An off-grid power system offers many advantages over grid-provided electricity. An off-grid system uses renewable, green energy sources that are better for the environment. It provides you with cheap electricity.
If there is a problem with the local electricity grid, a home with an off-grid electricity system won’t lose power. An off-grid power system can be installed in houses in remote areas where grid-provided electricity is not available. And a small off-grid power system can be used to provide all the electricity you need for boondocking in your RV.
Typical components of an off-grid power solution include:
- A battery
- Solar panels
- Wind turbines
- Water turbines
- A back-up generator
- A charge controller
- An inverter
Off-grid power systems typically make use of wind turbines or solar panels to generate electricity for domestic or business use. In rare situations, a water turbine may be used. Some off-grid power systems also utilize a gas generator or a connection to the power grid.
An environmentally friendly off-grid power solution will aim to use either wind or solar power or both of these. Connection to the power grid or a gas generator is only used as a fallback in case there is no wind for a long time or not enough sunlight.
Many small systems use wind only or sunlight only to generate electricity. A hybrid system will use both, which dramatically decreases the risk you’ll run out of power or need to make use of a fallback.
It is possible to create your own off-grid power system as a DIY project, though you will need to perform adequate research to ensure a successful and safe off-grid power solution is achieved. Alternatively, you can approach an expert in off-grid power systems to install your system.
Over the past decade, the cost of the components of an off-grid power system has dropped while the cost of an installed system has increased. You can save a lot of money by taking a DIY approach to your off-grid power solution.
Help With the Cost of Your Off-Grid Power System
An off-grid power system requires an up-front investment in equipment and installation. However, in some countries, it may be possible to gain grants from local government or power companies to help with this initial cost for homes or business properties.
Where grants are not available, a tax credit may apply to the purchase of a green off-grid power system. These incentives exist because many governments around the world recognize the need to generate as much power as possible in an environmentally friendly manner to preserve our planet and halt climate change.
For example, the US Department of Energy operates a Federal Tax Credit for Solar Photovoltaics. This tax credit is 26% of the cost of systems installed in 2020 and 22% of the cost of systems installed in 2021. When you file your tax return, your income tax is reduced by the amount of this tax credit.
There are similar but more complex tax breaks for wind turbine systems. You can learn about the grants and tax breaks in your area by entering “local green energy grants” or “green energy tax breaks” into your search engine.
In some cases, where you produce more energy than you require, you can sell your surplus to the local electric power corporation. Over time, you will not only recoup your initial investment, but you will also profit from your off-grid power solution. In every case, you pay up-front for your off-grid power equipment but get low-cost electricity thereafter. But you should be aware that ongoing repair and maintenance costs will be involved.
Know Your Energy Requirements
Before you purchase any components for your off-grid power system, you need to calculate the required load. This is simple math based on the appliances you use in your home.
First, list all your electrical appliances. Go from room to room to ensure you don’t miss anything out. Don’t forget any electrical heaters you’ve stored away for summer or garden equipment you’ve stored away for winter.
Second, gather the relevant numbers for each electrical appliance. Estimate how many hours you will use your appliance each day. Look up its power rating in the owner’s manual or manufacturer’s website. This is given in kW. For example, an electric kettle has a typical power rating of 3kW.
Third, calculate the Watt Hour for each appliance using the simple formula:
WATT HOUR = POWER RATING x HOURS USED.
Finally, add up the Watt Hours for all your products to discover the total Watt Hour for your home. Note that you will use different amounts of power at different times of the year, and you will need to design an off-grid system that can cope with the peak demand of your home.
Your peak demand will most likely be during the winter months if you use electrical heating. However, if you are seeking an off-grid power solution for a summer home that is closed-up over winter, your peak demand will be during the summer months.
Because solar panels and wind turbines don’t produce a consistent energy supply, you will require a battery to store the electricity generated and discharge it when needed. Deep-cycle solar batteries are used for this purpose. These look like car batteries. However, unlike car batteries that provide a burst of power for a brief period of time, deep-cycle batteries provide power at a steady rate over a long duration.
Deep-cycle batteries charge when your electricity generators are in operation, when the sun is shining or the wind is blowing, and slowly discharge when you require electricity. This enables your off-grid system to operate like a grid-linked system, lights coming on at the flip of a switch.
Lithium-ion batteries are advisable if you use the typical high-demand appliances found inside an average modern home. They are relatively compact but can be expensive. Lead-acid batteries, more similar to car batteries, are more affordable. They are also environmentally friendly because they are constructed from materials that are easily recycled.
