2023-09-23 17:00:00
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The climate emergency forces us to find alternatives to fossil fuels in all areas of our life, beyond industry or energy production. If we follow the recommendations of the Intergovernmental Panel on Climate Change, by 2050 we should already have halved greenhouse gas emissions, a very ambitious objective that will not be able to materialize without a profound revolution in a determining sector: transportation.
According to community sources, this sector is responsible for more than 30% of the CO2 emissions produced in the European Unionof which a 72% belongs to road transport. The electrification of the automobile fleet is one of the main milestones of this energy transition, but the green transport revolution It goes far beyond electric vehicles. In moving towards the energy transition, a key factor is finding a valid alternative for maritime and air transport.
less polluting ships
Although the aeronautical industry is taking important steps to get rid of fossil fuels, merchant ships remain the pending alternative. And it is no wonder, then, according to a study carried out by the International Maritime Organization (IMO)this sector emits into the atmosphere more than 1 billion tons of greenhouse gases per year.
But converting a sector as polluting as this is not an easy task. Solar energy can be an alternative for small or medium-sized boats, but move a huge container ship more than 400 meters long in the middle of the Pacific requires an alternative solution. Some of the world’s largest shipping companies, such as Maersk, have taken the lead in fueling their large ships with methanol, a fuel with much fewer emissions – and twice as expensive – but The vast majority of merchant ships that sail the ocean continue to move by burning fuel.
Taking these limitations into account, a more feasible strategy It could be fuel savings. This is the conclusion reached by a team of researchers from the universities of Huelva and Jaén who devised a new system so that ship engines emit less polluting gases.
The key is in the temperature
The boats are propelled by a series of high-power diesel engines that operate at 50% of their efficiency. That is, the other half of the thermal energy of the fuel is lost in the form of residual heat through the exhaust gases, whose temperature ranges between 300 and 500 ºC. The project eCCoSHIP It seeks, precisely, to take advantage of all that lost energy.
Half of the thermal energy of ships’ fuel is lost as waste heat through exhaust gases.
To this end, researchers have created a system of energy recovery known as the “organic Rankine cycle” (ORC), a model similar to that used by thermal power plants to pass water vapor through a turbine and convert it into electrical energy. In the case of the ORC, the water is replaced by an organic fluid that evaporates at a lower temperature, which allows us to use the exhaust gases in an exchanger that would replace the boiler.
The system would thus allow take advantage of part of that thermal energy produced by the ship itself to generate electricity, an alternative, its discoverers claim, especially efficient in ships equipped with electric propulsion systems, in which the diesel engine drives an electric generator that feeds a network to which electric motors that drive the ship’s propellers are connected. In these cases, the ORC device could be injected into the network and reused for ship propulsion. The only requirement is the replacement of direct current networks with alternating current ones, which allows the use of all that residual heat.
Fuel savings and emissions reduction
“The system allows the diesel engines to operate around their optimal operating speed,” explains Juan Pérez Torreglosa, professor at the University of Huelva and director of the project, to National Geographic España via email. The expert assures that There are currently studies that estimate around 20% fuel savings, while others quantify the emissions reduction around a 15 or 20% each way.
And that’s not the only benefit. According to Torreglosa, the change direct current provides other energy advantageshow can they be a lower weight of the boat’s electrical componentswhich could be reduced by between 115 and 85 tons, which would further reduce the amount of energy needed to move.
Photo: Istock
A large bulk carrier refuels at sea. Almost all large merchant ships continue to be powered by fossil fuels.
And for practical purposes, Would this device be used to move large tonnage ships?, we asked the expert. “In the last ten years, electric propulsion ships have been promoted primarily for cruise ships, warships, icebreakers, offshore oil and gas platform supply vessels, as well as liquefied natural gas transport vessels,” Torreglosa points out. , who argues that the global fleet of electrically powered vessels is growing. In this sense, he argues, it would not be strange if other types of large ships end up being included, such as merchant ships or ocean liners, which could benefit from the energy savings of a system like eCCoSHIP. It would be great news for a sector that alone represents more than 3% of anthropogenic emissionsa figure that could double in 2050 with the foreseeable increase in freight traffic.
The challenge of sustainable aviation
#Ships #recycle #energy #sustainable