The Project is from the Research Centre for Gas Innovation (RCGI) and has the ultimate aim of replacing fossil fuels by electricity and natural gas.
Engineers from the Research Centre for Gas Innovation (RCGI) study the development of hybrid power systems for ships. The aim of having a hybrid system for ships is directly related to saving fuel. One of the immediate consequences thereof is the reduction of emissions, as the use of batteries allows the use of smaller motors, always operating under conditions that are close to those of greatest efficiency. In addition, at a second moment, the primary source used would be natural gas – a fuel considered as a “transition fuel”, having a cleaner burning process than other fossils currently used in naval applications.
The project co-ordinator, Bruno Souza Carmo, who is a professor at the Polytechnic School of the University of São Paulo (Poli-USP), explains that the project includes the application of hybrid systems in three different types of seagoing vessels: escort tugs, offshore supply vessels (that give support to prospection oil rigs, being responsible for the transport of supplies and provision of assistance to maritime units) and shuttle tankers (cargo ships that are designed for the transport of petroleum from an offshore oilfield). These last vessels work with what is known as dynamic positioning (DP): they need to maintain a stable position on carrying out loading and offloading operations, regardless of the conditions of the sea and wind.
“The project is divided into three phases. The first phase is that of appraisal of the implementation of the hybrid systems in ships with the use of batteries for energy storage, together with the traditional bunker oils that currently move the ships. This first phase would take about two years.”
According to the engineer, the batteries used depend on the type of ship and also on its function. “One of the technologies we shall be using is that of lithium ion batteries. However, depending on the type of application and the kind of ship, the type of battery to be used could be different. We do not yet know the power of the battery we shall need for each type of ship, or the size thereof. What we do know is that more than one battery shall be required: these shall be battery benches”.
He also explains that there is significant concern about security issues, as the use of batteries on ships is a fairly new development. “It shall be necessary, therefore, to design places where these batteries shall be kept, with special attention being given to ventilation, for example, as they heat up. One of the engineers on our team shall be taking care exclusively of the security issue.”
The fuel saving thus made available through the use of batteries depends on the vessel considered. In the case of an escort tug, according to the engineer, the saving is between 20% and 30%. Mr Carmo adds that so far there is no regulation in the world for hybrids in terms of security aspects, specification of components and other factors. “This is all still being devised, still being studied.”
Natural Gas – In the second phase of the Project, known as Hybrid Systems based on Natural Gas, the aim is to include natural gas as a fuel for the ships. There are already ships running on natural gas (not many, but they do exist). These are mainly ferry boats for passenger transport. “These are widely used in Canada and in Scandinavia, in environmental protection areas, where emissions have to be lower”, Mr Carmo reveals.
Apart from reducing the emission of pollutants, there is another factor to motivate the use of natural gas as fuel in the vessels studied: that of making use of the gas that evaporates from the ships transporting natural liquefied natural gas (LNG). “These ships have enormous spherical tanks for the transport of liquefied natural gas. The natural gas evaporates as the transportation process occurs, as it is impossible to thermally isolate this fuel entirely. So what is done with the gas that evaporates? Nothing, the gas is lost. Whoever buys the LNG just wants the liquid, not the gas. So the idea is that of using it as fuel for the ship itself.”
The third and most ambitious phase of the Project is the use of fuel cells to get the ships moving. “At this point, we need to see which is most feasible: that of having a re-formation system for natural gas vapour on board, to transform the natural gas into hydrogen that shall be used in the cells, or if, four or five years from now, we shall already master a developed technology to make these cells operate on natural gas, something that we call dry re-formation. There is another project at the RCGI, co-ordinated by professor Fábio Coral Fonseca, of the Institute for Energy and Nuclear Research (Ipen), which is trying to develop this technology. Then we would have the best of both worlds: a cleaner type of fuel being used in a manner which is more efficient than combustion, as the fuel cell, all things considered, generates electricity.”
Apart from Mr Carmo, five more engineers are part of the Project, being responsible for specific areas: security (risk analysis), energy analysis, naval projects, batteries, and control systems.