If you have a suitable north facing roof it suits solar with electric booster. Or there's the relatively new electric heat pump hot water systems. We were told a few years ago when shopping for a replacement HWS they weren't the most efficient choice for our climate so we went with solar, which years earlier had also been described as not the most efficient choice for our climate. I suppose it's because the technology is always improving. Heat pumps are quite common here now and I believe there are government rebates available to encourage their installation rather than gas which is on the way out.

Thanks @macyjean, I did contact a company before but they do not recommend heat pumps for more than 3 people. Would like to know if anyone here has one and what their thoughts are for bigger families?

This year we replaced a gas storage system with a heat pump. We have an istore 270L that utilises the power that our PV solar generates... family of 5, including 3 teenagers. We are central Australia with a tonne of sunshine, but our desert winters can get down to minus degrees overnight. So far so good... super happy with our investment & have never run out of hot water, even on chilly winter mornings 5 showers in a row!

Thanks @rynmuir do you mind sharing which heat pump are you using?

It’s an istore 270L installed by local crew, but sourced from istore.net.au
All the info is on their site. Might be worth giving them a call & having a chat too. We did & they were helpful answering our questions. They are super efficient hot water heaters. The actual unit itself is pretty sizeable though- nearly 2m tall.

Thanks @rynmuir after your recommendation we got in contact with istore, so far sounds very promising !