ABSTRACT:
One key objective for vehicle manufacturers is to develop technology and infrastructure to facilitate the progression from combustion to conversion by the year 2050. In the short to medium term however, the combustion of fossil fuels such as petrol and diesel, coupled with advanced transmission innovations and emission control technology that are governed by strict Euro VI regulations appears to be the main path forward for the transport sector and the environment.
This paper presents the feasibility of utilising the developing compressed natural gas network capabilities as part of a systematic approach to establishing the necessary groundwork for a hydrogen based transport economy. Results of tests conducted by Dublin Institute of Technology to evaluate natural gas engine performance and exhaust emissions compared with conventional fossil fuelled engines were examined.
The paper also outlines Gas Networks Ireland’s vision for the future of transport and the use of compressed natural gas as a fuel alternative for the transport sector. The barriers to implementing a strategic plan for gas fuel for the transport sector are also reviewed.
This includes the public’s perception of gas as a transport fuel, on-board storage of gas, related weight and extreme pressure issues, range limitations, dual fuel operation, gas quality and the necessary fuelling infrastructure. By resolving some of these problems, the transition to a hydrogen based economy for transportation purposes may provefeasible by 2050.
SNIPPETS:
Rational:
Although highlights the contribution that electric vehicle technology may offer to fleet managers, this paper studies the benefits of promoting the use of Natural Gas Vehicles (NGV’s) as part of the passenger and heavy commercial transport fleet. From 2020, fuel cell technology utilising hydrogen gas has the potential to drive the transport sector forward.
Problems facing the Carbon Economy:
The internal combustion engine currently serves the transport sector worldwide. However the consequences of the combustion process regardless of the restriction being imposed on vehicle manufacturers and operators by the various Euro regulations from I to VI are now based on the growing volume of vehicles on the roads globally impacting on the planet.
This has highlighted the need for radical change in how people and goods are transported for the future. Converting energy as opposed to combustion offers a realistic solution, with hydrogen gas being converted as part of an electro chemical reaction into electrical energy.
Environmental Impact:
The combustion of hydrocarbon fossil fuels by a vehicle produces harmful exhaust gas contaminates that enter the environment. Petrol engines are referred to as spark ignition engines as they use a spark plug to initiate combustion.
Diesel engines are compression ignition engines utilises the ignitability of the fuel at high pressure to induce auto ignition in the fuel.The exhaust gas emissions for carbon based fuels, as listed in 1.3.1 are dependent on the composition of the fuel and the conditions under which it reacts with oxygen.
By-products of Petrol/Diesel Combustion:
- Carbon Monoxide (CO)
- Carbon Dioxide (CO2)
- Hydrocarbons (HC)
- Oxides of Nitrogen (NOx)
- Particulate matter (Soot)
- Sulphur (S)
Utilising Compressed Natural gas and Hydrogen:
With reference to the generation of electricity, Vincent Lagendijk and Geert Verbong
2012 outline the carbon based fuel energy transition process through history from
wood to coal, coal to oil and from oil to natural gas. A natural progression suggests that the future transport fuel being hydrogen. This is based on the fact that if one examines the composition of each of the fuels such as wood, coal, oil etc., the percentage of carbon reduces and the percentage of hydrogen, the main energy carrier
increases.
Types of Natural Gas Vehicles:
To facilitate a perceived lack of infrastructure and range anxiety for customers which
is a main barrier to commercialization, natural gas vehicles come in three types:
- Dedicated engine technology using 100% natural gas
- Duel fuel; operates on natural gas but using diesel injection for ignition and as a reserve fuel.
- Bi-Fuel; operates on natural gas while retaining the ability to use petrol as a reserve fuel.
Conversion as opposed to Combustion:
Hydrogen can be used in two ways to power a vehicle. Hydrogen as previously documented in the energy road map utilising fuel cell technology can also provide electrical power to drive a road vehicle.
The road map shows that the automotive industry has been researching fuel cell technology and introduced demonstrators into the market worldwide in an effort to achieve commercialisation by 2020 and full implementation by 2050. One of the main barriers to the changeover to a hydrogen economy is the establishment of an adequate hydrogen infrastructure to move this project forward past 2020.
Case Study:
Gas Networks Ireland owns, operates, develops and maintains the natural gas transmission and distribution infrastructure network in Ireland. Gas Networks Ireland
operates a world-class modern gas network through the flow of gas from entry points
with Scotland and the Corrib entry point in Mayo. The current gas network in Ireland
is made up of over 13,685km of pipeline, including 2,467km of transmission network,
11,218km of distribution network, and 398km of subsea interconnectors.
Future Vision:
In order to provide full national coverage, GNI is proposing to develop a 70 – station
CNG fuelling network, co-located in existing forecourts, on major routes or close
to urban centres to satisfy the requirements of the Alternative Fuels Directive
and to provide a comprehensive refuelling station network. This would allow a
transition to both natural gas and renewable gas as an alternative fuel.
Proposed Locations of Public CNG Refuelling Stations.
Testing of a Bi-Fuel Vehicle:
As part of this research,testing of a 3500kg, 1.8 litres Mercedes Sprinter bi-fuel
vehicle (CNG/Petrol) was conductedin the Advanced Vehicle Test Laboratory in Dublin
Institute of Technology (DIT). The test results allow for an evaluation to be made
of the vehicle driving in gas and petrol modes.
CONCLUSIONS AND FUTURE RESEARCH
The damaging impact of the continued combustion of hydrocarbon fuels is becoming
more and more evident with increased greenhouse gas levels, especially CO2 resulting
in global warming.
Moving away from a low carbon economy by 2050 involving some form of limited combustion as outlined in the White Paper and progressing to a hydrogen economy utilising conversion in the form of fuel cell technology as proposed by this paper has merit. Views and opinions on this topic are very strong an having consulted with various stakeholders who hold different opinions, there is an acceptance that more research needs to be conducted into the transition to a hydrogen economy.
Timing is critical and more direction at EU/Global level needs to be applied
to establishing a definitive pathway forward. The incentivised encouragement by
the government/EU and use of gas in a transport context will require a behavioural
shift on behalf of the public and this will require a process of education and
acclimatisation to eliminate the public perception and fear of gas as a dangerous fuel.
If the concept of utilising the existing pipe network to accommodate hydrogen transmission were to be pursued then future research is required to establish the requirements of such an arrangement. Research would also need to be conducted into the compatibility of various components, materials and structures that form part of a system.
Source: Dublin Institute of Technology
Authors: James Brunton | John Howlett | David Kennedy