Final empowering step

Today I had something very exciting (to me) happen: My hot water production is now 100% off-grid. Today the installers put in a special device that prioritises my solar electricity for the electric hot water cylinder. Those cylinders use up to around 40% of the power consumed in a typical house, in part because it switches on multiple times during the day.

My new system heats the water only when I’m generating electricity, which means I’ll buy far less power at night (lights, heating/cooling, TV, those sorts of things). Because I get moving fairly late each day (by “normal” standards…), by the time I use the shower the solar power has come online and the system will have heated the water. However, if I start having showers much earlier, or there are other people staying here, then I can set it to use power from the grid to heat the water before the sun is up to assure the hot water’s ready to go. In the summer, when the sun rises earlier (and there’s less rain), this won’t be an issue.

Overall, this should save me more money than I’d save otherwise, and it also means my hot water generation is 100% sustainable and green, however, the system I chose can also be fitted to do the same for a plug-in electric car, which would make my transport clean and green, too. If I end up doing that.

There are more efficient ways to heat water than a traditional electric cylinder like I have, but since at least three quarters of New Zealand’s power generation come from clean energy (chiefly hydro and geothermal—though some say it's 85%), an electric system is more environmentally-friendly than gas. Electric heat-pump hot water heaters are now available, and I’ve seen some heat-transfer systems promoted, too (the latter uses the heat in a house’s attic space to heat the water, so it’s less expensive than pure electricity, but I’m sure it’s not as efficient as a heat-pump water heater would be).

My hot water heater is only around 18 months old, so I couldn’t justify replacing it right now. In a few years, though, as technology advances, the savings may well justify the cost of switching before the lifespan of the current heater is up.

In the next few years, New Zealand will probably ban new residential natural gas connections as part of the country’s moves to dramatically cut greenhouse gas emissions. As it happens, though, the gas fields off New Zealand’s coast are running low, too, which means we’d need to import natural gas or LPG (what Americans call propane).

To deal with all that, the industry plans to introduce a mix with up to 25% hydrogen gas because most current gas appliances can use up to that level mix without being changed. Over time, dual-fuel appliances will be available, and then, eventually, hydrogen-only, probably by the time current gas appliances reach the end of their usable life. By that time there will also be a nationwide network of hydrogen refuelling places for hydrogen-powered cars. The attraction of this is that we can never run out (hydrogen is the most abundant element in the universe, and no one country or region can ever control supply), and also that when it’s burned the byproduct is water, so it’s clean. I’m watching these developments intently, but for my current situation, none of that matters because my current electric hot water cylinder is too new to replace with anything.

So, that’s my solar power system completed. I honestly have no idea how much money I’ll end up saving, but with my hot water heating now 100% off-grid, it should be significant. I’m really excited about all this, and Nigel would be, too. We really were a perfect match.

This is a revised and expanded version of something I posted to my personal Facebook earlier today.