Munich's first solar bus: MVG presents solar bus trailer

Source: Sono Motors GmbH, March 31, 2022

Sono Motors, the company that aims to revolutionize the future of solar-powered transportation, is introducing its proprietary solar technology for the first time to local public transport in partnership with Munich's public transport company (MVG) 

The novel solar bus trailer will be on the road in Munich's urban area, testing the energy yields and potential of the technology in daily operation. With a possible saving of up to 2,500 liters of diesel per year and an annual local CO2 savings potential of over 6.5 tons per bus, the Sono solar technology makes a contribution to climate protection and the reduction of inner-city greenhouse gas emissions. Twenty semi-flexible special photovoltaic (PV) modules provide over 2,000 watts to power the vehicle's battery, electrical loads such as heating, ventilation and air conditioning, and the trailer's steering system.

"The partnership with the Munich public transport company illustrates the enormous potential of our unique solar technology, which is now being used in public transport for the first time in the company's history. For Sono Motors, this is a milestone on the mission to equip every vehicle with solar cells," says Laurin Hahn, founder and CEO of Sono Motors. "Especially in times of rising energy prices and increasing emission regulations in urban areas, our solar technology offers great added value for public transport operators. City buses and coaches - whether electric or diesel-powered - offer a lot of space and are out on the road every day. The first solar bus trailer for MVG will be on Munich's roads in the future, allowing MVG passengers to experience solar mobility in daily use," Hahn continued. 

High CO2 savings potential thanks to powerful solar technology 

The potential CO2 savings from solar-powered vehicles and their contribution to urban air pollution control and climate protection are promising. For a medium-sized fleet of about 300 buses, calculations indicate that savings of up to 2,000 tons of CO2 per year are already possible. Further increases are conceivable in the future, as both the solar cells and the power electronics are expected to become more efficient. The "CO2 backpack" of this solar solution - i.e. the emissions caused in production - amounts to a one-off of around 1.5 tons of CO2 per bus or bus trailer and could already be offset after a short run of less than a year. 

Over 2,000 watts of power to improve the energy balance 

The solar technology was developed and tested specifically for use on buses. The concept for the customized solar bus trailer was developed together with MVG to ensure maximum space utilization and efficiency. In addition to the robust solar installation optimized for vehicle integration, this also includes electrical integration by means of power electronics developed by Sono Motors (MPPT Central Unit), called MCU. The solar charge controller has an intelligent algorithm that optimizes the energy yields of the PV modules. The ultra-fast optimization in the millisecond range and thanks to the multi-channel system, the PV yields can be transferred to the battery of the bus in the best possible way. The modules cover a total area of twelve square meters and supply the 24V battery with over 2,000 watts. In this case, the solar energy generated in this way is used to operate the HVAC system (heating, ventilation, air conditioning) and to support the trailer steering system. In addition to saving diesel, the additional power ensures the stabilization of the battery's energy supply, thus extending its service life and reducing maintenance costs. By means of integrated software, the energy generated can be read out online. 

Veit Bodenschatz, managing director and head of the bus division of Münchner Verkehrsgesellschaft (MVG): "With the photovoltaic system on our bus trailer, we can now test under real conditions how well the power generation works and whether there are perhaps routes in our network that are better suited than others for this type of power generation. The question of what energy savings can be achieved by using solar power are, of course, particularly exciting in light of current fuel and energy prices." 

Range extension for e-buses possible

Sono Motors' patented solar technology has been developed so that it can be integrated and licensed into a wide range of vehicles. "For e-buses that are equipped directly from the factory with our solar technology on the roof and sides, additional range can be generated through solar energy. This not only reduces downtime for charging, but also conserves the battery through a constant charging process. The  E-bus can consequently be operated for longer," explains Hahn. 

At the presentation and press conference on March 31 at the MVG depot West in Munich Laim, Munich's second mayor Katrin Habenschaden was a guest. 

Katrin Habenschaden: "We need a change of course in the transport sector. Traffic still misses the climate protection targets very clearly, and this has a direct impact on air quality in the city in Munich as well. The solar buses can be a building block in this urgently needed change toward climate-friendly mobility. I am convinced by the idea, because a lot of fuel can be saved here and CO2 emissions can be significantly reduced. We are already working with MVG to convert our bus fleet completely to electric drives. Harnessing the power of the sun is of course even more sustainable, and I hope that this pilot project will show that we can also extend the range of the e-buses with solar energy. I am particularly pleased about this cooperation with our MVG that such an innovative idea comes from a Munich company." 

After technical approval by the relevant regulatory authorities, the bus trailer will go into regular operation and can be used by all Munich:ins. 

Sono Motors has already been able to sign more than ten letters of intent and contracts with companies such as MAN, easymile or ARI Motors since the beginning of 2021. The Sono Solar complete solution includes a tailor-made concept including solar modules, power electronics, telematics and data, mechanical and electrical integration as well as after-sales and service. The technology lends itself to integration into existing vehicles as well as production-ready development and integration into new vehicles during the production phase. 

Read the full press release here.