At Busworld 2019 Solaris presented three zero-emission vehicles, the Solaris Urbino 18 electric – zero-emission bus with new batteries, the Solaris Urbino 12 hydrogen – new generation hydrogen vehicle and the Solaris Trollino 24 – a bi-articulated platform for zero emission public transportation vehicles.
Solaris has been developing its portfolio of alternative drivelines vehicles for over ten years now, having become one of the top players on the European electromobility market. Thanks to the tenders won by Solaris in the past weeks, the firm has turned a European leader in terms of deals secured for electric buses. The electric buses supplied by the company to 16 countries so far have traversed over 20 million kilometres in total, in varying climate conditions.
The distinctive line of the articulated Urbino 18 electric is known to many operators; over 200 models have been commissioned by clients so far. The bus displayed at the Busworld, however, has been uniquely equipped. What is an absolute novelty is the new-generation Solaris High Energy+ batteries which the manufacturer is showing in Brussels for the first time. The batteries stand out on account of their high energy density, thanks to which the bus will easily be able to cover 200 km on a single charging session, irrespective of road and weather conditions.
However, the perfected parameters of the energy storage will also allow to maintain a still significant passenger load at a much increased range – there will be room for 120 people on board of the articulated electric bus, 40 of them seated. 7 battery packs with a total capacity of 553 kWh have been installed in the Urbino 18 electric. 3 batteries have been stowed away in the rear end of the vehicle, and four – on the roof of the first section. The bus is charged via a plug-in connector or pantograph charging – depends on operator’s preferences.
The Solaris Urbino 18 electric on display has also been equipped with advanced driver assistance systems (ADAS) which significantly increase both travel comfort and – above all – safety. The Mobileye Shield+ device remedies the risk of collisions with pedestrians or cyclists thanks to a system of smart cameras which constantly monitor the so-called blind spots in a vehicle. The driver is alerted to potential dangers with audio and visual signals.
The electric Solaris will feature the system initiating automatic braking, i.e. the CMS (Collision Mitigation System). When a radar installed on top of the bus detects the risk of a potential head-on collision, the system goes into braking mode, reducing velocity and thus alleviating the consequences of a potential collision.
Where the side mirrors would be conventionally, the 18-metre Solaris features cameras that ensure improved visibility not only in bright sunlight, but also during rain or snowfall, as well as at night. What is more, the cameras increase the field of view substantially and they improve the aerodynamics of the vehicle. This new solution is already available for the whole Urbino family.
In order to reduce the energy consumption as much as possible, the articulated Urbino electric features air conditioning with a heat pump which uses heat from the outside to generate an adequate temperature inside the vehicle. This device uses carbon dioxide as the working medium which is currently considered the most environment-friendly solution. The implementation of the CO2 heat pump is intended to enhance the energy efficacy of the vehicle, and thus increase its drive range, but also to reduce noxiousness.
Yet another innovation applied in the vehicle is a traction inverter produced in the originative SiC technology, i.e. using silicon carbide. Owing to this, the device can operate at higher voltage, frequencies and temperatures, which in turn, results in a significant reduction of the mass and size of the power converter and in a general increase in efficiency of the whole system.
Solaris was one of the first electric bus manufacturers to direct its research and development efforts towards electric drivelines. Nearly a decade after the première of its first e-bus, Solaris is now supplementing its zero-emission bus range with the Urbino 12 hydrogen in which hydrogen is transformed into electric energy, which is then directly fed into the driveline of the vehicle. Hydrogen technology used for power generation will enable buses to traverse even longer distances completely emission-free.
Hydrogen-fuelled buses will allow to create a complementary emission-free bus portfolio thanks to which Solaris will be braced for contemporary challenges and the diverse needs of customers with regard to range, flexibility and operability of vehicles. The manufacturer believes that the development of all electromobility branches, be that battery buses, trolleybuses or hydrogen-fuelled vehicles, should proceed in synergy, and that this process is indispensable to ensure sustainable transport of the future.
The advantages of hydrogen as an energy source are indisputable. Thanks to its density and lightness, this element may constitute a clean energy source for vehicles, and it may enable them to cover a distance of up to several hundred kilometres. Considering the fact that hydrogen can be produced from water in the electrolysis process, it constitutes a really clean source of energy. It is also a perfect solution for operators who have access to hydrogen derived from renewable sources, or from the industrial processes.
