Opportunity Charged Electric Buses

opportunity charged electric bus

In today’s blog I have borrowed a lot of the material from my group mates Johan Larsson, Magnus Broback and from our manager, Jessica Sandström.

Volvo Buses has gained experience of charged electric buses, since the introduction of the Sunwin (Joint venture in China with 50% Volvo ownership) Super Cap bus in 2006.

super capacitor

Super capacitor since 2006.
Fast charging at every bus stop for 40 seconds. The system has challenges with high infrastructure cost and low energy storage capacity.

battery electric buses
Battery electric buses since 2010.
Battery swap system:  The system has challenges with: Low battery utilization and  time loss when swapping.
Battery overnight charging: The system has challenges with: Limited range and heavy and expensive batteries.

volvo 7900 hybrid

Volvo 7900 Hybrid was an in-house development and the first automotive application using lithium-ion battery technology. Volvo has more experience in automotive battery and control technology than any other HD automotive manufacturer.
When comparing opportunity charging to overnight charging, then the high utilization of charging infrastructure and the limited battery weight in the opportunity charging concept makes it superior in cost efficiency compared to  overnight charging.

increased speed improves efficiency

Opportunity charging has “unlimited” daily mileage giving high fuel saving.
The opportunity charged buses can be used in slow and rapid bus routes. By increasing the speed of the buses it:
- saves times for travellers
- gives higher passenger transport capacity.
Overnight charging limits the daily range and the passenger capacity.
In dialogue with cities I have found that some bus routes are today limited to less than 200 km and thus potential routes for overnight charging. Still, the ambition of the city is mostly to raise the attractiveness by higher speed and higher capacity. To go for opportunity charging is thus a future safe choice.

energy use

Each bus route has characteristic power consumption and it varies with the climate.
The system design needs to handle different routes and climate. I have been in dialogue with many cities to analyzing each route in the city to determine their specific needs. Again, mostly we find that opportunity charging and the battery buffer used, account for all eventualities.

opportunity charging ideal for solar and wind

Opportunity charging is ideal for electric supply by solar and wind
Many cities have decided to decrease imports of fossil energy and to increase local and sustainable electricity. Opportunity charging makes sense, to utilize the energy when it is most available.

To conclude, all types of electric buses utilize much less energy than diesel or gas alternatives. The longer the daily distance, the stronger the benefit.

Compromises are needed:

Passenger capacity                                 <->                   Battery weight

Driver/bus utilization                            <->                   Charging time

Cost for fast charging stations           <->                   Battery cost
We find that:
– High utilization of charging infrastructure and the limited battery weight in the opportunity charging concept makes it superior in cost efficiency towards overnight charging.
– The opportunity charging concept allows 17% more passengers.
– Overnight charged battery buses are convenient for testing the new technology in small scale, but have strong limitations in the daily range. This restricts it to slow routes, therefore with limited benefits.
-The opportunity charged buses can adapt to long workdays, high passenger capacity and high mileage. Thereby they deliver strong benefits for the city.

In the choice between different types of electric buses this is why so many cities now inves in opportunity charging infrastructure:
– The city wants to incest in a system that is future proof for increased mileage and speed.
– The city wants to secure transport/passenger capacity.
– The city wants to secure a reliable battery system that minimizes the risk of the investment (Volvo Turn Key solution allows cities to pay by the kilometer).
– They want to reach out to all routes, longer and faster transits as well as the down town business district.
– The city wants a local energy source and buses energy use that match the supply by renewable energy.
– The cities have analyzed the bus traffic pattern and found that the bus stops at the same spot every now and then for several minutes and wants to take the opportunity to charge the batteries to prolong the life and extend the distance.

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How much electricity do you need for an electric bus?

Or, did you ever ask you self: what is the fuel consumption of a hybrid bus?
The ElecTrip App has the answer.

The general answer to the initial questions is not satisfactory: “it depends on which route you think of”. The speed and topography are important. So are the stops. A stop directly after a downhill drive is really bad for the fuel consumption while an up-hill stop hardly has any negative impact. We clearly need to measure each route to give the answer.

