Want a solar powered house? Try this house for your solar power. Econet’s Powerhouse is one of the most interesting pieces of kit on display at AfricaCom in Cape Town this week, because it appears to take most of the pain out of going off grid.
There are two things which put people off putting solar panels on their roofs and making use of the free energy blasted at us every day by that great big ball of fire in the sky. The first is cost – solar power is effectively free, but the up front cost of equipment is a big price to pay – and the second is complexity.
Both of these issues are exacerbated by a very local problem. Unlike other countries, there’s no way to sell surplus solar back into the national grid in South Africa.
In the UK – for example – you fit a couple of panels to your roof and connect them to your mains box. When there’s no sun, you run off of mains. When the sun is shining you get paid for any excess power generated and fed back into the grid. This means installation is relatively cheap and your panels can earn their keep, repaying your investment quite quickly.
In South Africa, however, you can’t connect panels into the grid network. Since peak energy production is the middle of the day – exactly when there’s no-one home using electricity – this means that the only way to make a solar installation cost effective is to store excess energy locally and use it yourself when the panels are off. That means that on top of the cost of the panels and inverter circuits, you need to buy expensive batteries and – in most cases – build an extension to your house to store them in.
Econet’s Powerhouse is a straightforward way around that. It’s a metal cabinet that comes ready fitted with everything you need for domestic solar power. Weighing in at 1.2 tonnes, it can take up to 24 300W panels on its roof and 16 batteries inside. Econet reckons that if you switch to gas stove and a separate solar geyser too, it’s enough to go permanently off-grid.
As if that wasn’t enough, the Powerhouse also has a built-in WiFi hotspot and ZigBee home automation controller. Thanks to these, Econent has developed a funky mobile app that tells you exactly how much power each plug and light in your house is drawing and how long you have left on battery power. You can use it to remote control all appliances over the internet.
The Powerhouse isn’t available in South Africa yet, but is popular in Zimbabwe among Econet’s nine million mobile subscribers. Partly this is because there are some interesting financing models for the kit, which include using the same home monitoring system to vary a loan rate according to use, rather than straight interest terms.
The cash price alone is pretty impressive though. With everything but installation, the Powerhouse is expected to cost between R180 000 and R200 000. That should work out to an eight-to-nine year pay-back time, assuming no more increases in electricity prices from Eskom. Which, of course, there will be.