Electrifying agriculture

ELECTRIFYING AGRICULTURE

HOW EV TRACTORS CAN SUPPORT THE SECTOR’S SUSTAINABLE SHIFT

The electrification of the on-road transportation sector is well documented. What’s less discussed, however, are the off-road applications that can also benefit from electrification. That includes agricultural equipment. Here‘s how the agricultural sector can electrify, and the echnologies that can help.

According to the UK Government’s Department for Environment, Food, & Rural Affairs’ Agri-climate report 2021, in 2019, agriculture was the source of ten per cent of total greenhouse gas emissions in the UK. The sector was also responsible for 68 per cent of total nitrous oxide emissions, 47 per cent of total methane emissions and 1.7 per cent of total carbon dioxide emissions.

However, despite these figures, it seems the farming community is seeking change. The 2021 Farm Practices Survey indicated that 67 per cent of farmers consider recognising greenhouse gases to be either fairly or very important when taking decisions about their land, crops and livestock. One method of reducing emissions is to electrify equipment that traditionally runs on fossil fuels, such as tractors.

A NECESSARY CHANGE

Modern agriculture depends on a fleet of heavy-duty vehicles, from pickup trucks and small utility vehicles to massive tractors and combines that can weigh several tonnes, plus attachments. This machinery is commonly powered by diesel engines, mostly due to their higher torque and dependability. And here is where an electrification challenge may lie.

The electric sceptics of the agricultural industry claim that the largest problem with electrifying tractors and other heavy vehicles is that battery-powered options don’t have the energy density of a diesel model required to do long, hard work in the field. As load impacts on battery life, pulling a piece of heavy equipment would drain power fast. Using diesel, therefore, means a farmer won’t have to worry about filling the tank for 10 to 12 hours while out on the job.

Battery technology, therefore, needs to be developed in order to withstand the heavy loads of agricultural vehicles and supply a lasting and reliable source of power. Some manufacturers have produced compact, swappable batteries to extend the length of operation. Another option, developed by John Deer in 2019, features a long power cable that’s only available for farmers who are able to produce their own electricity via the use of solar panels, manure digesters or windmills.

Right now, despite its challenges, attempts to electrify farming vehicles are well underway. The work is being done, and given the mounting pressure to decarbonise all areas of industry, it won’t be too long before electrification becomes more accessible to the masses. In addition to the battery itself, manufacturers must consider the other components that make electrifying possible.

DYNAMIC BRAKING

Resistors will play a role in electrification, to support the process of regenerative braking. As part of regenerative braking, excess kinetic energy is used to recharge an EV’s battery. It is able to do this because the electric motor in an EV can run in two directions: one, using the electrical energy, to drive the wheels and move the vehicle, and the other, using the excess kinetic energy, to recharge the battery.

When the driver lifts their foot off the accelerator pedal and steps on the brake, the motor starts to resist the vehicle’s motion, “swapping direction”, and begins putting energy back into the battery. As a result, regenerative braking uses the EV’s motor as a generator to convert lost kinetic energy into stored energy in the battery.

Regenerative braking can support the ongoing dilemma of electric tractor battery range. However, to work effectively, other technologies are needed to make the process safe and effective. If the vehicle’s battery is already full or there is a failure, regenerative braking cannot happen as the excess energy has nowhere to go and must be dispelled safely. If not dissipated, it won’t be possible to slow down the vehicle, resulting in braking failure. To make electrifying agriculture safe, resistors are used to collect excess energy and dissipate it safely.

Cressall’s EV2 dynamic braking resistor converts excess kinetic energy during the braking process into heat that can be dissipated or used in other parts of the vehicle, like to heat the tractor’s cabin. It is a high-power density, lightweight and compact resistor that has proven to meet all major shock and vibration standards, suitable for all automotive applications, not just on-road vehicles.

While electrifying on-road vehicles has become well recognised, the same attention must be paid to other areas of the automotive industry. The agricultural sector is beginning to wake up to the prospects of decarbonising, and positive steps are being taken towards electrification. To make it happen, agricultural vehicle manufacturers need to consider the technology that can make agricultural EVs more efficient, and safer.

What’s still holding back EV sales

WHAT’S STILL HOLDING BACK EV SALES?

ELECTRIC VEHICLE (EV) UPTAKE IS INCREASING, BUT SOME DRIVERS REMAIN HESITANT

In his 2022 Autumn Statement, Chancellor Jeremy Hunt announced that electric vehicle owners will have to pay road tax from 2025. Critics say the move will further hinder consumers from purchasing an EV sooner than they need to. But, even as EV adoption continues to climb, what are the other reasons holding people back from making the switch?

Though EV uptake has been increasing in recent years, new electric car registrations still lag far behind petrol and diesel vehicles. The Government’s Vehicle Licensing statistics for 2022 showed that in the April to June period, 13 per cent of new car registrations were fully electric, with petrol still taking the majority at 53 per cent. But, when under increasing pressure to meet climate carbon targets, why is there still a reluctance to switch to an electric vehicle?

