Renewables require continued innovation efforts to reach the performance, reach and deployment in the Sustainable Development Scenario

Renewables require continued innovation efforts to reach the performance, reach and deployment in the SDS. The front-runners in deployment in the SDS, wind and solar, will require continued R&D into next generation modules, cells, turbines and system designs, as well as into balance-of-system components to ensure cost reduction trends are maintained.

More fundamentally, reaching high shares will require bridging innovation gaps in a host of integration technologies. New designs and prototypes are also needed to expand the reach of renewables, including floating off-shore wind turbines, ocean power or enhanced geothermal systems. Biomass technologies will require novel processes to reduce costs and tap into new feed-stocks. 

Onshore wind

Wind energy technology is already proven and making progress

Increased efforts in wind technology R&D are essential to realising the SDS, with a main focus on reducing the investment costs and increasing performance and reliability to reach a lower unit cost of energy. Good resource and performance assessments are also important to reduce financing costs. Wind energy technology is already proven and making progress, and while no single element is like to dramatically reduce costs, taken together improvements can ensure the cost trajectory is maintained.

In particular, innovation efforts are needed to aid in resource planning that minimises the impact of scaling up wind power capacity, and system-friendly integration of wind power through digital solutions and advanced power electronics.

Gap 1. Advanced contribution of wind power to grid integration

Why is this gap important?

Wind power generation creates well-known challenges for electricity grids and power systems through its variability and uncertainty and distributed nature. Wind power plants in many cases already contribute to their own integration through a range of upgrades, but their contribution will need to be ramped up in the SDS through a combination of regulation and grid codes and more innovative solutions for providing ancillary services and other services related to dispatchability.

Technology solutions

With an increasing share in power generation, stable wind turbine behaviour both during standard operation and during faults becomes key. Solutions exist for enabling wind plant to 'ride' through faults (TRL 10), which will have to be introduced to new markets and retrofitted into older turbines at low cost. More fundamentally, advanced solutions will need to be developed including multi-scale integration of control systems from wind farm to local grids, or dynamic line ratings and other solutions that improve the capacity of dedicated power infrastructure for wind power. Wind power can provide advanced ramping services through solutions in the research pipeline, including through probabilistic wind ramp forecasting (TRL 8).

What are the leading initiatives?

NREL is developing approaches to reduce integration costs by optimising energy, reserve and ramping services

Gap 2. Improve resource assessment and spatial planning

Why is this gap important?

Wind farm planning, both onshore and offshore, will require enhanced sensitivity assessment of the surrounding environment to ensure long term turbine efficiency and attractive return on investment.

Technology solutions

Modelling production costs accurately is key for determining wind power economics. As penetration increases and electricity systems become more complex overall, it is important to minimise the uncertainties of modelling wind production. Model outputs can be refined and validated against measured data (TRL 11), and higher-resolution grid models can be developed as well as methods for estimating the economics of co‑locating renewables and storage. The site layout can also be optimised for better use of wind resources (TRL 11), and aerodynamic-wake effects can be minimised.

Countries should introduce and develop a range of wind integration studies over time, progressively scaling up granularity in time and space, and undertake regional interconnection studies with neighbouring countries.

Challenges include improving the accuracy of offshore pre-construction planning to accommodate seasonal and yearly wind resource variations/changes, and optimising the use of varying seabed conditions.

Gap 3. Next generation turbine, power-train and system management technology

Why is this gap important?

Large rotor diameters and higher hub heights have higher upfront and per unit power costs but increase production and decrease costs per unit energy while making better use of the resource and decreasing variability of output.

