Why Solar Bicycles?

All you need to know about Solar Assist Bicycles

What is a Solar Bicycle?

Solar Assist Bicycles, also known as solar bicycles or solar bikes, are bicycles equipped with an electric motor, a solar panel and a rechargeable battery. These innovative bicycles combine the joy of traditional bicycling with the ease of solar energy assistance, making them perfect for anyone who wants to ride longer distances without exhausting themselves.

A  solar bicycle is a Hybrid Electric Vehicle (HEV) that uses a solar photovoltaic generator to charge a battery and/or power an electric motor to propel the bicycle.  One can ride a solar bicycle in three different modes - (1) Manual mode using pedals (metabolic energy), (2) Battery mode - by rotating a throttle handle, and (3) Solar Assist mode -  where the solar energy is used to assist the rider in making pedaling lighter (requires less effort) and more comfortable; and the ride experience - enjoyable and more pleasurable. 

 Though it is designed to be normally used in the solar assist mode, the other modes are also available to suit the user's needs depending on circumstances and external conditions. There are multiple levels of solar assist (typically five) in the solar assist mode, and by choosing the correct level, one can extract just the right amount of solar assistance needed without causing battery drain.  

On using the throttle mode, if the battery does get drained, then the battery charge can be restored by simply parking the bicycle for a few hours (typically 3 - 4 hours) under direct sunlight and with the solar panel facing the sun for best results. Under these conditions, since the source of energy is the sun, there are no fossil fuel emissions unlike other HEVs or Battery Electric Vehicles (BEVs).   

At times (when there is no sun-shine) a solar bicycle can be operated as a Plug-in hybrid electric vehicle (PHEV) or as a BEV  whose batteries can also be charged by plugging the vehicle into an AC mains power source.   On such occasions when there is dependence on the regional electricity grid, we cannot consider the bicycle to be emission free.   

Usually we don't account for human energy while considering green house gas (GHG) emissions. Actually, human calories burnt which is typically 75 kilocalories per hour when sitting idle or 350 kilocalories per hour when manually pedaling a bicycle, also contributes to global warming. Riding a solar bicycle in the solar assist mode actually lowers down the consumption of human calories and therefore can also be viewed as beneficial for mitigating climate change.   

Whether you're commuting, exploring new trails, or simply looking for a fun way to stay active, solar cycles offer a practical and exciting solution. Among the best solar bicycles available, the  BEM® Savitré™ 7 Speed Solar Assist Bicycles stand out for their ability to make transportation effortless and enjoyable, all while being eco-friendly.

*Battery electric vehicles (BEV): BEVs are powered by electricity, which is stored as chemical energy in batteries. The energy powers an electric motor that propels the vehicle.

How does a Solar Assist Bicycle Work?

A solar assist bicycle uses a combination of solar energy and metabolic energy to propel the bicycle. It operates through the integration of several key components that work together to enhance the bicycling experience. These include the solar panel, solar MPPT charger, motor,  battery,  controller, and other essential elements such as the brakes, drive train, and frame. Let's break it down:

1. Solar Panel:

The solar panel taps energy when direct sunlight falls on it, regardless of whether the bicycle is in motion or parked on the street. This energy assists the rider by substituting his own metabolic energy thereby making the ride less strenuous. When the bicycle is parked, the solar energy can be stored in a rechargeable battery for later use.

2. Solar MPPT Charger:

The solar MPPT charger is a software based charge controller that is capable of extracting maximum power from the solar panel in an smart and intelligent manner. This charger is responsible for making efficient use of  a smaller sized solar panel feasible.

3. Motor:

The motor driven by solar energy assists your pedaling by providing extra power, especially when going uphill or over long distances. It makes the ride smoother and less strenuous. The solar energy driven motor helps with acceleration or maintaining speed even when going up slope on a gradient.

4. Battery:

The battery powers the motor and determines how far you can travel on a single charge. It is typically rechargeable and designed to offer a sufficient range for daily commuting or leisurely rides.