High-performance lead-acid batteries are ideal for off-grid power systems, but they are more expensive than the average lead-acid battery. High performing lead-acid batteries include AGM (absorbed glass mat) batteries, gel batteries, and flooded batteries.
A solar panel converts sunlight into direct current (DC) electricity. You can fit a single solar panel for a small system, such as for boondocking in your RV, or a bank of solar panels for your home power system. The combination of panels you fit must be capable of fully charging your deep-cycle battery during a typical day in your location.
Solar panels are either polycrystalline or monocrystalline. Polycrystalline solar panels are more affordable but monocrystalline panels are more efficient. A polycrystalline solar panel converts between 16% and 19% of the sunlight energy it receives into electrical energy. A monocrystalline solar panel converts between 22% and 23%. If you are short on space, a monocrystalline panel is your best choice. If you have oceans of space, you should fit a bank of polycrystalline panels.
Solar panels generate electricity whenever there is daylight. It is not necessary for the light to be strong, for the sunbeams to fall directly onto the panels, or for the day to be hot. Solar panels work in winter when there is sunlight. However, panels typically generate between 10% and 25% as much electricity when the sky is cloudy compared to a clear sunny day.
When designing your off-grid power system, your geographical location and alignment are important. Solar panels are most efficient when installed in sunny locations and tilted toward the south (north in the Southern Hemisphere) with no obstructions that block sunlight. If your location is frequently windy but seldom sunny, a wind turbine is a better choice.
Before choosing a wind turbine for your home, you should ensure that your town or state has no regulations prohibiting you from erecting a wind turbine tower or mast. In many places, you may be required to obtain planning permission. Local authorities are typically more amenable to the use of solar panels on urban domestic properties.
Off-grid power systems for homes typically use a wind turbine that generates between 2.4 kW and 15 kW. This is a broad range of wind turbines designed to suit homes of different sizes and with different power requirements. Larger wind turbines that require a taller mast and take up more space are more suited to farms and other large properties than small urban houses.
The average home uses approximately 900 kW-hours per month. A single efficient 10 kW wind turbine installed in a good location can provide 1,150 kW per month with an average wind speed of 11 mph (5 m/s). This is based on technical data provided by a wind turbine manufacturer. Such a turbine can provide all the energy requirements of a typical modern home and produce a small amount of surplus electricity.
If you live in an area that is particularly windy, you will generate more electricity than this. However, if your home is situated somewhere where the average wind speed is much lower than 11 mph then solar panels or a combination of a turbine and solar panels are more suitable.
Siting Your Wind Turbine
Selecting a suitable installation site is key to getting the most out of your wind turbine. A location at the top of a windy hill or on the slope facing the prevailing wind will benefit most from the available wind. A mast (tower) is usually necessary to achieve optimum results from your wind turbine.
Any site you choose should ideally elevate the wind turbine 30 feet above any wind-breaking obstacle within 30 feet. To do this, it is likely you will need to mount your wind turbine atop a tower or mast. Obstacles include tall trees, buildings, and rock outcrops.
When choosing your site, also consider the future growth of trees and any planned structures. The best sites are upwind of any nearby obstacles, so the turbine is completely exposed to the prevailing wind.
When erecting a mast, there must be enough space to position the guy wires and to lower and raise the mast for essential maintenance. Another consideration is the length of wire required between your wind turbine and your home. The longer the wire, the more electricity will be lost due to resistance.
If you are forced to locate your turbine a long way from your home, position your inverter at the turbine rather than at your home. Losses to resistance are less when the wire carries AC (alternating current).
If your property happens to be situated beside rapidly moving or falling water, you may be able to install a domestic hydroelectric power system. Because a creek doesn’t stop running during the night or when the wind stops blowing, it is the most reliable source of power generation.
The potential problems with a hydroelectric power system come from seasonal changes in water flow and periods of drought. Traditionally, this problem is mitigated by the use of a millpond to ensure a reliable source of running water.
There are 2 common types of water turbines: impulse and reaction. Impulse turbines utilize uses cups to harness the energy of moving water. These require a pressurized jet of water, such as you might get from a waterfall. Reaction turbines utilize blades that spin in a strong current, so they are more likely to be found in a domestic hydroelectric power system.
Due to the low number of domestic hydroelectric power systems, you will not find the same wide range of products on the market as with solar or wind systems. This means components will often be more expensive. Also, you are less likely to find government grants or tax breaks to help you with the initial set-up costs.
