Offshore wind

ADVANCING OFFSHORE WIND

HOW CAN WE EXPAND OFFSHORE WIND TO REACH 2030’S 40 GW TARGET?

The UK’s history is enriched with maritime activity. Surrounded by water from John o’ Groats to Lands’ End, the surrounding waters have played a pivotal role in trade, travel, and most recently, electricity production. Achieving the Government’s target of generating 40 gigawatts (GW) of offshore wind power every year by 2030 will require continued investment and development in power equipment.

Offshore wind power plays to the nation’s geographical strengths while also providing a clean energy source to fuel the country’s path to net zero. The North Sea’s high quality wind resources and relatively shallow water make it an ideal location for offshore wind farms. According to the International Renewable Energy Agency (IRENA), around 90 per cent of global offshore wind capacity is located in the North Sea, which is why the UK is already a world leader in this renewable power source.

However, to reach the Government’s 2030 production goal, energy suppliers must make advancements in wind turbine technology, while simultaneously considering how their generated power will be safely transferred to the grid.

IMPROVED TURBINE TECHNOLOGY

Turbines capable of producing more power per rotation are essential for the development of efficient offshore wind farms. One way of improving turbine efficiency is to increase the blade length.

An increased blade length means that stronger forces will act on the turbine, so the blade material needs to be appropriately chosen. To achieve an adequate stiffness-to-weight ratio to avoid deflection, carbon fibre or fibreglass blades are typically favoured. However, there is an expanding market for hybrid reinforcements, which combine the two materials together for optimum sturdiness.

Improvements in wind turbine technologies have already triggered a move into deeper waters to use sites with better wind resources. Static wind turbines are still restricted to waters at a maximum depth of 60 metres, so to upscale the UK’s wind power output, floating wind turbines will be essential.

MORE SUITABLE SITES

Once all viable sites within 60 metres of shore have been constructed, floating wind projects will become vital to offshore’s growth. Floating offshore wind farms, which can be located up to 80 kilometres (km) from land, could play a key role in the long-term decarbonisation of the power sector.


Floating wind turbines sit on a steel and concrete floating system instead of a fixed base, meaning they can be placed in a larger number of sites up to 200 metres deep. They can also be towed, allowing them to be relocated without much additional cost. This broadens the potential output that offshore wind could provide and brings it one step closer to the 40 GW target.

SECURED POWER SUPPLY

Like all renewable energy, offshore wind can be unpredictable and inconsistent, which can make grid connection challenging. In periods of high wind, large inrush currents occur, which can lead to overvoltages on the grid and subsequent equipment malfunctioning.

It’s important to prepare for these inevitable inrush currents by integrating technologies such as pre-insertion resistors (PIRs). Already in use across many of the UK’s windfarms, Cressall’s PIRs have a high thermal mass, which allows them to absorb excess energy produced by the inrush current and safely dissipate it as heat. This prevents damage to the grid and improves the reliability of offshore wind’s power supply.

Offshore wind holds great potential in the shift towards renewable energy and could be the key to decarbonising electricity generation. However, we must continue to advance critical power protection technologies to prevent any obstacles in its upscaling and to enable this powerful resource to flourish.

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HYDROGEN CATALYST

THE HYDROGEN CATALYST TO THE EV REVOLUTION

 IS HYDROGEN KEY TO THE NET ZERO EV ROLLOUT? 

In November 2021, UK Prime Minister Boris Johnson announced the dawn of the electric vehicle (EV) revolution, fuelled by new regulations and investment pledges across all stages of the EV supply chain. From charging stations to electricity generation, new projects will begin across the United Kingdom in 2022. But there’s one key ingredient that will transform the sector’s sustainability credentials — hydrogen.

With bans on the production of new diesel and petrol-powered vehicles looming, encouraging widespread consumer uptake of more sustainable vehicle choices is becoming an urgent matter. Uptake seems to be increasing — according to The Society of Motor Manufacturers and Traders (SMMT) demand for battery electric vehicles (BEVs) more than doubled between November 2020 and November 2021. But if transport is to decarbonise before its 2050 deadline, there’s more to do to make BEVs carbon neutral.

BEVS’ SUSTAINABILITY SHORTFALLS

Fully decarbonising BEVs is tricky. Using energy from the National Grid means that the sources used for electricity generation directly affect BEVs’ environmental impact. The grid is becoming more renewable and is set to be net zero by 2050. But there is an added challenge. According to The Committee on Climate Change, electricity demand is set to double from today’s 300-terawatt-hour (TWh) requirement to 610 TWh by 2050 thanks to BEV uptake.

So, to complete the dual task of increasing supply and decarbonising electricity generation, the Government is investing in dispatchable low-carbon sources to support variable weather-dependent renewables in powering the grid when production falls short of demand. In the meantime, fossil-fuelled electricity generation is negatively impacting BEVs’ sustainability.

BEVs also have some additional environmental concerns regarding their reliance on lithium-ion batteries. Rare earth metals including cobalt, nickel and manganese are all major components of lithium-ion batteries. Mining these materials can result in huge environmental destruction, disrupting entire ecosystems, while the heavy machinery used contributes even more emissions. So, is there a more sustainable option?

HYDROGEN : THE FUEL OF THE FUTURE

Hydrogen is a promising resource that is key to delivering transport’s decarbonised future. Industrial production of hydrogen is typically delivered through electrolysis — using an electrical current to split water into hydrogen and oxygen. If a renewable source is used to produce electricity, then this creates an entirely carbon-neutral hydrogen fuel, known as green hydrogen.