5. Motor Controller:

The controller manages the motor's power and lets you adjust the level of assistance. You can change the settings using a display on the handlebars, making it easy to switch between different power modes.

8. Drive train and Frame:

The drive train, including pedals, chain, and gears, works with the motor to make pedaling easier, especially on hills. The frame supports the motor and battery, and is typically made from durable, lightweight materials to handle the extra weight and provide stability.

7. Brakes:

Solar assist bikes use reliable braking systems, such as disc or rim brakes, for safe stopping, especially at higher speeds. Some bikes also have regenerative braking, which helps recharge the battery as you slow down.

Together, these components create a seamless and efficient riding experience. The motor, battery, and controller work together to make cycling easier, while the brakes, drive-train, and frame ensure the bike remains safe, reliable, and comfortable. The integration of these elements allows electric bikes to offer a unique blend of traditional cycling with the added benefits of motor-assisted power, making cycling more accessible for a wide range of riders.

Key Features of a Solar Assist Bicycle

Solar assist bicycles come packed with features that make them efficient and user-friendly. Here are some of the most notable ones that enhance your riding experience:

1. Pedal Assistance:

Solar assist bicycles come with a motor that activates when you pedal, providing additional power and making your rides smoother and less tiring. This feature is especially helpful when climbing steep hills, navigating tough terrains, or riding long distances. With pedal assistance, you can enjoy cycling without feeling exhausted.

2. Eco-Friendly:

One of the most significant advantages of Solar assist bicycles is their environmentally friendly design. Powered entirely by solar, they produce zero emissions, making them a sustainable alternative to fuel-based vehicles. By choosing a solar assist bicycle, you contribute to reducing air pollution and promoting a cleaner, greener environment.

3. Rechargeable Battery:

Solar assist bicycles  are equipped with rechargeable batteries, typically lithium-ion, that provide energy for the motor. These batteries are efficient and convenient, with most models fully charging within 3 to 5 hours from direct sunlight or fast charging in 2 to 3 hours when plugged into an electric utility ac mains. This ensures you’re always ready for your next ride, whether it’s a daily commute or a weekend adventure.

4. Speed Options:

Solar assist bicycles offer multiple levels of motor assistance, allowing you to control the speed and effort needed for your ride. Whether you prefer a leisurely pace or a faster journey, you can customize the assistance to suit your needs, ensuring a comfortable and enjoyable experience every time.

5. Lightweight Design:

Modern solar assist bicycles are designed to be lightweight, retaining the simplicity and ease of use of traditional bicycles. Despite incorporating advanced technology like motors and batteries, these bikes are easy to handle and maintain, providing a seamless blend of functionality and convenience.

Benefits of using a Solar Assist Bicycle

Solar assist bicycles  are more than just a means of transport, they’re a lifestyle upgrade. They offer several advantages that cater to riders of all types:

• For commuters, solar assist bicycles  make getting to work quicker and less sweaty, especially in urban traffic.

• Fitness enthusiasts love solar assist bicycles  because they promote regular exercise while offering a helping hand when needed.

• Solar assist bicycles  are also an excellent choice for environmentally conscious individuals, as they reduce dependence on fuel-based transport and help cut carbon emissions.

• Plus, the low maintenance and operating costs of solar assist bicycles  make them a wallet-friendly option for long-term use.

Types of Solar Assist Bicycles

Solar assist bicycles  are versatile and cater to a variety of riding needs. Here are the main types to help you find the perfect fit:

1. Regular solar assist bicycles: Perfect for daily commuting, offering a lightweight frame and moderate battery range.

2. Mountain Solar Assist bicycles: Designed for rugged terrains, these come with durable frames and powerful motors.

3. Hybrid Solar assist bicycles: A versatile mix of road and mountain bikes, suitable for both city rides and off-road trails.

How to Choose the Right Solar assist bicycle?

