Natural gas vehicles (NGVs) currently range from passenger cars and vans to buses and trucks, but NG is increasingly being used to power oceangoing vessels in the United States and Norway, among other countries.
The feasibility of using NG as a marine fuel in Brazil is now being studied by a group of scientists at the Research Center for Gas Innovation(RCGI), supported by FAPESP, BG Group-Shell and various research institutions. In some quarters, NG is considered a “transition fuel” for ships because it is cleaner than oil and other fossil fuels.
The scope of the project was presented during the Sustainable Gas Research & Innovation Conference 2016, held on September 27-28 in São Paulo, Brazil. Some 140 researchers from RCGI and the Sustainable Gas Institute (SGI) at Imperial College London in the UK attended the event to discuss research, development and innovation related to NG, biogas and hydrogen, including new technology and ways to reduce greenhouse gas emissions.
“We’ll start by building a roadmap to evaluate the feasibility of using NG as a marine fuel in Brazil,” said Claudio Muller Prado Sampaio, a professor at the University of São Paulo’s Engineering School (POLI-USP) and one of the coordinators of the project.
According to Sampaio, the heavy fuel oil (HFO) that is used internationally as marine fuel today is considered the worst petroleum product in terms of sustainability and pollution. HFO is the residual oil left over after lighter distillate fuels have been fractioned off from crude oil, and it has to be heated and purified for use in a ship’s internal combustion engines.
When these engines burn HFO, they release large quantities of nitrogen oxides (NOx), sulfur oxides (SOx) and particulate matter into the atmosphere, Sampaio explained.
Shipping currently accounts for over 3% of global greenhouse gas emissions, and its contribution could reach 5% by 2050. In 2008, the International Maritime Organization (IMO) established Emission Control Areas (ECAs) in the Baltic Sea, North Sea, English Channel and North America, setting a 0.1% SOx limit for ships that pass through these areas as of 2015.
The IMO also established that shipowners may choose several different methods to comply with the new rules. These methods include the use of low-sulfur fuel such as liquid natural gas (LNG), scrubbers, and exhaust gas cleaning systems.
“The need to switch to low-sulfur fuel has made LNG competitive and worthwhile for the international shipping industry. LNG’s NOx content is low, and its SOx and particulate matter contents are practically zero,” Sampaio said. “Furthermore, large-scale production of shale gas in the US has greatly increased the global supply of LNG, helping to bring down the prices of this fuel.”
Some NG-producing countries, such as the United States, have first moved to build dual-fuel ships and to create LNG storage depots for ship refueling. More recently, they have started to design and build LNG-powered container ships and offshore supply vessels.
“Most of these ships are being developed in other countries, so we don’t yet know what techniques are used to build them,” he said.
“We plan to develop LNG-powered ships designed to operate under Brazilian conditions, including the need for smaller drafts and different dynamic positioning systems for automated heading and position control while loading or unloading, even in heavier seas and winds.”
The researchers will also evaluate the availability of NG from Brazilian reserves to project supply and demand for LNG as marine fuel in the coming decades.
With proven gas reserves of 500 billion cubic meters, Brazil ranks second in gas resources in Latin America, after Venezuela. Gas has grown 30% as a share of the Brazilian energy mix over the past six years; however, even so, a large proportion of the gas produced in Brazil is reinjected into oil reservoirs. This is the case even in the subsalt oilfields, which were estimated to contain 6.3 billion m3 in 2014. In that year, 5.1% of the total produced gas was burned off or lost, whereas 18.0% was reinjected. Compared with 2013, the volume burned off or lost in 2014 rose by 24.3%, and reinjection jumped by 47.8%.
“The amount of gas currently being injected into the subsalt oilfields is equivalent to a third of the total consumption in Brazil,” said Julio Meneghini, academic director of RCGI. “Brazil could stop importing NG from Bolivia and replace it with subsalt gas, if only we could solve issues such as purification, CO2 removal and distribution logistics.”
He said that one of the main problems with subsalt NG is its high CO2 content, making it similar to biogas. The researchers at RCGI have studied different ways of purifying it and making its transportation and distribution economically feasible.
“Today, at RCGI, we’re working on projects in three research programs: Engineering, Physical Chemistry, and Energy Policies & Economics. All of our research teams are multidisciplinary, comprising engineers, lawyers, economists, geographers, biologists, physicists, chemists and energy experts,” Meneghini explained.
RCGI is one of three new Collaborative Applied Research Centers established by FAPESP in 2015, involving major partnerships between corporations and universities or research institutions underpinned by ten-year agreements for the development of advanced research activities.
Resulting from a partnership between FAPESP, BG Group-Shell, POLI-USP, the Energy & Environment Institute (IEE-USP), and the Energy & Nuclear Research Institute (IPEN), RCGI aims to be a world center for advanced studies on the sustainable use of NG, to increase NG’s share in the overall energy mix of São Paulo State and Brazil, and to contribute to a reduction in greenhouse gas emissions.
“FAPESP’s investment in each Collaborative Applied Research Center is matched by an equivalent amount from each business partner and twice as much from each university or research institution. That’s a good rate of multiplication,” said Carlos Henrique de Brito Cruz, FAPESP’s Scientific Director, during his opening address. FAPESP President José Goldemberg also attended the conference.