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Fueling future transport: a 21st century balancing act

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In the post-Paris Agreement era, alternative fuels for transport will increasingly become the norm as we look for ways to cut carbon emissions and air pollution. Electric vehicles — of both the lithium battery and hydrogen fuel cell type — certainly seem to be the way forward. Some argue that we only need batteries. Others, such as Dr. Katsuhiko Hirose, who was integral to Toyota’s ecologically-friendly hybrid revolution, expects hydrogen to have a big role in a sustainable society.

Mobility is a vital constituent of human life. It shapes the places in which we live and influences every aspect of our lives from housing to recreation. This world on the move is fuel-hungry; a hunger that is currently met by oil.

The geopolitical tensions surrounding the use of this finite resource, alongside its major contribution to climate change and damaging impacts on human health and the environment, mean that the substitution of oil as the primary fuel for transportation must start without delay. Indeed, the revolution is already underway.

Vehicles designed to run on alternative fuels are steadily increasing their market share as governments and industry strive to meet stringent emissions and air quality targets. There is a growing consensus that electric vehicles are the way forward for low emissions and more sustainable mobility. The issue is how will this electricity be sourced.

Battery powered vehicles have tended to monopolize the headlines in recent years, giving the impression that there is one simple answer to this question.

However, the hydrogen fuel cell is now making a grand entrance onto the scene. A new generation of hydrogen fuel cell vehicles has recently been introduced and several others are due for 2017, while hydrogen infrastructure has received a major funding boost in many countries.

Moving to a post-oil society. Why the rush?

The environmental impacts of the extraction, distribution and usage of oil are wide-ranging and include climate change, disputes over land rights (particularly public land), as well as negatively affecting air, water and soil quality, and biodiversity. Of all these issues, climate change is the most urgent given the severity and scale of the consequences.

Direct GHG emissions of the transport sector between 1990 and 2010
Evidence of the link between anthropogenic carbon emissions and climate change is unequivocal.

Just last year, scientists at NASA’s Goddard Institute for Space Studies found that the first six months of 2016 each set the record for the warmest respective month globally in the modern temperature record. The six-month period was also the planet’s warmest half-year on record. This climate indicator is ultimately driven by rising concentrations of carbon dioxide and other greenhouse gases in the atmosphere.

Carbon emissions from transport have more than doubled since 1970, reaching 7.0 Gt CO2eq in 2010, with about 80% of this increase coming from road vehicles. On top of which, demand for transport will inevitably rise. Based on current rates of growth for passengers and freight, and if no mitigation options are implemented, the transport sector’s greenhouse gas emissions could increase by up to 50% by 2035 and almost double by 2050.

Transport is also one of the main sources of air pollution, particularly in cities and other urban areas. And despite improvements in emission-reduction technology, global urban air pollution levels increased by 8% between 2008 and 2013. Governments and city authorities are taking action to improve the situation. For example, in 2016 the authorities in Paris made public transport free on certain days and imposed restrictions on the use of vehicles (apart from hybrids and electric vehicles) because the city was experiencing its worst episode of winter pollution for at least ten years.

Air pollution is a very real public health issue. In 2012, one out of every nine deaths was the result of air pollution related conditions. Of those deaths, around three million were attributable solely to ambient air pollution. In China alone, more than one million people died from dirty air in 2012.

The electrical attraction

For decades governments and vehicle manufacturers have conducted research into alternative fuels and developed pilot vehicle fleets to trial these fuels, with the aim of developing more sustainable and cleaner modes of transport. There is general agreement regarding the fuel of the future that could best address all the current issues. And that fuel is electricity.

The two main types of electric vehicle technologies are hydrogen fuel cell electric vehicles (FCEVs) and battery electric vehicles (BEVs). Both vehicle types have electric motors that generate no emissions, no particles, and are completely silent. The difference is that BEVs rely on a chemical battery that is recharged when plugged in to the electric grid, while FCEVs create electricity onboard witha fuel cell that is usinghydrogen stored in a dedicated tank.

Although calculations vary according to sources, research shows that vehicles powered by electric motors are about three times as efficient as those powered by internal combustion engines.

As well as lowering carbon emissions through greater efficiency, electric vehicles can vastly improve local air quality in cities by moving emissions from vehicles to either power plants or hydrogen production sites. And since electricity and hydrogen can be generated by low carbon processes, then carbon emissions can be reduced even further.

