NDT Technologies Empowering Renewable Energy in 2025

The burgeoning renewable energy sector, driven by the imperative to transition to sustainable energy sources, requires robust strategies to ensure the reliability and longevity of critical assets.

Non-Destructive Testing (NDT) aids this endeavour by providing invaluable data on the structural integrity and operational performance of wind turbines and solar panels, along with the numerous avenues of renewable energy generation.

The growth of this field in the years to come is subject to growth in awareness and research on these NDT techniques, leading to improvement in the adoption of clean energy technology worldwide.

NDT Techniques in Renewable Energy

The renewable energy sector is rapidly expanding to be more sustainable globally, which requires resilient and efficient infrastructure. NDT ensures the safety, reliability, and performance of renewable energy systems.

NDT helps prevent failures in wind turbines, solar panels, hydroelectric plants, and more, by detecting flaws without damaging components, supporting a future that implements sustainable energy solutions.

To understand the impact of NDT on the renewable energy industry, a thorough understanding of how NDT is incorporated into this sector is imperative.

1. Wind Energy

Wind Energy

Wind turbines, subjected to cyclical loading from wind forces, experience significant fatigue stresses. This, coupled with exposure to harsh environmental conditions, can lead to critical issues such as blade cracks, delamination, and tower base corrosion. NDT techniques in wind energy play a crucial role in identifying these issues proactively. NDT Techniques used in wind turbine inspection include:

I. Ultrasonic Testing (UT):

This technique utilises high-frequency sound waves to detect internal flaws.

Pulse-Echo Technique: A common UT method where ultrasonic pulses are transmitted into the material. The reflected echoes from internal defects provide information about the size, shape, and flaw location.
Phased Array UT: This advanced technique employs an array of transducers to focus the ultrasonic beam and generate high-resolution images of internal defects. It is particularly valuable for inspecting complex geometries like in the inspection of wind turbine blades.
UT with drones: When used with drones, this technique can be used for remote inspections.

II. Eddy Current Testing (ECT):

This technique utilises electromagnetic fields to detect surface and near-surface flaws. It detects cracks, corrosion, and material thickness variations in conductive materials like turbine blades and towers. It is used to inspect wid turbine blades when used with array probes in wind turbine inspections.

III. Radiographic Testing (RT):

This method uses penetrating radiation (X-rays or gamma rays) to create images of internal structures. It is valuable for detecting internal defects in metallic components, such as welds or corrosion cracks in tower bases, which has helped secure the future of wind power technology.

IV. Acoustic Emission Testing (AET):

This technique is used to inspect wind turbine blades for cracks and damage using acoustic waves on the test subject.

2. Solar Energy

Solar Energy

Solar panels can degrade from exposure to UV radiation, temperature fluctuations, and micro-level stresses. Solar panel testing is crucial for maintaining peak performance and extending the operational lifespan of solar farms. NDT techniques are instrumental in ensuring optimal performance and extending the operational lifespan of these assets.NDT Techniques used here include:

I. Electroluminescence (EL) Imaging:

EL imaging reveals variations in light emission across the solar cell by applying electrical bias, highlighting microcracks, shunts, and dead zones that impede current flow and reduce energy output.

II. Infrared Thermography (IRT):

IRT detects temperature variations across the solar panel surface. Hot spots, indicative of localised resistive heating, can signal faulty connections, cell degradation, or shading effects.

III. Eddy Current Testing (ECT):

ECT and Array ECT are used to assess heat exchanger tube for the presence of defects.

IV. Long-Range Ultrasonic Testing (LRUT):

This technique is used to identify corrosion or defects in pipelines within the solar energy industry.

V. Visual Inspection:

VI identifies surface defects, such as cracks, delamination, and soiling, which can significantly impact energy output. Drones with high-resolution cameras can facilitate efficient and safe visual inspections of large-scale solar arrays aiding non-destructive testing for solar panels.

Storage tanks holdings water or other fluids can be inspected remotely with AER and robotic systems. Whereas, Magnetic Flux Leakage Testing, Vaccum Box Testing, Phased Array Ultrasonic Testing (PAUT) and Visual Inspection can be used for live inspections by operators.

The structural integrity of components used in solar plants can be assessed using UT or VT. However, the Advanced NDT Techniques used in Concentrated Solar Plants and Floating Solar Plants include:

3. Concentrated Solar Power (CSP) Systems:

Concentrated Solar Power (CSP) Systems

Concentrate d Solar Power (CSP) systems use mirrors or lenses to focus sunlight onto a receiver, converting it into heat energy for electricity production. NDT techniques help maintain CSP components, including solar concentrators, heat transfer systems, and thermal storage tanks. The NDT Techniques used in CSP include:

I. Thermographic Testing:

Thermography identifies heat transfer inefficiencies in molten salt systems by detecting thermal anomalies, indicating potential leaks or blockages.

II. Phased Array Ultrasonic Testing (PAUT):

PAUT helps evaluate the integrity of storage tanks and piping systems, precisely locating cracks, weld flaws, or corrosion.

III. Visual and Drone Inspections:

This monitors the alignment and condition of mirrors or heliostats, detecting surface degradation, misalignments, and contamination. Drones enable rapid, safe inspection of large-scale CSP fields.

The efficiency of CSP systems is highly dependent on defect-free components and precise operations. NDT provides proactive maintenance solutions, minimising energy losses and ensuring reliable performance over the plant’s lifecycle.