So my colleague Ulf Gustafsson and I discussed if we could use a smart phone with GPS to analyze any bus route in the world with the objective to calculate the expected CO2 emissions and energy use for different bus technologies. After logging some routes it was not too hard to say yes, it is possible but the GPS signal is very noisy, in particular in altitude, causing random errors and too high energy use for all technologies.

With the help of e.g. colleague Jonas Hellgren at Volvo research division we made the ElecTrip APP for iPhones ®.   The result was so unique that we filed a patent application that is pending. Still we have been able to make it available for the public and it is free.
The APP is pretty self-explanatory but the results may deserve some comments.

The first result display an overview of the logging:
Date: of the logging.
Distance: is the total distance from the start to the end of the route. My recommendation is to logg routes in two directions. Mostly routes are asymmetric and the result will depend on the direction.  Logging in two directions allows a more precise forecast.
Duration: is the time measured from the start to the end of the logging.
Departure address: indicate the postal address closest to the start point of the route.
Arrival address: indicate the postal address closest to the start point of the route.

Electrip app1

Next the calculated results of the logging are presented in a bar graph.
My screen dumps are unfortunately not very easy to read. To clarify the order in which the technologies are presented it’s always the same:

Diesel Bus Euro VI: Standard diesel fuel is assumed.
Gas Bus Euro VI: Compressed fossil CNG is assumed.
Volvo 7900 Hybrid Bus: The energy efficiency is calculated based on the real engine calibration of the Volvo Hybrid bus. For the CO2 emission data standard diesel fuel is assumed although Volvo Engines can use Hydrogenated Vegetable Oils.
Volvo 7900 Electric Hybrid Bus: The energy efficiency is calculated based on the real engine calibration of the Volvo Electric Hybrid bus. We have assumed a distance of 10 km between the charging stations, since many trips are not from terminus to terminus. For the CO2 emission data again standard diesel fuel is assumed although Volvo Engines can use Hydrogenated Vegetable Oils.
Volvo 7900 Electric Bus: The electric bus is assumed to use sustainable and renewable electricity.

Electrip app2

Electrip app3
The bars display the total fuel consumption in diesel liter equivalents, meaning that the data for the gas bus has been converted to the corresponding heat value of diesel to enable comparison. And the Electric Hybrid and the Electric Bus displays the corresponding electricity use.

We have confirmed the results for route speeds from 10 km/h to 30 km/h. Results from faster and slower routes are not reliable.
The blue bars below display the carbon dioxide emissions for the route:

Electrip app4

Electrip app5

Electrip app6

Disclaimer
In the first version we:
– don’t compensate for local hot or cold climate. The figures represent yearly average central European climate.
– the speed calculation is not sufficiently precise to differentiate harsh breaking and similar driver behavior induced effects on the emissions
– road quality and friction due to sharp curves is not included
– when logging short routes the error can be rather large
– routes with average speed less than 10 km/h or more than 30 km/h have not been validated experimentally and should be regarded as uncertain data.

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Vacation

After four weeks vacation without interrupt I now returned to the office.

Apart from my constantly failing ambition to exercise extensive laziness in the peaceful summer of Sweden a few other achievements can be reported in the blog today.

The Pater Noster Lighthouse viewed from Carlsten castle on the Marstrand island.

The Pater Noster Lighthouse viewed from Carlsten castle on the Marstrand island.

Gull nesting on a pole in Edshultshall harbor

Gull nesting on a pole in Edshultshall harbor

The first two weeks were spent sailing in the archipelago of Bohuslän. We have this year installed 80 W Solar panels on the yacht. We have also installed a small 35 W (running about 20% of the time) refrigerator to keep some grocery cold. A logger soon revealed that balance between solar power and energy used by the fridge was kept with a healthy margin both hot sunny days and darker cloudy days. No specific action has been needed to keep the solar panel in the sun. I just glued them on a free horizontal space on the deck.