Since few properties contain a convenient source of fast-moving water, domestic hydroelectric power is rare. However, approximately 20% of the world’s electricity is produced in hydroelectric power stations.
Wind vs Sun
Your property may be situated in a location where both wind turbines and solar panels are a viable source of energy, and either will generate sufficient reliable energy for your needs. You need to know what the best option is for you.
The cost of installing either a wind turbine or a solar panel-based power system can be similar. In the past, wind turbines were often cheaper, but the decreasing cost of solar panels has made them more competitive. The cost of either kind of system varies from location to location depending upon the average wind speed and hours of daylight. The less wind, the more turbines are required. The less sunlight, the more solar panels are required.
It is a good idea to produce two estimates for constructing an off-grid power solution that provides enough energy for your needs — one based on wind power and the other on solar power. This will inform you if a wind turbine or solar panel system is more affordable.
Wind turbines convert around 50% of wind energy into power, so they are arguably more efficient than solar panels. They also have the advantage of working during the night as well as during the day. However, sunlight is a more reliable energy source than wind, which can be intermittent.
Wind turbines contain moving parts which means they require more maintenance over the years. Wind turbine masts stand out from your property producing visual pollution and wind turbines create noise pollution. They also are known to kill birds and bats, though this is mainly the large commercial wind turbines operated by power generating corporations. It is claimed around 573,000 birds are killed each year by wind turbines in the US.
In many areas, wind turbine towers require planning permission, and they may be banned in urban areas. If you want a quiet life, love birds, don’t want to upset your neighbors, and you don’t want a tall mast in your backyard, then you probably should install solar panels on your roof.
It is also easier to site solar panels because they don’t need the higher ground and clearance that wind turbines require to work efficiently. However, in flat and rural locations where there is a lot of wind, wind turbine towers can be easy to install.
Hybrid Power Systems
You don’t have to rely on only one source of clean energy. In some locations, a hybrid power system is more suitable that utilizes both means of generating clean electricity. A property in an area that sees frequent cloudy weather and average annual wind speed less than 9 mph will benefit most from a hybrid system. A hybrid system is always preferable to a utility grid connection for anyone who wishes to use clean power.
To protect against a loss of power, your system can be connected to the local power grid. If a grid connection is impossible or the cost of a grid connection prohibitive, then a hybrid system provides more protection against a power outage. As a rough guide, power companies in the US charge between $15,000 and $50,000 per mile for running a power line from the utility grid to a remote property, depending upon accessibility and terrain.
If you are located somewhere truly remote, it will be much cheaper to install a stand-alone system and purchase more solar panels and turbines than to connect your system to the local grid. Of course, a gas generator also provides protection. However, a gas generator is not as environmentally friendly as an alternate source of green power.
You may decide to include a gas generator within an environmentally friendly system as a last resort in case of emergencies. For example, if you own a hunting or fishing lodge where you keep large quantities of locally sourced meat and fish frozen, you won’t want to lose it all due to a week of unusually heavy cloud cover and no wind.
Because sometimes the wind blows harder or the sun shines stronger, a device called a solar charge controller is fitted between your electricity generator and the battery to moderate the current and voltage. This protects your battery from overcharging and prolongs its useful lifespan. Given the cost of batteries and the hassle of replacing them, not to mention the downtime on your power system, a charge controller is essential.
When a battery’s charge is low, the charge controller allows any quantity of energy to flow through. When your battery achieves an optimum voltage, the quantity of energy is regulated. Some charge controllers can divert any excess energy to another application, such as heating water or contributing electricity to the local power grid, to prevent waste.
Charge controllers also block reverse current. Electrical current flows from areas of high voltage to areas of low voltage. Without a charge controller, an inactive wind turbine or solar panel could leech power from your off-grid power system’s battery.
You cannot use the same charge controller for both a wind turbine and a solar panel in a hybrid system because the two kinds of generator use different kinds of charge controllers. The charge controllers used for wind turbines also include features to prevent the turbine spinning out of control in high winds in order to protect the blades and generator. Because of this function, many wind turbines come with the charge controller already built in.
The 3 Kinds of Charge Controllers
The best kind of charge controller is an MPPT (maximum power point tracking). It is the most recently developed design and can pair batteries and generators that operate on different voltages. They are typically between 10% and 30% more efficient at energy conversion than other kinds of charge controller and minimize the charging time for your battery. MPPT charge controllers work best in cold environments.
