The Scottish Government

« Previous | Contents | Next »

Listen

4. Technology options

This chapter provides background information on the key vehicle and fuel technologies that have the potential, if applied in parallel with an appropriate framework to 'lock-in' benefits, to reduce carbon emissions in the road transport sector. It includes details of the types of technologies that exist, and the stage they are at in the development cycle.

We also explore some of the opportunities to stimulate the uptake of such technologies, as well some barriers to development that may exist. We consider efficiency improvements to internal combustion engines, alternative fuels (including biofuels), hybrid vehicles, EVs and hydrogen vehicles in turn. These technologies are all potentially applicable to all types of road vehicles - cars, LGVs, HGVs and buses. They are, however, generally regarded as being easier to implement in cars and LGVs, than HGVs and buses given the much higher power requirement of those larger, heavier vehicles. This is an emerging and developing market, and where possible we have included the indicative cost differential between the new technology and existing petrol or diesel equivalents. These costs are, however, very uncertain and are provided as guidance only.

Comparative information on emissions on 'tailpipe' emissions of LGVs are published on the Vehicle Certification Agency website (www.vca.gov.uk). The DfT has research underway to understand emissions from this sector and later this year the European Commission is planning to introduce legislation to reduce emissions from LGVs (essentially vans). For HGVs there is no test-cycle information and comparative information is difficult to obtain.

4.1 Efficiency improvements to internal combustion engines

Currently, nearly all road vehicles are powered by internal combustion engines, fuelled by either petrol or diesel. In a DfT review of the innovation system for low carbon technologies ²³, it was suggested that over the next 10 to 15 years, continued incremental improvements in fuel efficiency could be achieved in the road vehicle industry through additional refinements to the standard petrol and diesel internal combustion engines. These technologies relate to both improving the efficiency of the powertrain directly and also to non-propulsion elements. Examples of potential enhancements to the powertrain include variable valve actuation, direct injection and turbo charging, whilst non-propulsion developments include friction reduction, regenerative braking, low rolling resistance tyres and lightweight materials.

The King Review ²⁴ suggested that adopting a selection of the most cost-effective technologies could achieve a 30% fuel efficiency saving for the average new vehicle within the next 5-10 years. The cost of these measures depends very much on the scale on which they can be rolled out, but if rolled out on a sufficiently large scale, King estimates that the additional production cost could be around £1,000 to £1,500 per vehicle.

The immediate challenge is getting cars with these enhancements into production, as manufacturers will only produce such vehicles if they can be confident it will be profitable to do so. The King Review identifies the main barriers to these changes as being the high fixed costs of introducing the new technologies, coupled with the risk of small economies of scale, if the demand for these new vehicles is weak. The EU Regulation on new car CO ₂ (see page 6) will help provide an incentive for manufacturers to improve their vehicles to comply with targets set.

4.2 Alternative fuels, including biofuels

Notwithstanding the benefits of reducing emissions from petrol and diesel engines, alternative fuels are likely to become increasingly important due to the finite availability, and security issues, of fossil fuels.

Biofuels - liquid fuels that are derived from biomass such as plants and organic waste - offer potential for reducing CO ₂ emissions relative to fossil fuels because their carbon is absorbed from the atmosphere as the source plants grow, rather than being released from underground storage as is the case with fossil fuels. ²⁵

Currently the biofuels most commonly available as transport fuels are bio-diesel and bio-ethanol (first generation biofuels) which can be blended with petrol or diesel and used in a conventional combustion engine, with modifications only required for blends with a high proportion of biofuel (greater than 10%).

The King Review highlights that, in the longer term, biofuels have the potential to make a significant contribution towards reducing emissions in the transport sector. As referenced earlier, the Gallagher Review reported that biofuels could contribute to a sustainable transport system, but that there is a risk of current policies leading to a net increase in emissions, loss of biodiversity, and contributing to rising prices for some commodities, notably oilseeds. As a consequence, it recommended that the rate at which biofuels are incentivised through the Renewable Transport Fuel Obligation ( RTFO) should be slowed. The recommendation has been accepted by the UK Government, which is negotiating in Europe to ensuring a sustainable biofuel agenda across the EU.

