Date 10 May 2017

Time 16:30-18:00

Co-convenor Global Energy Interconnection Development and Cooperation Organisation (GEIDCO)

Hybrid energy systems typically consist of two or more different energy sources used in conjunction to ensure firm power output, increased system efficiency and ultimately a greater balance in power supply at lower overall costs. Some hybrid systems use hydropower’s flexibility to balance variable renewable supply, ensuring a firm power output to the grid and reducing spinning reserve requirements.

Other hybrid systems may include adding generation to existing systems, taking advantage of existing infrastructure and creating new revenue streams. Innovative hybrid systems are wide-ranging and can solve numerous problems faced by modern energy systems. Cutting-edge control technologies can also enable hybrids by offering automatic digital responses to

supply fluctuations for frequency control. Hybrid systems can have extensive and significant related social, economic and environmental benefits beyond simply providing stronger and more efficient power systems. Hybrid energy systems, along with renewable energy storage, may be key to the future of renewable energy.

This session explored recent technological innovations in hybrid renewable systems that include hydropower by bringing together experts from research, business, government and industry.

HYBRID RENEWABLE ENERGY SYSTEMS

International Hydropower Association

Chancery House, St Nicholas Way, Sutton, London SM1 IJB, United Kingdom

T: +44 20 8652 5290 F: +44 20 8643 5600 E: iha@hydropower.org

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SESSION REPORT

Speakers• Wang Weisheng, director, New Energy Department of China• Miguel Patena, director, Equipment Engineering and Innovation, EDP• Yang Cunlong, vice president, Huanghe Hydropower Company• Umakant Panwar, principal secretary, Department of Energy, Government of

Uttarakhand• Jerry Ji, president, EBG Energy Sector, Huawei• Jiang Liping, deputy president, China State Grid Research Institute (moderator)

2017 World Hydropower Congress

Global Energy InterconnectionDevelopment and Cooperation Organization

Key discussion points Wang Weisheng gave an overview of the current power generation system in China at the end of 2016, and outlined the distribution of renewable resources and exploitable capacity in the country.

He highlighted the regional heterogeneity of renewable resources and the long distances between renewable resources and demand centres.

As China is determined to increase the share of renewables in the energy mix, this will require integrated system planning across growing spatial and temporal scales. This is particularly important in order to maximise utilisation rates in power systems with high proportions of hydropower, wind and solar.

Giving both grid-connected and isolated grid examples, he stressed that high renewable contributions are achievable if available resource assessments, load demand, grid access and interconnections are all taken into account.

Miguel Patena presented a floating photovoltaic (PV) pilot project developed by EDP at the Alto Rabagao pumped storage reservoir in Portugal. He emphasised the complementarity of shared infrastructure, especially with respect to the transmission and distribution infrastructure. For example, there is greater efficiency due to water cooling from below, which results in less area required to produce the same amount of power.

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HYBRID RENEWABLE ENERGY SYSTEMS

Wang Weisheng Jiang Liping

Miguel Patena and Yang Cunlong

Miguel Patena

Umakant Panwar presenting

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The transmission infrastructure also receives additional benefits. The floating PV uses the existing lines, and the transmission line efficiency is increased, as it is often used when the pumped storage is idle. On the other hand, hydropower generation loses its market margin when not generating due to competing solar generation. Nevertheless the capital investment for the floating PV is optimised and PV fluctuations in generation are smoothed.

As the EDP project has only been in operation since late 2016, no definitive conclusions can be drawn at this stage. Both the installation and operation of the project have gone smoothly so far.

Patena stressed that scaling up floating PV plants would decrease overall costs, but that this would require special regulation and licensing for hybrid plants.

Additionally, virtual power plant managing systems would be needed to ensure efficient and optimal operation of both PV and hydropower.

Yang Cunlong presented the applications of hybrid systems in power grids that are already dominated by hydropower, using the Qinghai province in China as a case study.

He noted that hydropower currently generates over 50 per cent of power for the province, which is closely followed by wind

and solar power at 32 per cent. Qinghai is blessed with both high solar and hydropower resources, but a very small population. As the solar PV generation profile in the province does not meet the local demand curve, energy storage or hybrid operations are required.

Hybrid operations in this case regulate the output of solar PV to improve the safety, reliability and stability of dispatched power, and are cheaper than investing in dedicated energy storage options.

A significant benefit of this example of hybridisation is the increased utilisation and efficiency of the existing transmission and distribution system.

HYBRID RENEWABLE ENERGY SYSTEMS

L-R: Jerry Ji, Wang Weisheng, Umakant Panwar, Miguel Patena, Yang Cunlong, Jiang Liping

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Umakant Panwar offered an Indian perspective of the complementarity of PV and hydropower at a system scale. Citing his country’s ambitious renewable energy goals, he explained the challenges it faces due to the variability, uncertainty and intermittency of renewables.

These challenges are accentuated when solar and wind receive dispatch priority, as they reduce the efficiency of flexible generators, especially thermal generators. He stressed that policy reforms are necessary in India to increase hydropower capacity due to its complementarity with solar PV generation.

Jerry Ji presented innovative ICT solutions to integrating renewable energy into power grids. Using smart inverters for solar PV, which are connected via wireless internet to large data centres and centralised O&M centres, can result in higher yields, reduced O&M costs and higher internal rates of return. Adding this smart ICT technology to the ‘internet of things’ can help to strengthen the transformation of traditional power grids into digitised, renewable dominated systems.

Key outcomesThe hybridisation of variable renewables with hydropower can allow for smooth, stable and reliable output to power grids. More importantly however, co-location allows for the optimised use of existing transmission and distribution infrastructure.

Advanced control systems will be required to optimise the operation of the renewable energy system. Digitisation, including individual device sensors connected individual panels and turbines, will play a significant role in future systems.

What next?

HYBRID RENEWABLE ENERGY SYSTEMS

Wang Weisheng and Umakant Panwar

Jerry Ji

IHA, in collaboration with international experts and IHA’s knowledge network on this topic, will produce a series of case-studies on hybrid renewable energy systems at all scales, from bundled co-located projects to national and regional systems.