Frequently Asked Questions

This list is an adapted version of the FAQ of the British Wind Energy Association, the original can be found here.

The FAQ will regularly be updated in order to answer your questions the best way we can.However if you don’t find your answer, don’t hesitate to contact us.

Having your own wind turbine

How does a wind turbine make electricity?Most wind turbines have three blades which face into the wind; the wind turns the blades round, this spins the shaft, which connects to a generator. A generator produces electrical energy from mechanical energy. Find more details on our products page.
Can I have my own wind turbine?Yes! Small wind turbines are ideal for householders, farms, communities and small businesses to use for on-site energy generation. Your individual site specifications (such as location, wind speed and local landscape) will eventually determine the best turbine type and size for your needs.
How do I find out if my site is windy enough?There are different databases which tell you the average wind speed in your area. In New Zealand, you can consult the national climate database from NIWA (National Institute of Water & Atmospheric Research) and/or get in touch with your nearest airport. Click here to find a complete list of aerodromes or here to locate the nearest airport.The actual wind speed at your site will be influenced by the local topography and any nearby obstructions such as trees or other buildings. That’s why we can’t totally rely on nearby data and an expert advice will help determine what you can expect.Wind movement around buildings themselves is very fickle, so take expert advice if machines are fixed to buildings rather than free standing on a tower or mast.A site with an average wind speed of 4-5 meters per second is generally sufficient enough to make installing a small wind turbine worthwhile.Note that wind speed increases with height, most data given by airports or weather stations are recorded at a height of 10m. It is important to take this into consideration if your tower is 15m or 18m height (see below “How tall are wind turbines”)

Turbine details

What size turbine do I need?The table below can be used as a guideline for choosing the right model. A ‘normal’ household (a family with 2 kids) will use about 4,000 kWh annually. A heavy user might have a heat pump and have an annual consumption of 6,000 to 8,000 kWh. Normal wind speeds would be around 5.5 m/s on average, with high wind speeds around 6.5 m/s.

Purpose	Wind speed	Turbine
Contributes to saving energy	Any	Passaat
Self-sufficient normal household	High	Passaat
Self-sufficient normal household	Normal	Montana
Self-sufficient high electricity user	High	Montana
Self-sufficient high electricity user	Normal	Alize
Energy saving for a small industry or farm	Any	Alize

Find more details on our products page.

How tall are small wind turbines?Tower heights vary according to wind turbine models, but generally range from 6 to 24 meters. In general, the higher the tower, the higher the average wind speed that the turbine will experience and the smoother the wind. The higher the tower, the lower the price of the kWh.A tower will never be too tall and placing a turbine too low (generally below 10 meters for a 2-3kW turbine) is like placing solar panels in the shadow.
How much space do I need for a turbine?Ideally, stand-alone turbines should be sited as far away as possible from buildings or trees, which may block the wind and cause turbulence. As a guide, the wind turbine should be about twice the height of obstructions in the immediate front of it (for at least the prevailing wind direction). In general, the turbine should be above the height of nearby obstructions that are within a distance of 10 to 20 meters of the tower heights.Rooftop-mounting turbine is not something we generally recommend. It is fairly difficult finding a place on a roof that is strong enough to withstand the forces and has a good wind. Local turbulent airflow around the building, which causes reduction in generated output and could damage the turbine, must be considered as well. In general, the less turbulent and varying the wind, the better the wind power generation.
Do I need a planning permission?Yes! Small wind energy installations may require resource consent and you should always consult your local planning authority at the beginning of the project and preferably get them to confirm in writing whether resource consent is required or not. It is good practice to discuss your plans and aspirations with neighbours as potentially affected people.Relevant factors to consider include the effects on the environment, access to the site, noise and visual effects.Overall, central government policies support the development of small scale wind energy and provided the installation is located within a suitable location that has no more than minor adverse effects on the environment and affected neighbours give written approval to the project, the local planning authority should look favourably at your proposal and resource consent should be granted if required.
Can I build my own wind turbine?Yes! There are many books which relate to this topic. We recommend: ‘Wind Power Workshop’ by Hugh Piggott.
Are power and size proportional?No! Contrarily to PV (Photovoltaics) system for example, wind power increases with its blade size. Increasing the rotor diameter by 20% (from 5 to 6m for instance) increases the capture area and therefore the power generated by 44%.Nothing tells you more about a wind turbine’s potential than rotor diameter. The wind turbine with the bigger rotor will almost invariably generate more electricity than a turbine with a smaller rotor, regardless of generator ratings.