The Scottish Government also supports the Gallagher recommendation. The distribution and storage of bio-gasoline in remoter areas of Scotland may have particular implications for compliance with the RTFO that need to be properly assessed. Work is already underway by the UK Government, in consultation with the Scottish Government on these issues.

Argent Energy ( UK) Ltd
Based near Motherwell, Argent Energy is the only major plant in the UK producing bio-diesel to European standards from animal by-products - either tallow from the rendering process or used cooking oil from catering establishments. The company commenced selling bio-diesel in early 2005. In 2008, its production had reached 40,000 tonnes. Its customers include Shell, other independent fuel suppliers and Stagecoach West, which has converted eight vehicles to operate on bio-fuel. The company was voted Sustainable Bio-diesel Producer 2009 at the World Biofuel Markets Expo and Conference in Brussels.

The technology behind biofuels is currently being enhanced towards developing 'second generation' biofuels which should be able to produce a range of synthetic fuels from a wider range of biomass sources (particularly non-foodstock). The processes involved are more complex and expensive and are, as yet, not commercially viable.

Anaerobic Digestion ( AD) involves the break down of biodegradable material in the absence of oxygen by microorganisms. ²⁶ It is widely used to treat wastewater in the UK. It can be used to treat other organic wastes including biofuel crops. The process of AD provides a source of renewable energy. Waste is broken down to produce biogas. Biogas can, of course, be used as a vehicle fuel, having been refined into biomethane.

A six month study of a street cleaning vehicle fuelled by compressed biomethane ( CBM) in Camden has given an indication of its potential. The key findings included fuel savings per kilometre of 6% and emission savings per kilometre of 56% (taking account of CO2 released into the atmosphere during fuel production and distribution) without any adverse reliability issues arising. Implementing CBM in the street cleansing operations has enabled a continuous cycle to take place: from waste collection to waste decomposition to biogas production to vehicle fuel - and back to waste collection again as the fuel is being used to collect more waste ²⁷.

Clean Air Power Ltd
Clean Air Power Ltd, an active technology developer, has developed a dual fuel system which allows heavy trucks to operate on both diesel and natural gas with reported significant cost savings and low carbon emissions. Developments have led to a project involving a small fleet of trucks using this dual fuel system with bio-methane gas produced from a landfill site.

4.3 Hybrids

Hybrid vehicles combine an internal combustion engine that burns petrol, diesel or biofuels with an electric battery powertrain.

There are several types of hybrid vehicle currently available, with graduating abilities to use the battery to power the vehicle. The most basic type is the stop-start or 'mini hybrid'. This has the ability to shut down the engine when the vehicle is stationary and use the energy in the battery to start the vehicle. A slight advancement on this is the 'mild hybrid'. This model saves energy and reduces carbon emissions by not only shutting the engine down when the vehicle is stationary, but uses the energy created from braking to charge the battery. Collectively, these models are sometimes referred to as 'micro hybrids'. In contrast, a 'full hybrid' vehicle has the capacity to run purely on the electric battery power for limited distances without burning any fossil or biofuels, thereby increasing efficiency and reducing emissions.

In addition to these models, plug-in hybrid electric vehicles ( PHEVs) not only use the main engine to recharge, but can also be plugged into a charging station to augment their range. To do this, they have greater battery capacity than other hybrids. Such vehicles may be an attractive option for consumers due to the extended range and the fact that the costs of running a vehicle on electricity alone are likely to be considerably lower than refuelling with liquid fuels ²⁸.

It has been suggested that mini hybrid vehicles have approximately 6% lower emissions than comparable conventional vehicles, mild hybrids 20% and full hybrids 30% ²⁹. Although currently only produced on a very small scale, PHEVs may ultimately have the potential to offer even greater CO ₂ savings.

All of the above types of hybrid vehicles are currently available on the market, though they are still constrained in their commercial viability against standard vehicles. The key constraint is battery capacity, particularly in the full hybrid vehicles. In many of these vehicles, the capacity of the pure electric range is typically less than 2km ³⁰.

