RENEWABLES Archives - Page 2 of 5

Wasted wind and the UK’s curtailment challenge

WASTED WIND AND THE UK’S CURTAILMENT CHALLENGE

Why clean energy goes unused and how technology can help

According to the Times, in 2025 UK households effectively paid £810 million for Scottish wind farms to stand idle, highlighting a growing problem in the country’s renewable energy sector. Here, Mike Torbitt, managing director of Cressall, explores the causes behind the UK’s wind curtailment issue and explains how resistor technology can help stabilise the grid and make the most of renewable energy.

How curtailment works

Curtailment happens when wind farms are asked to reduce or shut down generation of electricity, even where generation conditions are optimal. The reason is rarely the turbines themselves. It usually happens when the grid cannot take in the amount of power being generated, or there is no demand for it at that time.

On paper it sounds like an occasional technicality. In practice, it has become a regular issue of the UK’s energy system. Every time turbines are switched off, revenue is lost, bills rise and carbon savings are wasted. For consumers, that means paying for energy that never reaches their homes — a frustration that grows as wind makes up more and more of the power mix.

Most of the UK’s wind power comes from Scotland, where land and wind resources are plentiful. The challenge is transporting that electricity to where it’s needed. Transmission south of the border is limited so when output surges, the system cannot always absorb it. In June 2025, the Financial Times revealed that wind farms were paid to switch off 13 per cent of the time they could otherwise have been producing.

The costs are also mounting. Operators are compensated for shutting down, but those payments ultimately come from household energy bills. Environmentally, the waste is even starker: each megawatt-hour curtailed means another load of carbon that could have been avoided — the equivalent of the electricity used by around 330 homes.

The scale is particularly clear in Scotland: according to Recharge News, the nation’s grid-constrained producers curtailed 37 per cent of their output in the first half of 2025. That amounts to about 1.5 terawatt-hours of lost clean energy — enough to power 1.2 million homes for a year.

How to capture lost power

There is no single solution to preventing curtailment, but there are possible ways forward. New grid infrastructure and cross-border interconnectors would allow Scottish surplus wind to reach areas of higher demand. Vast storage schemes, from factories producing batteries to pumped hydro, would be capable of soaking up excess power and delivering it at the appropriate moment. More advanced control systems would also even out the peaks and troughs of supply and demand.

Protective technologies have an important function in surge control in renewable energy. Resistors act as thermal valves for high-voltage systems, dissipating excessive electrical power as heat to prevent overvoltage or equipment loss. Dynamic braking resistors (DBRs), for example, can be connected to generator circuits or inverters to absorb sudden spikes in power output, helping to stabilise voltage and maintain grid frequency.

Elsewhere, neutral earthing resistors (NERs) limit fault currents in high-voltage direct current (HVDC) systems and protect transformers and switchgear against thermal and mechanical stress. Properly engineered NERs ensure that the system can safely tolerate transient faults without triggering unnecessary trips, maintaining grid reliability and stability.

By incorporating DBRs and NERs, energy systems can safely handle the variable nature of renewable generation, absorbing or redirecting excess energy rather than wasting it. This improves overall grid efficiency and allows a higher proportion of renewable energy to reach consumers.

Curtailment is not just about wasted energy. It’s about missing the opportunity to cut carbon, lower bills and strengthen the UK’s energy security. With the right infrastructure and the right protective systems in place, the country can capture far more of the renewable power already being produced.

Cressall provides expert NER and DBR resistor solutions to help grids safely manage renewable energy surges. For more information and to view technical datasheets, visit the website.

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Solar panels in space: The future of renewable energy

Resistor technology will play a crucial role in space-based solar power

In the first study of its kind, researchers at King’s College London have discovered that space-based solar power (SBSP) could cut Europe’s renewable energy requirements by up to 80 per cent. Here Mike Torbitt, Managing Director of resistor manufacturer Cressall, discusses what this means for the future of renewable energy, and the role resistor technology will play in making these developments possible.

