Cleaning up automotive emissions

CLEANING UP AUTOMOTIVE EMISSIONS

IT’S TIME TO START ADDRESSING NON-EXHAUST EMMISSIONS

 Road transportation is widely recognised as a large contributor to carbon emissions, responsible for 24 per cent of the global total. However, carbon isn’t the only thing the world’s vehicle fleet emits —non-exhaust emissions also have a detrimental impact on the health of the population and the planet.

Electric vehicles (EVs) are often referred to as ‘zero emission’, but this is not entirely true since non-exhaust emissions are produced by all vehicles, irrespective of their fuel source. In fact, the EV rollout is not expected to have any impact on non-exhaust emissions.

IT’S NOT JUST CO2

Non-exhaust emissions are particles released from brake, tyre and road surface wear, resulting in the production of particulate matter — all chemical compounds and materials in the air that are not gas. Particulate matter is classified depending on the diameter of the particles. PM10 and PM2.5 refer to particles less than ten micrometres and 2.5 micrometres in diameter.

Particulate matter from non-exhaust emissions originates from surface wear, which leads to abrasion and the release of small particles that become airborne. Friction between brake pads and the rotating disc and between the tyre and the road both lead to abrasion, component wear and the release of particles from the surfaces into the atmosphere.

THE PROBLEM WITH PARTICULATE MATTER

The minute size of these particles means that some of the toxins that they include are small enough to enter the human body through the bloodstream, where they can cause serious damage to the heart, brain and respiratory systems. According to the World Health Organisation (WHO), nine out of ten people worldwide breathe polluted air, and seven million people die a year because of the health effects of air pollution.

In addition to the detrimental effects on human health, particulate matter can seriously damage the environment. Once airborne, it can be carried large distances and settle on the ground or in water where toxins can lead to catastrophic ecosystem disruption, altering the nutrients of water and soil and contributing to increased acidity and agricultural destruction.

With so many issues, it comes as a surprise that several nations lack a policy regulating non-exhaust emissions. The current legal limit for PM2.5 is 25 micrograms per cubic metre air (µg/m3) in the UK, 20 µg/m3 in the EU and 25 µg/m3 in Australia, all of which exceed the WHO’s recommended limit of 15µg/m3. Therefore, it’s essential for vehicle manufacturers to consider how they can reduce non-exhaust emission through design.

SUSTAINABLE BY DESIGN

When considering how to reduce particulate matter emissions, it’s important for transport manufacturers to consider the factors that determine the production of non-exhaust emissions. Reducing brake wear is the key area for transport manufacturers can concentrate their efforts to reduce emissions thanks to regenerative braking technology.

In regenerative braking, upon deceleration, the vehicle’s kinetic energy is recovered and stored in the vehicle’s battery, increasing EV range and improving energy consumption. However, it’s important that these systems have a safety mechanism in place for when the vehicle’s battery is in a high state of charge. If the battery is full or there is a failure it will be unable to store additional energy from thebraking system. Therefore, the energy must have an alternative pathway to keep the vehicle’s power system functional.

A dynamic braking resistor is an essential component of a regenerative braking system, safeguarding the EV by removing excess energy and dissipating it as heat. Most of the time, electric brakes will be sufficient to slow the vehicle, meaning that the mechanical system will only be used at very low speeds when the motor cannot generate sufficient braking force to stop the vehicle quickly. Less reliance on the brakes leads to minimised brake wear, resulting in a reduction in particulate matter and non-exhaust emissions.

The 2030 ban on petrol and diesel vehicles will ignite the elimination of exhaust emissions, but the idea that this will result in a zero-emission fleet is incorrect. Although some of the contributing factors to non-exhaust emissions may be out of our control, it’s important to minimise those that we can, like vehicle mass and brake wear, to reduce risks for the population and the planet.

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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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Ensuring safe BEV operations

LOAD BANKS ARE CRUCIAL AT EVERY STAGE OF THE BEV CYCLE

As the battery electric vehicle (BEV) market continues to flourish, and impending fossil fuel bans creep closer and closer, it’s crucial for manufacturers at every stage of the chain consider how best to ensure the correct functioning of their components. Whether it’s at the beginning, end or extreme of the BEV scene, load banks play a role in securing safe operations.

There’s no denying that the future of the automotive market is electric. According to the International Energy Agency’s Global EV Outlook 2022, EV sales doubled between 2020 and 2021, reaching 6.6 million globally. Yet with transition deadlines looming, matching demand with supply is becoming more urgent. This brings an absolute need for reliable, operational vehicles and their enabling technology.

As an essential piece of testing kit, load banks play a vital role in ensuring BEVs and their infrastructure are safe and consistent by validating the proper operational performance of components across the sector — from EV charging point testing to end-of-life battery discharge, and even Formula E pitstops.

FROM THE BEGINNING

EV charging points are a huge new focus for the automotive industry. With a target of delivering 300,000 new charging points in the UK, 500,000 in the US and 6.8 million in the EU all by 2030, production rates are rapidly on the uptake to reach these goals.

Before deploying these charging points, they must undergo quality control to ensure their operational performance. This is where load banks come into play. By stimulating an electrical load, load banks test the charging points postproduction, ensuring they are fit for purpose and to prevent any unexpected failures once set up at their designated sites.

TO END OF LIFE

As well as ensuring the operations of the EV infrastructure from the beginning, load banks also ensure the safe end-of-life disposal of lithium-ion batteries. In general, BEVs are typically expected to last between 10 and 20 years. So, although end-of-life practices aren’t a huge concern right now, they will be by the end of the decade thanks to the ongoing sales boom.

Once an EV reaches the end of its operational life, its batteries need to be safely discharged. EV batteries are typically recycled to recover their scarce heavy metal components — lithium, cobalt, manganese and nickel. But before these processes can take place, there’s an additional step that must be taken.

Even when an EV battery appears to have no charge left, it still naturally generates a small amount of charge, which can be enough to be dangerous if not completely released. By plugging the battery into a load bank, it can automatically determine the battery’s current capacity and continuously discharge it, dissipating the excess electronic load. Removing any remnant charge makes the battery safe for dismantling and metal component extraction, for reuse in the next generation of EV batteries.

AT THE EXTREME

While the electrification of commercial vehicles dominates the automotive market, there are additional applications sitting at the extreme of the electric revolution. That includes the rise of Formula E — the all-electric FIA World Championship. In the electrical future of motorsport, there remains additional considerations regarding the safety of mechanics during pitstops.

While pitstops are not mandatory at the moment in Formula E, thanks to the extended battery life and the use of all-weather tyres, they can still be required in the event of a puncture or other damages. In Formula E, because there are so many electrical components running at such a high voltage, there’s a great risk of electrocution if a fault results in the car’s body becoming live.

To protect mechanics and drivers, load banks are used to consume the car’s electrical circuits power and dissipate, temporarily discharging it and ensuring the system is safe for close contact.

As time goes on and EVs become more widespread, both on the road and track, load bank testing for BEVs will become commonplace. While the EV rollout may be in full swing, getting the right technology in place to ensure safe, correct operations at the beginning, end and extreme of the market is crucial to success.

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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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