With governments around the world declaring hydrogen to be central to the future, an Australian firm is developing the first domestic hydrogen products.

The cost of NSW's biggest dam project could blow out to $2.1 billion, or more than triple the original estimate, delivering what is likely to be the most expensive water in the Murray-Darling Basin.

In an open letter to the Berejiklian government, the association says TransGrid should have detailed other options in its EIS to the building of two giant overhead transmission lines.

The Bureau of Meteorology is forecasting a severe heatwave to set in over Friday to Sunday with extreme conditions expected in some areas along the NSW coast.

Hundreds of forestry jobs are at "imminent" risk because of the lack of available timber following last summer's bushfires, the state-owned logging company warned in a letter to the environmental watchdog.