**3. Heavy Fuel Oil (HFO)**

After the decisions of IMO, the debates and preparations for the new world combustion system had already started for decades. The industry intends to make investment decisions by the lights of the expert's predictions, but the experts do not have any specific clue about the future. Since ships were operating around the

world, thus exploitation of the resources has been continuing making the prices of oil increase. However, what happened in 2015? The prices of oil fall dramatically from 120 USD/ton to 30 USD/ton against the market predictions [5]. In 2018, it was raising to 100USD/ton again, and the predictions were to reach 400 USD/ton. However, the other experts are expecting that the prices are going to fall again since the consumption of oil is decreasing.

The price of HFO is directly affected by the ship's operational costs since an average Panama Size ship consumes 24 ton in a voyage day. So, for the shipowners who are entirely in debt to banks with loans, this kind of investments are critically important. One prediction for the future is evident that half of the today's ship owners are going to bankrupt after 2020. HFO is still an option when the shipowners and operators are concerned about the price increase and availability of complaint fuels but to be an alternative. HFO price graph is given in **Figure 3**. Scrubber technology makes HFO reasonable for managements which is installed by shipyards. To install this unit shown in **Figure 4**, significant investments must be paid [6]. An average Handymax ships conversion cost calculated as 6 million USD.

Current operational expenses such as sludge handlings, chemical consumables will go up by increased power consumption. In **Figure 5** the types of the scrubber technologies can be seen.

This scrubber technology, which is shown in **Figures 4** and **5**, can be adapted to new building vessels as well as currently navigating vessels.

In MS Fryken, a scrubber laboratory is carrying out experiments for Chalmers University. Obtained test results indicated so far that the scrubber technology has a potential to meet both 0.5% and 0.1% emission regulations. In **Figure 6**, we can see a closed-loop scrubber system. If in an open-loop system, the sea water is used to

**Figure 3.** *Fuel Oil Prices last 15 years [5].*

*A Review of Alternative Marine Fuels DOI: http://dx.doi.org/10.5772/intechopen.97871*

wash out the SOx in the exhaust, then in the closed-loop system uses chemicals such as caustic soda [8]. Closed loop scrubbers are installed on ships which are sailing in freshwaters [6].

In the open loop system, the used seawater discharge back to the sea. Discharging to the water in some locations is prohibited according to the MARPOL. Since the other ports will force the same regulations in the next years, a hybrid type of scrubbers is most likely to be used in many ships.

Current fuel type HFO has an extensive distribution network, and the engineers onboard are familiar with handling and operating the current fuel oil. The technical departments of the shipping companies work as an advisory team and technical problems in an average aged ship happen quite often. This advisory team is familiar with HFO and they can respond to any problems very promtly. Primarily by the

**Figure 6.** *Closed-Loop Scrubber [7].*

influence of the technical department which consist of chief engineers, the shipping companies will insist on using HFO until it will disappear from the market. This prediction shows that the ships yards are going to be entirely busy with handling scrubber installations to meet the rising demand for scrubber technology.

Related to the safety domain, current HFO has its own risk inside. Currently, most of the ships in the market are using HFO and MGO as consumption. During the voyage in open seas, the engines use HFO, in the ports the generator runs by MGO, in the Sulphur Emission Control Area (SECA) areas they run with LSFO. Since the operating temperature is different (for example MGO is usually operated at 35C, and HFO is mostly at 135C), the risk of thermal shocks is highly possible during the oil change over. This shock may damage the structure of the pipeline and fuel systems [9].
