Determinant of Pertamax Fuel Demand in Purwokerto

This research is aiming to analyze the effect of several factors such as Pertamax price, Pertalite price, income, year of vehicle and vehicle type on Pertamax fuel demand in Purwokerto and analyze which one is the most influencial factors on the Pertamax fuel demand using elasticity test. The data used in this research are primary data taken from 100 respondents all around Purwokerto then analyzed using multiple regression analysis. The result of multiple regression analysis indicated that income and vehicle type have significant effect on Pertamax fuel demand in Purwokerto while the other factors such as Pertamax price, Pertalite price and year of vehicle have no influence on Pertamax demand in Purwokerto. This research also indicated that vehicle type was the most influencial factors on Pertamax demand. From all the result that has been found, the result of regression shows that people in Purwokerto have a tendency to keep putting the quality at any price level set by the government. In this case government have to further intensify massively on advertising on good impact of Pertamax either for machine or environment and expected to improve better performance and quality either in terms of services on each gas station or oil distribution.


INTRODUCTION
Economic activity is one of the main activities in the fulfilment of human needs. Related to the fulfilment of this needs, human beings are confronted with the necessity of energy as a support for other activities such as consumption, production, and distribution. Oil is one of the vital energy that can always be highlighted by every statisticry in the world (Lin & Ouyang, 2014). Most of people will need oil to turn on their machine whether for industry or for transportation and of course every statisticry has they own rules to manage their oil supply, distribution even price (Romero-Jordan, Rio, Jorge-' OE fU ˜ µOEPµ]oo}U îìíì•. In Indonesia, especially in the regime of Joko Widodo, fuel are divided into 3 kind, which are Jenis BBM Tertentu (JBT), Jenis BBM Khusus Penugasan (JBKP), and Jenis BBM Umum (JBU). JBT is a kind of gasoline consist of kerosene and solar oil and subsidise by the government, JBKP consist of Premium (RON 88) which is not subsidise by government but the price evaluated every 3 months by the government, and the last is JBU consist of Pertalite, Pertamax Series, and Dex Series, the price of these gasolines are following market condition (BPH Migas, 2015). By this classification, the government then has a data that can show us which one is the most demanded kind of fuel in Indonesia represent in figure down below. From this figure, we known that JBU (Jenis BBM Umum) has the largest number of demand when it compared to JBKP (Jenis BBM Khusus Penugasan) and JBT (Jenis BBM Tertentu). JBU has sold 44,453,906.80 liters in 2015 and increase to 48,655,005.97 liters in 2016. It means that people demand more of gasoline that contain in JBU which is Pertalite, Pertamax series and dexlite rather than gasoline contain in JBKP and JBT. The change in the fuel consumption pattern is due to the high rate of fuel consumption for private vehicles (Demirbas, Balubaid, Basahel, Ahmad, & Sheikh, 2015). It is directly proportional with vehicle sales in Indonesia which also rose sharply from 19 million vehicles in 2000 to 114 million vehicles in 2014 with an annual average increase of 13.7 percent (Outlook Energi Indonesia, 2016).
In Indonesia, the type of fuel which used for passenger vehicles has various kind, but in general the fuel for engines that do combustion with ignition is gasoline fuel. This gasoline fuel types have different qualities in each combustion and calculated in units of Research Octane Number (RON) (Speth et al., 2014). The types of gasoline fuel based on its RON are: (1) Premium (RON 88)  Speth et al., 2014). The higher the RON means the better the combustion because it does not contain lead in the mixture, so the price of fuel with higher RON level will be more expensive when compared to the fuel with lower RON level (Morganti, Mun, Brear, Yang, & Dryer, 2013;Rankovic, Bourhis, Loos, & Dauphin, 2015;Speth et al., 2014). RON is the amount of pressure given before gasoline is burned (Anderson et al., 2012). If vehicle wants to have good durability, then it should use the octane fuel which is corresponding to the compression ratio of the motor engine.
Contents with RON 88, premium is included to the fuel that is not environmental friendly. Premium has been reduced due to the use of vehicles manufactured over year 2000 have different engine (Ekholm, Krey, Pachauri, & Riahi, 2010). For example, on a motorcycle with an output year above 2000 has been using an injection system so that the use of premium will make it more wasteful and more quickly damaged. This is because the premium is flammable so before the premium flow to the spark plug it is already burning and the remaining combustion turn to be crust or we called it lead.