A further constraint is the additional cost of full hybrid vehicles, which have been reported to be in the order of £2,000-£4,000 greater than the equivalent conventional vehicle type ³¹. Similarly, although PHEVs offer a partial solution to the battery capacity constraint, the additional batteries required for these vehicles (compared with other hybrids) currently add a cost increment of approximately £6,500 for a 45km range ³².

Alexander Dennis Ltd. ( ADL)
Alexander Dennis Ltd. ( ADL) produces a wide range of low floor single and double deck buses, plus a full portfolio of coaches, welfare and mini vehicles.
Enviro400H is a hybrid drive double deck derived from the Enviro400 diesel version, with significant reductions in fuel consumption and greenhouse gases. Enviro400H's hybrid technology derives from a partnership with BAE Systems. The Enviro400H is a hybrid solution designed specifically for buses; its batteries do not need mains recharging during their life cycles.

4.4 Electric Vehicles

Full electric vehicles are a further advancement on the hybrid concept. They only incorporate a battery and do not have internal combustion engines. These batteries tend to have larger capacities than the hybrid vehicles and are, therefore, able to undertake longer journeys in purely electric mode.

EVs are currently not available in significant numbers, although the advantage of them is that they have zero emissions at point of use. Moreover, if electricity as a transport fuel is produced from low carbon sources such as renewables, it can have low or even negligible emissions over its life cycle. As electricity is distributed via a grid in most areas, the underlying components required for a charging infrastructure for such vehicles are predominantly in place. Partly because of these advantages, a number of other countries including Germany, Sweden and Israel, are setting ambitious targets for the uptake of EVs.

Allied Vehicles Ltd
Allied Vehicles, based in Glasgow, is part of the Allied Vehicles Group. Working in partnership with Axeon, Allied has developed a range of EVs based on the Peugeot Boxer, Boxer Monarch, Expert and Expert Eurobus models for the light commercial and passenger vehicle markets.

However, as with the plug in hybrid vehicles, there are barriers to the development of full electric vehicles. Currently, initial purchasing costs are relatively high in comparison to traditional vehicles (although lower fuel costs may help reduce these differences over the vehicle lifetime). They may also require further development of a comprehensive infrastructure necessary to charge them, whilst the key barrier is the battery capacity that they are currently able to offer. There is currently a limited range of distances that electric vehicles can travel before needing re-charged; present electric vehicles are estimated to have a range of approximately 100-150km. Additionally, the charging process is relatively slow, and recharging a battery may require an overnight charge. Fast charging technology has the potential to reduce charging times significantly and these are currently being trialled in a number of locations, such as Japan.

Innovation will be required to overcome some of the barriers associated with high battery prices and the range of some electric vehicles, for example, to amortise the cost of the battery from the cost of the vehicle. Israel, Denmark and Hawaii have signed up with Better Place ³³, whose business model is based on a network of slow charge points supported by a number of battery swap stations to help overcome consumer anxiety over the range of vehicles. However, it is unclear whether this model would be suitable across the UK, especially given concerns over the costs, processes and safety of battery swap technology, and that Better Place is tied to a small number of specific vehicle manufacturers.

Glasgow Electric Car Pilot

Glasgow is poised to be at the forefront of the UK's electric car revolution. A Scottish consortium has been offered more than £1.8m under the UK Technology Strategy Board's Ultra Low Carbon Vehicle Demonstrator Programme ( ULCVDP) to run a pilot electric car scheme in Glasgow over the next three years. The ULCVDP was funded by the Department for Transport through the Low Carbon Vehicle Procurement Programme.
The trial will involve 40 electric vehicles produced by Allied Vehicles, Glasgow. Dundee-based Axeon Ltd will supply the batteries for the cars. Other consortium partners are ScottishPower, which will provide charging points and Strathclyde University, which will provide technical assistance. The bid was supported by Glasgow City Council, which is taking several vehicles into their fleet and supporting ScottishPower with the charging infrastructure rollout. The total project has a value of £3.8m.
Glasgow City Council is also involved in the Department for Transport's Low Carbon Vehicle Procurement Programme and will be acquiring a number of low-carbon vans for use in its fleet.