Issues to consider
Are wind turbines noisy?No! Our small wind turbines have been designed to be very quiet, for instance by having direct drive systems to avoid gear box noise and to increase efficiency. In general, the wind itself makes more noise than a wind turbine. It is most unlikely that any noise from small wind turbines will be heard at more than 30 m.
Do wind turbines affect radar systems or TV reception?No! Small wind turbines are unlikely to have any detrimental effects on aviation and associated radar or navigation systems. In general, turbines with small diameters are unlikely to have effects on television and radio reception. If this occurs it is likely to be highly localised and technically easy to overcome.
Will small wind turbines have a ‘flicker’ from the turbine blades?Yes but… Potentially, sunlight passing through moving blades can cause a flickering effect in ‘line of sight’ directions. The possibility of the shadow from the wind turbine causing flicker should be considered at the site selection stage. Reflections from the blades are unlikely, especially as the coatings used on modern turbines have been selected to minimise reflection.
Will small wind turbines affect birds?No! Experience and careful monitoring by independent experts shows that birds are unlikely to be damaged by the moving blades of wind turbines.
What about lightening strikes?Fortis, in over 25 years of manufacturing wind turbines, have had one occasion of a turbine which was damaged by lightning. Considering the costs of protecting the turbines against strikes, we prefer not to do so.

Electricity generation

Can I use my turbine for heating?Yes but… small wind turbines can be used for direct heating, e.g water heating as well as for battery charging and they are also ideal in remote off-grid locations. However, the energy required to heat a building is usually significantly more than the energy used in electricity, so a much larger turbine would be needed for building heat. Direct heating is only done with excess energy, for example when the batteries are full. Small wind turbines are very effective for powering a heat pump, which can heat your house.
Can I connect my turbine to the grid?Yes! Small wind turbines can be connected to the local electricity network. When a wind turbine connection to the mains supply is made, it has to be approved by your local electricity distribution utility. This company will require the connection to be of a satisfactory technical standard. Therefore the cost of incorporating power import and export metering and approved electrical protection equipment will add to the total cost. The company may also limit the electrical capacity of the wind turbine that may be connected to a particular distribution line, depending on the loading of the electrical distribution system in the vicinity.
What’s the difference between a grid connected system and a stand alone system?A grid connected system is a wind turbine that is physically interconnected with the grid of an electricity distribution system. Such systems are capable of feeding the surplus of electricity to the grid whereas they can take electricity from the grid in the generation is not enough.A stand alone system is an electric power system independent of the grid. Those systems are mainly used in remote locations where the cost of getting connected to the grid is prohibitive. In most cases, the electricity is stored in batteries, we call it a battery charging system.
How much of the time do wind turbines produce electricity?A modern wind turbine produces electricity 70-85% of the time, but it generates different outputs dependent on wind speed.
What happens when the wind stops blowing?First of all, even if the wind stops blowing, thanks to the inertia of the blades, the turbine will still run and hopefully be turning until the next breeze. If the wind stops blowing for a long moment, electricity continues to be provided by other forms of generation in an isolated system (e.g. batteries, diesel generator), and by the grid in a grid-connected system.
What happens if the turbine produces more than what I consume?If the installation is a battery charging system, the surplus of electricity will be stocked in the batteries in order to be used once it will be less windy.If the installation is a grid connected system, the surplus of electric will feed in the grid. Different agreements can be found with your local distributor to buy your surplus.
How do wind turbine perform compare to PV (Photovoltaics)?It’s really hard to compare renewable energy between themselves as they are very different and too many contraints. In order to compare them, calculations are made to give a price per kWh. First the wind speed is a major factor in wind power generation, it is safe to say that above 4m/s, a wind energy system will easily out perform PV. The second major actor is the installation size. As we have seen above, contrarily to PV system, wind power increase with its blade size, therefore the bigger your wind turbine, the cheaper your price. Therefore the Montana and Alize will definitely give you a much better price per kWh that PV for the same energy output.

Costs and funding

How much does a wind turbine cost?The price of small wind turbines depends on many things. The size and type of a model you buy (800W, 1.4kW, 5kW, 10kW) and the type of installation (stand alone or grid connected system) are the main 2 costs that are visible. But there is also the location of the site which can increase the price for foundations, wiring.Contact us if you want us to study your project.
Are there any hidden costs?No! When you will sign a contract with us, all the costs included will be specified and there won’t be additional cost until the tower is erected and the blades are rotating. In the contract, we will clearly notify every part of the installation done by ourselves and the one done by you if there is any.
Isn’t it cheaper to save electricity?Since most of us are not fully efficient in using energy, it is almost certainly cheaper to reduce electricity consumption than to buy it or generate it yourself. Nevertheless, electricity generation is necessary. Therefore, to combat climate change and to have security, it is essential both to increase the proportion of renewable energy and also to have energy efficiency.

Turbine lifetime

How do I look after my wind turbine?The conception of FORTIS turbine is maintenance free. Bearings are greased for life and sealed so you will not have to have they greased annually.
How long do wind turbines last?FORTIS wind turbines typically last around 20 years. This is not theory, because their firm is already in business for over 25 years and they have had clients that came back after 21 years, to buy their second turbine because the first one was worn out but still running.
Can the turbine be re-sited?Yes! Provided the new site is suitable. Costs will be incurred to dismantle the turbine, transport it to the new site and re-install it. An estimate of these costs can only be prepared after a survey of the old and new sites.

Frequently Asked Questions

Having your own turbine

Turbine details

Issues to consider

Electricity generation

Costs and funding

Turbine lifetime

Having your own wind turbine

Turbine details

Issues to consider

Electricity generation

Costs and funding

Turbine lifetime