number of visitors and provided an excellent forum for dissemination purposes. More than ever, our efforts aim to engage within and beyond our network, providing up-to-date information and ultimately contributing to relevant outcomes and impacts.
The detailed results of the different PVPS projects are given in the Task reports of this annual report and all publications can be found at the PVPS website. As a unique feature, the current status of photovoltaics in all PVPS member countries is described within the country section of this annual report.
Our work would not be possible without a committed community of experts and colleagues. I therefore wish to thank all Executive Committee members, Operating Agents and Task Experts, for their ongoing and dedicated efforts and contributions to IEA PVPS.
7th April 2016
The story of the last 10 years explains what happened in the PV sector. The introduction of the feed-in tariffs in Germany allowed the industry to move from a niche market to an industrial-size market. Policies that are now negatively seen and that have led to the boom of PV in many countries, have allowed the market to develop and the prices to go down significantly, thanks to economies of scale in the industry and technology improvements. The market moved rapidly from 1,4 GW in 2005 to 16,6 GW in 2010 and 50 GW in 2015. OECD countries and in particular European ones, Japan and the USA contributed significantly to PV development in these 10 years. However, for a few years, developing countries have been contributing to PV development, mainly in Asia, as well as on other continents. The Asia-Pacific region represented around 59% of the global PV market in 2015 and is the first ranking region for the third year in a row. Europe’s market share fell again to 18%, despite a growth in absolute terms. The PV market in the Americas continued to grow with the USA, Canada and Chile leading the pace, ahead of several new markets. The Middle East had many project announcements and set up some installations, while the African market declined. Still, the most important element was witnessed again in China with its market progressing to 15,3 GW. The second largest market was Japan with 11 GW in 2015, ahead of the European Union and the USA with more than 7 GW each. India, with 2 GW appears to be the rising star in the PV sector. In 22 countries, the annual PV contribution to electricity demand has passed the 1% mark, with Italy at the top of the list at around 8%, followed by Greece at 7,4% and Germany at 7,1%. The overall global PV contribution amounts to around 1,3% of the world’s electricity demand.
The results are the consequence of pro-PV decisions that have been taken in numerous countries with little experience and in many case with a real willingness to allow PV to develop. The result as we see it in 2016 is astonishing: PV is now one of the most promising sources of electricity for dozens of countries on all continents. Its prices are continuously declining and History will only remember how it revolutionized the energy sector in a couple of decades. IEA-PVPS intends now to continue providing expertise and researching the best way for PV to pave the way for the future sustainable, decarbonized and of course renewable electricity mix.
9th March 2016
While PV develops in all parts of the world, a successful COP21 climate conference pushes us all to remember why PV develops and why the question of sustainability is essential. The Task 12 of the IEA-PVPS program focuses on the analysis of sustainability aspects of PV development, and especially the understanding of the complete life-cycle of PV components. Two new studies from IEA-PVPS are defining and updating guidelines for life-cycle assessment and net energy analysis of PV plants. These two new studies are building on an already long series of past documents and studies aiming at paving the way for a better understanding of the impact PV has on the environment.
In 2016, PV is still questioned about its ability to recyclable, emit almost no CO2, use available materials which exploitation does not cause damaging effects on the environment and consumes small amount of water compared to most sources of electricity. The task 12 of the IEA-PVPS program aims at providing sound, scientific and reliable answers to most of these questions, and the two reports recently published are an excellent example of a successful international cooperation on these key subjects.
22nd January 2016
On January 22nd, 30 representatives from European utilities met in the IEA offices in Paris to discuss the evolution of business models for PV applications. This second IEA-PVPS meeting aimed at exchanging views on business models based on self-consumption of PV electricity in key European countries.
The conclusion of this second workshop was extremely simple: customers are willing to invest in PV systems to reduce their electricity bill and benefit from clean energy. The major question consists in identifying how to propose adequate, cost-competitive solutions to allow electricity customers to become prosumers, directly or indirectly. Should customers install directly PV systems on their roofs and finance them? Or should they opt for renting or leasing contracts? Or should they simply invest in PV systems installed elsewhere in exchange of free and clean electricity? All these solutions have already been tested and are proposed in several European countries by local or nation-wide utilities, with some success.
IEA-PVPS intends to recognize, through these workshops, the capital role of existing utilities in developing the PV market for prosumers. During the two workshops, major utilities from France, Germany, Spain, Italy, Portugal, Austria, Switzerland, Sweden or Finland brought the expertise and contributed to make this workshops successful. IEA-PVPS intends to continue providing a platform for utilities, where these companies can exchange about how PV will reshape their business models and ensure their position in that fast developing industry.
