The appointment of Mr Maycock, who is also a former chief executive of CSR and who began his career with Shell Oil in Britain as an engineer, follows the resignation last August of the former incumbent Kerry Schott after she was named as the energy regulatory supremo.
Mr Maycock, who is also a part chairman of Arrium, will replace interim chairwoman Julie Stanley. Rick Francis, managing director of TransGrid shareholder Spark Infrastructure, will remain as deputy.
Dr Schott resigned from TransGrid in August to take up the position of independent chairwoman of the Energy Security Board, a new regulator set up by the federal government on the recommendation of the Finkel Review into energy security. She has since taken a lead role in drawing up the government's latest proposed energy policy, the National Energy Guarantee.
Mr Maycock said he was delighted to join TransGrid as chairman "at this time of extraordinary industry change and exciting growth for the business".
"As we look to a lower carbon future and a greater role for large scale renewable energy, we will see a number of significant energy market reforms advanced," he said.
"TransGrid is well placed to support that reform to deliver lower cost energy to households and businesses through its extensive knowledge and experience in building and maintaining a reliable high voltage network, which will be critical for supporting large-scale renewable energy developments."
Growing outside regulated sector
TransGrid was privatised by the NSW government in 2015, acquired under a 99-year lease for $10.3 billion by a consortium headed by Hastings Funds Management and including Canadian and Middle East funds, as well as Spark. It has been expanding in wind and solar farm connections and studying opportunities in telecommunications as it grows its business outside the regulated sector.
The regulated networks are facing several uncertainties, including the impact of the abolition of the Limited Merits Review, which has effectively removed the option of appealing regulatory rulings on tariffs.
However, that impact is "manageable", Moody's said in its outlook for the sector for 2018, adding that it "should not detract from the transparent and predictable nature of the regulatory framework".
Mr Maycock's track record has been focused on competitive businesses, sitting on the board at AGL for 11 years, including seven as chairman. His experience at AGL was highlighted by Mr Francis as he pointed to TransGrid's work to become "a customer-focused, innovative and efficient electricity transmission business".
The change in chairman comes as grid owners continue to face criticism about overinvesting in networks, contributing to increases in power prices for consumers. TransGrid is among those that have argued for further investment in power lines and gas pipelines to help distribute energy more evenly between states and ultimately bring down prices.
In its recent application to the Australian Energy Regulator it proposed to reduce the cost of services for NSW and ACT energy consumers by 3.9 per cent on average over the next five years. A final decision on the tariff settings for 2018-23 is due in April.
Mr Maycock is also chairman of Port of Brisbane Pty and a director of charity The Smith Family. He retired as AGL chairman after the annual shareholders meeting in September.