From analysing NASA designs, researchers at King’s found that SBSP had the potential to reduce energy battery storage needs by over two thirds.

The feasibility of solar panels in space is still yet to be determined; there are significant technical and cost limitations to overcome first. However, it is hoped that it could become possible by 2050. If successful, it would be a giant leap towards international net-zero efforts.

NASA’s concepts, involving satellites in geostationary orbit, would allow for a continuous harvesting of sunlight that could then be beamed to Europe as microwaves. The result would be dispatchable, zero-carbon power that is unaffected by varying weather conditions.

The advantages are clear, but the challenge, of course, is navigating the technical complexities and initial investment required to complete such an ambitious project.

As highlighted by NASA, SBSP would likely exceed anything built in space before in terms of scale, other than maybe very large satellite constellations with huge combined mass and area. So, it is by no means a given that the current concepts are achievable.

Requirements for resistor technology in solar power

Resistors are vital for controlling the flow of current to make sure each electronic component receives the right level of voltage. By dissipating excess energy, they can prevent systems from overloading and overheating.

For land-based solar panels, resistors are also used for braking to ensure panels that move or tilt towards the sun stop when required.

While there will be overlaps in resistor functions in land- and space-based solar panels, SBSP will require advanced resistor technology that is both reliable and durable in space.

A major challenge will be during the launch, when resistors need to regulate electronic systems while withstanding extreme vibrations and thrust.

Resistor technology will also be needed for the testing of SBSP designs through load banks. These allow engineers to test how electronic systems will handle different conditions, to ensure faults are identified and resolved before the launch. For such projects, thorough testing is absolutely essential.

Designing resistors with resilience to extreme conditions

Resistors within the electronic systems will require highly specialised designs to make sure they can effectively withstand the harsh conditions of space.

With increased radiation and extreme variations in temperature and pressure, the conditions of space present unique challenges to engineers. Every aspect of the design, from the overall structure to the smaller details like resistors, must be carefully considered, with optimal materials used throughout.

A challenge for engineers is designing resistors that can handle the vibrations during launch and remain durable in space, while being lightweight and compact.

Combined with this, each component must have sufficient radiation resistance to withstand the sun’s ionising effects. As such, engineers will generally need to focus on materials that are lightweight with high melting points.

Navigating the cost of SBSP

Alongside the technical complexities, cost is another factor that has held back developments in SBSP. The potential savings are huge once solar panels are successfully implemented in space, but the design, development and launch of the spacecraft will involve significant costs.

As the weight of spacecraft impacts the launch costs, all components, including resistors, will need to be as small and lightweight as possible. This needs to be achieved while ensuring all power demands are met, which is no easy feat for such a complex project.

Operating in space raises the stakes for any application, and so there will be a pressure to keep all electronic faults to a minimum to avoid project failure. Again, this is why load bank testing is so important in the development process.

By reducing the need for land-based renewables in the continent, space-based technology has the potential to reshape the energy landscape once fully implemented. In fact, researchers at King’s predict that SBSP could lead to savings of up to 15 per cent of costs in Europe, equivalent to €35.9 billion per year.

Considering the potential advantages of SBSP, it would be an incredibly exciting development for the renewable sector.

On a large scale, it has the potential to boost Europe’s efforts to achieve net zero, but the advantages extend beyond that. As engineers work to overcome the complex technical challenges of SBSP, we can expect to see advancements in just about every aspect of the electronic designs, and resistor technology is no exception.

To find out more about the role of resistors in renewable energy generation, speak to Cressall’s experts.

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Renewable project power partner

Choosing a renewable project power partner

Four things to consider before beginning a project

The Association for Renewable Energy and Clean Technology (REA) predicts that the UK’s renewables sector will be worth £41 billion by 2035, providing significant growth opportunities for engineering companies. But they cannot succeed alone — green energy projects need partners and suppliers to ensure power reliability. In this article, Mike Torbitt, managing director of Cressall, offers advice on what to look for in a renewable project power partner.

