The type of energy you choose for the container cranes and other lifting equipment at your port significantly shapes your operations. Many of your shipping company customers today are seriously trying to minimize their carbon footprints. In practice, this means using energy more efficiently throughout the container shipping chain, with a view to phasing out the use of fossil fuels. To handle their business as a key link in the chain, your cranes and lift trucks should be as productive and eco-efficient as possible.
This article is intended to help you understand your energy options in container handling equipment that is mobile and on rubber tires. You have three main alternatives: diesel, hybrid and electric.
1. Diesel
Traditionally, mobile container handling equipment has been powered by diesel fuel in diesel engines. There are many benefits to choosing diesel. Diesel engines are long-established, and in recent years their efficiency has been greatly improved. Diesel has been a relatively cheap fuel, easy to obtain everywhere, and it’s quick to fill up the tank when it runs out. Independently of other power sources, it offers high portability and adaptability, particularly in off-road equipment. The best modern diesel engines adjust to the load, so they’re always running at optimal efficiency. They can also be powered by high-grade diesel, or a biofuel substitute, with few or no adjustments.
Unfortunately, even the best diesel engines have an efficiency threshold, and will always produce some carbon emissions, vibrations and noise, no matter what fuel they use. In addition, fuel needs to be delivered somehow and biofuels can be expensive because they are new to the market and not yet available in some areas. Diesel engines have significant maintenance costs, require frequent servicing, and produce waste like old oil that needs to be disposed of. Because they are not able to store or generate “buffer” power, diesel engines in crane applications have to be sized bigger based on the peak power requirement rather than the average power demand, which is often many times smaller. The required peak power is only about 15% of an operational duty cycle. High transitory loads in combination with low power idling leads to increased fuel consumption and increased emissions.
Diesel engines used as primary power sources in high duty crane applications rarely last longer than 10-12 years, then they need to be overhauled or replaced.
Despite these drawbacks, diesel will definitely stay with us for the foreseeable future. It’s still vital in places where electricity is not available, and a diesel generator can provide the main battery charge or backup power on a hybrid machine. Although synthetic fuels are very promising, distribution is problematic and power output is never as good as the real thing. But ever-improving design and developments like Diesel Exhaust Fluid (DEF) in combination with Selective Catalytic Reduction (SCR) are making the next generation of diesel engines more efficient.
“Looking ahead, a diesel-powered crane could even be run on hydrogen, and the only exhaust would be water,” says Ingo Schmuland, Product Manager for Konecranes Port Services. “It would retain all the benefits of diesel, but without emissions.”
2. Hybrid
Hybrid equipment is a blend of both diesel and electric, using
diesel fuel in a diesel generator (genset) to produce electricity stored in batteries.
Hybrid equipment offers the advantages of diesel with the efficiency of electrification and the flexibility of two sources of power. A relatively small battery recharges quickly, and produces no emissions, and very little vibration or noise. Braking and load lowering movements provide energy that can be recovered and stored for an even longer charge. A small genset gives reduced fuel costs, reduced emissions and less maintenance than a full-size diesel engine, and can provide power instantly if the battery runs out during operation. There are no infrastructure costs in terms of building charging areas, and there are no external connections so there is full freedom of movement.
However, the diesel engine prevents a hybrid machine from being totally free of emissions. Battery storage including the control system and downsized diesel generator require more installation space. After about 8-10 years, the power capacity often starts to decrease and needs to be replaced and disposed of carefully. As a relatively new technology, it makes some customers hesitant because it is not nearly as widespread as other power options. However, industry experience is growing and very encouraging usage facts and data are emerging.
It's hard to imagine the batteries of the future, because battery technology is continuously developing with faster charging, longer life, and safer use and disposal. Synthetic fuels are helping to reduce emissions in the genset. Hydrogen is not viable at the moment, but future developments might change that.
“Utilizing the best of both worlds, flexibility is the beauty of the hybrid machine,” says Joona Merimaa, Chief Electrical Engineer, Konecranes RTG Cranes. “This is an eco-efficient technology that doesn’t need an infrastructure investment to get started.”
3. Electric
Cranes can be connected to mains power via cable reel or busbar, and lift truck batteries can be replenished via special charging points around the terminal.
Electricity is easy to access 24/7 from the local utility provider. Electric motors have extremely high efficiency, and are clean to run, easy to service, and with no combustion engine, produce no direct emissions and very little vibration and noise. Supercapacitors can give a power boost to high power requirement actions like lifting, and with a battery on board, recovered energy from braking and load lowering extends the charge. The battery can also be the primary power source on electric lift trucks. On cranes, it allows more freedom of movement and can replace mains power if necessary. There is no need to rely on the delivery and storage of fuel.
Electrifying port equipment always brings a number of challenges. Whether a greenfield development or a brownfield upgrade, it requires a significant infrastructure investment because mains connections and charging points are essential. Mains electricity must be steadily available in high wattage. Not all locations have access to electricity produced with renewable resources. In addition, busbars need space between container stacks, lengthy reel cables need to reel and unreel safely, and both have to be disconnected when e.g. RTGs need to be moved to another container stack.
Many of the newest cranes are all-electric, and eventually, electric container equipment will be dominant in container terminals. It is not that complicated on the crane side to replace a diesel engine with batteries but effort is needed to install the charging equipment. Batteries are easily scalable and their size-to-capacity ratio is getting better continuously. Developing battery technologies like hybrids, fuel cells, and charging while driving (induction charging) offer a lot of promise and interesting alternatives.
“Everyone should be thinking about going electric in the future,” says Kai Lüthje, Manager, Energy and Drives for Konecranes. “A battery takes up the same space as a diesel engine, but produces no emissions, conserves power, and is far easier to maintain.”
Reducing your carbon footprint
In the short term, the efficient use of energy saves money today. But in the long term, it is part of a global megatrend towards decreasing the level of carbon dioxide in the Earth’s atmosphere to mitigate climate change. This is seen in global bodies like the UN making international agreements, local authorities around the world issuing very strict regulations on the management of emissions, and port operators wanting to shoulder some of the responsibility by using the latest eco-efficient equipment.
This has strongly affected global business. Container terminal operators around the world demand equipment with the best energy efficiency and the smallest impact on the environment.
Container handling equipment is a big investment for any transport hub. Whether you choose diesel, hybrid or full electric is based on your budget, how it affects the environment, local regulations and the availability of energy sources. And, of course, the requirements of your customers. You can follow your environmental commitments and still run your business according to your needs.