Technology solutions

The scaling of turbine sizes has led the way in reducing the capital costs of wind power plants. Continued turbine scaling, emphasising low material use and more efficient manufacturing processes, remains a key option, with cost reductions estimated at 11‑20% by 2030. As rotors become larger with longer, more flexible blades, a fuller understanding of their behaviour during operation is required to inform new designs. Notable rotor-research areas include advanced computational fluid dynamics models; methods to reduce loads or suppress their transmission to other parts of the turbine, such as the gearbox or tower head; innovative aerofoil design; nanotechnology to reduce icing and dirt build-up; and lower aerodynamic noise emission. Additional cost savings can be achieved through technology developments that reduce electrical losses in the generator and attendant electrical/ electronic components. Enabling technologies include innovative power electronics, use of permanent magnet generators, and super conductor technology

Digitalisation, through advanced sensing and controls, enables predictive maintenance and is already reducing operation and maintenance costs (TRL 9). As turbines reach higher hub heights, it will be necessary to design and operate them under different atmospheric regimes, under conditions that are currently not well understood. More precise understanding and forecasting of weather conditions can be accomplished through high-fidelity modelling, verification and validation. Combined, these measures reduce the uncertainty of annual production and cost estimates, and consequently reduce investment risk and the cost of obtaining financing. Finally, plant lifetimes can be extended from the current 20 years to 30 years by 2030 through the use of advanced controls (TRL 8), reducing costs per unit of electricity produced by an estimated 25%.

At the early development stages, big-data analytics from plant-level measurements, including neural network/AI controls, and component 3D printing and hybrid materials for wind towers, are both potentially highly disruptive areas.


Long-term, sustained and substantially higher research, development and demonstration resources

Geothermal energy technologies have differing levels of maturity. The exploitation of hot rock resources, e.g. by means of EGS which is currently in the validation phase, has particular potential for improvement

Long-term, sustained and substantially higher research, development and demonstration resources are needed to accelerate cost reductions and design, and bring novel geothermal concepts to market. These advanced technologies have to be proven in pilot plants, meaning that strong government support for innovative small plants is needed.

R&D will need to focus on understanding better how fractures open and propagate in different stress regimes and rock types, in order to be able to better assess the hot rock potential. Similarly, a common approach in identification of advanced hydrothermal resources will help assessing its potential.

Gap 1. Development of advanced drilling technologies

Why is this gap important?

Drilling costs account for 40‑70% of the total capital costs of a geothermal power project. It is also a very time-consuming part of the project.

Technology solutions

The economical drilling of low-cost, exploration-only boreholes and drilling into deep, hard rock formations poses technical challenges that require new and innovative solutions.

Improving geophysical data inventories and geoscience exploration methods, as well as innovative geothermal resource assessment tools, would reduce exploration risks and thus diminish this investment barrier.

Two key research areas are state of stress and lost circulation events. State of stress refers to the condition of the fracture networks below the surface that permit geothermal energy to permeate and become usable for transformation into power and useful heat. This is particularly important in enhanced geothermal systems, as the stress field is measured exclusively through exploration-only drilling. Therefore, extending understanding and monitoring of fracture networks could make it easier to site wells more optimally and reduce overall exploration and drilling costs.

Lost circulation events happen when fluids are pumped into the reservoir to aid in drilling and are then lost to other underground formations and are not recoverable. Being able to better predict these events and reduce their impact would also reduce drilling costs.

What are the leading initiatives?

Bergakademie Freiberg technical university is carrying out leading research, and important research is also being done in other universities across Germany, at the University of Tokyo together with Tohuku University, and by other organisations.

The US Department of Energy (DOE) has announced it will put up to USD 7 million towards the research and development (R&D) of innovative subsurface geothermal technologies, with a component dedicated to improving geothermal drilling efficiency, focusing on state of stress and lost circulation events.

Although geothermal energy has significant technical potential globally, it receives minimal investments compared with other clean technologies, with funding provided mainly by public research programmes.

Gap 2. Expanding geothermal energy use

Why is this gap important?

So far, utilisation of geothermal energy has been concentrated in areas with naturally occurring water or steam, and relatively permeable rock. However, the vast majority of geothermal energy within drilling reach – up to 5 km with current technologies and economics – is in relatively dry, low-permeability rock. Heat stored in low-porosity and/or low-permeability rock is commonly referred to as a hot rock resource, and in contrast with most hydrothermal resources in use today for power generation, hot rock resources are available worldwide.