Data from the 2024 report Green Skills Outlook, which surveyed 1,000 global business leaders, reveals that 93 per cent of respondents consider green skills to be important to their company’s operations and objectives. Yet, only half are planning to upskill their staff on these capabilities — opening a worryingly large green skills gap.

To effectively transition to a more sustainable economy, businesses should look to partner with organisations with the necessary green skills. The United Nations’ Sustainable Development Goals highlight the importance of partnerships to improve knowledge sharing, accelerate access to renewable technologies for the least developed countries and enhance progress measurements.

This need is particularly pronounced within the power sector, since renewable projects rely on intermittent power sources such as wind, solar and tidal. These energy sources are less predictable than fossil fuels, meaning they can cause issues with the grid if it cannot handle energy fluctuations. Therefore, entering a partnership with a supplier who understands these challenges is a must.

So, what markers should businesses look for in potential power partnerships to ensure their success?

Proven experience

For renewable projects, sector-specific experience is a must, especially in the case where the business themselves is new to green infrastructure projects.

Partnering with an experienced supplier allows companies to tap into their partner’s knowledge of the challenges and technical demands associated with renewable energy projects. Cressall has extensive experience in providing resistors for renewable infrastructure projects, including wind, solar, tidal and biomass. We also partner with multinational energy services companies such as GE Vernova to equip them with harmonic filter resistors for high-voltage direct current (HVDC) projects.

HVDC infrastructure contributes to the success of a range of offshore projects, enabling effective transmission between the grid and remote windfarms or tidal projects. However, when HVDC is converted back to alternating current (AC) at the local grid level, this results in harmonic distortion, which can lead to overheating and increased likelihood of equipment failure.

Cressall’s thorough understanding of HVDC transmission allows us to provide tailored harmonic filter resistors to mitigate this problem and increase the efficiency of energy transmission projects.

Durable components

Another key consideration when selecting a supplier for a green energy project is whether it can manufacture components that withstand harsh conditions.

As of February 2025, the UK has over 30 gigawatts (GW) of offshore wind either installed or committed. While offshore windfarms benefit from higher wind speeds and consistency in direction, the effects of harsh winds and saltwater can be damaging for the equipment.

Opting for a power partner that can produce durable components is beneficial for offshore developments. For example, resistors used in these kinds of projects can be manufactured from materials with a high chromium content, such as 316 grade stainless steel, which helps to create a protective layer against corrosion caused by saltwater.

Thorough quality assurance

Renewable energy equipment needs to perform reliably in challenging and changeable environments, underscoring the importance of thorough testing and quality assurance

When selecting a power partner, it’s worthwhile researching its quality control process. In the case of resistors, a range of specialist tests are used during product development to ensure dependable performance under real-world conditions.

Essential quality measures include thermovision testing, which help engineers to detect hotspots and assess overall thermal performance. Understanding thermal behaviour enables appropriate cooling selection, reducing the risk of thermal shock, lubricant degradation or component failure.

Vibration testing resistors for shock and seismic resistance is equally important. This is particularly relevant for offshore wind farms or grid-side equipment in earthquake-prone regions.

Custom engineering capabilities

The benefit of partnering with a supplier that offers custom solutions is that they can be tailored to the specific challenge that they are facing.

Although resistors are a well-developed, mature technology, custom design allows proven techniques to be applied for new problems. Custom resistor engineering capabilities offer purchasers increased choice when it comes to cooling methods, materials and power ratings.

While made-to-order resistors offer a wider range of options, it’s worth looking for a manufacturer that also offers off-the-shelf solutions. Many renewable projects face hold ups, whether that is due to community opposition or delays connecting to the grid. For developments with tight timelines, ready-made solutions are ideal as they can decrease further delays during the product design, test and manufacture process.