Because of that issue, PT. Pertamina (Persero) releases a new type of fuel that is called Pertalite. The purpose of this Pertalite is to add some alternative fuel for vehicles that use compression equivalent to premium. Different from the premium, this Pertalite has RON above premium and lower than Pertamax. With RON 90, Pertalite can be categorized as a fuel that meets the durability and economically standards. It will not cause interference to the engine because of the octane 90 is compatible with the compression ratio of vehicles in Indonesia. Other than that, Pertalite has a higher Air Fuel Ratio to the fuel consumption, so that engine performance can be more optimum and efficient when traveling long distances because fuel operating costs Rp / Km will be more efficient compared to premium (Pertamina, 2017). Unlike the Pertalite, Pertamax is a more environmental friendly fuel. A vehicle that is made with the technology of catalytic converters and electronic fuel injection (EFI) are advised to use Pertamax because it is already contain with additives which is EcoSave Technology with function to keep the purity of fuel and clean engine. The combustion that occurs when using the Pertamax only when in contact with the spark plug which is causing the perfect combustion and leave no crust or lead.
In the period of January-July 2016 and January-July 2017, premium sales declined from 79.6 percent to 41.6 percent, while fuel types Pertalite and Pertamax respectively grew from 9 percent to 40.6 percent and 11.4 percent to 17.8 percent. However if we can seen it further, the decreasing in premium which is very drastic occurred by deduction amount of supplies of premium based on Presidential Regulation number 191 year 2014 about Supply, Distribution and Fuel Retail Selling Price Article 3 Section 2 and 3 which says that JBKP distributed to all area in Indonesia except DKI Jakarta, Banten, West Java, East Java, Central Java, DI Yogyakarta and Bali. Besides a premium presence is slowly eroded by the emergence of alternative fuel (Pertalite) in 2015, it is also advised by PT. Pertamina to gas stations outlet throughout Indonesia to replace premium with Pertalite.
Since this research take case in Purwokerto, so in Table 2 there is a data described about Pertamax demand in Purwokerto which is conducted from 4 gas station in north Purwokerto, west Purwokerto, east Purwokerto and south Purwokerto. Based on the data listed on Table 2, it can be known that in 2012 Pertamax sales in Purwokerto only 740 Kilo Liters and reached 9,396 Kilo Liters in 2016. This increasing in sales shows that there is a The theory of consumer behavior is the grand theory of this research. Consumer theory explains the nature of the demand of the community, what is the reason for consumers to buy more goods at lower prices and reduced the purchase at a higher prices, or how a consumer can buy two combinations of goods in accordance with the income that he has (Sukirno, 2013). Based to the theory, this research also using factor price as one of independent variable. Price factors divided into the price of Pertamax and the price of Pertalite as a substitution good and this two kind of prices will be measured by likert scale. The likert scale will show us the perception of Pertamax consumer to the price and it will give us explanation how people can make the decision to buy it or not in the certain price. According to the theory, if the price of goods increase, the demand of items will be reduced, if the price decrease, the demand will increase. On the other hand, the demand of a person also depends on its perception towards other goods prices. For example, if the price rises, then the Pertamax demand against Pertalite will increase, this also applies vice versa. In economic theory, Pertalite is called substitutes goods (Sukirno, 2013).
In addition to the price factor, the demand of Pertamax can be based on the type of vehicles as we know that the demand of gasoline for car is more than motorcycle (Karathodorou, Graham, & Noland, 2010), and it is also can lead to year of vehicles which the demand of Pertamax can be based on the year of the vehicle since Pertamax are highly recommended for vehicle produced after year 2000. Besides, income also be a factor that can have an effect on the number of demand. In fact, this income effect is on a person's expenditure budget lines where the increase and decrease in the revenue budget lines curve can shift to the right and to the left (Romero-Jordan et al., 2010).