For example, a 2013 report examined three low carbon technology scenarios for Europe. The scenarios were based on different projections of deployment and market penetration rates for key electric vehicle technologies (BEVs, hydrogen FCEVs, plug-in hybrid electric vehicles and hybrid electric vehicles). These scenarios showed that direct vehicular CO2 emissions could be cut by between 64% and 93% by 2050. Also, tailpipe emissions of harmful pollutants would be cut by more than 85%, with soot particles down by more than 70%.

Mind the gap

The media focus in recent years has leaned towards BEVs as the most likely replacement technology for gasoline and diesel powered engines, and it’s not hard to see why: electricity can be generated by renewable and low carbon emitting processes; vehicle batteries can be charged at any electric power point; and maintenance costs are low since there is no need for an exhaust system or oil changes. However, these attributes have been well known for decades. The root cause of recent media attention is the falling cost of lithium-ion batteries, and the perception that these costs will continue to plummet.

These diverse benefits mean that BEVs will undoubtedly play a major role in future transport. However, BEVs are not without drawbacks. They have a limited range compared to conventional vehicles, a much longer refueling time and they raise some infrastructural issues. Let’s look at these points in a little more detail.

Shown above is the maximum driving distance from Madrid with a middle range electric car (155 miles)

In terms of range, one of the best-selling BEVs, the Nissan Leaf, has a maximum range of 155 miles. This is fairly typical for most electric cars today (although the technology is improving steadily and new luxury electric cars claim to offer much more distance on a single charge). Moreover, range extension will require disruptive innovation in the energy density of batteries as we are already close to the physical limits, because more range means more batteries. And adding more batteries adds more weight, thus negatively impacting on range. Tackling this issue is one of the main focuses of BEV manufacturers today.

This kind of range isn't necessarily a deal-breaker

A recent study showed that the energy requirements of 87% of vehicle-days could be met by an existing, affordable electric vehicle. The problem is the remaining 13%, which represents in contrast more than 75% of CO2 emissions (see EU Power train report). This small but significant proportion of daily car energy use that exceeds a single battery’s capacity can be a deterrent. Why exchange a tried-and-true gas-guzzler for something that might make longer distance travel more complicated? Adding to the disincentive is the fact that the initial purchase price of a BEV is currently higher than its conventional counterpart.

A fear that switching to BEVs might mean a loss of convenience also applies to recharging. We’ve all become accustomed to refueling at gas stations. It’s a five minute job or less. Well, this is a habit that BEV drivers need to unlearn. Charging a BEV is typically done at home (for garage owners at least) and is an overnight process: level 1 and level 2 chargers offer between 2 to 20 miles of range per hour of charging; while fast charging facilities, which are available in streets, car parks, charging stations, shopping malls, etc., provide 50 to 70 miles of range per 20 minutes of charging. Even the latter remains far removed from the world we know: where five minutes is sufficient to provide the average car with the means to travel another 400 miles or so. Old habits die hard.

Regarding infrastructural issues, the electricity grid will need reinforcement to cope with the new demand, as well as new electricity production facilities in the case of a massive BEV deployment. In some cases, plugging in an electric vehicle is the equivalent of adding three houses to the grid, raising real concerns of power outages.

Electric car usage tends to be concentrated in certain regions. Where, when and how cars are charged are the key factors.

Public fast charging stations on commercial grids are generally up to the task. The problems arise when electric car owners install dedicated charging units at home, and do so in significant numbers in the same area. If BEV ownership is to increase considerably, then it will be essential for these units to facilitate staggered charging to avoid overloading the grid during peak hours (for example, when people arrive home after work). This problem is exacerbated by the fact that electric car usage tends to be concentrated in certain regions. These big increases in the power demand in some neighborhoods would be well above the capacity for which their electricity supply was designed.

RTE (a branch of the energy company EDF) has also highlighted the potential electricity supply and distribution problems associated with BEVs. It estimates that if five to six million BEVs are on the road by 2030, and if these cars cover a similar distance to today’s average (about 35km per day), then this would require the output of an EPR nuclear reactor (1,650 megawatts). Furthermore, Enedis, an EDF branch that manages the distribution network, estimates that if six million drivers recharge their vehicles at the same time, even using slow chargers, then this would equate to a demand of 15,000 megawatts. During peak times this could account for as much as 30% of the production capacity, thereby running the risk of destabilizing the electricity network.

Mix and match

Batteries alone cannot be the only solution. Bubbling away underneath the media interest in BEVs are several automotive manufacturers who are advancing with hydrogen FCEVs. Dr. Katsuhiko Hirose led the emission and fuel consumption area of Toyota’s Hybrid Synergy Drive. Since then he has worked on advanced fuel cell system development, hydrogen storage technologies, and hydrogen energy and infrastructure development.