23 October 2015 - A Complex Market
This year marks the 20th edition of the Trends in Photovoltaic Applications report. from the first version to the 20th, the PV market has boomed to reach the quasi mainstream technology it represents today.
This edition of the Trends shows that the global PV market is far from being homogeneous:
- Modules and system prices continue to vary significantly from one country to another, driven by local regulations and market specifics. Prices remain significantly higher for rooftop PV applications in the USA and Japan than in Germany for instance.
- The segments are not developing homogeneously and while utility-scale PV dominates in emerging markets, distributed rooftop PV continues to represent around 45% of all installations.
- 40 GW were installed in 2014, far less than what many expected due to the stagnation of the Chinese market and the major decline of the European one. In addition, emerging markets in emerging economies accounted for less than 3 GW in 2014.
Many other conclusions could be derived from the analysis done in this edition of the Trends report that are all going in a similar direction: the PV market has continued to grow, together with its complexity and the associated challenges. In the coming years, the PVPS program of the IEA will continue to highlight the most important evolutions in this sector and provide accurate information about the evolution of the PV market and its industry.
20 May 2015
The closer PV comes to the market, the more relevant it becomes for utilities. Although IEA-PVPS is in touch with several utilities worldwide since many years, there is a clear need to foster and extend these relations: In order to come closer together IEA-PVPS invited European utilities on April 10, to discuss about PV as a possible current and future business for utilities.
12 representatives from EU utilities exchanged with IEA PVPS Experts at the IEA Headquarter in Paris about residential PV applications and the role of self-consumption and the role of PV in comprehensive energy services that utilities will offer in future. the group discussed general aspects on financing as well as other topics, showing the interest raised by PV for many utilities.
The major focus consists in identifying profitable business models for utilities in the PV sector.
A similar workshop for Asian utilities will take place on September 3, 2015 in Bangkok, Thailand along with the Asean Power Week conference.
Since the feedback of the European meeting was very positive and the need for a continuation was mentioned by most attendants, IEA-PVPS intends to proceed with this task force already this autumn; the next 1-day meeting will take place at a date to be defined this fall at the IEA headquarter in Paris.
As a conclusion, the PV sector will have to find a common ground with traditional utilities if it has to develop further. IEA-PVPS intends to position itself as a bridge between the two worlds to envision the future of business models that utilities could develop to enter the PV market.
13 March 2015
While the PV market continues to develop globally, challenges related to its development are becoming more global as well. IEA-PVPS will publish numerous reports in the coming months, starting with reports on PV in developing countries: two news reports have been published in 2015, focusing on business models for PV in developing countries and PV for rural health facilities. These present a different point of view on emerging PV business models than the ones we used to see in developed markets.
In parallel, IEA-PVPS looked at the future of the technology and in particular the life-cycle analysis of future PV modules at the 2030-2050 horizon. This new report highlights how PV can contribute to the energy demand in the future while respecting constraining environmental regulations.
Finally, IEA-PVPS started long ago to focus on large-scale PV systems while this was only a far dream. Now that ground-mounted PV plants have reached more than 500 MW in size (and larger ones are announced ona regular basis), the last edition of "PV in the desert" will be published in March 2015.
More reports are expected in the coming weeks and months, especially the annual PV market estimates of IEA-PVPS that will indicate how much the market finally grew in 2014 and a complete report on self-consumption and net-metering policies.
Through these numerous reports, IEA-PVPS confirms its status of prime PV research institution in the world, gathering some of the most renewed experts in their fields and delivering a wide range of quality, unbiased reports.
16 January 2015
After a slow growth in 2014, the prospect for PV remains strong in 2015 according to most market experts. Whatever the number of PV installations during this year, the questions that remain open are numerous and require increasingly complex researches to which the IEA-PVPS intends to contribute.
In 2014, the IEA-PVPS published new reports on market development, including in developing economies, but also reports on quality and reliability of PV systems. We also contributed to the research on the integration of PV in distribution grids. These subjects will continue to be researched in 2015: new reports are expected with regard to the analysis of long-term PV performance, and the effect of PV in the electricity grids.
Additional reports will be published this year on subjects such as new business models for PV in emerging economies, the evolution of self-consumption measures in key countries, LCA and LCI analysis and more. The publication of the last report on large-scale PV in desert areas is part of this year's work program while on the other side of the spectrum, IEA-PVPS will launch two new activities.
The first one intends to continue researching how BIPV components could finally find a way to the market. A new research program (Task 15) focusing on BIPV will capitalize on former research activities in order to explore the future of BIPV.
The second one intends to create synergies between the PV world and electric utilities. With PV becoming one of the most promising sources of electricity in numerous countries around the world, a task force gathering PV experts and utility representatives will explore the impact on their business models, and the way how utilities could benefit from the PV technology.
