Pollutant emissions from non-road mobile machinery (NRMM) significantly contribute to air pollution by emitting carbon oxide (CO), hydrocarbons (HC), nitrogen oxides (NOx), and particulate matter. NRMM is defined as any mobile machine, item of transportable industrial equipment or vehicle that is not intended for carrying passengers or goods on the road and is installed with a combustion engine. This covers a wide spectrum of different machinery including; small gardening and handheld equipment, larger agricultural and farming machinery, locomotives, inland waterway vessels, generators … and of course, construction machinery. There are a large number of factors affecting the exhaust emissions of construction equipment, many are difficult to measure and quantify their degree of impact on the rate of emissions. However, overall the factors can be categorized into four groups; equipment type and condition; equipment maintenance; operating conditions and equipment operations.
Equipment Type and Condition
The rates of exhaust emissions from construction equipment are mainly determined by engine year of manufacture, engine model, engine size and horsepower. Different equipment manufacturers or makes can also contribute to variations in equipment emission due to their difference in engine design, automatic control system, and configurations. Engines of newer generations (for example, Tier 4 Final engines) can have significant reductions in emission rates and fuel consumption. Equipment deteriorates with the equipment’s age and usage i.e. amount of hours worked. The equipment condition is also dependent on maintenance quality, daily care, and operation history. Equipment in good condition is more fuel efficient with lower emissions in operations. Use of high quality diesel can help to extend equipment life and reduce emissions.
Good maintenance strategy of the equipment keeps the equipment in good working condition with efficient use of fuel in delivering output power. Both routine maintenance (changing of oil, grease, filters, clean-up etc.) and major maintenance such as engine overhaul should be properly scheduled and implemented. There is already a consensus that delayed maintenance or run-to-failure maintenance is a poor maintenance strategy which can lead to higher equipment repair costs, resulting in higher rate of fuel consumption as well as high emissions due to clogged air flow and insufficient burning of engine fuel. Any faults in the engine, if not diagnosed and repaired immediately, can cause underperformance of equipment and increase the amount of exhaust emissions. Timely replacement of worn ground-engagements such as tyres/tracks is important to reduce emissions from unproductive job activities.
Off-road construction equipment is deployed for construction activities such as digging, loading, hauling, backfilling, compaction, lifting etc. Different job activities have different work conditions and requirements, which influence the time the equipment is working in different load conditions and engine status. The fuel consumption and emissions of equipment inevitably increase in tough working conditions involving hills and slopes on jobsites, or medium to hard underground or ground soil conditions. The amounts of fuel consumptions or emissions can increase up to 2-4 times for heavy duty works, as compared with light duty applications for the same equipment. Equipment operating in severe weather such as cold winter consumes more fuel with more emissions due to engine performance issues and longer time in engine start-up and warmup to reach efficient working conditions.
Equipment should be properly selected for a specific job. If the equipment overmatches the site conditions and tasks or overloads, more fuel is burned with more emissions, in addition to higher equipment cost. Idling time and operational skills are critical for equipment emissions. Skilled and experienced operators can reasonably minimize idling time by reducing such interruptions as miscommunications, poor understanding of work tasks, and poor coordination with others. Skilled equipment operators consume less fuel per operating hour compared with less experienced and poorly skilled operators as skilled operators take good care of equipment, identify equipment problems in a timely manner, reduce idle time, follow correct working procedures, and operate equipment in the smartest and most cost-efficiency way.
Emissions from NRMM engines are regulated by Regulation (EU) 2016/1628 (NRMM Regulation). The NRMM Regulation defines emission limits for NRMM engines for different power ranges and applications. It also lays down the procedures engine manufacturers have to follow in order to obtain type-approval of their engines – which is a prerequisite for placing their engines on the EU market. The impact of the new NRMM Regulations is both good for business and good for the environment by; protecting people’s health; protecting the environment and improvement in air quality; ensuring the good functioning of the internal market for NRMM engines avoiding market distortions and market fragmentation (ensures a level playing field on global markets) and avoids unfair competition from non-compliant low-cost products. Engines sold today are approximately 95% lower in emission limits than Tier 1 limits introduced in the mid-1990’s.
Alternative Fuels and Technologies
Cost and the profitability for machine users will be the deciding factor in determining the success of a mainstream alternative for fuel and technologies. The alternative fuels and the necessary powertrain concepts are not yet available for practical application, and many are still under various stages of development. The most important for future fuel potential are; raw material, energy efficiency, production technology, technical maturity or stage of development. Rapeseed oil fuel and biodiesel were considered as best alternatives to diesel fuel in agriculture and forestry; least advantageous was electrical drive with hydrogen fuel cells. There is a limited demand for retrofitting of non-road mobile machinery to ethanol which are not compatible with current fuel injection systems. Natural gas provides an interesting opportunity, as creation of the infrastructure offers potential to switch to bio-methane in the future. Dual fuel has potential but is not yet fully mature, and a conversion to dual fuel (methane and diesel) is better suited for new machines than existing ones.
Large infrastructure projects rely on non-road mobile machinery equipment for construction. However, construction equipment emissions are a major concern to the environment and human health, especially in densely populated areas. The degree of impact of equipment emissions can vary with different projects, different equipment types and different operations. The main strategy in the short term to control emission levels is the NRMM Regulations which has had a significant impact over the last two decades. However, we are still some way from the widespread use of alternative fuels and technologies.
At AE Faulks, we’re committed to minimising our potential impact on the environment. We operate in compliance with all relevant environmental legislation and strive to use pollution prevention and environmental best practices in everything we do. We provide a variety of operated and self-drive construction equipment throughout the heart of the Midlands in England. So, if you’re looking for plant hire in Nottingham, plant hire in Leicester, plant hire in Derby or plant hire in Birmingham, or any of the other areas we cover, please do not hesitate to contact us today.