Partnering with the right power partners and suppliers can help infrastructure developers to accelerate the green transition, but it’s important not to rush into ineffective partnerships in the hurry to roll out renewable projects. Considering whether a potential manufacturing partner is the right fit helps to ensure the success of renewable projects, both in the development phase and once operational.

Could your renewable project benefit from some resistor expertise? Reach out to our knowledgeable team.

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Preparing for change

PREPARING FOR CHANGE

RESISTORS HELP TO GET THE MOST OUT OF WIND POWER

In January 2025, the UK government announced new measures to unlock up to thirteen major wind projects as part of its Plan for Change. But with wind curtailment — the switching off of wind turbines — reaching record levels in 2024, how can we make the most of the energy generated? Here, Mike Torbitt, managing director of Cressall, explores the role that resistors can play in preventing the wastage of wind power.

The government’s Plan for Change aims to modernise the ‘outdated and archaic’ infrastructure regulations to increase the pace at which offshore wind projects are constructed. In total, the measures could generate up to 16 Gigawatts (GW) of electricity and around £20-30 billion of clean energy investment.

The announcement is promising, but much of the newly harnessed wind power could be wasted. Turbines are frequently turned off in periods of high wind, to protect the grid system from being overwhelmed by the power generated.

According to a report from electricity supplier Octopus, enough energy was wasted in the first nine months of 2024 to power two million UK homes for a year. Not only does wind curtailment limit the UK’s ability to fully transition to clean energy, but it also results in higher bills for consumers.

And the problem is growing — the costs of wind curtailment will reach £3.7 billion by 2030. As the UK continues to invest in wind power, it’s important that additional energy generated is put to good use. So, why is energy being wasted and how can this be prevented?

DISTANCE ISSUES

The key reason for switching off wind turbines is distance — both from the grid and from demand.

Offshore farms are much further from the grid than their onshore counterparts, meaning there are less readily available connection points to distribute power to the transmission network. Consequently, in the case of strong winds, there are fewer options available to distribute the energy elsewhere.

The remote location of offshore windfarms also means they are located far from high-demand areas. For example, Scotland currently has seven operational offshore windfarms, many of which are located near the north of the country where population density is low. Demand for energy is greater elsewhere, but inefficient cable networks mean that a lot of power is lost during transmission.

HANDLING THE EXCESS

Energy experts have several suggestions on how to tackle wind curtailment. For instance, the Octopus report recommends zonal pricing, which means that people living near turbines can benefit from cheaper energy rather than it going to waste. The research suggests that businesses could save in the region of 65 to 99 per cent on energy costs by moving to Scotland and benefitting from zonal pricing. While the prospect of lower bills would hopefully encourage people to welcome the development of renewable energy projects within their communities, moving to energy-abundant areas isn’t feasible for all businesses.

Another way to minimise wastage is by improving the infrastructure that transmits energy from offshore sites to high-demand areas. In March 2025, construction will begin on the Eastern Green Link 1 (EGL1), which will enable the transmission of energy from Torness in Scotland to Hawthorn Pit in the North East of England. Once complete, the high-voltage direct current (HVDC) project will deliver enough electricity for two million homes.

HVDC enables efficient power transmission over long distances between offshore wind farms and the grid, thanks to its consistent current density. Resistor technology is essential in HVDC systems, safeguarding against grid failures by absorbing excess wind energy until the transfer is safely halted. Additionally, DC neutral earthing resistors provide further protection to the system, both onshore and offshore, within HVDC converter transformers.

Cressall has extensive experience in supplying resistors for renewable projects, including a GE Vernova partnership covering five HVDC projects in the North Sea.

The government’s aim to amend inflexible planning restrictions and boost wind power generation projects through its Plan for Change initiative is a welcome development. However, to create real change, the rollout of energy transmission projects must keep pace with offshore wind developments. HVDC systems supported with reliable resistor technology will enable the UK to reduce wind curtailment and make the most of the renewable resources available.

Contact a member of the Cressall team for advice on selecting the right resistors for your renewable project.

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