The Government has set a target to produce five gigawatts (GW) of green hydrogen by 2030 and has already announced investments into projects like Whitelee Windfarm near Glasgow, which will use wind power to generate electricity for hydrogen production.

Hydrogen produced in this way can then be used as a fuel source for an alternative to BEVs: fuel cell electric vehicles (FCEVs). FCEVs are powered by proton exchange membrane fuel cells. FCEVs turn hydrogen into electricity by combining the hydrogen fuel with air and pumping it into the fuel cell. Once inside the fuel cell, this triggers a chemical reaction, resulting in the extraction of electrons from the hydrogen. These electrons then create electricity, which is stored in a small battery used to power the vehicle.

FCEVs fuelled with green hydrogen are completely carbon-free, thanks to the renewable origins of these fuel cells. The only end products of the fuel cell reaction are electricity, water and heat, and the sole exhaust emissions are water vapour and air. This makes them a more-aligned choice with net zero goals, enabling a widespread, carbon-neutral EV rollout.

MAKING HYDROGEN VIABLE

Although the benefits of FCEVs are clear, the technology behind them still needs refining. Fuel cells are unable to work under heavy loads for a long time, which presents issues when rapidly accelerating or decelerating.

Studies into fuel cell function have shown that, when an FCEV begins accelerating, the fuel cell’s power output increases gradually to a point, but then it begins to oscillate and drop despite velocity remaining consistent. This unreliable power output presents a challenge for automakers.

The solution is to install a fuel cell for a higher power requirement than necessary. For example, if a FCEV needs 100 kilowatts (kW) of power, installing a 120-kW fuel cell would ensure there is always 100 kW of power available, even if the fuel cell’s power output drops. Opting for this solution requires a resistor to remove the excess energy when not required, to perform a “load bank” function.

Cressall’s water-cooled EV2 is designed specifically for heavy-duty applications including hydrogen-powered FCEVs. It absorbs excess energy from the system and dissipates it as heat, which can be used to warm the vehicle’s passenger cabin. This protects the electrical system, allowing FCEVs to be very reactive to high-power demands, and accelerate and decelerate rapidly without storing excess energy in a battery.

The EV rollout is well underway, with pressing deadlines for the retirement of fossil fuelled vehicles edging closer and closer. Although BEVs are the main player in the decarbonisation of transport, it’s important to not rule out the distinct benefits that FCEVs bring to the market. But combining the two could be the key to unlocking the EV revolution

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ELECTRIC MINES

POWERING THE SHIFT TO ELECTRIC MINES

According to a 2020 McKinsey report, the global mining industry is responsible for between four and seven per cent of total greenhouse gas emissions, so any technology that contributes to the sector’s decarbonisation is valuable. For decades, diesel-powered machinery and vehicles have dominated mining. Its long success is down to the fact diesel engines can handle the extremely harsh conditions of underground mines, enabling access to once unreachable depths.

THE PROBLEM WITH DIESEL

Diesel’s power doesn’t come without problems. From an environmental perspective, the use of diesel engines doesn’t support mining’s decarbonisation agenda.

However, there is another reason why moving away from diesel is a good idea — its negative impact on worker safety. According to the International Labour Organisation, despite only employing one per cent of the global labour force, mining is accountable for eight per cent of fatal workplace accidents.

Two major sources of hazard in underground mining are ventilation and noise, which are both worsened by the use of diesel-powered machinery. The emissions from diesel mining equipment are a large contributor to the toxic gases found in underground mines, which require vast, comprehensive ventilation systems to clear the air for workers to breathe. In addition, the noise produced by large diesel engines adds to the noise pollution, which is already significant, and can lead to noise-induced hearing loss.

THE MOVE TO ELECTRIC

EVs eliminate the noise and emission problems associated with diesel power systems. However, currently only 0.5 per cent of mining vehicles are fully electric, and many mines are reluctant to make a complete shift due to performance concerns.

The same worries holding automotive consumers back from changing to an electric car hold true for mine operators, who are reluctant to move away from diesel’s reliability due to concerns around battery capacities. 

With operations taking place hundreds, or even thousands, of metres below the ground, underground mining vehicles need to consistently perform well. Equipment failure in underground mines can not only result in huge repair costs and significantly impact production, but it can also risk health and safety, so it is critical that electric mining vehicles can meet the demands of this application.

THE REGENERATION GENERATION

Underground mining equipment encounters some of the harshest conditions out there — unseen holes, tight tunnels and uneven terrain can all place stress on automated equipment. Therefore, vehicles must be designed with these conditions in mind.

An essential component of any EV is its dynamic braking resistor (DBR). Heavy duty applications like mining require heavy duty components to withstand the tough operating conditions they face.

When a mining vehicle brakes, using the principles of regenerative braking, the first option is to store the excess energy produced in the vehicle’s battery for reuse, improving the energy efficiency of the vehicle and keeping the system operational for improved safety.

However, when the battery is close to its full charge, this is not possible. A dynamic braking resistor is the simplest, most reliable and cost-effective solution to this problem as it dissipates the excess energy as heat, allowing the EV to stop when required. This is particularly useful in mining applications, where operational efficiency and reliability are crucial.

Cressall’s EV2 water-cooled DBR has a unique design, meaning it takes up just ten per cent of the volume and 15 per cent of the weight of a conventional air-cooled DBR. Units can be combined in up to five-module assemblies to meet high-power requirements.

Mining techniques have evolved many times throughout its rich history. With increased pressure to decarbonise, mining EVs will play an essential role in bringing the industry into the 21st century, making operations efficient, reliable and safe.

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