SURGING ELECTRICiTY COSTS

With energy bills doubling over the past year, the cost of powering an EV is a major barrier to their adoption. A poll by the AA suggested more than three in five drivers have been put off owning or switching to an EV due to skyrocketing electricity costs.

And those who can’t charge their vehicle at home need to pay even more for their electricity. Public chargers can cost up to twice as much, with the RAC Charge Watch reporting a 42 per cent price increase in 2022 for using a public rapid charger.

LACK OF RAPID CHARGERS 

According to Zap-Map, out of a total 36,000 public charging points across the UK, only around 7,000 of these are rapid or ultra-rapid chargers. With non-rapid chargers potentially taking several hours or even overnight to charge an EV battery, there’s a very noticeable difference when switching from a petrol or diesel that takes only minutes to refuel and has a much longer range on a single tank.

The charging times of non-rapid chargers can also mean that a charging point is taken up for several hours, unlike a petrol station where each pump is only occupied for minutes. When it comes to electric power, the number of charging points needs to reflect the number of cars as well as their expected recharging times.

UPFRONT COST

Many potential customers are discouraged by the initial cost of an electric vehicle, often considerably higher due to the more expensive technologies used in EVs. Insurance firm LV found new EVs to be an average of £7,000 more expensive than their petrol and diesel equivalents. And this trend follows into the used car market, with a used electric hatchback up to 27 per cent more expensive than its petrol counterpart.

With mounting pressure to reduce carbon emissions on the roads, it’s inevitable that drivers will need to switch to EVs before long. But what can manufacturers do now to help improve the EV uptake?

BOOSTING EV EFFICIENCY

Increasing EV uptake, particularly before the ICE deadline, will require effort from all stakeholders — be that automakers, infrastructure developers and government. When designing EVs, there are several considerations manufacturers can make to boost their efficiency and thus make them more commercially attractive.

One way of boosting vehicle efficiency, which positively contributes to EV driving range, is implementing regenerative braking. This process takes the excess energy generated when the vehicle is braking, and reverses the flow of electricity, putting it back into the battery.

But there may be situations where the energy generated in a sudden burst is too high for the battery to take in, such as when making an emergency stop. This can lead to overvoltages, damaging electrical components within the system, and there are other factors to consider when designing a safe and effective regenerative system.

To dissipate the excess energy safely, resistors should be used. Compact, high power dynamic braking resistors with simple connections are easily installed into existing circuits. Modular resistors can also be put together to match the level of braking power required depending on the type of vehicle.

Though much progress has been made in increasing EV uptake, there are still many drivers who are yet to be persuaded. But we’re not at the end of the road yet, and there are many considerations EV manufacturers can make to make their vehicles a more enjoyable, efficient, and safer drive for end users.

Fuel cell versus battery trucks

FUEL CELL VERSUS BATTERY TRUCKS

HOW CAN AUTOMOTIVE MANUFACTURERS CREATE A ZERO EMISSION FUTURE?

By 2040, all new heavy goods vehicles (HGVs) sold in the UK must be zero-emission. Advances in green energy technology mean this is possible, but automotive manufacturers are still in disagreement about what type of power source is best. In this article, Simone Bruckner, managing director of resistor manufacturer Cressall, explains the pros and cons of fuel cells and battery power, and what these mean for electrifying HGVs.

There are two main types of electric vehicle, categorised by their power source. Battery Electric Vehicles (BEVs) rely on a lithium-ion battery for power. Fuel Cell Electric Vehicles (FCEVs) on the other hand use a fuel cell, which combines hydrogen gas with oxygen to generate electricity.

HYDROGEN POWER

Hydrogen is the most abundant element in existence, so future supply is not an issue. Hydrogen power also has a much higher energy density than batteries, at around 35,000 watts per kilogram of hydrogen, while lithium-ion batteries only have around 200 watts per kilogram.

This increased energy density allows FCEVs to travel distances comparable to petrol or diesel vehicles, and up to 100 miles further than BEVs. For HGVs in particular, it also means that much heavier payloads are possible, with the ability to carry an extra two tonnes or more depending on the vehicle.

The main problem with hydrogen fuel remains with its production. Similar to the way we often refer to more environmentally friendly processes as “green”, hydrogen is colour-coded based on its method of production. Most of the hydrogen produced currently is defined as “grey”.

Grey hydrogen is generated using methane from natural gas, producing about ten times more carbon dioxide than hydrogen. Recapturing the carbon dioxide produced is possible, but it’s still not a perfect solution, only being able to capture up to 80 per cent of the generated carbon.

The ideal type of hydrogen is green, produced by separating hydrogen and oxygen molecules in water using electricity. Provided that the source of this electricity is renewable, this is the most environmentally friendly form of hydrogen. At present, the cost of production is the main barrier for this method, though it is expected to fall to a level that’s more competitive with grey hydrogen by 2035.