Finally IEA-PVPS will continue to communicate the results of its activities through public and expert workshops and conferences, all around the world. With more than 100 experts from all continents and various fields of expertise, IEA-PVPS will continue to be your global network for international cooperation on PV development.
We wish you a Happy and Sunny New Year 2015.
6 November 2014 - New Grid Integration Reports
The massive deployment of grid-connected PV in recent years has brought PV penetration in the electricity grids to levels where the conventional fit-and-forget approach to interconnecting PV reaches its limits. In many cases, constraints and limitations of existing electricity infrastructure already have evolved to one of the key barriers delaying or impeding the realisation of PV projects.
While until recently grid issues associated with increased PV Penetration levels have been an issue in just a few local markets mainly in Europe, it has since then become a truly global issue attracting global interest and attendance. In many cases PV has already become a game-changer in the way utilities, transmission as well as distribution system operators
plan and operate power system infrastructure. Last but not least the grid integration of High Penetration PV has been identified as key prerequisite for the future development of the world-wide solar industry.
It is clear that resolving these global challenges requires the broad collaboration of experts from different stakeholders involved and the access to global information on experiences and best practises. Consequently, the Photovoltaic Power Systems Programme of the International Energy Agency (IEA-PVPS) has put up grid integration of on top of its research agenda, following its strategic mission to enhance the international collaborative
efforts which facilitate the role of photovoltaic solar energy as a cornerstone in the transition to sustainable energy systems.
Coordinated by Task 14 (High Penetration PV in Electricity Grids) a worldwide group of experts has been working together exchanging expertise and developing innovative solutions addressing technical as well as non-technical challenges for the advanced integration of PV. From its beginning Task 14 has focused on working together with utilities, electricity industry, and leading research to develop the technologies and methods to enable the widespread deployment of distributed PV into the electricity system.
Task 14 addresses integration challenges and technologies on two main levels of the power system, local distribution grids and the overall power transmission system.
The two new reports specifically covers aspects related to distribution integration, presenting a worldwide selection of best-practice case studies and the latest findings from the working period from 2010 to 2013 within the IEA Task 14 Subtask 2. They present the main features of the evolution from uni-directional grids to bi-directional grids, under the pressure of PV development.
In the coming years, Task 14 will continue focusing on the most important aspects of PV impacts on distribution and transmission grids, on system stability and, in countries where this makes senses, the impact on the electricity system and markets. These subjects will remain at the cornerstone of PV development, with more markets reaching penetration levels, sometimes locally, that require to at least partially rethink the way how our electricity systems will be managed in the future.
8 October 2014 - Trends in PV Applications
Following the difficult year of 2012 in terms of market growth, industry consolidation, policy uncertainty and ongoing fast cost reduction, 2013 has seen a slower evolution on the cost side but also a growing worldwide market again, although with a different split of dominant markets compared to the past.
The fast rise of PV markets in Asia and America has been confirmed as has the decline of the total market in Europe. Overall, 35 GW of PV were installed in IEA PVPS member countries during 2013 (2012: 25 GW), whereas the global PV market is estimated to be at least 39 GW, translating to more than an average of 100 MW installed on a daily basis throughout the year. The global installed total PV capacity is estimated at roughly 140 GW at the end of 2013. PV system prices have seen a slower decline than in the years before or even small increases, indicating that the speed of future cost reduction may be reduced. On the supply side, the indicators suggest that the consolidation phase in the industry starts to be overcome although competition remains high.
At the same time, at the present comparatively low prices, some price flexibility for different applications can be expected. With PV life cycle costs of electricity reaching socket parity with electricity grids in some countries, self consumption and new business models gain importance while Feed-in Tariffs continue to evolve. Overall, this is an encouraging sign for the growing competitiveness of PV and the increasing occurrence of self-sustained markets. Clearly, policy support is changing over time but is still considered essential for the near term development of PV markets worldwide.
Quantitatively, the number of countries experiencing PV as an essential part of their electricity supply is increasing, with Italy in first place with close to 8% of annual electricity demand coming from PV, followed by Germany (> 6%) and Greece (close to 6%). In terms of peak capacity, these high shares of PV start to affect and pose challenges to the integration in the electricity system. New business models and market designs will emerge in response to this development. All of these developments are clear signs that PV is becoming more mature and a relevant part of the electricity supply system.
Download the report (and former editions) here.
27 August 2014
National Survey Reports
2013 was another record year for PV installations and 2014 looks even more positive with a growing demand in many regions of the World. IEA-PVPS has collected and analyzed information related to PV markets and industry development for more than 20 years and this will continue. The National Survey Reports, prepared by national administrations or local PV experts detail the main evolutions that happened in a country the year before. But the most interesting aspect of PV development in 2013 was the remarkable development of Asian countries and the speed at which the knowledge about PV potential is disseminated in dozens of new countries, triggering development plans.