Dr. Katsuhiko Hirose, Hydrogen & Fuel Cell Engineer, Toyota

I was skeptical about hydrogen at first,” admitted Dr. Hirose. “At the successful launch of the hybrid, I didn’t see the potential of hydrogen. We were achieving very high efficiencies with the hybrid, so conversations with my boss were always about how we could improve its fuel efficiency even more. But my opinion rapidly changed once I began working in hydrogen research. We made such progress in fuel cell technology that I became convinced that it would soon become competitive with the hybrid.

Hydrogen: one proton, one electron, one part of the solution

So what does Hirose see as some of the benefits of hydrogen FCEVs? “The hydrogen fuel cell vehicle is powered entirely by electricity. The only byproducts are water and heat, much like battery vehicles. However, unlike battery vehicles, refueling a fuel cell vehicle takes just minutes. It’s very similar to filling a conventional gasoline vehicle. Moreover, the range of hydrogen FCEVs is parallel to gasoline and diesel engines. So it has the convenience of a conventional vehicle.

For Hirose, the way forward is the evolution of both technologies, a coexistence, with each fulfilling different segments: “We see the huge potential of the battery vehicle. But the customer chooses the vehicle and the technology according to convenience, price and also performance. As manufacturers we need to provide choices for the customer, and we see the battery vehicle and fuel cell vehicle as the future options.

“It is not a conflict. Today the average driver has a choice between diesel and gasoline.

In several years hydrogen fuel cell and battery vehicles will be like diesel and gasoline now.

People never asked whether the future would be gasoline or diesel. Why do we have to choose one option?”

This idea of the coexistence of the two technologies is persuasive because they are inherently suited to different applications, for example, the limitations of BEVs in terms of energy density and charging speed mean that it is difficult to envisage BEVs being applicable for heavy duty trucks.

History suggests a positive outlook for infrastructure

What about the necessary infrastructure for hydrogen distribution and storage? Wouldn’t this be prohibitively expensive? “We do not need a huge number of hydrogen stations from the beginning,” said Hirose. “Let’s look at conventional fuel stations. In Paris, fuel stations are disappearing fast but people in the city are still driving. They refill somewhere, either near the home or on their way to the office. One station on this route is enough. That’s the same for hydrogen. For example in Japan we have 80 hydrogen stations countrywide, these stations can support thousands of hydrogen cars.

Toyota’s success with the hybrid is another reason for optimism regarding what can be achieved in terms of hydrogen infrastructure. “At first the necessary infrastructure for the hybrid was simply not there, but twenty years or so later and the evidence suggests that this problem has all but disappeared”, said Hirose. “Toyota now sells 1.3 million hybrids a year, which is about 15% of its total car sales, while in Japan hybrids now represent half of its sales. Clearly, the hybrid’s popularity is not being dampened by a lack of infrastructure. All of which has been steadily built up over twenty years following the car’s introduction.

The dieselization of the European car fleet provides a further example of how changes in transportation can and do happen. And much like the development of the hybrid, it is a subject in which Hirose has personal experience, as he was stationed in Europe from 1993 to 1996. “In just 10 or 15 years there was a massive development of infrastructure in Europe so that countries could support automotive fleets with proportions of diesel vehicles as high as 60% to 80%,” explained Hirose.

“New technologies usually need some time before they can flourish, but change can be quicker than people think.” — Dr. Katsuhiko Hirose

Fueling hope for the whole world

The potential of hydrogen technology is far-reaching. Hirose’s personal belief is that “advances in hydrogen fuel cell technology will one day enable developing countries to produce their own energy, using solar power, bio waste or any kind of renewable. The hydrogen they generate could be used for many purposes, including energy for fuel cell cars, and heating and electricity for homes. This is something that could really change the world.

Developing countries spend a high proportion of their GDPs on importing gasoline to stop their economies from stalling. But when they become able to produce their own energy, their economies will become much more sustainable. Hydrogen can be the ideal solution for both local environment and global carbon dioxide emissions when it is generated from renewable energies, such as wind in Northern countries or solar in the South.

The main issue here that we shouldn’t lose sight of — regardless of whether we think the future belongs to BEVs, hydrogen FCEVs or that there is room for both — is that the era of zero emission vehicles is close at hand. When more than 90% of city residents around the globe breathes air that does not comply with WHO air quality guidelines, and evidence of human-induced climate change and its impacts mounts on what feels like a daily basis, this is one revolution that cannot come quickly enough.