REFUELLING AND RECHARGING

Refuelling remains a hot topic for FCEVs. In terms of refuelling time, FCEVs have a huge advantage over BEVs, taking around three to five minutes to refuel. This means that lorries can get straight back onto the road with minimal downtime, without hampering delivery expectations.

In contrast, BEVs can take anywhere between 30 minutes to ten hours to recharge, depending on the voltage of the charger and the battery size. Considering the battery size required to power a HGV compared to a passenger car, it’s likely that most HGV charging times will sit on the higher end of the spectrum on a standard charger.

Rapid chargers operating at a higher voltage can be installed at HGV depots instead, giving access to much faster recharging times, though they will still not be as quick as FCEVS to refuel. It’s important to note, however, that UK legislation requires drivers to take regular breaks regardless.

By law, drivers should take a 45-minute break for every four and a half hours driving, and drive for a maximum of ten hours per day. Factoring in these numbers, the slower refuelling time of a BEV may not be as much of an issue as once thought, provided it can refuel sufficiently to reach the next point in its journey.

The abundance of charging points means that a BEV is never too far away from a top up. In contrast, there are only around 15 stations in the UK currently providing hydrogen fuel. Choosing FCEVs right now, therefore, means that careful route planning is required to ensure the lorry can safely reach a station.

Encouragingly, investments are being made in this area. Bosch has committed to set up 4,000 hydrogen fuelling points worldwide by 2030, and as the cut-off deadline looms for new petrol and diesel vehicles, it’s likely that similar schemes will follow.
The problems with lithium power
Most BEVs are powered by lithium-ion batteries. These have decreased substantially in price since they first started appearing in electric vehicles, making electric lorry fleets a lot more financially viable.

However, this downward pricing trend is not expected to last. High global demand of lithium is predicted to result in chronic shortages by 2030. While there is still enough lithium in the ground, lacking infrastructure means that not enough of it can be mined to meet modern demands for much longer.

Another issue with BEVs is their heavy reliance on the power grid, as more than half of the energy on the grid is provided by non-renewable sources. Grid reliance can also be tricky in the cases of power cuts and blackouts. Overnight power disruption may result in a half-empty battery the next day, having a knock-on effect to scheduled deliveries and supply chains.

PRESERVING BATTERY LIFE

In response to these issues, manufacturers should be looking for ways to ensure that their HGVs can get the maximum value out of their fuel. Preserving battery life can help to ease the pressure on the lithium supply, as well as lower overall fuel demand.

One of the ways that battery life preservation can be achieved is through regenerative braking. In an electric vehicle, the electric motor runs in two directions. The forward direction drives the movement of the wheels and the vehicle. Reversing the motor direction takes the excess energy away from the braking system and puts it back into the battery. Using regenerative braking, the kinetic energy from braking that would otherwise be wasted can be saved and reused elsewhere.

Batteries only have a limited capacity though, and a full battery has nowhere for the excess electricity to go. This can lead to component damage as well as overheating. To dissipate the excess electricity safely and prevent this from happening, a dynamic braking resistor, or DBR, can be used.

DBRs are also useful in ensuring that emergency braking can be done safely, which is essential in heavier vehicles. FCEVs struggle with fast acceleration and deceleration, as fuel cell output is not consistent due to the method of generating electricity. The solution is to install cells that have a higher output than what is needed, meaning that there is always sufficient energy available, and using the DBR to safely remove the excess.

Choosing a lightweight DBR like Cressall’s EV2 helps to reduce the overall weight of a HGV, maximising its payloads. The EV2 also has a modular design, allowing multiple modules to be combined to give up to 125 kW in one single unit, which could be then put in parallel or series with others for higher power for safe emergency braking. And at only a tenth of the size of conventional convection cooled DBRs, the liquid cooled EV2 provides a compact solution to safer braking.

It’s clear that there’s still a long way to go to providing cost-effective and sustainable fuel for heavy vehicles. But boosting battery life can go a long way in meeting overall demand. By implementing technologies like regenerative braking, even the largest of road vehicles can benefit from cleaner, greener fuel technologies.

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Cressall Resistors is Cyber Essentials certified

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CRESSALL RESISTORS IS CYBER ESSENTIALS CERTIFIED

Cyber Essentials is an internationally recognised, UK Government-backed certification scheme launched in 2014 as part of the Government’s National Cyber Security Strategy.

Developed by the National Cyber Security Centre – a part of GCHQ – and delivered by IASME, the certification scheme supports organisations of all sizes to guard against online threats and demonstrate a commitment to cyber security.

Cressall first achieved certification in 2021 and has just successfully renewed following rigorous re-assessment. As the nature of threats develop and working practices evolve the certification requirements are reviewed and changed frequently, hence the requirement for annual renewal.

Cressall takes our commitment to protecting data very seriously and this certification provides evidence of that commitment to our Customers, Suppliers and other stakeholders.