Technology assessment

Is diesel better than petrol at reducing carbon footprint ?

On the one hand it is well known that diesel engines have lower fuel consumption and therefore emit less CO2 per km than a gasoline car with similar specifications. On the other hand diesel engines emit more air pollutants like nitrogen oxides and soot (black carbon). Their main impacts are the formation of ozone (O3) – which is a strong greenhouse gas – through photochemical reactions caused by NOx and black carbon which has a warming impact on surface temperatures due to absorption of sunlight. So – from a climate change perspective – do the higher pollutant emissions from diesel engines outweigh the reduction in CO2 emissions due to a better fuel economy?

Recent research shows that the answer is 'No'. This is because CO2 has a much longer atmospheric residence time of hundreds of years compared to a few months (ozone) or a few days (black carbon) and therefore imposes a much longer warming effect on the planet. Moreover, many modern diesel cars are equipped with particulate filters that effectively reduce the black carbon emissions to gasoline engine levels. There are also technologies that reduce the NOx emissions down to gasoline levels and they will penetrate into the market within the next decade (latest by 2014 with the introduction of the EURO6 standard) and diesel engines will be on one level with petrol engines but with lower CO2 emissions. A very attractive alternative are hybrid cars because they achieve a similar or even higher fuel economy than diesel cars but with the low air pollutant emissions of today's petrol engines.

The Neutral Group therefore concludes that modern diesel cars with particulate filters are a viable option to reduce the climate impact of corporate company cars. Apart from diesel, hybrid cars also offer great advantages over conventional petrol cars.

A more detailed report is available by contacting us.

What's the right measurement system to drive fuel savings?

Gathering and analysing operational data is essential for the creation of performance metrics and for the on-going management of efficient transport operations. This can be aided considerably by automating most of the operational data gathering process through to use of vehicle telematic systems.

The engineering definition of 'Telematics' is the transmission of information over a long distance via a telecommunications link. Vehicle telematic systems incorporate satellite tracking with a variety of other sensors to provide information about the operation and performance of the vehicle, the driver and the condition of goods carried or some other ancillary system.

Unfortunate there is an increasingly long list of suppliers of vehicle telematic systems, each offering a wide selection of product features and services.
TNG's engineers have developed an assessment methodology, for both the client's application and the proposed telematics systems, that aid the initial selection, in-theatre trials and the subsequent fleet wide implementation of the preferred system.

A more detailed report is available by contacting us.

Engine choice - conventional or hybrid ?

The main engine configurations are conventional combustion engines, hybrids, hybrids with hub motors and ultracapacitors, full electrics, and full electrics with hub motors and ultracapacitors.

As the word 'Hybrid' suggests, this kind of engine configuration uses both an electric motor and the internal combustion engine to power the vehicle. The main advantages are the use of regenerative braking to recover a part of the kinetic energy back into the battery and the downsizing of the combustion engine while keeping the overall performance the same. There are two different types of hybrid configurations. Parallel hybrids have the electric motor do some of the work in place of the conventional engine. Series hybrids, in contrast use the combustion only to charge the battery which feeds the electric motor. The vehicle is therefore only powered by the electric motor. This has the advantage that the engine acts like a generator and can therefore be operated at constant load close to its most efficient point, enabling greater efficiency. Furthermore, a series hybrid can also drive on electric power only, for example to allow zero emissions in urban areas.

A more detailed report is available by contacting us.

How to measure and manage energy consumption effectively?

"You can't manage what you don't measure" is a useful saying to start any energy reduction programme with. Organisations need to know not just whether they are controlling and reducing energy consumption, but by how much and how quickly. With accurate and detailed information on actual energy consumption energy saving ideas and equipment programmes can be targeted and the payback on investment assessed.

Remote energy monitoring enables consumers to do this, by measuring on-site consumption and recording the data on, typically, a half hourly basis. This requirement has become standard in many industrialised countries, where the energy companies are obliged to install the necessary equipment and provide the data to the customer. Adding additional sub-meters on main equipment loads in industrial sites is also usually worthwhile to target the performance of key equipment, such as refrigeration plant or lighting systems. Energy saving measures and retrofits can then be justified and implemented on the basis of costed business cases. Site energy loads can be reduced and optimised; staff incentivised to save energy because they can see the results shown by the meters.

More frequent electricity data sampling also enables the identification of electrical supply issues such as voltage over-supply, or harmonics caused by on-site equipment. Correction of these types of common problems alone can reduce overall site electricity consumption by as much as 6 to 12%.

A more detailed report is available by contacting us.

Warehouse air handling

Destratification is the solution to eliminate stratified layers of air inside a warehouse. Stratification is the consequence of warm air rising to the top of a warehouse where it is 'trapped' because warm air is lighter than cold air. Air handling systems can effectively eliminate destratification by directing (hot) air down to floor level. Estimated heating benefit is in the range of 10%. Retrofitting destratification can have a long payback. However, past projects indicate potential for new builds.

Solar walls can reduce the gas heating demand by collecting solar heat. A sun-absorbing all-metal cladding creates a small space between the (south-facing) facade and the building. Outside air is drawn in through tiny holes by ventilation fans located at the top of the wall. Warmed by the solar panels, the trapped air rises to a plenum (duct) at the top of the wall; from there it is routed to the nearest dedicated ventilation fan – or into the building's HVAC system. Savings of over 10% of heating requirements have been independently verified for a 3 month period from April to June. However, the efficacy of solar walls depend on the solar irradiation which is weakest in Winter when heating demand is the highest. The benefits from solar walls are generally greatest during the spring and autumn months when there is a substantial heating demand while the solar irradiation is still strong enough to provide effective heating.

A more detailed report is available by contacting us.

Lighting – simple and taken for granted

Installing the right type of lighting in a facility might on the face of it seem a straightforward enough decision. But improvements in technology over recent years have created a wide range of lighting types, which differ greatly in up-front costs, electricity consumption, through life performance and level of automatic control. Yet many new build facilities are equipped with basic old-technology lighting which typically consumes twice the power of new systems. Manual control of lighting over large areas of buildings can often leave some areas unnecessarily lit, while traffic and operational blackspots remain dangerously dark.

Much debate continues about the relevant merits of new LED based lighting systems against the latest T5 or T8 standard fluorescent bulbs. The requirement to operate lighting in extremely cold or hot conditions further complicates this, while it is essential to take into account the design of the light fitting itself and its control mechanism.

A more detailed report is available by contacting us.