Breaking the ice

THE ROLE OF RESISTORS IN POWERING ICEBREAKERS

Sea ice covers around twelve per cent of the world’s oceans, blocking the path for ships attempting to travel across the Earth’s coldest regions. Although they aren’t a new concept, icebreaker ships consistently play a crucial role in clearing these routes for trade, research projects and travel.


Icebreaker ships are a special class of vessel designed to break through even the thickest of ice sheets. Initially developed to open up trade routes that experience either seasonal or permanent ice conditions, ice breakers are commonly found in areas like the Barents Sea, Artic Ocean and the Saint Lawrence Seaway. More recently, they’ve also been used to support scientific research projects in the Arctic and Antarctic.

DETAILED DESIGN

To meet the challenges of ice-covered waters, icebreaker ships have a very specific, carefully considered design. The bow of an icebreaker has a unique shape that is smoother and rounder than a standard vessel, to allow it to easily glide over thick ice sheets with minimal opposing force. As it glides over the ice in this way, the weight of the ship descends onto the ice, crushing it and clearing the path.

To power the icebreakers to smoothly move over this difficult seascape, the vessels also require a significantly enhanced electric propulsion system that matches the power requirements for the icebreaker’s thrusters to break through the ice. 

As the sole enabler of transportation through these ice-covered waters, it’s essential that the propulsion system — and all of the components that it includes — are reliable, effective and safeguarded. If an icebreaker were to fail in transit, there could be major disruption to the global supply chain in the repair time. Think the Suez Canal fiasco in 2021, but much colder.

RELIABLE RESISTORS

One component that plays a crucial role in ensuring the safe operation of an icebreaker’s electric propulsion system is a dynamic braking resistor (DBR). When there is no ice in the vessel’s path, there’s less load on the system, meaning that any excess energy produced is surplus to requirements. To dissipate this excess energy, a DBR is integrated into the system, which acts as a load dump during propulsion and icebreaking activities. This load dump activity stabilises the power system, giving a constant load to the vessel’s gas engines.

It’s important to include a DBR in the electric drive system of an icebreaker for several reasons. Without the DBR, the power system would destabilise, risking potential damage to other components of the power circuit. If this continued, it could eventually lead to the loss of the vessel’s icebreaking function and complete failure of the power system.

Therefore, integrating a DBR is an absolute essential for icebreaker vessel design engineers. However, it’s not as simple as just selecting a DBR. There are several design elements for this specific application that must be considered to ensure the drive’s optimal performance.

MARINE MATTERS

When designing electrical components, like resistors, for use on icebreakers, there are several application-specific factors to consider. Each component needs to be able to withstand the salty, cold and unstable conditions that are common at sea. 

In terms of structural stability, conducting rigorous testing procedures like finite element analysis (FEA) provides evidence of a component’s ability to withstand unpredictable, inhospitable conditions. It’s also important to design in line with standards outlined by the global testing, inspection and certification specialists Bureau Veritas, for global compliance.

The saline atmosphere at sea is corrosive, so selecting the right material is essential to prevent salty sea water from leaving equipment inoperable. For metal components, it’s important to use stainless steel with a chromium content of at least 10.5 per cent. This enables the stainless steel to react with oxygen to produce a protective layer that prevent corrosion, even in an unpainted condition.

Icebreaker vessels are an indispensable part of the marine transport system. While their function is simple, having the right electrical components, including DBRs, designed specifically for icebreaking applications, is crucial to their safe and successful operation, making even the most treacherous of routes in the Polar regions accessible all year round.

Cressall designs and manufactures DBRs specifically for icebreaker vessels. Our team of expert engineers works together with our customers to develop the ideal, customer DBR solution for each application. For more information, please get in touch here.

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Industry the planet’s close friend

INDUSTRY: THE PLANET’S CLOSEST FRIEND OR MOST SWORN ENEMY?

industrialpollution and global warming

REALISING THE GOVERNMENT’S BUILD BACK BETTER PLAN

Britain — the birthplace of the Industrial Revolution, the golden age of innovation that transformed society. However, the fossil fuels that powered the revolution have left a detrimental mark on our world, which we are fighting to change with Net Zero. Is the industry that triggered the climate crisis in the first place part of its solution?

The Industrial Revolution transformed the world, igniting technological development that continues to this day. But it has also had disastrous consequences for the planet, with carbon emissions from fossil fuel use triggering the climate crisis. 

However, the necessity of industry is well recognised. The UK’s manufacturing and refining sectors contribute £180 billion to the economy and provide millions of jobs, both directly and indirectly across the entire manufacturing value chain, presenting a dilemma — is industry a help or a hindrance to the planet’s future?

INDUSTRY’S CARBON CONTRIBUTIONS

The Industrial Revolution triggered a rise in the Earth’s core temperature that is yet to stabilise. Since 2018, the Intergovernmental Panel on Climate Change (IPCC) has been warning us that a temperature increase of more than 1.5 degrees Celsius (°C) above pre-industrial levels will result in irreparable damage from extreme weather, failed harvests and species extinction.

