It is estimated that public transport (bus, rail, taxi) accounts for a little over 1% of Ireland's overall non-ETS carbon emissions, and less that one-twentieth of the emissions from the transport sector. Accordingly, converting our public transport fleets to lower-carbon alternatives will have a limited, though positive, impact on reducing national CO2 emissions. That said, I am convinced that moving to low-emission alternatives for public transport is important so as to promote and normalise the use of non-conventional lower emitting fuels and technologies to the general public. So, in order to show leadership in this area, we have a comprehensive programme of work underway to reduce the sector's carbon footprint.
Also, improving public and active transport services and infrastructure is a key priority if Ireland is to cater in an environmentally sustainable way, for increasing travel demand and to provide a meaningful alternative to the private car. Under Project Ireland 2040, €8.6 billion in investment has been committed to public and active transport. Major sustainable transport projects planned include the BusConnects Programme, investment in the DART Expansion Programme, and the MetroLink, as well as a multi-annual urban cycling and walking infrastructure investment of over €110 million in our main cities.
It is clear that prioritising investment in our public transport network is working - during the reporting period of 2017 alone, an additional 16 million public transport passenger journeys were made in Ireland while the number of walking and cycling trips also increased dramatically, particularly within the Greater Dublin Area. To ensure that the carbon footprint of this significant modal shift is minimised it is critical that our public transport fleets continue to improve in energy and emission efficiencies.
In the urban bus fleet, a clear trajectory to low emission buses has been outlined. We are committed in Project Ireland 2040 to no longer purchase diesel-only buses for the urban public bus fleet from this July. In preparation for both this immediate transition and the development of a longer-term low-carbon bus procurement strategy, my Department, together with the National Transport Authority, Dublin Bus and Bus Éireann, has undertaken a comprehensive series of low-emission bus trials which are expected to conclude in the coming weeks. Under the BusConnects Programme it is expected that approximately half of the public urban bus fleet will have moved to lower emitting alternatives by 2023 with full conversion by 2030.
It is equally important to consider the potential contribution of electrified rail to the decarbonisation objective. An estimated €2 billion is earmarked for investment in the DART Expansion Programme which will create a full metropolitan area DART network for Dublin and high-frequency electrified services to Drogheda, Celbridge/Hazelhatch, Maynooth and M3 Parkway, as well as new interchange stations with bus, LUAS and Metro networks. We also expect to accept delivery of our first new diesel-electric trains in 2022, which will enable the enlargement of the rail fleet by approximately some 300 new rail carriages. These major rail projects will help supplement the range of viable low carbon alternatives to private passenger car travel and positively impact our sectoral emissions profile.
In relation to the taxi, hackney and limousine sector, it is clear that electrification presents an achievable pathway towards decarbonisation. To this end, I established the Electric Small Public Service Vehicle Grant Scheme in 2018, providing purchase reliefs of up to €7,000 for battery electric vehicles and up to €3,500 for plug-in hybrid electric vehicles, in addition to the range of other incentives supporting electric vehicles. I have allocated €500,000 from my Department's Green Public Transport Fund in support of this initiative further into 2019.
I have, of course, met with Minister Bruton to discuss decarbonising the transport sector as we work to prepare the forthcoming new All-of-Government Plan to Tackle Climate Disruption.