Althought, the Swedish summer is usually not challengingly hot it is useful to keep some of the food at lower temperatures than provided by the air and the sea.

Previously, I filled half the box with ice to keep it cool for some 4-5 days. Others connect to the electric grid in each harbor.

Seals resting on a rock outside Grundsund.

Seals resting on a rock outside Grundsund.

Sailing takes us close to nature. The seals are not much disturbed as we pass them serenely in the light breeze.

Hasselösund viewed from the bridge by mid-night.

Hasselösund viewed from the bridge by mid-night.

Even sailboats now days have an engine for the last mile docking or for getting to the targeted harbor. We filled up the tank with 13 liters diesel fuel after two weeks. Since we were 3 persons on board (in average that is, since we constantly had kids, friends and crew signing on and off the boat) we have used 2.2 litre diesel fuel per person and week.

For coking on the stove we use LPG on board. We consumed almost exactly one bottle of 2.3 kg Propane/Butane mix or 0.4 kg per person and week.

Once we are in official harbors we use the public bath rooms and showers there. I have estimated the energy for the hot water and the energy used for some visits to restaurants to 0.2 kWh per person. However, we mostly stay in natural harbors.

Zoie dog waiting for a guided tour to Munthes Hildasholm at Leksand, Dalarna.

Zoie dog waiting for a guided tour to Munthes Hildasholm at Leksand, Dalarna.

The third week we went by car to visit the Isabell daughter on internship at the chemical lab at ABB in Ludvika, Dalarna. The energy details are gathered below. We looked at gardens and visited the mines of Bergslagen.

On the trip back from the county of Dalarna we visited friends in Karlstad. Karlstad is a city with a lot of focus on public transports.

Like many cities around the world, Karlstad is adressing the capacity issue of the public transports. There are plans to introduce a proper BRT route. And, a lot of priority is put on promoting biking.

Karlstad makes the street space utilisation difference for bikes and cars explicit.

Karlstad makes the street space utilisation difference for bikes and cars explicit.

The fourth week was split in some days on the yacht and some days maintaining our house and garden.

Energy Summary

Week Diesel fuel Gas (for coking) Electricity solar Electricity from grid
Vacation Liter/person kg/person kWh/person kWh/person
1 2.2 0.4 0.9 0.2
2 2.2 0.4 0.9 0.2
3 22.5 19
4 10.7 19
Reference
Work week
24 38

Carbon emission summary

Week Diesel fuel Gas (for coking) Electricity solar Electricity from grid
Vacation kg CO2 kg CO2 kg CO2 kg CO2
1 6 1.2 0.0 0
2 6 1.2 0.0 0
3 59 0
4 28 0
Reference
Work week
63 0

Judging from this years’ vacation, a conclusion is that much less energy is required for the vacation than for ordinary life.

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ElectriCity rapid implementation of Linje 55

In mid April this year, the Lindholmen bus stop was still a construction site. In parallel the construction of charging station at the other terminal station, at Johanneberg science park was ongoing. Linje 55 (route 55) is a good example to show that the lead-time to go from traditional buses to an electrified bus system is close to equal to the delivery time of the buses.

lindholmen indoor bus stop april 15

Lindholmen indoor bus stop and charging station was still under construction in April, 2015.

The project leader, Johan Larsson, was dedicated and worked closely with the partners in the ElectriCity project. In the background: the rapid door, the ElectriCity bus and the SVP for City Mobility in Volvo Buses, Jessica Sandström.

The project leader, Johan Larsson, was dedicated and worked closely with the partners in the ElectriCity project. In the background: the rapid door, the ElectriCity bus and the SVP for City Mobility in Volvo Buses, Jessica Sandström.

On monday the 15th of June the bus traffic started on the new bus route in Gothenburg, “Linje 55”. The press conference was hosted by the top management of the Volvo Group, Håkan Karlsson and Volvo Buses CEO Håkan Agnevall met with the international invitees.
As the Volvo Ocean Race ships finish this week the buses will give service to several hundred invitees from all over the world already the second week.

