How much CO2 emissions will be prevented by a wind system?
Every 1kWh generated by a wind turbine means 1kWh less has to be generated by conventional power stations. According to the Carbon Trust the carbon produced to generate 1kwh of electricity is .537 tonnes. Therefore a typical 6kw turbine, producing 16,000 kwh of electricity per annum is saving 8.592 tonnes of CO2.
What is the life expectancy of a wind system?
The turbines we install are designed for a 25 year life time, but are expected to last much longer, as long as annual servicing is maintained.
Is bird strike likely?
There are rare incidents where birds do come into contact with wind turbines, though this is more likely for wind farms than single turbines. The RSPB has stated that “the available evidence suggests that appropriately positioned wind farms do not pose a significant hazard for birds”. For more information see: the RSPB website and the AWEA website. It is estimated that over 10,000 birds are killed by road vehicles each year, to give some perspective.
Do wind turbines create a lot of noise?
The wind turbines we supply are all direct drive machines with no gearboxes (gearboxes can be a source of turbine noise) and have been designed for quiet operation. All machines are relatively quiet and noise figures can be supplied for all of the machines. If you wish we can arrange for you to visit a site and hear for yourself.
Can turbines be installed in urban areas?
Generally speaking we discourage installing wind turbines in very urban areas. In urban areas wind speeds are reduced and turbulence levels are a problem. To work most effectively a turbine needs to be in clean (turbulence free) air above surrounding obstacles. If in doubt we are happy to advise.
Can turbines be building mounted?
Wind turbines can be mounted on buildings, though the turbulence effects of the building can present significant impacts on turbine performance. To work effectively the turbine needs to be well above the building and any surrounding buildings. Because of the effects of turbulence, it is generally recognised that buildings are not the ideal first choice for mounting a turbine. The loads imposed by the wind on the turbine mast are considerable. Where a turbine is to be mounted on to a building the building must be capable of withstanding these loads and any vibration effects. Installing a turbine to a new building where the building has been tailored to accept a turbine presents few problems. Retrofitting to an existing building can be much more difficult and many buildings will not be suitable. In all cases, a structural engineer must be consulted. Access for inspection and maintenance also needs to be considered for building mounted turbines. Chimneys are not generally suitable for mounting a turbine and must be avoided if the chimney is still in use.
What is the best site for a turbine?
The ideal site for a wind turbine is on the top of a smooth, rounded and exposed hill – clear of any turbulence or losses created from obstructions such as trees, buildings or cliffs. In practice, such sites may not be available. It is important in selecting a site to consider that the power available to a turbine is related to the wind speed cubed – even a small increase in wind can give a large increase in output. Wind speed increases with height; hence an increase in tower height can yield a significant improvement in turbine performance. To maximise output and minimise the effects of turbulence, the turbine should be mounted away from and above obstructions such as buildings or trees. The key point is to keep the turbine clear of large obstacles, particularly in the path of the prevailing wind. This should take account of possible future obstructions such as tree growth.
What is the minimum annual mean wind speed required for a turbine?
The minimum annual mean wind speed for a site to be considered suitable for a wind turbine is generally taken to be between 4.5 and 5m/s. We are able to provide averaged wind speeds for your location from a national database of statistics. However the data will only provide an initial estimate for a 1km square. Topological features such as terrain, trees and buildings will very significantly affect wind strength at a given site.
How can the annual output for a particular wind turbine be estimated?
The annual output (kWh) of a turbine depends on the average annual wind speed “seen” by the turbine. This depends on the average wind speed for the site; the height of the tower and local site factors (e.g. is it a grassy hill top). Accurate estimates can only be achieved by the installation of wind logging equipment for a period of at least a year. However, the cost and time constraints of such monitoring mean that such analysis is usually only implemented for wind farms or large turbines. Initial estimates of site suitability and turbine output can be made using the wind speed calculator, corrections for local effects and manufacturer’s data.
What is the typical annual output (kWh) from a wind turbine?
The power available to a turbine is related to the wind speed cubed; hence even a small increase in wind can give a large increase in output. Consequently it is not possible to give a “typical” annual output for a turbine.
What is the difference between kW and kWh?
KWh (kilowatt-hour) is a measure of electricity use (or generation) over time. A 1kW (kilowatt) load running for 1 hour will use 1kWh of electricity. Similarly, a 1kW generator running for 1 hour will generate 1kWh. Electricity is bought and sold in kWh (often termed “units”). The instantaneous output of a turbine is measured in kW and the energy production over time is measured in kWh.
How are wind turbines rated?
Wind turbine systems are typically rated in kW – kilowatt – the rated instantaneous output of the wind turbine at a defined wind speed.
Can the system be used to run a dedicated load?
A grid connected system feeds into the whole building electricity network, feeding any loads that are running at the time. Feeding a single load in such circumstances is not feasible. However, when designing the wind system, it can be sized to meet the notional demand of a single load.
Do installations need batteries?
A grid connected system does not need batteries. Batteries add significantly to the cost of an installation and also significantly reduce the overall efficiency (typically by 20-30%). They are also toxic and have a relatively short lifetime. Batteries are only used where they can’t be avoided such as for an off grid application.
What happens during a power cut?
A grid connected system instantly switches off when a power cut occurs. This is required to meet electricity regulations and is implemented by control circuits integrated within the inverter. Disconnection during a power cut is necessary to ensure power quality and protect workers who may be repairing the fault. The system will automatically re-start once the power cut ends (a 3 minute restart delay is required by regulations).
What happens if there is no wind?
On calm days a wind system produces no electricity – all electricity required by the building comes solely from the national grid.
What happens if the system generates more than the building is using?
When the wind turbine is generating more electricity than the load demand in the building, all excess is exported to the grid. Export occurs automatically and can be measured (and income collected) using an “export meter”. We can advise on the best way to export your surplus electricity.
How is the wind electricity used?
The output from a grid connected wind turbine system is fed directly into the existing circuits in the building, usually by a connection at the main distribution board. The inverter ensures your wind generated electricity exactly matches the electricity from the grid. Your surplus electricity that is that not being used in your building is automatically sold to your energy supplier.
How do turbines work?
Turbine blades capture the energy in the wind causing them to rotate. This rotational energy is converted into electrical energy by use of an electrical generator housed in the turbine head.
Grid connected wind turbine system an overview
A grid connected wind turbine system is an installation that provides electricity from the wind. The system is connected directly into (and synchronised with) a building’s existing mains supply. On a windy day, the power generated by the wind turbine reduces the amount of electricity that needs to be purchased from the electricity company. On very windy days, or at times when not many loads are turned on, electricity production are usually greater than the demand in the building – and the excess will be exported out into the grid. The system consists of three elements: The wind turbine (the part that generates the electricity); Inverter – control system (electronic devices that control the turbine output and safely convert this output into AC “mains”); Cables, display(s) and switchgear.