Selecting the best solar assist bicycle depends on your specific needs. If you’re looking for a reliable commute, go for a city e-cycle with a sturdy build and long battery life. For adventurers, a mountain solar assist bicycle with strong suspension and higher motor power is a great choice. Consider the battery capacity to ensure it aligns with your average travel distance, and check for features like gear systems, display panels, and comfort. Choosing a trusted brand, like the BEM® Savitré™ 7 Speed Solar Assist Bicycle ensures quality, durability, and excellent after-sales support.

Ready to Ride Smarter? Say Hello to Solar assist bicycles! 

Solar assist bicycles are revolutionizing the way we move, offering a perfect blend of convenience, fitness, and sustainability. They empower riders to explore more, commute smarter, and reduce their carbon footprint, all while having fun. Whether you’re cycling through bustling city streets or heading out on scenic trails, a BEM® Savitré™ 7 Speed Solar Assist Bicycle adds a sense of ease and adventure to every journey.

So, are you ready to experience the change? Discover how a solar assist bicycle can transform your rides today.

Why Bicycle Trails?  Benefits of Multimodal Streets (The Netherlands' Model)

Road fatalities (0.15 million/annum) or (1 in 10,000 population) in India is the highest in the world. If we, in India, wish to take important matters such as the quality of human life, or assign a higher value to  human life, we need to  start by studying the streets of other countries.  We believe that it would be a waste of energy to educate the public about following traffic discipline to reduce the fatalities. It would makes better sense to choose the correct model and approach the authorities and decision makers after an analysis, study,  debate and a pilot.   

India is currently following the US (private car) model, while the rest of the world (even US is beginning to) is following the Netherlands (public transport and bicycle) model with multimodal streets. 

Streets must be designed to serve different modes and provide multiple mobility options for its users.

Multimodal streets offer people options for safe, attractive, and convenient travel by foot & bicycles, on transit, as well as in motorized vehicles. Multimodal streets help to make cities more efficient. A reduction of private cars on streets has a direct link to reduced production of greenhouse gases, related to climate change. This shift also helps in increasing space for commerce and public use, and contributes to a better quality of life and economic growth.

For more details on Multimodal streets and their benefits, click here.

Why Solar Bicycles?  Represents Smallest Footprint

A solar bicycle is a result of extreme engineering.  It represents a personal mobility vehicle for commute and cargo with the smallest footprint in many aspects and categories. In terms of  carbon footprint, the manufacturing emissions (< 160 kgCO2eq. in comparison to 10 tonnes CO2eq.  for cars). Physical dimensions - solar bicycle:  l x b x h = 195 cm x 65 cm  x  110 cm  vs. an  SUV : l x b x h = 500 cm x 200 cm  x  160 cm. Weight  - under 30 kg  for a solar bicycle vs > 2000 kgs in case of an SUV. Fatalities (death on bicycle lanes < 0.01% of those on roads built for cars, of equal  lengths.  Speed 25km/hour for a solar bicycle vs  120 km/hour for an SUV.   Power sink (motor < 300W), in comparison to 1600 cc engine or 40kW motor in the case of an SUV.   Power source (40W solar panel of solar bicycle) vs.  gasoline or electricity in case of an SUV, represents a savings of  0.133 kg or 0.08 kg of CO2eq for every kilometer of travel with a solar bicycle that substitutes an  ICE or electric SUV respectively).   

A solar assist bicycle is the most efficient man-made personal transport vehicle consuming only 6.69 Wh of energy per kilometer. It can offer unlimited distance coverage, by tapping about 2.0 Wh / kilometer of energy from the solar panel on a continuous basis. The solar assistance can help reduce the rider's metabolic energy by 30% from 24 kcal/km to 16.81 kcal/km. Since the  2.0 Wh/km of solar substitutes 7.19 kcal/km (or 8.35 Wh/km) of metabolic energy, it also offers a corresponding saving of  CO2eq, in comparison with every kilometer of travel over a regular non-motorized bicycle!  

With the addition of 24.5 GW of new solar power capacity in 2024, India's total installed renewable energy (RE) capacity reached 209.44 GW as of December 2024. Solar energy accounts for approximately 47 percent of the total RE segment, making it the most significant contributor among renewable sources. 

