As we move towards a carbon free society, zero carbon transportation will be as important as zero carbon homes and buildings. And the two will be intimately connected. As zero energy homes and buildings evolve towards positive energy homes and buildings that produce more energy than they use, and as commercial buildings, warehouses, and garages get outfitted with solar collectors, buildings can supply a significant amount of the renewable energy required to power the electric cars and commercial vehicles of the future – all while saving owners money. At the same time, because of the upfront investments, challenges, and time involved in making the transition to an all electric transportation system powered by renewables, there is an important role for low carbon alternative modes of transportation.

The Many Benefits of Electric Vehicles

In spite of the many myths about electric vehicles (EVs), they are superior to those powered by internal combustion engines in many ways. Electric vehicles, even when powered from the grid, have a lower cost of ownership resulting from lower fuel cost per mile, fewer maintenance costs, and minimal need for part replacement compared to conventional fossil fuel powered vehicles. They also produce less net carbon emissions and fewer atmospheric pollutants than fossil fuel vehicles. This is true even when the vehicle is charged with grid power sourced from coal or natural gas. Grid power is significantly cleaner in some areas of the country than others, but even sourcing the dirtiest grid power results in less pollution from EVs due to the much higher efficiency of electric motors compared to internal combustion engines. Most importantly EVs perform better and are more fun to drive!

Challenges with Powering EVs with Renewable Energy

Powering an all-electric transportation system based on renewable electricity from the grid poses important challenges. Can renewable energy production keep up with the new demand? Even though the amazing growth of renewable energy over the last ten years suggests that it is possible to decarbonize transportation, there will be challenges as illustrated by a recent dip in the growth trajectory of renewables. In 2018, electricity demand grew by 4% worldwide, but renewables supplied only half of that new demand. In the US, solar installations declined by 14% in 2018, while overall electric demand grew. In other words, for a variety of reasons, growth in electricity demand outpaced the growth of solar electricity production. While this may not be a long term trend, it reminds us that powering an electric transportation system from an electric grid based on renewables will take decades and require diligent effort.

Powering Electric Vehicles from Home and Business Rooftops 

Point of use rooftop solar can help fill this gap. Already many electric car owners have solar panels and at least in part power their cars from the sun. Many zero energy homes end up producing more energy than they consume and are already powering electric vehicles in part or in full from the sun with no additional cost for solar panels. According to one estimate, just nine solar panels can power an EV for 12,000 miles over a year. There is a simple calculation to determine how many solar panels it may take to power an electric vehicle. Electric cars may also play a key role in making a renewables based electric grid more feasible. Commercial vehicles and company fleets are expected to transition quickly to electricity and can utilize solar panels on parking garages, warehouses, and rooftops. In some areas, companies can purchase renewable energy from their utility or directly from solar farms as solar subscribers. Soon there will be public charging stations powered by point of use solar and there will be EVs with solar collectors built into their surface that will reduce the amount of externally-sourced electricity vehicles will need, whether it comes from solar charging stations, rooftop solar on homes or businesses, or the grid.

Electric Public Transportation

Electric buses are on the way. From Indianapolis to Los Angeles cities are electrifying their public transport systems. Electric school buses are beginning to show up, too. In Shanghai, the bus depot is covered with solar panels that will power their fleet of electric buses and Indianapolis is doing the same thing. As we move towards a renewable electric power based public transportation system, the location of residential neighborhoods and apartment buildings will become crucial to the success of these systems since convenience for passengers is essential to the success of public transportation.

Electric Freight Haulers

We’re beginning to see electric tractor trailer trucks from Daimler/Freightliner and Tesla, as well as from BYD in China and Toyota’s fuel cell electric truck. Many trucking companies have large warehouses, terminals, and loading areas that can be covered with solar panels to help power their vehicles. Moving our public transportation and freight hauling systems from diesel to all electric will have the added advantage of reducing particulate pollution that causes such high health costs and produces black carbon which adds to global warming.

The Challenges to Transitioning to All Electric Transportation

There are three main challenges to making a smooth transition to all electric vehicles powered by renewable energy from the grid. The first is a chicken and the egg conundrum. Will there be enough charging stations to convince mainstream drivers and businesses to trust that an EV will be practical? And will there be enough EVs to warrant the investment in EV chargers? While this seems to be working out for cars in larger population centers and along many principal highways, the big challenge will come with electric commercial vehicles and in states where EVs are less popular and distances are greater. Charging from homes and businesses, especially from those with rooftop solar, may be the answer here. With many newer EVs a charge at home while sleeping or at work can provide from 200 to 300 miles of travel per day.

The second challenge is the fossil fuel cost of producing solar collectors and electric batteries. This includes the energy used in mining the minerals used, disposal of the waste, and manufacturing and transportation of the batteries and panels. These collateral fossil fuel requirements for a renewable, all electric, transportation system may be high – especially during a transition period – so it would be wise to conserve our fossil fuel resources now to help make this transition. On the other hand, the fossil fuel industry also uses a lot of fuel itself and has a huge carbon impact. A hopeful example of a self sustaining renewable industry can be found in Tesla Gigafactories which generate much or all of their energy for making cars and batteries from rooftop solar.

Third, while transitioning from fossil fuels to renewable energy, we are moving from a fully mature industry with mountains of infrastructure and capital to a nascent industry that must quickly scale up to meet demand. That being said, our high quality oil wells have passed their peak and the infrastructure and environmental costs of fracking may put many fracked wells into a negative energy balance, using more energy (and borrowed money) than may be recovered from the wells. Transitioning to an all renewable grid powered transportation system will be costly and slower than many hope. However,  sticking with fossil fuels will be even costlier. The best path forward is to install sufficient solar panels for charging EVs in our homes, businesses, and at public charging stations. At the same time, we will need to focus on increasing energy conservation and energy efficiency to achieve a low carbon transportation system.

Electric Bikes and Scooters

Compared to cars, electric bikes and scooters are easily charged, use small amounts of energy, take very little space, and are inexpensive. In many cities they are widely available to residents and visitors. They will complement an all electric public transport system and help speed the transition in dense urban areas.

Conservation and Energy Efficiency Are Still Key to Our Future

Energy efficiency gains and energy conservation must continue to be a key component of getting to a zero energy/zero carbon future. And that applies to transportation as well as the building sector. In fact, energy saved in a highly energy efficient building powered by solar panels can be repurposed for transportation. In addition, walking, bicycling, and public transportation should become prime modes of transport. These alternative modes of transportation are also intimately connected to our homes and buildings as the location of homes, stores, schools, and commercial buildings is key to efficient and effective alternative modes of transportation. So while we are transitioning to a renewable all electric society, renewables, combined with electric vehicles, walking, biking, and public transportation, offer the hope of allowing us to continue our current lifestyle while reducing carbon emissions to zero. And if done right, this investment will return a profit and be better for our health.