MPPT charge controllers are also the most expensive and trickiest to install. PWM charge controllers (pulse width modulated) are more affordable, more durable, and deliver adequate protection for your battery. However, a PWM charge controller can only be used when your battery and electricity generator operate on the same voltage. This limits its use to mainly small solar panel powered systems. PWM charge controllers work best in warm environments.
An on/off charge controller (shunt charge controller) is the cheapest kind of charge controller but lacks the extra features of more modern designs. On/off charge controllers are the simplest kind, easiest to install, and very reliable.
Wind turbines and solar panel arrays produce direct current electricity (DC) but household appliances must be powered by alternating current electricity (AC). A charge inverter converts the DC into AC so you can use it.
There is a wide range of charge inverters designed for specific uses. An important distinction is between completely off-grid systems and grid-linked systems. If you plan to connect your off-grid system to the local power grid for back-up or to sell surplus energy, you will require a grid-tied charge converter that is compatible with the local power grid. A completely off-grid power system can use an off-grid power converter.
Another important distinction is between the use of a single charge inverter for a bank of solar panels or wind turbines and the use of a dedicated charge inverter for each panel or turbine. A single charge inverter is more affordable and simpler to install but less efficient than the use of dedicated charge inverters for each generator.
Off-grid charge inverters are manufactured with a variety of DC inputs and AC outputs. The DC input of off-grid charge inverters is 12V, 24V, or 48V. The DC input of your charge inverter must match the output of your off-grid power system’s battery, which will also be one of these 3 voltages. Grid-tied charge inverters use input that matches the wind turbine or solar panel’s output.
FAQs About Off Grid Power Systems
Q: What is the best off-grid power source?
A: This depends upon your location. If you live somewhere sunny with little wind, solar panels will work best. If your location is cloudy and windy, a wind turbine will provide a better solution. Hydroelectric power is the most reliable of all, but few properties contain the necessary source of fast-moving water.
Q: What do I need for an off-grid solar system?
A: You require an electricity generator (solar panel, wind turbine, or water turbine), a deep-cycle battery to store the power, a charge controller to protect the battery, an inverter to convert the DC electricity into AC to power your appliances, and the wiring to connect these. You may also choose to utilize a back-up gas generator. In some locations, you may need planning permission to install a wind turbine mast.
Q: What are some disadvantages of living off-grid?
A: To be honest, there are not many, and they can be overcome. The main disadvantage is that your power source could fail. For example, if you rely on a wind turbine but there is insufficient wind to charge your battery, or if your wind turbine broke down. This can be countered by installing a hybrid system that utilizes both wind and sun or a back-up gas generator.
Another disadvantage is the initial set-up costs of installing an off-grid power system. This can often be mitigated somewhat by government grants or tax breaks as well as the opportunity to sell your surplus energy production to the local power grid.
Q: What is the cheapest way to produce electricity?
A: Again, this depends upon your location. Typically, in sunny places, solar panels will be cheaper because you won’t need to install many of them to achieve your energy needs. Similarly, in windy locations, you can purchase a smaller wind turbine to provide your energy requirements. You should produce estimates for both kinds of power systems based on your local conditions.
Q: Will my solar power system work in winter?
A: Yes. All you need is sunlight to generate power using a solar panel. However, in the north of Alaska when there may be only a few hours of daylight for around 3 months in midwinter, a solar power system is not advisable. When planning your off-grid power solution, you must take note of the daylight hours during midwinter to ensure you install sufficient solar panels to charge your battery during a typical winter’s day.
Q: What will my off-grid power system cost?
A: Once more, this partly depends upon location. It depends even more upon your domestic power requirements.
If you live in sunny southern California, you can build the average solar power system for as little as $12,000 and reduce that to $8,880 after the tax credit. In neighboring Arizona, the average power consumption is higher and solar systems cost around $20,000, or $14,800 after the tax credit. If your energy requirements are even higher, you may spend as much as $30,000 on an adequate solar power system, or $22,200 after the tax credit.
Wind turbines come in a wide variety but, much like solar power systems, the typical cost of a wind turbine power system ranges between $12,000 and $30,000. It all depends upon where you are and how much power you require.
Save Money and Help Save the Planet
At this point, you may be thinking off-grid power systems are more complex than you expected. However, think of the benefits of installing an off-grid power system in your home, business property, or RV.
After an initial investment, you potentially gain free energy. You can sell surplus energy to make a profit. You can live far from urban smog and still benefit from all the conveniences of modern life. And, most importantly, you can do all this without polluting the atmosphere and damaging our beautiful planet. Isn’t that worth a little time spent in research?