The National Transport Authority has announced it's ordered 120 fully electric double-deck buses.
Most of the vehicles will be used by Dublin Bus while the rest will be operated by Bus Éireann in Limerick.
It's part of plans to order up to 800 electric buses over the next five years.
Anne Graham, CEO of the National Transport Authority, says it's an historic day:
"The bus may look the same , but from the point of view of our carbon admission targets it's an extremely important day. It will be the first 100% zero emission bus that will be on the streets of Dublin, and our cities. It's the start of our move towards zero emissions across our entire transport fleet".
Stephen Kent, Chief Executive of Bus Éireann, says they're cleaner and quieter:
"It's better for the environment and it's quieter ride for passengers. And from our prospective, in terms of consuming energy we're continuing to reduce our carbon footprint. So it's very good from all those points of view".