Electric bus in Tyumen: the chase for trends and problems of exploitation

The article considers the issues of the progressive development of electric transport in the world and in Russia. The special accent was placed on analysis of electric buses promotion for the city passenger transport market. The history (facts, chronology) of attempts of electric buses exploitation in Russian cities is considered. The information about the technical solutions used in electric buses is given. Data on the economic aspects of electric buses exploitation is presented. We consider the experience of technical exploitation of electric bus LiAZ-6274 in Tyumen and provide information about specifics of technical rejections of this bus during 11 months of usage. President of GAZ Group V. Sorokin and driver of Passenger Motor Transport Enterprise № 1 in Tyumen who worked on the electrical bus gave their opinion on the issues of electric transport in Russia. In conclusion, advantages and drawbacks of electric buses exploitation in Russia at the current moment are considered.


Introduction
The monopolistic era of automobiles with internal combustion engine lasted for more than 100 years. It started on the 9 th December 1914 when the fire destroyed Tomas Edison's lab in West Orange, New Jersey and simultaneously all materials and theories connected with independent sources of energy and electric transport [1]. During the work on autonomous sources of power supply, Tomas Edison devoted much attention to the issues of the fast charging accumulators. By the summer of 1914, he started to cooperate with the leader in the automobile industry, Henry Ford. Their goal was the full replacement of the internal combustion engine (ICE), by electromotor, that would lead to being ecocentric and be independent of limited resources in the future. But the next century became the era of automobiles with the ICE. And only 100 years later within the fifth technological paradigm automakers returned to the electric transport.

Overview of the interest to the development of electrical transport in the world
In the last years electric transport has been actively developing. The reasons of that fact are complex and determined by marketing and ecology considerations. The Electric Vehicle World Sales Database [2] provides the statistics on electric vehicles market as of July 2018. During the first half of 2018 783000 units of electrical transport were delivered, that is 66 % higher than at the same period in 2017. 64 % of electric transport are battery electric vehicles (BEV) and remained 36 % are plug-in hybrids (PHEV).
It's a global average statistic, the relation between amount of BEVs and amount PHEV significantly varies in different countries.
The 88 % of electrotransport market in Netherlands is represented by plug-ins, while there is only 12 % in Finland.
In the whole Europe in the first half of 2018 51 % of electrotransport was presented by BEVs, in China BEVs stand for 73 %. In USA until recent times this number was 53% but with deliveries of Tesla Model-3 in July BEV share started shifting towards.

Electric buses LiAZ: technical solutions
Official release of LiAZ-company [7] describes next information about technical solutions, used in electric bus LiAZ-6274.
The main components of electric bus equipment are:  Lithium-ion batteries «LioTekh» that provides high energy density, exploitation safety, long service life and wide range of working temperature. Characteristics of batteries allows to execute the fast charge (up to 70% of capacity in 20 minutes) without significant reduction of life duration.   Indication display represents information about current operating mode, state of accumulator battery and main components of power circuit (power sources, power cable, motor controller).
 Traction asynchronous electric motor that transforms electrical energy in kinetic energy of electric bus. In the recuperation mode it provides partial return of electrical energy to accumulator battery.
 Traction inverter works in the mode of vector control of electrical motor that allows to achieve high accuracy and efficiency of speed and torque engine regulation. It also provides high energy conversion efficiency through minimization of losses on heating and remagnetization.
 Charging device that provides charge of accumulator battery with direct current. Traction inverter is used as charging devices, it gets nutrition from three-phase electrical grid with 380V voltage.  Almost threefold difference between calculated standards of 1 km. mileage cost of the electric bus and diesel bus doesn't support electric buses.

Problems of exploitation of electric buses in Russia
President of «GAZ Group» V. Sorokin named the decision of Moscow about procurement of 300 electric buses as political euphoria that doesn't consider Russian climate. V. Sorokin said: «At temperature below than minus 20 ºC degrees 8 0% of electric bus accumulator energy goes to heating of windshield, rear-view mirrors and driver's seat. Saloon can't be heated. And 20 % of energy is used for movement».

The experience of electric bus LiAZ-6274 exploitation in Tyumen
In order to study the advantages and drawbacks of electric buses in real exploitation conditions Tyumen Town Hall decided to buy electric bus LiAZ-6274 that costs nearly 32 mln. rub. (the cost of analogous large class diesel bus LiAZ-5293 is nearly 9,5 mln. rub.) Electric bus LiAZ-6274 had worked in the mode of everyday exploitation for 9 months (put in service on 27.12.2017, withdrawn from service on 03.10.2018). Electric bus worked on Tyumen route № 10 that connects airport, railway station and bus station. Actual mileage was 16879 km, bus worked for 93 days and made 930 voyages, while according to the plan it had to work for 203 days and should have made 2030 voyages. Thus, the regularity of electric bus work (relation between accomplished and planned voyages) is 45.8%. The main reasons of the low bus efficiency coefficient are technical rejections and as the consequence awaiting of repair. According to the terms of the service contract repair should be carried out by specialists from LiAZ. Table 3 gives data on rejections of electric bus LiAZ-6274 that were registered during exploitation in Tyumen.

that drove electric bus in Tyumen
In general expert opinion of the driver about electric bus LiAZ-6274 is positive. The driver noted a high level of comfort, the absence of vibration and noise, smoothness of running and braking, fast racing of the engine. In winter and in summer specific problems connected with temperature conditions arise. At high temperatures (higher than 25 ºC) accumulator batteries inefficiently cool and, as the consequence, overheat. In the winter saloon can't be heated up. Diesel heater copes with this function but the electric bus has the ecological advantage. In the winter power consumption increases not significantly (by 5…10 %) and it's a good result for Tyumen climate.

Conclusion
1. Russia is making attempts to transit to new transport and logistics technology which include electrical buses. Usage of public electrotransport with improve ecological situation in Russian cities [9][10].
2. But at the same time there are two big problems in the sphere if electric transport:  High cost of electric buses;  Low reliability of electric buses in exploitation. Solutions of these two problems are interconnected. Improvement of construction and growth of consumers' interest in electric buses will lead to increasing production up to industrial scale and that will decrease cost and increase demand on electric buses.
3. The elimination of technical defects and the adaptation of electrical bus design to the conditions of the Siberian winter can lead to displacement of buses with internal combustion engine (ICE) by electrical buses like LiAZ-6274. This is the point of view of professional driver with 20 years of experience.