Using reverse electrolysis, hydrogen fuel cells are relatively small in size and they generate energy during the operation of the vehicle. That is why they are an ideal solution when a long drive range has to be ensured. Hydrogen refilling takes little time and is quite convenient, not differing much in essence from refilling a vehicle with other fuels (e.g. CNG).
Solaris gained its first experience in hydrogen when it designed battery vehicles using fuel cells as range extenders. As part of the JIVE initiative, Solaris has supplied two Urbino 18.75 electric to Hamburg and 10 trolleybuses with hydrogen-based range extenders to Riga. At Busworld 2019, Solaris is taking its next steps towards progress presenting new generation of hydrogen bus – Solaris Urbino 12 hydrogen.
The Urbino 12 hydrogen is fitted with a cutting-edge fuel cell that acts as a miniature hydrogen power plant on board of the vehicle. Thanks to the use of advanced technology, the bus will be capable of covering up to 350 km on a single refill. In a hydrogen fuel cell, electric power is generated in a process called reverse electrolysis and then passed on directly to the driveline. The sole products of the chemical reaction occurring in the fuel cell are heat and steam. Consequently, the vehicle does not generate any noxious substances whatsoever.
A set of 70 kW fuel cells was used in the Solaris hydrogen buses. The hydrogen system also contains auxiliary devices, responsible for instance for the supply of hydrogen and oxygen at an adequate pressure, for the recirculation of the resource that has not been used up, and also for maintaining a proper and stable temperature of the fuel cells during operation.
The novelty of Solaris’ portfolio will be also fitted with a small Solaris High Power traction battery which is to support the fuel cell whenever the demand for energy is the highest. The battery is filled with energy derived from hydrogen and through the regenerative braking, though it is also possible to recharge it by means of a plug-in socket. Complementing the driveline is an axle with integrated electric motors.
Presented to the public for the first time at the Busworld 2019, the bi-articulated Trollino 24 is the longest vehicle assembled by the Polish manufacturer so far. The idea behind the Trollino was to create a platform for the future serial production of 24-metre vehicles with an electric or hybrid driveline and of trolleybuses.
The Trollino 24 is a technically highly advanced model. Its driveline consists of two traction motors of 160 kW each, propelling two drive axles. A pack of 58 kWh batteries installed in the bus is charged during the drive, collecting current from the overhead line via a bipolar pantograph traditionally in use in trolleybuses. What is more, the energy accumulated in the batteries will be used to fuel the trolleybus whenever it is detached from the electric traction line.
In order to ease manoeuvres in urban traffic, the fourth axle of the vehicle has also been made the steering axle. Apart from featuring a unique door layout of 1-2-2-2-2, the vehicle has also been fitted with an electric power steering (EPS) system, among others. Up to 215 persons will be able to ride on the trolleybus. This début model features cameras in lieu of side mirrors.
The Solaris Trollino 24 presented at this year’s Busworld 2019 has been prepared in accordance with the MetroStyle design package. The unique design was developed for the exceptional bi-articulated vehicle. The decision on whether to offer the MetroStyle design version in other Solaris models will be made by the manufacturer at a later date.
The firm’s latest development are the Solaris High Energy+ batteries. These were designed by the Solaris Research and Development Department, bearing in mind the needs of carriers who want to cover at least 200 km on a single charge, regardless of the weather conditions, and thus regardless of air-conditioning or heating working.
The Solaris High Energy+ batteries are characterised by an extremely high energy density. Thanks to this feature, the company managed to fit 79 kWh into one pack. This means that in the case of 7 packs – that is how many can be installed in an articulated bus at the most – it reaches a nominal energy rate of 553 kWh. And 5 packs of that battery will fit into a 12-metre bus. This battery type can be recharged using a power equalling its capacity.
It may be worth underscoring that the solution is the result of cooperation between the Solaris and BZM Poland Research and Development Departments. Batteries of this type can be used only in Solaris vehicles and as of today, no other producer in the electric bus market is offering them. The contractor executing the design initiated by Solaris is BMZ Poland, a leading European manufacturer of intelligent power supply and energy storage systems based on lithium-ion technology.
All of the above batteries, which are offered with electric buses of Solaris, boast a nominal voltage ranging between 600 and 700 V. The energy storage tanks used in the Urbino electric are capable of working in temperatures between -15 and +50 degrees Celsius. In order to optimise their efficiency, and to extend their service life, they are warmed up or cooled down. The battery cooling system is based on liquid-cooling.