In the longer term, widespread adoption of electric vehicles could significantly increase demand for electricity. To illustrate the implications, it is estimated that, if 100% of Scottish cars were full electric vehicles, it would require an additional 5TWh of electrical energy per annum (equivalent to approximately 15% of projected Scottish demand by 2020). Furthermore, to deliver the emissions reductions per vehicle kilometre that might be hoped for, this electricity would need to come from renewables such as wind and wave.

However, in the case of both EVs and PHEVs, this extra electricity usage may not require the construction of additional capacity if vehicles are predominantly charged during off-peak hours. This could be facilitated via the implementation of an electric pricing system that is linked to levels of demand, for example, a two-tier tariff where electricity is cheaper at night than during the day, or flexible smart metering to encourage use of generating capacity at peak production periods, such as from renewable sources. Furthermore, vehicles charged during periods of low demand may also provide a market for surplus electricity that is produced from renewable sources where production can be intermittent. Despite the factors, it is still likely that, where significant local clustering occurs, some local grid reinforcement may be required.

4.5 Hydrogen

Like electricity, hydrogen also has potentially attractive properties as a fuel for vehicles. Hydrogen offers reductions in CO ₂ emissions relative to conventional petrol and diesel engines because the only significant emission is water vapour. If hydrogen is made from low carbon energy sources, very low lifecycle emissions are a possibility, although some ways of producing hydrogen ( e.g. using coal-fired electricity) have significantly higher lifecycle CO ₂ emissions than petrol or diesel.

Hydrogen powered vehicles are not currently available on the mass market. The key prototypes are models in which hydrogen is either burnt in an internal combustion engine or by generating electricity in a fuel cell.

There are many challenges to the development of hydrogen vehicles and the prospect of them becoming viable products commercially. Firstly, there continue to be difficulties in storing hydrogen in an energy dense form, which is required if it is to be used in road vehicles. Secondly, there are no natural sources of hydrogen, meaning it has to be specifically produced. At present, the process for doing this is relatively energy intensive and expensive ³⁴. Thirdly, hydrogen cars would require a major new supply infrastructure to be developed. However, the drivers for introducing this infrastructure may be subtly different for hydrogen, which is likely to be first deployed in larger commercial vehicles. Consequently, there may be an expectation that the freight logistics industry will lead the development of this infrastructure, which is very different than the consumer-led growth expected in electric cars.

Royal Mail
Royal Mail, the UK's postal delivery service, has taken delivery of three hydrogen fuelled postal vehicles, believed to be the only hydrogen fuelled postal vehicles in the world, outside of North America.
The two Ford transits (internal combustion engine conversions) will soon be on their way to Stornoway, where they will be fuelled by green hydrogen (see above). The fuel cell powered microcab vehicle will be used on Birmingham University's campus as the mail delivery vehicle and will also be fuelled by a green hydrogen source.
Royal Mail, CENEX, PostEurop and FuelCellEurope have announced that they are working together on developing a universal design specification for hydrogen fuel cell postal vans.

4.6 Uptake of low carbon technologies and fuels

As has been demonstrated, a range of low vehicle technologies could potentially assist in reducing CO ₂ emissions from road transport, assuming these benefits are locked in. Each option has its own strengths and weaknesses.

Due to major uncertainties around rates of technological development and energy prices, forecasting the future of fuels with any confidence is extremely difficult. This highlights the importance of adopting an approach that ensures flexibility remains for the market to respond to changing circumstances. However, it may be likely that, in the medium-to long-term, a range of different fuels will be in operation simultaneously. This is because:

• fully electric, plug-in hybrids, or hydrogen powered cars are still a long way from achieving significant market penetration;
• biofuels may be unlikely to represent the dominant part of a fuel mix as a result of land and other constraints;
• different fuels may suit different purposes. For example, the current range and recharging times of EVs may make them better suited to short city trips, whilst larger vehicles may be able to accommodate the larger tanks required for gaseous fuels such as hydrogen; and
• the niche availability of energy sources may make some fuels better suited to certain geographic areas. For example, areas where there is a surplus of renewable energy, including wind and hydro, might find that it is more cost-effective to convert this into hydrogen for road transport uses.

