The deal includes the purchase of Lotus Energy Systems, including all of its existing contracts, assets and staff.
It is part of a previously announced €650m group pipeline investment, the buyer said. Financial terms of the transaction were not disclosed.
The newly expanded operation will create an additional 50 jobs in the next five years. It is expected to contribute €5m in revenue.
Optinergy offers specialised O&M services for the wind industry, both in Ireland and throughout Europe, it is part of Galetech Energy Developments Group.
Optinergy managing director Aiden Watters said: “We are delighted to announce this important acquisition. This expansion further enhances Optinergy’s position as the largest independent O&M provider in Ireland.
“The Lotus Energy Systems team have developed an excellent business with a very strong focus customer service. We look forward to working with them to build a force in the Irish wind industry."
Watters continued: "The jobs which we are announcing today are mainly for engineers and advanced trades people. To date, this work has often been carried out by international companies, coming to Ireland on a project by project basis.
“We are delighted to be building a business which can provide jobs locally, across Ireland, and can compete in an international market.“
Optienergy has worked with several big players in the wind industry including Brookfield, Bord Na Mona, Wind NI and many leading independently-owned wind farms and utilities.
At present, there are about 228 wind farms in Ireland which generate about 3000MW of onshore wind power and it is expected to add another 1550MW of projects due to be delivered in Ireland under REFIT 2.