RESEARCH METHOD
The data are collected from Pertamax consumers in Purwokerto. The object of this study leads to variables such as the price of the goods, the price of other goods (substitution), income, year of the vehicle, and vehicles type. Data are conducted through direct interviews to respondents using a questionnaire tool. Respondents are expected to fill the questionnaire with the circumstances of real event. Questionnaire contains questions and filled by respondents. The population of this research is consumers of Pertamax in Purwokerto. The sampling technique used is accidental sampling. Author looked for respondent in a line of gas station spread along Purwokerto districts accidentally without having any data of respondent before. Therefore, the sample size determined in this study was calculated based on the Slovin. This study uses Multiple linear regression analysis.   This Research shown us that mostly respondents who lived in east Purwokerto is 20 percent from 100 respondents, west Purwokerto has 30 percent from 100 respondents, south Purwokerto has 23 percent of 100 respondents, and north Purwokerto has 27 percent from 100 respondents. This respondents selected randomly from 9 gas stations in all around Purwokerto. The data shown us that most of respondents income mostly on range Rp1,000,000 to Rp4,140,000 with 56% from total respondents and Rp4,140,001 to Rp 7,280,000 with 36% of total respondents. Therefore, the percentage of this income is taken from random people so all the respondents have a same chance although the income is quite same. To analyze the effect of variable independent to dependent, this research using regression analysis calculated by software SPSS.17. Based Table 8, expressed estimation as follows:

Multiple Linear Regression Result
L zäxru E rätsr 5 F räszy 6 E säwyt 7 F rästuu 8 E tsärzw 9 The price of Pertamax variable noted as X 1 has no significant effect to the demand of Pertamax. The actual reason behind this calculation is because most of Pertamax user will always stay in Pertamax whatever the price is. This also not in accordance with the demand theory which stated šZ š ]( šZ ‰OE] ]v • U u v }( •}u P}} • Á]oo OE • ~^µl]OEv}U îìíï•X /š } •v[š u v šZ š the theory is wrong, it is just because Pertamax is a unique kind of goods which people needs especially for people who are concern with the quality. They thought that Pertamax is suitable for their vehicles so even the price is increasing, they will always using of Pertamax in concern of quality.
As a substitution good, variable price of Pertalite or noted as X 2 no significant effect on Pertamax demand. The actual reason behind this calculation is barely same with the variable X 1 . Whatever the price itself and the substitution price is, the demand for Pertamax will never change in order to the quality decision.
Regression coefficient of Income (X 3 ) is positive 7.384. This means if income increase Rp1,000,000, the demand for Pertamax will also increase 7.384 liters. In addition to regression coefficient, t-statistic of this variable is 2.144 which is more that t-table 1.960 with probability value equal to 0.035 means income has a significant effect to demand of Pertamax. As demand theory said, an increase in income will affect to the demand for goods. The consumer can afford to buy the highest price level of product in this case Pertamax fuel because they have an addition of money to buy more goods or luxury goods (Hellweg, Frischknecht, & Hendriks, 2010).
The theory which is implemented on this research about shifting in demand curve because of the change in Y axis and its impact to change in X axis through income increasing has been proved. Income has a positive effect on demand for gasoline (Romero-Jordan et al., 2010). Logically, people with higher income will choose the best fuel for their vehicle in order to the quality, of course they can afford it because their income is high and that is why income can affecting the demand for Pertamax fuel (Baranzini & Weber, 2013;Romero-Jordan et al., 2010).
Year of Vehicle (D 4 ) also suspected have any influence on demand for Pertamax, the reason is vehicle year above 2000 recommended for using Pertamax because their engine is compatible with this kind of fuel. In this research, vehicle year using a requirement for vehicles from developed statisticry (Singapore) which rules that maximum vehicles year has to be only 10 years. If today is 2018 means vehicles minimum year is 2008. This research using D 1 = vehicle year > 2008 and D 0 = vehicle year < 2008. From Table 13, it shown that t statistic up to -0.616 which means less than t table 1.960 with probability value equal to 0.540 and located in H 0 accepted area it shows that this variable has no significant effect on demand for Pertamax. Logically, when people are comfortable using Pertamax as their daily fuel, even if they vehicles are less than 2008 or even less than 2000, they will always make Pertamax as they first choice. Back then to the reality, Pertamax has a good quality and more suitable for vehicles.
It has been mention that variable vehicle type (D 5 ) are using dummy variable D 1 = car and D 0 = motorcycle. Based on Table 6, it shown that t statistic equal to 6.288 which is more than t table 1.960 with the probability value 0.000. This calculation means that variable vehicle type has significant effect to demand for Pertamax and D 1 = car which is suspected as the influencer. Logically, car tank is bigger than motorcycle so demand for car will much more than motorcycle.
