Although there is some pressure to change from gas to electric from community expectation, the discharge of CO2 from domestic gas consumption is low.
New Zealand has several capped gas wells that will keep gas going for a long time unless the government prohibits it. In the future, biogas may take over from natural gas. The main ingredient of biogas is methane, the same as natural gas. It is generated from growing things instead of extracting it from underground.
If you want to move from gas, and use a lot of hot water; then you should upgrade to a large storage tank.
There are better ways to heat tanks. Heat pump water heaters have become cheaper over the years and have similar savings to solar and gas. We have installed a lot of them and customers do not connect the immersion element in them relying on the heat pump only. They are very reliable. Some models can take heat from ceiling spaces to improve efficiency and have time clocks to limit heating times to warmer parts of the day and noise at night.
Solar panel system is still viable and again has dropped in price. Some have installed electric solar panels and use the excess power to heat water. Solar hot water panels are a cheaper way to heat water and take up a lot less roof area.
Replacing gas cooktops is not so easy. Converting to a 9kg LPG bottle is the short-term solution until that stops. After that, induction tops are good, but they need a large cable to generate all that heat. For many running a larger cable to the fuse board may be required where you currently have a 3pin plug.
Some of these solutions are time-consuming to put into place so it pays to plan. Solutions using solar and batteries can take months to years to put into place often forcing building owners to take a short-term solution when their current water heating solution fails.
On the home heating front, gas is still an option for a long time, but in the distant future, it will be high levels of insulation to limit the heating requirement, heat pumps, and wood fires if they are still permitted.