Oil and gas supplier Woodside will invest $7 billion in low carbon energy by 2030 while still benefiting from a recently-announced merger with BHP's petroleum business.

Chief executive Meg O'Neill on Wednesday told investors that while she expected liquefied natural gas would remain an important energy source for decades, Woodside should support customers' efforts to lower carbon production.

Ms O'Neill did not say where the $7 billion will be spent but did rule out some categories.

Solar and wind projects had low setup costs, hotly contested markets, and would not be pursued.

Woodside is interested in developing ammonia and liquid hydrogen, which requires the technical skills of its workforce.

The company's main export, liquefied natural gas, is gas which must be cooled to take liquid form. Liquid hydrogen also requires cooling.

The company has four projects planned in Australia and the US to provide cleaner energy.

These include producing hydrogen and ammonia from the Kwinana industrial site, south of Perth. Another project in the Bell Bay area of Tasmania would use hydropower and wind to produce hydrogen and ammonia.

The first of these projects is expected to be running by the mid-2020s.

Woodside anticipates lesser returns and longer time frames for low carbon energy projects than oil and gas ones.

The energy projects would provide a return of more than 10 per cent within 10 years, according to the capital allocation framework.

This compared to returns of more than 12 and 15 per cent, and shorter time frames, for oil and gas.

However these shorter time frames are being partly driven by the shift towards cleaner fuels.

Ms O'Neill said the Scarborough natural gas resource off the West Australian coast was discovered about 40 years ago. Woodside could not wait decades to take advantage of similar opportunities given the pace of change in the energy industry, she said.

Environmental groups have criticised Woodside for taking on BHP's petroleum business and proceeding with the Scarborough gas project.

The proposed merger still needs shareholder and other approvals. It is due for completion in the second quarter of next year.

Woodside claims it will still achieve net zero direct emissions by 2050.