Technology solutions

Hot rock resources are characterised by limited pore space and/or minor fractures, and therefore contain insufficient water and permeability for natural exploitation. Hot rock resources can be found anywhere in the world, although they are closer to the surface in regions with an increased presence of naturally occurring radioactive isotopes (e.g. South Australia) or where tectonics have resulted in a favourable state of stress (e.g. in the western United States). In stable, old continental tectonic provinces that have low temperature gradients (7°C/km to 15°C/km) and permeability, but a less favourable state of stress, depths will be significantly greater and developing an enhanced geothermal system (EGS) resource will be less economic.

Technologies that allow energy to be tapped from hot rock resources are still in the demonstration stage and require innovation and experience to become commercially viable; the best-known such technology is EGS. Other approaches to engineering hot rock resources, which are still at the conceptual phase, experiment with methods other than fracturing the hot rock. They aim instead to create water inlet and outlet connectivity, for example by drilling a subsurface heat exchanger made of tubes underground, or by drilling a 7‑km to 10‑km vertical well of large diameter that contains water inlets and outlets at different depths.

EGS research, testing and demonstration is also under way in the United States and Australia. The United States has included large EGS RD&D components in its recent clean energy initiatives as part of a revived national geothermal programme. A global map of hot rock resources is not yet available, but some countries, including the United States, have started mapping EGS resources.

Gap 3. Improving understanding of geothermal resources

Why is this gap important?

Geological databases already exist for several parts of the world, but they could benefit from incorporating and aggregating the more complex data emerging from advanced remote sensing and monitoring of hydrothermal resources around the world. Combining these at the greatest granularity, extending them geographically, and reinterpreting, recompiling and standardising them would enable the creation of a publicly accessible, globally relevant database for use in assessing, accessing and exploiting geothermal resources.

Technology solutions

Industries and research institutes are now working towards an integrated approach for comprehensive characterisation of hot rock resources in a variety of geological settings. To better assess hot rock potential, R&D will need to focus on understanding how fractures open and propagate in different stress regimes and rock types. Similarly, a common approach to identify advanced hydrothermal resources will help to assess potential.

R&D is also required to enable exploration and assessment of hidden hydrothermal geothermal systems and hot rock resources. Rapid-reconnaissance geothermal tools will be essential to identify new prospects, especially those without surface features such as hot springs. Verification is needed on whether airborne-based hyperspectral, thermal infrared, magnetic and electromagnetic sensor tools can provide data inexpensively over large areas (TRL 10). Other tools might include ground-based verification, soil sampling and geophysical surveys (magnetotelluric, resistivity, gravity, seismic and/or heat flow measurements).

Exploration-only drilling technology is vital to enable EGS, because the in-situ stress field can only be measured in boreholes, but it needs to become much less costly to be practical

Ocean power

Technology innovation and learning by research are key to advance ocean power to maturity

Technology innovation and learning by research are key to advance ocean power to maturity. Research should focus on key components and sub-systems, simplifying installation procedures to keep costs down, Advanced design concepts that are currently in the very early stages of innovation could break through, including ocean thermal energy conversion (OTEC), salinity gradient power and ocean current technology.

Gap 1. Exploiting ocean energy through advanced design concepts

Why is this gap important?

The vast majority of ocean technologies today are either wave or tidal energy. Increasing annual generation to reach SDS levels will also require that investments be diversified towards other alternative concepts and technologies such as ocean thermal energy conversion (OTEC), salinity gradient power and ocean current technology.

