The recent United Nations COP21 climate change summit in Paris highlighted the need to cut greenhouse gasses, such as CO2, by as much as 80% in many countries by 2020. But the problem is not just constrained to developed countries writes Akin Adamson, Middle East Director, Transport Research Laboratory
The UAE’s Vision 2021 National Agenda throws the spotlight on the significant role that sustainable development and transport plays in the countrys efforts towards social and economic growth. Focusing on programs and initiatives directed to improve air quality, water resource preservation, reducing solid waste and the development and implementation of a green growth strategy, the UAEs 2021 blueprint clearly shows the need to deliver a long-term sustainable energy resource plan to serve as a pillar for the countrys future. This is evidenced by Dubais recent move to launch the worlds largest solar project. Under this project, concentrated solar power (CSP) is expected to be attainable in the next five years. Once completed, the solar project can help reduce carbon emissions by more than 6.5 million tonnes of harmful CO2, helping Dubai and the UAE to meet its commitment to the Paris Agreement to keep global warming temperature increases below 2 degrees Celsius by the end of this century.
Aside from the solar initiative, electric vehicles (EVs) have also started to make inroads in to the UAE – with Dubai taking the lead in introducing various initiatives to make EVs more attractive, from subsidised pricing to the installation of 100 new charging stations by the end of 2015. Electric vehicles offer an ideal solution to tackling the current air quality problem. They provide zero tailpipe emissions, as well as very low grid-to-wheel CO2 emissions if using electricity from renewable sources. The problem is currently that range and utilisation are constrained by battery limitations and charging times, particularly given the need to power ancillary systems in cars in the region, such as air conditioning. So for longer journeys on strategic roads or outside of cities, EVs are not practical. This then severely reduces the range of available vehicles and transport applications for which they could be used.
While improvements are being made in battery capacity, these incremental increases will place additional strain on plug-in charging infrastructure and wont deliver the ground-breaking range required to make EVs comparable with ICE vehicles. So in order to accelerate adoption, we need to find an alternative way of powering vehicles.
Is Wireless Power Transfer (WPT) the breakthrough enabling technology?
Wireless power transfer (sometimes called contactless charging) is a relatively well established technology for the static charging of vehicles when they are stationary over an in-road installed inductive loop (a charging pad).
A coil placed in the ground generates a magnetic field when a high frequency current is passed through it. A second coil, placed on the vehicle, when within range of the magnetic field, generates its own current. Therefore, electrical energy is transferred to the vehicle completely wirelessly. A similar concept is the one being used for wireless charging of smart phones and other consumer electronic devices.
This provides a simple mechanism for recharging a vehicle and removes the requirement for the driver or user to interact with any charging infrastructure, thereby increasing the practicality and user friendliness of the charging process. Charging pads can be conveniently installed at any location where a vehicle is likely to be stationary for any period of time, for example, in parking bays without the need for complex or unsightly above ground charging infrastructure.
Another use case for WPT is to extend the range of public transport busses. Charging pads can be installed at bus stops so, when a bus is stationary (even for a few minutes), it can receive a charge that will allow it to travel much further than if it had to rely on stored battery power alone. Such systems are already in operation and the UKs Transport Research Laboratory (TRL) is running trials across a number of cities in the UK (including London and Milton Keynes) to assess performance and suitability for wider use.
Is on-road charging the answer?
One possible solution is the development of a cost-effective and energy efficient way of providing power to vehicles on the move. This not only reduces the need for large, expensive batteries on board vehicles, but reduces the dependence on plug-in infrastructure, optimising utilisation. However, many people have questioned whether on-road charging is really viable.
To assess the viability of on-road charging, the UKs Transport Research Laboratory (TRL) recently completed a feasibility study for Highways England into dynamic wireless power transfer (DWPT). The study sought to understand whether DWPT technology can be used on Englands strategic roads to prepare for, and potentially encourage, greater take-up of electric vehicles.
For those not familiar with DWPT, it uses multiple inductive-loops along a stretch of roadway to provide power to vehicles when moving at motorway speeds. Unlike other alternatives, it does not require installation of excessive, over-ground infrastructure and removes the requirement for driver or user interaction, increasing the practicality and user friendliness of charging.
Results from tests around the world so far indicate that efficiencies of such DWPT systems should be comparable to plug-in charging. Findings from the feasibility study showed that existing DWPT systems have already proven to be able to deliver power of up to 140kW to moving vehicles, with higher levels possible.
In addition, one of the big advantages of DWPT over plug-in charging is efficiency. DWPT systems are designed to supply power to the electric motors in the vehicle directly, thus avoiding the inefficiencies of battery charging and discharging. It also enables vehicles with very small batteries to cover large distances of equipped highway in a mostly fully electric mode, for example hybrid HGVs.
Combined with the cost of the DWPT equipment and road installation, costs per km are substantial. However, when you consider that the technology would enable thousands of vehicles each day to drive in full EV mode along the equipped sections of the road, the benefits quickly become apparent.
Creating a flexible charging ecosystem
Wireless power transfer is already a reality across a number of sites in Europe for the static charging of vehicles; dynamic wireless power transfer simply takes this technology to the next level. Its not intended to replace the need for plug-in charging, but to provide an option for opportunistic charging or powering of the vehicle over long journeys.
Despite the focus of the TRL study being DWPT, this technology is not the only solution for road electrification. Other examples include the use of cable catenary systems over highways to provide power to electric trucks via pantographs In fact, Siemens has already developed something similar for its eHighways system which is now being tested in Sweden and the US.
Regardless of the method chosen for the UAE the prospect of providing power to vehicles on the move offers exciting possibilities and could play an important role in helping many regions to achieve their vision of becoming smart, connected and sustainable. However, in order to be certain of the anticipated performance and benefits the technology first needs to be extensively trailed in a representative environment before piloting on a public road. If successful, DWPT, together with conventional plug-in charging in selected locations and urban areas, could provide a flexible, user friendly and fit-for-purpose charging ecosystem that will help the region achieve its vision of becoming smart, connected and sustainable.