These developments shows that the old recipe started ten years ago in Europe are used again: feed-in tariffs and tax breaks are still driving a very large part of the PV installations all around the world. Markets driven by net-metering schemes are emerging and, where PV has already reached grid-parity with retail electricity prices, markets partially driven by installations self-consuming a large share of their PV electricity are unlocking new challenges and questions. In order to avoid repeating some mistakes done in the last years in several countries, National Survey Reports allow to better understand the evolution of national policies, with a focus on market development policies, but also industry developments, and R&D policies.
2 June 2014
Quality and Reliability of PV Systems
Quality and reliability of PV systems is at the core of discussions during this year’s Intersolar Europe fair in Munich. While the PV market grew significantly in the last five years, the question of PV systems performance becomes central to continue lowering both the cost of PV electricity and the cost of financing PV installations.
Following four years of PV systems performance and reliability research, the IEA PVPS programme’s Task 13 has begun delivery on a series of five reports summarizing these years of intensive research activities. These reports focus on several aspects of PV performance and reliability and cover the main aspects of quality-oriented activities in the PV sector.
Three new reports focus on PV Performance and the impact of PV module failure, for both crystalline silicon and thin-film technologies. They show that the question of quality and reliability can be managed in a scientific way and that in recent years much progress has been made, in parallel with the growth of the PV markets and industry.
28 April 2014
The 2013 IEA PVPS Annual Report has been published and is now available on this website. It shows the speed at which the PV sector has evolved and how the country involvement in this PV program has progressed.
In 2014, Thailand already joined the PVPS program and more countries are discussing their possible participation: this shows the rapid evolution of mentalities with regard to PV, and reflects what currently happens globally.
In parallel, the energy environment is changing fast and the challenges linked to PV evolution are shaping the PVPS activities in order to best reflect it. For sure, PV is not considered anymore as a marginal source of electricity and while it will produce only slightly more than 1% of the world electricity demand in 2014, its future is at the center of many studies. One example is the April 2014 release of the final draft of the IPCC’s fifth report, Working Group III ‘’ (that can be found here)
In this report, the Intergovernmental Panel on Climate Change (IPCC) has announced that "" in mitigating harmful emissions from electricity production.
This announcement shows how expectations are high for the PV technology and how important the availability of adequate and objective information will remain.
The Annual Report can be found here.
31 March 2014
After two years of market and industry consolidation, the PV market grew again in the 2013. In total, about 36.9 GW of PV capacity were installed in the IEA PVPS countries and the other major markets during 2013 (2012: 29.4 GW; 2011: 29.2 GW; 2010: 16.7 GW). This raised the total installed capacity in IEA PVPS countries to 123.2 GW with another estimated 10.8 GW of capacity installed in other major countries. These are the main outcomes of the latest IEA PVPS “Snapshot of Global PV” report, published on 31 March.
After several years of rapid growth and a stabilization in 2012, the PV market grew in 2013 to at least 36.9 GW. The Asia Pacific region represented around 59% of the global PV market in 2013, a premiere in more than a decade. While Europe still represented 59% of this global market in 2012, its market share fell to 28%, a consequence of a reduced market in Europe and a growing global PV market. The PV market in the Americas went above 5 GW for the first time. The Middle East and Africa remain regions in development for the PV market. However, the most important growth was observed in China which has progressed quickly and was the very first market in 2013 with 11.3 GW of PV systems connected to the grid. The second largest market in 2013 was Japan with 6.9 GW, ahead of the USA, with 4.75 GW and finally the first European market was Germany at 3.3 GW.
The annual PV contribution to electricity demand has passed the 1% mark in 15 countries, with Italy at the top with at least 7.8 % and the overall European PV contribution amounting to around 3% of Europe’s electricity demand.
27 February 2014
Managing grids with high shares of variable renewables is one of the main challenges of PV (and Wind) development. In a new study published in February 2014, the IEA shows that any country can reach high shares of PV and Wind electricity cost-effectively.
The inherent variability of wind power and solar PV is raising concerns: Can power systems remain reliable and cost-effective while supporting high shares of variable renewable energy (VRE)? The study shows that integrating high shares – i.e., 30 percent of annual electricity production or more – of wind and solar PV in power systems can come at little additional cost. However, costs depend on how flexible the system currently is and what strategy is adopted to develop system flexibility. Exploring the differences between developed and developing countries, the study highlights the necessary steps to integrate high shares of VRE cost-effectively, the impact on incumbent generators and the electricity system in general, especially in developed countries with stable electricity systems. It shows how the transformation challenge in stable systems is twofold: scaling up the new, flexible system while scaling down the inflexible part of the old.