4.7 Projections

We do not have specific projections for the uptake rates of different vehicle technologies in Scotland, but the UK Committee on Climate Change ( CCC) has modelled potential UK uptake rates ³⁵ across a number of scenarios, including:

• A 'Current Ambition' scenario includes identified measures that would cost less per tonne than the forecast carbon price, and/or which are covered by policies already in place. It also includes cautious estimates of emissions reductions from these measures.
• An 'Extended Ambition' scenario incorporates more ambitious yet reasonable, assumptions on the penetration of energy efficiency improvements and a number of measures that would cost appreciably more per tonne of carbon abated than the predicted carbon price. These are seen as being important stepping stones on the path to 2050. It is broadly in line with policies that are committed to in principle, but a precise definition and implementation of policy is still required.
• A 'Stretch Ambition' scenario adds further feasible abatement opportunities for which at the moment no policy commitment is in place, including more radical new technology deployment and more significant lifestyle adjustments.

Although there are likely to be differences between uptake rates in Scotland and across the UK, these potential uptake rates are demonstrated for illustrative purposes in Table 3 below, whilst Figure 5 over the page demonstrates a potential high level road map for the UK's decarbonisation of road transport.

Table 3: UK uptake rates for different technologies in CCC scenarios in 2020

Source: CCC, 2008

Figure 5: High level technology roadmap for the UK's decarbonisation of road transport³⁶

Encouraging such market demand and successfully integrating LCVs and alternative fuels into Scotland's transport system will be dependent upon comprehensive charging and supply infrastructures being in place. Indeed, the development of charging infrastructure will need to keep pace with the developing market to ensure consumer confidence in the ability to recharge vehicles with minimal inconvenience. Within this, there will need to be standardisation of recharging systems to maximise commonality and minimise development of manufacturer specific systems. While this document does not discuss infrastructure requirements in detail, possible roles of different groups in the provision of this infrastructure are referred to later in this paper.

Following the pattern of current literature, the discussion above has focused predominantly upon 'tailpipe' emissions - i.e. emissions at the point of use of a vehicle. However, as we move towards alternative fuels in general, with lower CO ₂ emissions over their life cycle, the dominant fuel-related emissions will move from being tailpipe emissions to upstream emissions - i.e. emissions associated with the original production of energy. For information, Figure 6 below demonstrates some estimates of CO ₂ efficiency from a range of car technologies under different grid mix scenarios.

Figure 6: Car CO ₂ emissions per kilometre under different grid mix scenarios

Source: E4 tech, 2007

Questions

1. Which low carbon technologies and fuels do you envisage will be first to be influential in reducing GHG emissions from the transport sector? Why?
2. Which low carbon technologies and fuels do you believe will ultimately have the greatest emissions abatement impact? Why?
3. What timescales do you believe are feasible for the development of specific low carbon technologies and fuels? Are there any important intermediate milestones within these timescales?
4. What timescales do you believe are feasible for the uptake of specific low carbon technologies and fuels? Are there any important intermediate milestones within these timescales?
5. Are there other barriers to the development of such fuels and technologies that are not mentioned in this document? If so, what are they?
6. Are there other barriers to the uptake of such fuels and technologies that are not mentioned in this document? If so, what are they?
7. Are there any negative social impacts associated with either the development or uptake of such technologies/fuels? If so, what are they?
8. What, if any, technical challenges would the grid reinforcement upgrades be likely to present? How might these be overcome?
9. Who would fund any grid upgrades? And, how might these costs be recovered?
10. Do any of the technologies present any specific challenges or opportunities to island communities and sparsely populated rural areas in Scotland? If so, how might these challenges by addressed, and by whom?

« Previous | Contents | Next »