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The government’s Plan for Change aims to modernise the ‘outdated and archaic’ infrastructure regulations to increase the pace at which offshore wind projects are constructed.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.

CRE66

Enabling great British energy

ENABLING GREAT BRITISH ENERGY

A ZERO-CARBON GRID REQUIRES SPECIFIC TECHNOLOGIES TO ENSURE RELIABILITY

As part of Labour’s plan to boost the UK’s renewable energy production, ‘Great British Energy’ will see the production of a greater number of floating offshore wind farms and tidal power projects. However, for these technologies to be a success, it’s essential to have the right enabling mechanisms in place. Here, Mike Torbitt, Cressall’s managing director, explains the role of resistor technology in making GB Energy a success.

While the exact details about what GB Energy will involve are still uncertain, we can paint a pretty good picture of it from the current information at hand. Starmer’s government intends to invest £8.3 billion of funding into a new, publicly owned green power company as part of wider energy security and sustainability goals.

DELVING INTO GB ENERGY

GB Energy will work with the private sector to provide investment into emerging energy technologies like green hydrogen, floating offshore windfarms and tidal power. It will also scale investment into existing renewable technologies like onshore wind and solar power.

By boosting the UK’s renewable energy power, GB Energy is projected to create 650,000 new jobs across the UK, lower energy bills, increase energy security and create a zero-carbon energy system to the UK by 2030. Labour has pledged to establish GB Energy within its first few months of parliament by passing a new Energy Independence Act, meaning we could see GB Energy materialise by the end of the year.

While the benefits of transitioning to a 100 per cent zero-carbon energy system are abundantly clear, there are certain logistical and technological considerations to make to eliminate fossil fuels from the energy system completely.

THE CHALLENGES OF RENEWABLES

Whether it’s energy from the Sun, sea or wind, renewables have one thing in common — their input energy is extremely variable. For tidal and wind projects, the turbines work in a very similar way, so manufacturers must ensure they can safely manage what can often be high and unpredictable surges of power.

There may be times where winds or waves are so strong that high inrush currents occur. These can result in overvoltages in the system, leading to component damage, or even failure in extreme cases. When renewables like these make up the entire energy system, preventing component failure from scenarios that we know will occur at some point is essential to continuity of supply.

As renewable resources grow in sophistication, it is vital that other systems also keep pace in order to effectively manage the power they create.

GETTING IN CONTROL

Overvoltage issues can be remedied by using resistor technologies, which all work by limiting or regulating the flow of electronic current in a circuit. Depending on the specific renewable application, there are different solutions to prevent overvoltages.

For tidal turbines, a dynamic braking resistor (DBR) can be integrated into the generation and control circuit to protect against any excess power generated by strong currents. Cressall’s EV2 advanced, water-cooled resistor is designed for these applications. The range is modular, so multiple resistors can be combined to handle power outputs up to one Megawatt. The EV2 also boasts an IP56 ingress protection rating, making it able to withstand harsh marine environments and suitable for tidal turbine applications.

In wind turbines, overvoltages are avoided by using a pre-insertion resistor (PIR). Insulated for the full system voltage, PIRs like Cressall’s mitigate against temporary overvoltages, such as those caused by exceptionally strong winds. They also absorb and control transient magnetising currents within transformers throughout the network. This control helps keep voltages consistent with minimal dips, reducing potential disturbances for users of the power network.

While the specifics of GB Energy are still yet to be announced, a fully renewable energy grid is certainly on the cards in the coming years. The industry will need to consider the importance of having the right technology in place to deal with the challenges that renewables bring, and make green energy a viable system nationwide.

CRE660/08/24

Securing data centre power

SECURING DATA CENTRE POWER

In Devon, a public swimming pool is being heated by an unusual source ─ a small, local data centre. Data centre use is ubiquitous, with virtually every business using its own, or someone else’s, data storage system. But power outages continue to pose a problem for these services, which, by the nature of their application, need to be available 24/7.

So how can we minimise the risks? Here, David Atkins, projects director at Cressall explains.

Data centres are physical facilities housing an organisation’s IT infrastructure, including its networked computers and data storage. These centres support many aspects of a business’s online applications and activities, whether it’s virtual desktops or enterprise databases. With the accelerating pace of digitalisation, the demand for data services is growing exponentially, with McKinsey and Company forecasting the demand for data centres in the US to grow ten per cent year-on-year until 2030. Similar growth has been forecasted in Europe and the Far and Middle East.

However even with the growth demand, data centres have an increasing problem ─ power outages. According to a 2022 report by the Uptime Institute, 20 per cent of organisations experienced at least one severe outage within the last three years. And more than half of those outages are costing businesses upwards of 100,000 GBP/Euros/USD in losses.

