Nowadays many houses are being equipped with solar panels. They generate energy “for free”. Maybe not entirely for free because you need to buy, install, maintain and depreciate them, but once you get them working you have less worries about the electricity bill.
There are two problems with solar panels: they look ugly, and they produce electricity when you don’t need it.
Let’s start with the looks
Solar panels can be ugly.
The picture needs little explanation.
We think this isn’t necessary. Also: why first build a roof and then cover it again? Sounds like over-doing it. Better use the solar panels themselves as the roof cover. And why not make the entire roof from solar panels? If you pay a little attention to detail we think it looks very sleek. This is what you could do.
Building a house with a full electric roof has a few challenges though. The most obvious one: what are you going to do with all that electricity? Because a full solar roof produces too much electricity at the wrong time and it will be difficult to consume all that energy in dish washers, washing machines, let alone lighting. So we need to either push the electricity back into the net, or store it locally and use it later to heat the house.
Push back, or store?
Pushing it back into the net is not very cost-effective. First you buy expensive panels for electricity that you can’t use so you push it into the net. Then when you really need electricity you have to buy it from the net at almost double the price. Sounds like a bad deal? It is a bad deal!
Storing electricity locally in batteries is expensive. The battery-pack in a Tesla costs approximately 30.000 US$ for 85 kWh so that is 350 US$/kWh, and with 85 kWh you can heat an average house for a few hours at most. After a few cold and rainy days you will run short on electricity, and you will have to buy electricity back from the grid, at double the price for which you pushed it into the grid. A Tesla Power Wall costs the same: Tesla advertises the 10 kWh Power Wall 3.500 US$, so still 350 US$/kWh. Not good. Prices will come down, but for the moment you can not economically store all your electricity in battery packs.
Energy flow model
This is just a start. The exact model would have to be calculated for each individual house and situation. Also: this will not allow you to live “off the grid”: you will still need to get electricity from the grid for the peak-shaving. But we are sure: the decreasing cost of solar panels and of energy storage will seriously change the way we generate and store energy in the coming years.