Marine diesel electric and hybrid drive systems have been used in large ships and submarines for many years. These hybrid drive systems have not yet been successfully transferred to smaller craft, despite claims to the contrary. Numerous attempts have been made, some very recent, but all have been sub-optimal. And most have failed completely. These failures are due to a lack of underpinning research and the lack of certain key components.
The HYMAR project had the following objectives:
- develop an open systems architecture which will make marine hybrid propulsion available to the widest possible market;
- deliver more fuel efficient and sustainable propulsion and power options for small craft;
- deliver systems which satisfy the market demand for increasing amounts of electrical power on board;
- reduce the environmental impact of small craft by reducing fuel consumption and cutting noise and vibration.
With respect to the hybrid drive system, the focus is on: (i) zero emissions to air, zero external noise and vibration in ports, (ii) reduction of overall fuel consumption by 30%, tending to >90% on long distance sailing boats using regenerative techniques, (iii) CO2 reduction of >30% in all off design point applications (e.g. fishing boats and small commercial ferries) and (iv) 50% reduction in HC and NOx.
The market for small hybrid drive systems is tens of thousands of units and the aggregate social and environmental benefits are substantial. A holistic approach was taken to total energy consumption and production on board. The centre of the new system will be a comprehensive energy management module. This module will supervise and control energy flows in and out of a specially designed battery bank. The NMEA 2000 standard was developed as necessary for the new data formats. Safety issues were addressed by developing new ISO standards. Major technical results were among others:
- a load following, self pitching propeller;
- a new generation of Thin Plate Pure Lead ('TPPL') batteries with optimised geometry and electro-chemistry for hybrid applications;
- an Energy Management Module monitoring all elements of the system and providing efficient and holistic control;
- new power electronics components;
- new permanent magnet DC motors, generators and controllers;
The final deliverables are a validated hybrid drive system for small craft, a design tool, critical new components including a new propeller, and contributions to NMEA and ISO standards.
Hybrid systems are capable of delivering higher fuel efficiency for propulsion on a cruising duty cycle. The major cost benefit is in overall energy management rather than just propulsion fuel efficiency. Spin off benefits are substantial. A critical note: energy efficiency is more complex than appears at first sight!
The project will result contribute to greener and cleaner, thus adding to the sustainability agenda: less fuel consumption, reduction of emissions and reduction of noise/vibration.
A wide range of propeller types has been tested in a conventional diesel drive. The resulting data has been collected and stored. The following propeller types have been tested:
- Volvo Penta 4 blade folding;
- Autoprop self pitching;
- Gori feathering;
- Maxprop feathering;
- Varifold folding;
- Flexifold folding;
- Fixed pitch conventional;
- Under pitched and over pitched.
Innovating for the future (technology and behaviour): Promoting more sustainable development