Technology solutions

Ocean thermal energy conversion (OTEC) (TRL 4) is a technology to draw thermal energy from the deep ocean and convert it into electricity or commodities. This technology requires a temperature difference of 20ºC between the warm surface water and cold deep water and, as such, is only feasible in certain areas of the world; the tropics are the best area for this technology. The key uses for OTEC are to generate electricity, desalinate water, provide heating and cooling, and support the cultivation of fish or other marine life for food.

Salinity gradient power (TRL 3) is energy produced from the chemical pressure that results from the difference in salt concentration between fresh water and saltwater. This can therefore be exploited at river mouths where fresh and saline water meet. Two technologies are being developed to convert this energy into electricity: pressure-retarded osmosis (PRO) and reverse electrodialysis (RED), both in TRL 3 stage.

Finally, ocean current technology (TRL 3) can harvest energy from sea currents, which always flow in one direction and are driven by wind, water temperature, water salinity and density among other factors; they are part of the thermohaline convection system that moves water around the world. Ocean current energy technologies are being developed to capture the kinetic energy carried in this constant flow of water: the primary design concepts are based on water turbines deployed in arrays.

What are the leading initiatives?

  • Leading research institutions on OTEC include TU Delft in the Netherlands.
  • Xenesys Inc. of Japan and the Pacific Petroleum Company formed a joint venture to industrialise and commercialise OTEC in French Polynesia.
  • A consortium of French industrial and public partners launched the IPANEMA initiative, aimed at facilitating the emergence of renewable marine energy technologies, including OTEC.
  • Lockheed-Martin (LM) and the Taiwan Industrial Technology Research Institute (ITRI) pledged to collaborate on a 10‑MW OTEC plant project in Hawaii.
  • REDstack in the Netherlands is a successful 1‑MW pilot plant for reverse electrodialysis technology, built along the Afsluitdijk, a 32‑km causeway separating brackish and fresh water. The pilot is highly scalable.

Recommended actions over the next 10 years

  • Governments and regulators should: develop an integrated policy framework with ocean energy-specific regulations; develop international guidelines and standards; institute regulatory reform and planning, leading to efficient and appropriate consenting processes.
  • Industry, academia and governments should develop prototype devices to withstand the marine environment through demonstration and testing facilities, research and innovation support, and enable technology support to reduce costs and improve performance.

Gap 2. Scaling up low cost mechanical concepts and manufacturing for wave energy

Why is this gap important?

Wave power captures kinetic and potential energy from ocean waves to generate electricity. Wave energy converters (WECs) are intended to be modular and deployed in arrays, but at present there is little design consensus for wave energy devices with no industry-standard device concept. Due to the diverse nature of wave resources, it appears unlikely that there will be one single device concept that is used. Rather, there will probably be a small number of device types that exploit different regions of this vast resource. These concepts however need to be trialed at scale.

Technology solutions

Research in wave energy should focus on key components and subsystems, tested in a variety of conditions both separately and integrated into a whole device. While no one technique for anchoring may emerge given the variety of conditions, anchoring devices and transmission cables should be able to withstand stresses from movement of the structure and hydrodynamic forces, and installation and decommissioning need to be simplified to reduce costs.

As installation procedures also need to be simplified to keep costs down, spillover learning from offshore wind power could be helpful (e.g. in towing processes or pre-installation of structures). There could even be a sharing of offshore wind platforms, infrastructure and export cables.

Digitalisation can help scale up demonstrations and eventually production: sensing and control systems (TRL 9) can help anticipate and mitigate mechanical stresses, and big data analytics can aid in co‑ordinating turbine systems and adjusting loads on electrical equipment or generators (TRL 8), as well as predictive maintenance.

Wave energy converter power take-off systems (PTOs) (TRL 3) convert irregular low-frequency waves and swells to grid-compliant electricity. These systems require near full-scale demonstration in real sea conditions for validation. There are presently many different PTO arrangements, including turbines, hydraulic-system gearboxes and linear generators. Control systems, particularly for wave devices, will be important to ‘tune’ devices to local conditions and, in the future, to individual incident waves. Pitch control systems for tidal current blades will increase yields and survivability.