The Government’s Net Zero strategy provides a roadmap to successfully combatting the climate crisis. Published in October 2021, Build Back Better gives details on how the UK will achieve Net Zero carbon emissions by 2050. Industry is at the heart of this challenge, both as a carbon contributor and emission eliminator.

Industry is a major source of carbon emissions, producing 15 per cent of the UK’s total. The Government estimates that emissions associated with industry need to drop by as much as 96 per cent by 2050 to achieve Net Zero status — demonstrating the magnitude of its current contribution to the climate crisis.

RESOLVING INDUSTRY’S PROBLEM

Industry’s damage to the planet has incrementally decreased over the last couple of decades. However, to keep momentum, further innovation is necessary to reach Net Zero in this huge carbon-emitting sector, both directly and indirectly. 

According to the International Energy Agency (IEA), industry’s indirect carbon contribution through its colossal energy consumption accounts for 40 per cent of the globe’s total. The move to a decarbonised renewable power supply will help eliminate this. 

However, the situation is more severe with direct CO2 industrial emissions. Since some crucial processes don’t currently have a carbon-free alternative, emission elimination is not always possible — reduction is as far as it can go. CCS is key to aligning industry with Net Zero, ensuring essential carbon-emitting processes continue without the climate consequences.

INDUSTRY’S INNOVATIVE INPUT

Despite being responsible for a large proportion of emissions and acting as a catalyst for the birth of the climate crisis, industry is also the planet’s saving grace. 

The Government’s Net Zero strategy is striving for a fully decarbonised, reliable power supply that integrates both renewable sources, like solar and wind, and dispatchable net-zero sources like natural gas with carbon capture and storage (CCS). In transportation, the goal is to ensure all cars are zero-emission capable by 2035, end the sale of petrol and diesel heavy goods vehicles (HGVs) by 2040 and achieve a net-zero rail network by 2050. 

Reaching these challenging targets involves key manufacturers developing innovative products and services to enable Net Zero. For example, at Cressall Resistors, we manufacture a range of resistors crucial to reaching Net Zero. For the automotive market, the EV2 dynamic braking resistor facilitates regenerative braking in electric vehicles, helping to increase vehicle range and improve the viability of a fully electric national fleet at an unrivalled weight and size to power ratio.

When it comes to decarbonising the nation’s power supply, pre-insertion resistors are used to prevent overvoltages caused by renewable energy’s variable input, while load banks safeguard all power systems by proving their power generation capability. Resistors are necessary to protect every electrical system and make Net Zero a realistic goal.

The Industrial Revolution is by and large to blame for the catastrophic levels of CO2 that have been emitted into our atmosphere since the eighteenth century. But it’s also a crucial part of the solution. Not only through eliminating its own carbon footprint, but also by developing the components to decarbonise other sectors. 

With the full Net Zero strategy revealed, now’s the time for industry to step up and take responsibility for preventing more damage to the planet and shift its position from the planet’s most sworn enemy to its closest friend. 

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Electric vehicles’ unsustainable secret

ELECTRIC VEHICLES’ UNSUSTAINABLE LITTLE SECRET

BATTERIES ARE THE WEAKEST LINK IN THE SUSTAINABILITY CHAIN

Electric vehicles (EVs) have been heralded as the answer to transportation’s sustainability issues, providing a scalable solution for the notoriously difficult-to-decarbonise sector. However, there’s one key component that needs some work if EVs are to become a completely sustainable method of transport — the battery. Here, Simone Bruckner, managing director of automotive resistor manufacturer Cressall, investigates the dark side of EV batteries. 


The electrification of the automotive market is a necessary step to reduce greenhouse gas emissions and ward off climate change’s consequences. Every automaker is in support of the rollout, with more affordable models being released by the day to encourage consumers to make the electric shift. At the same time, governments are enforcing change through legislation that bans the sale of new fossil fuelled vehicles from as early as 2025.

The urgency of the climate crisis and looming legislation changes has resulted in the exponential growth of the EV market. A recent McKinsey report estimates that by 2035, the three largest automotive markets — the European Union, United States and China — will be fully electric. However, while driving an EV is ‘zero emission’, an unsustainable secret hides in production.

THE PROBLEM WITH BATTERIES

Traditional diesel and petrol-powered vehicles benefit from lead-acid batteries, which are widely recyclable. However, the same can’t be said for EVs, which use lithium-ion batteries instead. Typically made from raw materials including cobalt, nickel and manganese, lithium-ion batteries are extremely expensive to produce and require high levels of mining activity. 

Mining raw materials can lead to huge environmental destruction, releasing elements into the atmosphere that can contaminate soils and disrupt entire ecosystems. What’s more, lithium-ion batteries are significantly more challenging to recycle, contributing to further environmental damage if improperly disposed of at the end of their life. 

Aside from environmental devastation, lithium-ion batteries are also in short supply. Battery production capacity across the globe is expected to increase twenty-fold, but this won’t be enough to meet the expected future demand. 

Although several industry players are developing recycling methods and reducing the reliance on raw materials, any significant progress is far off. For now, to ensure demand is met and improve the output for using these materials, it’s important for automakers to consider how they can make existing batteries last longer.