The result calculate that adjusted R-Squared is 0.483 means that variable Pertamax (X 1 ), price of Pertalite (X 2 ), income (X 3 ), year of vehicle (D 4 ) and vehicle type (D 5 ) together can describe to variable Y (Demand of Pertamax) equal to 48.3 percent, the other 51.7 percent are describe by another variable outside this research.
F statistic is 31.516 and F probability equal to 0.000 and F statistic > F Table (17.238 > 2.48), means that all independent variable together simultaneously affecting the dependent variable or variable price of Pertamax (X 1 ), price of Pertalite (X 2 ), income (X 3 ), year of vehicle (D 4 ) and vehicle type (D 5 ) together simultaneously affecting demand for Pertamax in Purwokerto.
According to alpha 0.05, the constant value equal to 20.787 and has significant effect to Pertamax demand with probability 0.037. This means in the normal situation without any concern of independent variable such as price of Pertamax, price of Pertalite, income, year of vehicle and vehicle type there will be constantly has a positive change 20.787 percent to the demand of Pertamax.

Elasticity Test
This research using Eviews 9.0 to find out the elasticity test described in table down below: As written before that the significant factors to dependent variable only income (X 3 ) and vehicle type (D 5 ). Elasticity at means of variable income is 0.127200 and elasticity at means of variable vehicle type is 0.166006. So, it means that variable vehicle type (D 5 ) is the dominant variable that has biggest contribution to dependent variable. It is because car tank will need more fuel than motorcycle so the demand of car is higher than motorcycle (Labandeira, Labeaga, & López-otero, 2017). The value of elasticity at means of these two variable are < 1, it means that this variable is inelastic, in other word the change in income and vehicle type will not affecting much to the demand of fuel because fuel is a kind of goods that will always needed for everyone.

CONCLUSION
Based on previous chapter explanation about the result of this research, so it can be conclude that: (1) Based on f-test, simultaneously variable price of Pertamax, price of Pertalite, income, year of vehicle and vehicle type affecting the demand for Pertamax in Purwokerto. Partially, independent variable X 1 which is price of Pertamax, X 2 which is price of Pertalite and D 4 which is year of vehicle have no significant effect on pertamax fuel demand in Purwokerto, but variable X 3 which is income and D 5 which is vehicle type have positive significant effect on Pertamax demand in Purwokerto.
(2) Based on elasticity test, the most dominant variable on this model is vehicle type (D 5 ). So it means the demand for pertamax is mostly affecting by vehicle type rather than income. Implication is the final goal that a researcher should suggest to the party who are related to this research based on what researcher has been found. The implication of this research are as follows: (1) The price variable both Pertamax price and the price of Pertalite as substitution goods states that these two variables have a negative effect on Pertamax demand, it shows that Pertamax consumers in Purwokerto have a tendency to keep putting the quality at any price level set by the government so it gives a positive trend to a Pertamax demand in Purwokerto. Government in this case PT Pertamina (Persero) regional IV have to further intensify massively on advertising on good impact of Pertamax either for machine or environment.
(2) Vehicle type has the greatest significant influence on Pertamax demand because car has a bigger tank than motorcycle. As of 100 respondents, about 79 percent of consumers stated that PT Pertamina (Persero) has been able to provide fuel for the community and 21 percent said not yet because many areas are still unable or even difficult to access fuel. So some of them are forced to buy fuel from 'Pertamini' because it is difficult to reach the gas station. Nevertheless, out of 100 respondents, about 80 percent stated that PT Pertamina (Persero) has been able to be customer oriented and feels that PT Pertamina (Persero) has provided good service to consumers as evidenced by never having vacancies or delay in tanks in pom gasoline around Purwokerto. Based on research results, PT Pertamina (Persero), especially for regional IV marketing office is expected to improve better performance and quality both in terms of service and distribution in order to continue to excel in competing with the competitors.
Along description of this research, there are also limitations contained in this research such as: (1) Research only held in Purwokerto so it is not generally represent all consumer because it is only small part of Banyumas Regency.
(2) Alpha used in Slovin formula is 10% because it shows only 99.96 or 100 respondents to be investigated rather than using alpha 5% that shows 397 respondents due to the limitations of fund, time and human capability.
(3) There are 12 outlier data which has extreme value and cannot be included on data analysis. (4) Expenditure used in the questionnaire is a proxy of income.