Linje 55 has already become a success. The buses are busy all day.
While Linje 55 already is ground breaking and extraordinary a lot if side projects has started and I’m sure I will have good reasons to come back to Linje 55 in the blog to report further on the progress.

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UITP Milan 2015

This year’s UITP congress was hosted by the agent and wonderful city of Milan. Milan has 7.5 million inhabitants in the metropolitan area and thus a multitude of public transport challenges. The requirements for preserving an antique city center in combination with the demand for swift public transport services poses many challenges.

The new generation of buses certainly made an impact. Sustainability is high on the agenda. Being clean is not enough anymore. Strong performance in energy efficiency, noise and CO2 footprint becomes important requirements for cities that build sustainability for the future.

UITP_volvo_electric

Volvo presented for the first time in public the electric bus concept now running in the ElectriCity route in Gothenburg. The bus use opportunity charging facilitated by the rapid charging station. The concept enables virtually unlimited range and solution to challenging routes and is compatible with Electgric Hybrid buses and plug-in buses. The charging standard is open for any stake holder to use.

UITP_volvo_ceo

Volvo CEO Håkan Agnevall was busy hosting the crowded Volvo Bus stand

In front of the electric bus a new back-lit Volvo brand iron mark finds it place

In front of the electric bus a new back-lit Volvo brand iron mark finds it place

We are convinced that the new bus systems that Volvo has developed will meet the demands of cities that today struggle to balance a number of ostensibly contradictory requirements.

We welcome the electric bus to the Volvo family of Hybrid and Electric Hybrid buses.

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More cities want to become smart

Recently, I visited Curitiba to take part in the Smart City Business America. There is a strong interest from cities in Latin America in general and specifically from cities in Brazil to apply new smart technologies for more or less every function in the city.

Gustavo Fruet (Curitiba Mayor) hosted the conference and about 1000 participants (my estimate) out of which 15 City Mayors joined the meeting. Mayor Fruet spent a lot of time at the conference and gave a lot of feedback to the speakers. The genuine interest in the well-being of the citizens is a true inspiration for innovation and development of Smart business within a lot of fields.

smart city business

Gustavo Fruet hosting the mayors session.

The UN Habitat session was heavily visited and the transport session hosted by Volvo got a lot of attention. Volvo presented new ways for electromobility to support the capacity requirements of high capacity BRT routes.

Growing cities face a number of challenges. The need for developing cost efficient public transports is common for most of them. In few places the public transports are as efficient as in in Latin America. The rule models for replacing low capacity by high capacity are called BRT. The most efficient BRT routes have traffic priority and separate layers for busy crossings.

Jaime Lerner invented the concept during his years as mayor in the city. Volvo is proud to have contributed to developing the high capacity buses to the level we have today and, to continue the development to the new concepts for tomorrow. Mr. Lerner continues to develop and innovate within the field of high capacity buses. Daring new designs and elevated guided bus-ways are some of the new concepts, in the pipe line.

Former Mayor Jaime Lerner

Former Mayor Jaime Lerner, innovator of BRT, is still a target for the press.

Fabio Scatolin, Secretary of Finances, presented how Curitiba plans to realize a completely new show case for not only transports but city planning, innovation and education, the Green Line. There are lots of green-field cities in the world but this is the first Green Line I have heard of. Instead of thinking in the usual way “How to support the city with roads and transports” Curitiba inverts the concept and build new city functions around a completely new transport corridor. It will be most exciting to follow the development and, hopefully to contribute to.

One thing I have learnt after some years of travelling megacities around the world: Where there are ladies walking their dogs in the morning, the jogging is safe.  There are few better ways to learn to know a city than by spending an hour or two in the morning pulse as the city wakes up in the morning. I got a beautiful morning tour jogging crossing the city.

