Everyone dreams of living that quite, off the grid life but it remains a distant dream for most. It’s not easy. The simple necessities of modern life which we take for granted, especially in cities, quickly emerge as one of the biggest obstacles.
One of the most common issues is availability of energy. You can buy a generator but you are then dependent on fuel availability nearby. If want a long term solution, you might wonder if a windmill can work for you.
Here is what you need to know about a small windmill system for an off grid cabin.
Can a Wind Turbine Power an Off the Grid Cabin?
If you want a simple answer, yes it is possible. But, and it’s is a big but – it depends on a number of factors.
The most important factor that matters is the wind resource at the given site. Keep in mind that local terrain has a huge influence on the wind flow and it can vary significantly within a small area of a few miles.
Don’t just rely on the local weather stations or airport wind data as their data is never going to be as reliable as the actual site data.
You can buy wind maps to determine whether adequate wind resource is available at your location for a windmill powered energy system. It’s recommended to buy 30 to 40 m wind maps.
There are also affordable wind data collection systems available today that should be installed for at least a year at the site to collect adequate data.
Obviously if there are big wind turbines everywhere you look, chances are that you’re in an area where you can use wind power.
So if it’s a given that wind power can be a thing, the problem becomes a practical one: can any small wind turbine create enough power by itself?
These systems typically consist of wind vanes, anemometers and temperature sensors mounted at a height close to the expected height of the hub. If someone has a small wind turbine system installed nearby, you might also be able to obtain the required data from them.
You will also need at least 1 acre of clear land for installation. You also need to make sure the local zoning codes allow installation of wind turbines. The next step is to figure out the amount of power you need for your cabin.
Size of the Wind Turbine: Diving Into the Math
If you have done your research and have determined that your cabin has the right location for a windmill, the next question you need to ask is the size of windmill you need.
Thankfully, windmills or wind turbines are available in a wide range of sizes ranging from 20 W to more than 100 kW.
The smaller sized turbines are typically designed for charging batteries for sailboats or recreational vehicles. Similarly, up to 10 kW turbines are typically used for pumping water and other similar applications.
A typical household in the US consumes around 11,000 kWh of electricity annually though you will need to calculate your own requirements in order to determine the right size of wind turbine for your cabin.
To give you an idea of the size, a 15 kW wind turbine is typically enough for a home that requires 300 kWh of energy each month if it is located in a place where the average annual wind speed is approximately 14 mph.
When you’re comparing different wind turbines, here is a handy formula you can use to the compare the performance of different windmill systems.
AEO = 0.01328 D² V³
- D refers to the diameter of the wind turbine rotor, measured in feet.
- V refers to the average annual wind speed in your location, measured in mph.
- AEO refers to the annual energy output generated by the windmill, measured in kilowatt-hours per year.
There is also a handy Microsoft Excel spreadsheet tool provided by https://windexchange.energy.gov which you can find here (https://windexchange.energy.gov/files/docs/small_wind_economic_model.xls).
This Excel spreadsheet is designed to help you roughly estimate the economics of a small wind electric system. Once you input the required data, you will get a simple payback estimation in years.
In short, it will help you determine whether a wind energy system is financially practical for you.
How Much Energy Can Wind Turbines Provide
According to ecavo – and alternative energy specialist, wind turbines can be a useful way to provide off the grid energy however they are rarely the best option as a standalone.
Even that site points out that having a wind turbine in combination with solar panels almost always makes way more sense. This means you’re producing more energy through two different methods and all that power can be set up to go to the same storage battery.
You also have the option of building multiple wind turbines, but is this really going to be the most efficient method?
Most of the time the answer will be no.
Storing the Wind Energy
You are never going to get a consistent output from your small windmill and this is the reason, you will need to think of a way to store the energy generated by the wind turbine.
You can’t just flick on a switch and expect your appliances to work without an energy storage system in place. It is presumed that you are not connected to the energy grid.
When it comes to the energy storage, you will get the best performance from 12 V batteries. The biggest advantage of these batteries is that the system can be scaled up.
You can start small and once you are ready to invest more, you can simply buy more batteries and amp up your system.
Here is what you should know about the storage capacity of a 12 V battery. A single battery is capable of storing around 125 Ah (Amp Hours). If you invest in a 10 kWh turbine, it will generate around 16,000 kWh annually which is around 44 kWh per day.
In short, a 10 kWh turbine is capable of charging 29 such batteries daily (12 v battery with capacity of 125 Ah).
You must have heard of the Tesla Power wall which is a lithium ion based battery storage system though it still going through iterations but many people who have used it are impressed by the system.
Usually, deep cycle batteries are recommended for use in the power storage system. These batteries can be easily charged and discharged many times without any real loss in charging capacity.
Installation
As far as installation of the system is concerned, you can always do it on your own provided you have the necessary tools and knowledge.
Keep in mind that if you’re trying to do it on your own, you will need to be well trained in pouring a concrete foundation as the tower foundation needs to be sturdy enough to keep it steady even in strong winds.
You will also need to learn about electricity as batteries supply DC whereas the most of the appliances in your house are designed to use AC. There is a lot of wiring involved.
The power generated from windmill needs to be stored in the battery system and the battery power also needs to be converted for use in your cabin.
In case you don’t know much about these systems and would like to hire a professional, get in touch with your local utility or the state energy office to get a list of local installers who are well-versed with such systems.
You can also use your favorite search engine to find professionals with expertise in installation of wind energy systems.
Maintenance
One of the most overlooked aspects that has a significant effect on the financials of wind energy systems is the maintenance. If a small windmill system is maintained properly, it has the potential to keep working almost flawlessly for at least 20 years.
In fact, it can operate even longer with proper maintenance.
As far as the maintenance requirements are concerned, you need to regularly check the electrical connections as well as all the bolts.
Corrosion is one of the biggest problems and you will need to periodically check for any signs of corrosion and if there are any, you need to take care of those.
The turbine blades might get damaged with time. You will need to have a system to check the edges of the turbine blades and repair or replace them, if needed. Usually, the turbine blades as well as bearings need to be replaced after 10 years.
Conclusion
It’s possible to use a small windmill system for your power requirements in an off grid cabin. In many cases, people like to invest in a hybrid power system that combines a small solar electric system with a small wind electric system, allowing you the best of both worlds.
To conclude, it is recommended to invest in a small windmill energy system if the average annual wind speed at your cabin location is at least 9 mph and you have at least one acre of clear land.
Everything else is about calculations and whether it’s feasible for you to make the necessary investment in the windmill energy system to be completely free from dependence on the local utility for power.
So, use the information shared above and get started on building your own small windmill power system for your off grid cabin.