"We have four or five ready to go in Australia and they're all very big projects," said chief executive Vince Hawksworth.
"You need many options because when you are developing projects you don't know which one will be the most attractive to the people who are going to buy the output," he said.
The wind farm project process is complex, and involves researching wind resources, engaging local landowners over leasing wind turbine sites, as well as local and state authorities on development rights, and identifying development partners and output buyers.
"You don't know the outcome until after you begin the process," said Mr Hawksworth.
"Strategy is all about developing choices about the things you will and won't do.
"And once you've decided what you are going to do, it's about making good choices on the actual project development."
Peter Calderwood, Trustpower's general manager strategy and growth, echoed that theme, noting that there were too many variables to predict exactly what would happen during the planning and development process.
"You need to develop options and create a pipeline of potential projects," said Mr Calderwood, who added a key part of the process was developing relationships with potential buyers for the generated power.
Origin Energy takes the current output from the Snowtown Wind Farm on a fixed rate basis. Trustpower worked with turbine suppliers Suzlon on stage one and Siemens on the just completed stage two.
Trustpower was not yet at the stage of confirming a development partner for any of the current project options, he said.
Another major factor, and one Trustpower learned a lot about during its decade-plus involvement with Snowtown, was the need to develop a good relationship early on with landowners and the local communities, said Mr Calderwood and other Trustpower executives.
Mr Calderwood said Trustpower's Australia policy had been driven by the fact that under the RET, local power retailers were required to provide generating company certificates to the regulators demonstrating the extent of their commitment to meeting the scheme's targets.
Geoff Swier, an Australia-based Trustpower director, said the regulatory environment was complex because while energy had always been a state responsibility, there was now a national grid and the states had to co-operate with the federal government.
Some right-wing elements in Mr Abbott's coalition Government tended to oppose the RET scheme, but the environment minister was supportive, said Mr Swier.
"Opponents would need to get support for a change in legislation through the Senate [upper house]," he said, and that seemed unlikely at present. "At the moment, the politics doesn't affect what we are doing."
Andrew Harvey-Green, a senior equity analyst with Forsyth Barr, said he saw Trustpower's investment in Australia having more potential if the politicians in Australia made decisions that were favourable for building further wind farms over there.
"My reading is that they are unlikely to rescind the current policies," he said.
Trustpower chairman Bruce Harker told the Bay of Plenty Times the company was in Australia because it had deep competencies in wind power.
"We don't think of Australia as a different place because we have been here for a long time," said Mr Harker.
"We see Australia as part of the same sphere as our other operations.
"We monitor and schedule the Snowtown turbines from Tauranga and we treat them as part of our overall business in terms of operations and management, but we bring revenues back to New Zealand."
Mr Harker said the company had done some creative thinking about other potential overseas markets with acceptable country risks where it could operate in a similar way.
Possibilities included Chile and Uruguay, said Mr Harker, but he stressed that any such moves were at a very early stage and there was no time frame envisaged. The current priority was to continue developing in Australia, he said.
-Trustpower met the cost of David Porter's trip to Snowtown.