4. Floating Solar Farms:

Floating solar farms are installed on water bodies and offer efficient land use and increased energy generation. The exposure to water and environmental stresses requires non-destructive evaluation in solar farms to inspect floating structures, mooring systems, and underwater cabling. NDT Techniques used here include:

I. ROV-Assisted Visual Inspections:

Remotely Operated Vehicles (ROVs) inspect submerged mooring systems and platform structures for wear, corrosion, and mechanical damage.

II. Ultrasonic Testing (UT):

UT can detect weld defects and material thinning in floating platforms, ensuring structural reliability under dynamic water conditions.

III. Eddy Current Testing (ECT):

ECT helps identify corrosion and cracks in submerged metallic components, particularly in mooring chains and structural connectors.

Exposure to water and harsh environments makes floating solar farms vulnerable to corrosion and mechanical failures. Implementing NDT ensures long-term durability, operational safety, and maximum energy output.

5. Hydroelectric Infrastructure

Hydroelectric Infrastructure

NDT in renewable energy also extends to hydroelectric infrastructure. Components like turbines, penstocks, and concrete dams require continuous monitoring, where NDT techniques come into play. NDT Techniques used here include:

I. Acoustic Emission Testing:

AET aids in the early detection of fatigue cracks in turbines and penstocks. Civil structures like dams are also heavily dependent on this technique to monitor their condition and preemptively detect problems.

II. Magnetic Particle Testing (MPT):

Surface crack identification in ferromagnetic components is carried out using MPT.

III. Ultrasonic Phased Array Testing:

UT helps in inspecting welded joints in turbine housings.

IV. Laser Shearography:

This can detect stress-induced defects in composite hydro components.

6. Hybrid Renewable Energy Systems

Hybrid Renewable Energy Systems

Hybrid renewable energy systems integrate multiple sources, such as wind, solar, and energy storage, to enhance grid stability. NDT techniques assess the health of interconnected components, including solar arrays, wind turbines, and energy storage units, ensuring seamless energy integration. NDT Techniques used here include:

I. Multi-Technology Inspections:

This combines ultrasonic, thermographic, and visual inspections to monitor diverse components like turbine blades, solar panels, and storage units.

II. Digital Twins:

Herein, virtual models simulate real-time system performance using NDT data, enabling predictive maintenance and fault prevention.

III. Advanced Robotics:

This utilises drones and underwater robots to access hard-to-reach areas for inspections, improving safety and efficiency.

Hybrid systems reduce reliance on a single energy source but introduce complexity in system maintenance.

7. Small Modular Reactors (SMRs) Supporting Renewables

Small Modular Reactors (SMRs) offer scalable, low-carbon energy and can stabilise renewable-heavy grids. Due to their compact, high-pressure design, rigorous NDT protocols are critical for safety and reliability. NDT methods inspect reactor vessels, heat exchangers, and pipelines, preventing structural failures and radiation leaks. NDT Techniques used here include:

I. Radiographic Testing (RT):

RT provides detailed imaging of welds and pressure vessels to detect internal flaws and ensure containment integrity.

II. Magnetic Particle Testing (MPT):

MPT detects surface and near-surface cracks in ferromagnetic components like reactor internals and support structures.

III. Acoustic Emission Monitoring:

AET offers real-time monitoring for crack growth and structural stress, enabling early intervention.

SMRs operate under extreme conditions; precise, continuous NDT inspections are important for sustainable energy growth.

8. Waste-to-Energy (WTE) Systems

Waste-to-Energy (WTE) Systems

Waste-to-energy (WTE) systems convert waste materials into usable energy, supporting circular economies and reducing landfill dependence. NDT in renewable energy, specifically for WTE, helps inspect incinerators, turbines, and heat recovery boilers. NDT Techniques used here include:

I. Thermographic Testing:

Utilises infrared imaging to monitor temperature distribution across incinerators and boilers, identifying thermal anomalies and ensuring optimal combustion performance.

II. PAUT:

Advanced ultrasonic inspection evaluates weld integrity in high-temperature zones of pressure vessels and piping, detecting internal flaws and stress corrosion cracking.

III. Acoustic Emission Testing (AET):

Real-time monitoring of pressure vessels and boiler tubes detects crack initiation and propagation, providing early warnings of structural compromise.

WTE facilities are susceptible to corrosion, fatigue, and thermal stress due to extreme thermal and chemical conditions. Applying precise NDT techniques ensures continuous, safe operation and maximises energy output.

9. Energy Transmission Infrastructure

Efficient transmission infrastructure is essential for delivering renewable energy to the grid. High-voltage systems, transformers, and substations must be continuously monitored to prevent faults and blackouts. NDT makes transmission components more reliable by identifying insulation failures, mechanical defects, and electrical hotspots in cables and equipment. NDT Techniques used here include:

I. Partial Discharge Testing:

This detects early-stage insulation breakdown in high-voltage cables, preventing electrical failures and prolonging the component lifespan.

II. Infrared Thermography:

It can identify hotspots in transformers, circuit breakers, and cable connections, highlighting areas of excessive heat due to poor connections or overloading.

III. Vibration Analysis:

This technique monitors rotating machinery in substations for mechanical imbalances, misalignments, and bearing defects.

The reliability of transmission infrastructure directly impacts the stability of renewable energy distribution. NDT tools for sustainable energy systems reduce downtime and prevent costly failures.

10. Biomass Energy

Biomass Energy

Biomass energy plants produce energy using organic materials. NDT ensures the integrity of biomass boilers, storage tanks, and pipelines, reducing leaks, corrosion, and structural failure. NDT Techniques used here include: