This is a summary from the presentation by the same title by Paolo Patroncini from 4e Consulting, at the Future of Electrification 2023 conference. Watch the full session here:
At the Future of Electrification 2023 conference, Paolo Patroncini from 4e Consulting presented their case study "Converting a Small Marine Vessel Into Electric Drive." The study delved into the process of transforming a diesel-powered vessel into an electric propulsion system. Its primary objective was to develop an economically viable, dependable, and ecologically sound solution to cater to the increasing demand for boats in marine protected areas.
The span of marine protected areas in Europe nearly doubled between 2012 and 2021, with the community aspiring to protect at least 30% of European seas by 2030. These valuable sea areas are designated for conserving water, wildlife, and heritage. The increasing focus on conservation is not only good for the environment but also creates opportunities and incentives for businesses. Traditional boats face restrictions in marine protected areas due to concerns about pollution and noise, however, electric boats can move freely through them. The use of electric-powered vessels allows researchers, conservationists, and tourists to effectively explore and appreciate these protected environments.
According to Patrocini, the European market for electric propulsion systems has recently witnessed significant growth, particularly for lower-power systems. 4e Consulting’s case study specifically focused on the potential of low voltage systems as they offer easier implementation and are widely accepted due to their cultural familiarity.
The first step in the study was to gain an understanding of the requirements for the boat. Patroncini explained that it needed to be able to operate for 12 hours at a speed of 10 knots and have the ability to completely recharge within eight hours. The delta weight could not exceed 250 kilograms. To accomplish these goals, the team calculated the power and current absorption required for the electric motor.
The team at 4e Consulting selected an iconic Italian boat model as the subject of the conversion. This model is commonly used for pleasure, taxi, and rental services and was handcrafted out of wood at a renowned shipyard in Portofino. It was chosen specifically to help support the goal of promoting the use of electrified boats, particularly for taxi and rental services, within the Gulf of Delillo, a restricted area where internal combustion engines are prohibited.
During the presentation, Patroncini explained how the team was able to create a clean, efficient, and reliable electric propulsion system for the boat. They used a mix of off-the-shelf and custom components to keep costs down and ensure a safe and efficient system.
Patroncini noted that one of the biggest challenges in designing this system was the need to balance battery size with charging time. A larger battery would increase the range but also increase the charging time. The team decided to use a low-voltage system with a 48-volt battery to minimize charging time while still achieving the desired range.
Patroncini explained that to maintain the boat's weight distribution and ensure safety, minimal modifications were made to the existing structure. The team designed a double onboard charger and a dedicated ventilation system to fit in the electric motor compartment. They used a transmission with a belt system to reduce engine noise and vibration and ensure the quietest possible operation. Noise reduction and vibration control were prioritized to minimize disturbance to marine wildlife and enhance the overall boating experience.
To ensure safety LFP (lithium iron phosphate) was chosen as the chemistry for the batteries. It is commonly used in construction and industrial equipment and is certified for use in marine environments.
To test the system, the team carried out a measurement campaign on the boat, recording speed, power absorption, and other data. They found that the electric motor could be tuned more closely to the propeller's needs than the previous diesel engine, resulting in a more efficient system. The boat had a range of up to 30 hours, making it suitable for long excursions.
During his presentation, Patrincini also covered the cost implications of converting a boat to electric propulsion. The total cost of ownership was considered, which includes fuel savings, maintenance costs, and other factors. By comparing the costs of the electric system with those of a diesel-powered system, the team estimated a potential savings of approximately 15,000 to 20,000 euros per year. Therefore the initial investment in electrification could be recouped within a relatively short period, usually within one to two and a half years, which aligns well with the boat's lifespan.
This case study demonstrated that it is possible to convert marine vessels from diesel to electric power while maintaining safety, reliability, and efficiency. The benefits of this conversion included reduced pollution, noise pollution, and long-term cost savings. As the demand for environmentally friendly and sustainable solutions rises, the conversion of small marine vessels to electric power is expected to become more prevalent. The key to a successful conversion is careful design and engineering. With the right approach, marine vessels can be converted to electric power without sacrificing performance or range, offering a green solution to explore marine protected areas.