What are the leading initiatives?

The Sotenäs project in Sweden and Wello’s Penguin prototype at the European Marine Energy Centre (EMEC) are two recent key initiatives.

In addition, two new wave energy projects are expected in Scotland by 2020: a floating hinged structure (Mocean) and a fully submerged point absorber (AWS).

Solar PV

Continued focus on increasing the performance of commercial PV systems

Innovation in solar power needs continued focus on increasing the performance of commercial PV systems and a shift to cell and technologies that are now only in the pipeline. At higher penetrations, innovation can enable PV to contribute to their own integration through smart grid capabilities, which can mitigate the impact of incidents on the grid. Innovation in digital technologies applied to solar PV systems can also deliver a higher share of mini- and off-grid systems and increase energy access in developing countries.

Gap 1. Increased integration of off-grid electrification systems

Why is this gap important?

The wide array of system designs now available – off-grid, mini-grid and on-grid – increases the number of methods available to obtain electricity access. Off-grid technologies (such as stand-alone solar home systems), mini-grids and energy-efficient appliances are complementing efforts to provide electricity access from grid expansion. Such decentralised systems can help fill the energy access gap in remote areas by delivering electricity at a level of access that is currently too expensive to be met through a grid connection, and in urban areas by providing back-up for an unreliable grid supply.

Technology solutions

So far, solar home systems, which are increasingly cost-competitive with kerosene and diesel, have been the technology most widely deployed with these new mobile platforms and pay-as-you-go (PAYG) financing. PAYG (TRL 11) helps consumers overcome the high upfront costs of the technology that traditionally has been a significant barrier to uptake in poor communities. Mobile technologies, such as cloud-based metering and software platforms (TRL 10), can also be paired with larger systems such as mini-grids, which could be used to offer households additional services and provide power for productive uses such as irrigation, for example.

Highly efficient household appliances integrated with a core solar product are being more widely deployed but could benefit from further innovation in both offerings and technology bundles. Decreasing electricity demand through the use of efficient appliances can reduce the upfront costs of a system, such as a PV panel, delivering significant cost savings even when the increased cost of the appliances is taken into account.

Beyond its use for billing and asset monitoring purposes, the wealth of data generated by many off-grid systems could be subjected to big data analytics and artificial intelligence interpretation to enable better tailoring of equipment and modular asset scale-ups, better planning, improved device management and maintenance, and wider commercial offerings.

Solutions that link to productive-use appliances and energy carriers (e.g. agricultural implements, refrigerators) have a great potential to accelerate these systems. Large suppliers of mini-grids, industrial captive power or larger stand-alone systems, and that have knowledge of the productive-use market, could benefit from collaborating with smaller-scale providers of off-grid systems that are deploying innovations to manage large numbers of households smartly.

What are the leading initiatives?

BBOXX, M-Kopa, Off-Grid Electric and Mobisol have entered the market in Africa, bringing new business models that target areas covered by mobile networks but not electricity grids.

Gap 2. Maintaining the cost reduction trajectory for solar PV

Why is this gap important?

While dramatic scale effects have been achieved in solar PV, R&D efforts focused on efficiency and other fundamental improvements in solar PV technology need to continue to keep on pace with the SDS. Mainstream technology at present is dominated by crystalline silicon. Within it, screen-printed Al-back surface field cells (Al-BSF) holds around three quarters of the market, with the remaining quarter dominated by Passivated Emitter Rear Cell technology (PERC).  Strong global demand for higher-efficiency modules is driving a shift towards PERC and the next generation of technologies, like n-type HJT and IBC.

Technology solutions

P-type cells, built upon a positively charged silicon base (to which Al-BSF and PERC belong) are the traditional PV development pathway that has dominated the industry – to some degree because in the early days of development dominated by space applications, p-type cells proved better suited to withstand radiation.