The following day I spent in the Curitiba BRT system. It is evident that Curitiba is a bit ahead of most cities in the development of efficient bus services. In some aspects Curitiba bus system is the most well developed in the world. By combining feeder buses, express buses, BRT, and circular lines the system is well trimmed to meet the transport needs of the city.

curitiba brt

Curitiba BRT still busy at noon. Large doors secure rapid boarding. The average stop time, clocked by me was 8 seconds.

Unfortunately, the financial crisis has struck the development of public transports all around the world. In Curitiba the system has reached its capacity limit, the car fleet is growing and additional actions are required. During the relatively short time I spent in the system a few observations that surely the transport authority is aware of are mentioned here (just a few that is outside the scope I deal with): improved road quality, drive-by lanes for bus stops, signal priority for traffic signals. Whenever the city finds the financial strength, there will be a new spring for BRT in Curitiba as well.

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Volvo Ocean Race stop-over at Itajai

Being a passionate sailor myself it’s hard to decline an invitation to the Volvo Ocean Race event. The event is visited by hundreds of thousands every third year when it takes place. It is truly one of the most challenging sailing contests on the planet.

Lots of school kids visit the Volvo Ocean Race to learn about climate change and environment challenges for the oceans.

Lots of school kids visit the Volvo Ocean Race to learn about climate change and environment challenges for the oceans.

For Volvo Buses it is an excellent opportunity to display our offers of buses and services to the public and to our customers and key partners. In Itajai we were honored by visits of our most valuable partners in South America.

I presented our new hybrid and electric hybrid (by some called plug-in) offers. In short it is a complete range of advanced buses that have our modular platform of electromobility components and services in common.

Volvo was first in the heavy duty vehicle industry in introducing Lithium Ion Batteries. We have successfully taken the energy storage to a new level. It is now generally recognized that Lithium Ion batteries will be an important part of the ongoing paradigm shift to electromobility and Volvo has the longest and most successful experience.

over 2000 volvo hybrids sold

I believe that the key to our success is that we manage to deliver on our promises on fuel consumption, reliability and total cost of ownership. We have kept an honest and transparent communication that gradually has been confirmed by operators, institutes and authorities.

Graph: Fuel Consumption vs average speed plot of individual hybrid buses in the period 29th of November 2014 to 29th of December 2014. Each dot is accumulated monthly data for one bus. The lack of data from similar diesel buses in the same traffic as the hybrid buses gives less confidence therefore the red line above is set at the 95% confidence interval for all reference buses in South America. The implication of this is that the fuel saving is more than 33% with 95% probability.

Graph: Fuel Consumption vs average speed plot of individual hybrid buses in the period 29th of November 2014 to 29th of December 2014. Each dot is accumulated monthly data for one bus. The lack of data from similar diesel buses in the same traffic as the hybrid buses gives less confidence therefore the red line above is set at the 95% confidence interval for all reference buses in South America. The implication of this is that the fuel saving is more than 33% with 95% probability.

The most recent baby in the family is the South American Double Decker. She will become a success for any city that prioritizes comfort as well as environmental performance. This is most welcome where cities need to offer attractiveness for car users.

The new Volvo DD Global Hybrid (Body by Marcopolo) with Volvo Ocean Race striping

The new Volvo DD Global Hybrid (Body by Marcopolo) with Volvo Ocean Race striping

Volvo has sold more than 500 hybrid buses in South America. And the feed-back and experience is overwhelming. We are immensely proud to be able to contribute to upgrading the role of the bus to become the leading contributor of environmentally sane city renewal.

Unfortunately, I had to leave right before the in-port race got started but I got a couple of snapshots of the boats as they were tumbling in the port.

Volvo Ocean Race Team SCA in Itajai harbor

Volvo Ocean Race Team SCA in Itajai harbor

Volvo Ocean Race Team Dong Feng

Volvo Ocean Race Team Dong Feng

Beach Panorama from morning jogging at Balneário Cambóriu

Beach Panorama from morning jogging at Balneário Cambóriu

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