Before we moved, Farmer Bob and I decided that one of the first things we wanted to do on the farm was to switch to solar power. Solar is appealing to each of us for different reasons – I like the idea of using a more sustainable source of energy, treading more lightly on the Earth and being self sufficient. Farmer Bob, on the other hand is preparing for the Zombie Apocalypse (he’s only half kidding) and likes the idea of being self sufficient. In any case, solar energy was a priority.
If you’re prepared for zombies, you’re prepared for most things. Farmer Bob
We started researching options before we left the city. One of the biggest questions that came up was “Do we want to have a grid connected, off-grid or hybrid system?”This question was quickly followed by “What size system do we need?” I’ll get to the second question in another post. We opted for a 5 kilowatt system, the largest we could have and still be grid connected.
First questions first. A grid connected system is one where the solar panels are connected into the electrical grid. The power your solar panels generate either goes directly to the grid or the passes through your home with the excess feeding into the grid. Your electricity provider is government mandated to purchase the power from you (for now). In our case, the buyback rate is 7cents per kilowatt hour.
When the sun is out, we are fully powered by the sun. When there is no sun, or there is not enough sun to meet our power consumption, we buy power over what we produce from the power company at 26cents per kilowatt hour. At the end of the month, we get a credit to our account.
This option was more palatable a few years ago when government incentives put the buyback rate at 88cents per kilowatt hour. Early adopters are still reaping the benefits of that scheme. Our system is a 5 kilowatt system. A system of this size is capable of producing 6572 kilowatt hours of power per year – which, if we are careful should be enough to fully power our house. However – and here is the catch – mid summer at noon we produce surplus. This surplus quickly goes away on a cloudy or winter day and, most obviously, at night. Because we don’t have any way to store the power we make, we are dependant on grid power in the evenings, on cloudy days and when we use high drain devices (basically anything that makes heat or cool). Also. when the power goes out we have no power even though we have solar panels.
So why the heck haven’t we gone off-grid? An off-grid system has the same solar panels as the grid connected system – you can go as large as you can afford or have space to house. What makes it a replacement for grid power is a bank of batteries that are added to the system to store power. Batteries come with complications as they need to be temperature regulated, are expensive and do not mix well with fire. You can choose the level of redundancy – how much power you can store – but this directly correlates to cost. Most off-grid systems have a 2-3 day redundancy meaning that you can go 2-3 days on stored power alone.
A hybrid system sits in the middle with a small battery bank and a low redundancy.
The reason we are still on the grid – cost. It’s on the list for the future, but for the moment, we’re still connected.