Crystalline silicon p-type PERC technology is poised to reach 24% efficiency, a key milestone, and efforts need to continue to maximise its potential and complete the market shift. Among the barriers that remain, improved cleaning, passivated contacts, interconnection, embedding, and new metallisation pastes particularly are needed.

In n-type cells, the basis of the cell is inverted to yield a number of advantages: n‑type cells are not subject to Light-Induced Degradation (LID; degradation over time from exposure to light), are less prone to defects and impurities in the silicon, and generally have greater power output over time. A variety of designs are in development. Overall, there a pressing need to identify a means to get n‑type technologies to the market (TRL 7).

Passivated contacts promise further improvements, but production throughput, homogeneity, yields and metal paste-contacting remain challenging. TOPCon technologies (an umbrella term for passivated contacts) hold special promise as a follow-up to PERC technology. In standard contacts, which consist of pure metallisation on the wafer, losses are high. Passivated contacts reduce losses and have higher efficiencies than almost any other design structure, but they are complex to manufacture (requiring additional equipment and steps, a more expensive wafer, etc.), which is a key barrier in a traditionally conservative PV industry. Fundamentally, the metallisation paste is proving a key area of focus for scaling up.

What are the leading initiatives?

  • R&D is relatively well funded, but commercialising novel n‑type technologies and improving PERC beyond 24% are challenging. While well followed, there is a need to develop commercial designs and products.
  • China’s Top Runner Program has chosen some next-generation PV technologies for deployment, including TOPCon technology.
  • Longi Solar/CPVT-verified 24.6% PERC cell and PV Celltech technologies are being developed.
  • OECD statistics shows the most innovation within all generation technologies coming from more efficient solar PV

Gap 3. Smarter inverter systems and BOS cost reductions

Why is this gap important?

Higher PV shares, particularly in distribution grids, will necessitate the development of new ways to inject power into the grid and to manage generation from solar PV systems. The inverter and the rest of the power control system is generally the gateway for smart-management measures, and while technology has been proved, systems will need to become smarter and provide a broader range of voltage, reactive power and other ancillary services to the grid. Beyond making inverters smarter, the overall balance-of-system (BOS) costs (which include inverters) should be a key area of focus, as they can take up 40‑60% of all investment costs in a PV plant, depending on the region.

Technology solutions

Solar smart inverters need to enable rooftop solar PV systems to automatically stabilise their own collective disruptions to the grid. At higher PV penetrations, they need to incorporate communication equipment that interacts in real time with utilities, increasing the visibility of the overall condition of low- and medium-voltage grids. Increasingly, they will also need to offer ancillary services such as reactive power or ramping controls.

There is currently no standard communication protocol to manage active power from large numbers of PV plants, and further work is required on interoperability and standardisation of both the ICT and PV systems.

Beyond inverters, most solutions for reducing BOS costs focus on 'soft' measures that nevertheless could benefit from increased R&D and other innovation efforts.

Offshore wind

A great potential for cost reductions, or even technology breakthrough

A great potential for cost reductions, or even technology breakthrough, exists in the offshore wind sector. In particular, innovation is needed in installation processes and foundation designs. An improved understanding of the requirements of wind technology in offshore conditions, as well as the management of large numbers of wind farms will be necessary to design turbines, systems and farms. Changes in design architecture and an ability to withstand a wider array of design considerations including hurricanes, surface icing, and rolling and pitching moments, are also likely to be needed. Improved alternative-current (AC) power take-off systems or the introduction of direct-current (DC) power systems are also promising technologies for internal wind power plant grid offshore and connection to shore. 

Gap 1. Innovation in installation processes for offshore wind plant

Why is this gap important?

Soft costs for offshore wind take up a substantial share of total installed costs, and together with interconnection they are a key challenge for reaching SDS cost goals. Offshore wind farms also need to incorporate high levels of resilience to stronger wind regimes and meteorological conditions off shore, particularly to mitigate the impact of long-term exposure to seawater.