EXTENDING LIFESPAN 

Automotive design engineers should consider the benefits that regenerative braking can bring in extending lithium-ion battery lifespan. A study by the Institute for Electrical Energy Storage Technology concluded that a higher level of regenerative braking usually reduces battery ageing by reducing lithium plating.

Lithium plating refers to the accumulation of metallic lithium on the battery’s anodes, which can cause irreversible damage over time and significantly reduce battery lifespan. Lithium plating is exacerbated long charging periods, but regenerative braking can help to alleviate this issue.

Regenerative braking occurs when an EV recovers energy while decelerating by using its electric motor as an electric generator and converting kinetic energy into electrical energy. This electrical energy is then stored in the vehicle’s battery, increasing range and efficiency between charges. Incrementally recharging the battery each time the vehicle brakes reduces the length of the charging period, therefore reducing the accumulation of metallic lithium and improving battery operations and life cycle.

Resistors play a crucial role in regenerative braking, by removing excess energy from the system in the event that the battery is already fully charged. This prevents overcharging or catastrophic damage to the system. Cressall’s EV2 resistor is designed specifically for EV applications and is the most compact and lightweight dynamic braking resistor model on the market, making it ideal for EVs.

EVs are central to a more sustainable transportation system but we mustn’t cite them as an answer to all of our environmental issues. Recognising the problems that they bring and considering both long and short-term solutions is necessary in order to create truly sustainable transportation. While lithium-ion battery recycling could be a viable option in the future, extending battery life through techniques such as regenerative braking is essential to see us through and reduce reliance on finite raw materials from today.

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COP 26

COP26 round up: the path to coal-free

Clean energy future and resistors role

INDUSTRY’S NEXT STEPS TO A CLEAN ENERGY FUTUREI

The COVID-19 pandemic has shown the world how quickly global threats can take over, making this years’ Conference of the Parties (COP), COP26, the most imperative yet. As the world’s leaders debated how to limit climate change, phasing out coal power became a vital discussion point. Here Simone Bruckner, managing director Cressall, explores the energy goals made at COP26 and the technology that can help achieve them.

From the UK going coal-free for two months in 2020 to Venice’s canals clearing of pollution, restrictions during the COVID-19 pandemic had several positive effects on the environment. While these consequences were cause for short-term celebration, the pandemic highlighted the significant impact normal lifestyles and industrial operations have on our planet. 

In addition, despite temporary reductions in greenhouse gas emissions during the pandemic, the United Nations (UN) United in Science 2021 report found that their concentration in the atmosphere continues to rise. Alarmingly, the report also concluded that there’s a 40 per cent chance that average temperatures in one of the next five years will be 1.5 degrees Celsius warmer than pre-industrial times.

IMPORTANT TARGETS

It’s clear that, while much of the world’s operations paused during the pandemic, climate change continued. This placed particular importance on COP26, with some viewing it as the last chance to save the planet from climate disaster. The resulting COP26 agreement calls for countries to accelerate the phasing out of coal and subsidies for fossil fuels. This is a world first, as previous UN climate agreements have not specifically mentioned fossil fuels. 

In pledges made at COP26, more than 40 countries committed to transitioning away from coal. In order to phase out coal power, countries must increase the proportion of clean energy in their networks. This will not only require scaling up of renewable projects, but also incorporating technology that increases their efficiency.

RELYING ON RENEWABLES

For instance, solar tracking can increase the efficiency of solar panels by using motorised systems to move the panels so that they are always in direct alignment with the sun. This increases efficiency by overcoming a common issue seen with solar panels, where their power generation peaks at midday. 

Incorporating a solar tracking system can increase average solar panel power output by 35 per cent, and high efficiency can be further ensured by incorporating a dynamic braking resistor. In the motorised system, a dynamic braking resistor can be installed to dissipate the excess voltage of a decelerating motor. This makes sure that the motor doesn’t overshoot, which would cause the panel to land in a sub-optimal position.

Another renewable energy system that can benefit from additional technology is wind turbines. The majority of wind turbines use a doubly fed induction generator (DFIG), which enables them to operate at variable speeds. However, in exceptionally high winds, the rotor speed of a DFIG can exceed the maximum operating range of the system. This in turn can lead to high voltages that destroy elements of the system.

To avoid this issue and ensure high efficiency of the wind turbine system, a crowbar resistor can be fitted to the DFIG. Connected to the rotor windings of a DFIG, a crowbar resistor can prevent damage to the generator by disconnecting the converter when the rotor speed reaches its limit. 

RESISTORS TO THE RESCUE

With over 100 years’ experience in electrical engineering, Cressall is a trusted supplier of resistors to the renewable energy industry. For instance, our crowbar resistors for wind turbines can withstand high currents while remaining operational. In addition, our braking resistors for solar panels have no wearing components, so last as long as the panels themselves.

A commitment to phasing out coal power was a key outcome of COP26, and countries must increase their reliance on renewable energy if society is to bid farewell to fossil fuels. However, incorporating more clean energy into the network requires not only scaling up installation projects, but also taking advantage of advanced technology that can increase the efficiency of power generation. 

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