India added around 18.5 GW of new solar capacity, in 2024, an increase of 280 per cent  over 2023, in the utility-scale solar segment. The surge in the solar power sector is mainly attributed to the falling module prices and subsequent growth in the commercial and industrial sector installations. 
India added around 4.59 GW of new solar capacity, in 2024, an increase of 53 per cent, in the rooftop solar sector, thanks to the launch of the 'PM Surya Ghar Muft Bijli Yojana'.  Also in the off-grid or distributed segment, solar capacity of 1.48 GW was added in 2024, and increase of 197 per cent. 

The above table shows that India's   CO2 emissions  has increased by 197% in 2023 in comparison to the year 2000.  India is also having the largest increase in  CO2 emissions in relative terms (+6.1%) in 2023 when compared to 2022.  

So why isn't the total installed renewable energy (RE) capacity (of 209.44 GW as of December 2024) helping in reducing the  CO2 emissions?  The answer is simple. The renewable energy is used to fuel additional load from new growth in infrastructure in industrial, commercial, agricultural and residential sectors. The renewables are not at all effective in reducing the fossil fuel consumption of the installations that existed in the year 2000. India is arguing that its emissions should be analysed in terms of amount of CO2 per capita. The growth of India's population is also used as a justification for the increase in  India's CO2 emissions.  Whatever the reason for the increase in India's CO2 emissions, it cannot be a justification for failure to achieve its goal of net zero emissions  in order to  limit global warming to 1.5 ℃.   

Our analysis of the solar installations show that the government subsidies for solar are causing more damage than good to the environment. The consumers who are opting for solar rooftop installations by availing the solar subsidy are doing so only to offset their more expensive fossil fuel based units imported against the cheaper solar units earlier exported, under the Net-metering tariff . In this manner, the consumer is able to charge their Electric Vehicles at night with fossil fuel based energy from the utility, practically free of cost.  The EVs are also available to the consumer at a lower price thanks to the EV subsidy offered by the government. All put together, the consumer is able to significantly reduce his own utility bills and enjoy the luxury of driving an EV, at the cost of the environment. An audit of the consumer's fossil fuel units imported before and after the solar roof top installation would show that the imported units have actually increased post installation. Unfortunately, this audit is never carried out and all that is visible to the happy consumer is the reduction in his electricity bills. 

One may argue that the solar units exported by a customer can be used to feed a fossil fuel driven load, hence it would result in reduction in CO2 emissions. This is also not true since maximum solar units are generated and exported usually at noon.  The Indian utilities wonder what to do with the excess solar generation that they are unable to store and the best option open to the utilities is to offer them practically free of cost to the agricultural sector where much of the energy goes unmetered and gets consumed on a HorsePower (HP) based tariff. Farmers are often seen to keep their pumps in the 'always ON state' on the agricultural feeders; hence, when they are energised by the utilities with solar energy,  this results in overdrawal of water and fall in level of the water table.  Fall in water level means that more powerful pumps need to be deployed that consume more energy. Thus it results in more damage in terms of CO2 emissions.

 It should be noted that manufacturing solar cells also result in CO2 emissions. Hence, if these  CO2 emissions cannot be recovered through the generation of electricity  from these very solar cells, then  a typical 4 kW solar rooftop installation over a residential consumer's premises that use thousands of these solar cells thus can result in more damage in terms of CO2 emissions, than good.

On the other hand, the solar bicycles that are fitted with 40 W solar panel substitutes an EV (or an ICE engine).  The 40W solar panel represents just 1/100 of the 4 kW solar panels that are found over a typical rooftop installation. When the EV or the car with an ICE is parked at home, the solar bicycle rider would be saving in terms of  CO2 emissions significantly.   Every kilometer run by a solar bicycle represents a direct saving of  0.133 kg or 0.08 kg of CO2eq., assuming that the vehicle that it substitutes is an SUV with an ICE engine of 1600 cc or an electric motor of 60 kWh respectively.