Technology solutions

System design needs tool development to minimise loads across the components to optimise for specific conditions including offshore, cold and icy climates, or tropical cyclone climates. Today's standards and model tools are based on European sea and meteorological conditions, and will have to innovate to continue to be relevant as wind power expands to new regions in the US, Japan, Korea or emerging economies. Improving model tools requires measurement campaigns both in the field and in controlled test facilities. Changes in design architectures and an ability to withstand a wider array of design considerations including surface icing, and rolling and pitching moments, are also likely to be needed.

A number of innovations can potentially improve the installation of offshore wind plant. Pre-commissioning of onshore wind turbines is a market-ready solution, where the rotor and turbine can be assembled onshore in the short term (TRL 10). In the medium-term, concepts for integrating structures could deliver further gains including joint installation of turbine and foundation (TRL 9). 

What are the leading initiatives?

A number of simulation projects in place aside from commercial opportunities, including the Far and Large Offshore Wind Programme at ECN in the Netherlands.

The European Wind Energy Technology Platform, as well as the Offshore Wind Cost Reduction Task Force both have initiatives in place to accelerate installation processes. The UK Offshore Wind Catapult is a leading example of tools to accelerate deployment.

Gap 2. Reducing cost and risk of transmission and distribution of electricity from offshore wind

Why is this gap important?

As turbine costs drop in the SDS, interconnection and balance-of-system take up a higher share of overall installation costs. Learning on design concepts as well as fundamental technology improvements to power engineering equipment will be necessary.

Technology solutions

Reducing the volume of HVAC infrastructure on the plant side is a priority. High voltage interconnections using DC are key in deep-water projects, and further loss reductions and cost drops of cabling equipment are needed. Increasing voltages in offshore wind farm cabling and infrastructure to reach 400 kV (TRL 9) would result in reduced losses. Low frequency transmission could further reduce losses, but few initiatives are in place. Array interconnection, streamlined cable layouts.

What are the leading initiatives?

The US National Offshore Wind R&D consortium allocates USD 41 million in total to offshore wind research, with the first request for proposals as of March 2019 including reducing the cost and risk associated with the transmission and distribution of electricity from offshore wind.

The Danish Technical University has a leading programme in low frequency transmission. 

Gap 3. Tapping deeper offshore wind resources through floating wind turbines

Why is this gap important?

The richest offshore wind resource is located in deep waters, where attaching turbines to the seabed is not practical. Floating offshore foundations, offer the potential for less foundation material, simplified installation and decommissioning, and additional wind resource at water depths exceeding 50 m to 60 m. Several regions (e.g. the US or Japan) have a low share of their resource in shallow waters. Floating foundations may also be attractive for mid-depth projects, where saturation of onshore or near-shore potential or the possibility of standardising floating foundation designs and do not need heavy-lift vessels to transport foundations.

Technology solutions

New tools will be required to capture the design criteria for floating platforms, which include the need to address weight and buoyancy requirements as well as the heaving and pitching moments created by wave action. Current floating concepts include the spar buoy, the tension leg platform and the buoyancy-stabilised semi-submersible platform.

Vertical axis turbines, which disappeared from land, may have a second chance at sea. Although they have a higher material need to cover same swept areas and have some dynamical structural issues, their lower centre of gravity and fewer parts may be suitable in offshore wind. 

What are the leading initiatives?

Two demonstrations show good performance: Hywind, with 30 MW in place; and US/PT, a 2 MW prototype off the Portuguese coast

Vertimed, an EU-funded project led by EDF-Energies Nouvelles with Nenuphar and Technip, aims to install around 20 MW off Fos-sur-Mer in the French Mediterranean

The US National Offshore Wind R&D consortium allocates USD 41 million in total to offshore wind research, with the first request for proposals as of March 2019 including developing innovative mooring and anchoring technologies for floating wind 

Other initiatives include Macquarie/Ideol's first floating wind farm in Japan and the Glosten tension-leg platform and Principle Power semi-submersible concepts.