More than 40 per cent of outages that are classed as ‘significant’ in terms of their downtime and financial impact are related to power, with the single biggest cause of power incidents being uninterruptible power supply (UPS) failures. So why are outages such as a big problem with data centres, and what can we do to prevent them?

PREVENTING OUTAGES

Data centres are estimated to be responsible for around one per cent of the world’s total electricity usage. Devices and equipment run constantly to ensure an always-available service, consuming energy and generating a lot of heat, which in turn requires an advanced cooling system.

Combined with other common problems, such as machines reaching their end-of-life and equipment failures, means that the maintaining the infrastructure of a data centre is something that needs to be planned and supported. Making them more reliable doesn’t need to be complicated; with the right design, planning, and maintenance testing programs in place, data centres can maximise their efficiency and minimise potential downtime.

Ensuring sufficient infrastructure is in place right from installation helps to ensure that the facility has everything it needs to support its operations. Trying to squeeze in additional equipment at a later stage, though tempting, is only likely to increase the risk of potential problems caused by systems running at overcapacity or overheating the existing cooling systems in place.

It also doesn’t leave any servers free to reroute services to if another one fails, making contingency planning much more difficult. It’s important when making plans for potential failures that all potential problem areas are considered. For example, hot weather can put additional strain on cooling systems, so it’s recommended to leave some allowance for environmental factors.

Plans should also be made in case of blackouts. Data centres rely on the availability of a constant stream of electricity. In the case that this cannot be provided, there must be a working backup generator that can keep operations afloat.

THE IMPORTANCE OF TESTING

Implementing regular testing programs and inspecting all items of equipment is key in preventing outages and ensuring that all machines are operating correctly. But testing in these environments can be challenging. With many data centres designed to maximise equipment space, there may be limited room for maintenance workers to carry and move large testing equipment.

Furthermore, the testing must be carried out to a level that is representative of its working load. This is particularly relevant when it comes to backup generators, which may be called upon at any moment to provide power.

It may be difficult to find a tester that maintains its portability while being capable of handling the voltages present within data centres, but opting for a more compact solution like Cressall’s EV2 could be the answer.

Frequently implemented in electric vehicles to aid regenerative braking, the EV2 offers a high power-to-weight ratio of 9.3 kW/Kg. Its modular design also means that multiple units can be combined to cope with loads of up to 600 kW per cubicle making it ideal for these environments. The EV2 can also tap into the data centre’s existing liquid cooling system to dissipate the generated test power, meaning no further heat is lost into the air when testing, so putting no further strain on the existing air-cooling systems in place.

With demand for data centres only set to increase, improving their efficiencies and minimising downtime is high on the agenda for operators. And with the right design, planning and testing programs in place, the threat of outages no longer needs to cause alarm.

CR537

Floating wind farms for the future

FLOATING WIND FARMS FOR THE FUTURE

pre-insertion resistors for turbines

ARE FLOATING WIND TURBINES THE ANSWER TO RENEWABLE POWER?

Back in 2019, then-Prime Minister Boris Johnson promised 40 GW of UK offshore wind power by 2030. In early 2022, the Government raised that target to 50 GW, with an additional five GW from floating wind turbines. But are floating wind farms the solution to existing offshore power problems?

Many of us will be familiar with the sight of wind turbines. After all, there are more than 10,000 of the structures on land and at sea in the UK. In terms of efficiency, offshore wind turbines often have more favourable wind conditions, producing more electricity per turbine than their onshore counterparts.

But traditional offshore wind turbines have their limitations. Traditional offshore turbines are built onto a large steel column, fixed into a concrete foundation on the seabed. These can only be installed in relatively shallow waters, up to depths of around 60m. Not only does this limit the potential areas for turbine installations, it also means that the turbines have less access to the stronger winds that are often found further out to sea.

FLOATING FARMS

To capitalise on the stronger winds further out, floating wind turbines can be built instead. These are turbines built on huge floats, anchored to the seabed with weighted subsea cables.

Operating in much deeper water, floating wind farms make use of vast areas that were previously considered not suitable for offshore wind power. Being further out to sea also means that turbines can be a lot larger in size than their counterparts, producing even more electricity per turbine.

Kincardine, the world’s largest floating wind farm based in Scotland, has five operational floating wind turbines. Three cylindrical floats arranged in a triangular formation support each turbine, and pipes between the floats allow liquid ballast to be pumped around the structure. In this manner, the weight of the turbine can be shifted to stabilise it in harsh conditions, as well as orientating it for the wind direction.