On- or Off-Grid, That is the Question...
OK! Let's go OffGrid; Right now...
Wouldn't it be wonderful; no more electricity bills, your lights are shining bright when all your neighbours' are in the dark after that big storm this afternoon, your solar panels generated so much electricity the other day you couldn't consume it all and the wind turbine is putting out so much power you are having to warm the garage just to stop it from spinning out of control! Idyllic. And the government is paying me for every kWH generated irrespective what it is used for.
First though; What do we get by being OnGrid?
Before going off grid, it may be useful to understand what being OnGrid actually gives you. Once you leave the grid behind, you have to recreate all the previous stuff you were used to receiving in return for the daily standing charge. Trust me, the daily standing charge is extremely good value for money. After all, your electricity is available 24 x 7 x 365, of course!
The National Grid provides you with as much energy as you want whenever you want it up to the limit of your mains fuse, typically 100A or 25 kW. You can turn everything on or off at the same time. Should you have installed a wind turbine or some solar panels then the National Grid will consume all the energy you have installed without complaint.
Needless to say, all of the above have to be considered in creating a fully functional OffGrid system.
OffGrid Step by Step...
- Understand your requirements, loads etc
- Create your own Grid
- Add energy storage
- Add green energy generation
- Add a backup generator if desired
- A User Interface
- Monitoring - capture what is going on
How SMA do it...
SMA is a German company that manufactures its own equipment in Germany and gets consistently high ratings for quality. (Some recent (sept 2017) boxes have had 'Made in China' on the label). The SMA Sunny Island (a yellow box) is a controller that provides all the functions you require to make your replacement for the national grid. It manages power to your loads as and when you want it. It integrates wind and solar generation, batteries and generators and a user interface.
Add batteries with sufficient storage capacity and output capablility to meet your load requirements. Your OffGrid system is now functional! However, next is to supply a source of energy.
A diesel generator is typically installed to automatically startup whenever there is insufficient power in the batteries to meet your requirements and the Sunny Island (SI) Yellow box can do all this as and when necessary, your job is to ensure the generator has fuel and water with which to run.
Wind Power is added by installing a wind turbine. This will have its own control box which converts wild AC voltages from the turbine into DC voltage which is in turn fed into an inverter (Red Box) which feeds power direct to your new grid.