Many areas where small but important improvements in technological development are needed

While hydropower is a mature power generation technology, with high energy payback ratio and conversion efficiency, there are still many areas where small but important improvements in technological development are needed. Work is underway to identify and apply new technologies, systems, approaches and innovations, including experience from other industries, that have the potential to make hydropower development more reliable, efficient, valuable and safe. Improvements along the lines of those made in the last 30 to 50 years will also need to continue, though with smaller incremental benefits: mainly in physical size, hydraulic efficiency and environmental performance.

Gap 1. Innovative hydropower designs

Why is this gap important?

Dams have a high social and environmental cost, heavily disrupting ecosystems and populations where they are developed. Alternatives that do not require damming or resettlement of populations would help reach SDS levels.

Technology solutions

Zero-head or in-stream turbine technology has a lower environmental impact. No dams or head differential are necessary, they do not alter the course of a river and do not require high capital investments or large civil engineering works. The technology works best in areas where there are small water courses with discharge rates (the flow rate of water through a given cross-sectional area) of 1 m3 per second.

The recent surge of research activity and investment in technology to capture tidal energy has already produced successful prototypes. Most of these underwater devices have horizontal axis turbines, with fixed or variable pitch blades. Electrical generators tend to be direct or hydraulic drive, or have rim-mounted stators.

Relicensing dams to continue operation often involves more stringent environmental criteria that can have an impact on operations, limiting generation and impacting some of the flexibility and revenue streams of hydro plants. Complementing large installations with small-scale hydro plant such as in-stream turbines can therefore augment their generation.

Gap 2. Reducing the cost and impact of civil works

Why is this gap important?

The cost of civil works associated with new hydropower project construction can be up to 70% of total project costs, and their social and environmental impacts can be considerable, so improved methods, technologies and materials for planning, design and construction have considerable potential.

Technology solutions

roller-compacted concrete (RCC) dam is built using much drier concrete than traditional concrete gravity dams, allowing speedier and lower-cost construction. Trapezoidal cemented sand and gravel (CSG) dams (e.g. in Japan) use more local materials, reducing costs and environmental impact. Recent improvements in tunnelling technology have also reduced costs, particularly for small projects.

Some improvements in turbine technology aim directly at reducing the environmental impacts of hydropower, such as fish-friendly turbinesAerating turbines use the low pressures created by flows through the turbines to induce additional air flow. This increases the proportion of dissolved oxygen, protecting aquatic habitats in waters below dams. Oil-free turbines use oil-free hubs and water-lubricated bearings to eliminate the possibility of oil leakage into the river. Other benefits include easy maintenance and lower friction than with the oil-filled hubs.

Extensive research to reduce mortality as fish pass downstream through the hydraulic turbines has significantly improved turbine design. In recent years, minimum gap runner (MGR) technology has achieved fish survival rates in excess of 95% for large axial flow units in the field. New designs, such as the Alden turbine, expand the range of fish-friendly units to smaller turbine applications but have not yet been widely applied.

Continuous improvements in material properties have been driven by requirements to: improve resistance to cavitation, corrosion and abrasion to extend component life and reduce outages; reduce runner weight and improve efficiency through increased strength of materials; and improve machinability to increase power output as more complex shapes can be manufactured. This has led to increased use of proven and new materials such as stainless steel and corrosion- or abrasion-resistant coatings in turbines, and lower-cost and higher-performance fiberglass and plastic materials in construction.

Recommended actions in the next five years

  • Environment and energy/resource ministries should promote policy frameworks that cover the development of sustainable and appropriate hydropower projects that avoid, minimise, mitigate or compensate any legitimate and important environmental and social concerns.
  • Industry should consider sustainability issues in the co-ordinated operation of hydropower plants.
  • Intergovernmental organisations and multi-lateral development agencies should provide capacity building for regulatory frameworks and business models to help developing countries implement sustainable hydropower development.