Micro and small wind turbines generate renewable electricity from wind. Rotor blades are aerodynamically engineered to take optimal power and then turn a turbine to generate electricity.
The power of a wind turbine increases exponentially in a relation to the speed of the wind and the diameter of the blades. This makes larger turbines with higher wind speeds more cost effective e.g. the energy payback for larger turbines in windy places is multiplied but good wind speeds at the micro level, can also generate considerable energy.
There are two types of domestic-sized micro wind turbine:
- Mast mounted: these are free standing and are erected in a suitably exposed position.
- Roof mounted: these are smaller than mast mounted systems and can be installed on the roof of a home.
If a micro wind turbine eligible for
feed-in tariffs is connected to the grid in a location with high wind speeds, consumers can sell generated electricity to an electricity supply company, and earn an added export tariff. If a wind turbine is not connected to the Grid, surplus electricity can be stored in a battery. Wind turbines need to be appropriately sited on or off the electricity grid. The issue of intermittency has to be taken into consideration, as well as amenity issues in terms of noise and visual amenity.
Performance issues
Energy Saving Trust's field trial on wind turbines is a useful sourced of information of this topic. These field trials demonstrated that small wind turbines need to be sited appropriately with good wind resource. Turbines may generate most energy in Scotland, or on moors, or near the coast. Approved installers can advise on the best locations and accurately predict energy outputs.
Small wind turbines with good wind speeds and no obstructions nearby, for example near the coast, or in high or exposed locations pay back financially, and in terms of carbon, in a relatively short time. Energy outputs for wind turbines are very site-specific, so DECC recommends:
- At least a three month period of advance wind speed testing is put in place before making a decision to install a wind turbine (or seek advice from an MCS installer company)
- MCS certified (third party tested) products and MCS installer companies are used. MCS wind turbines are tested over a period of time to robust weather conditions. They verify manufacturers’ durability, safety and performance data.
The benefits of wind electricity
- Wind is a plentiful energy source: the UK has 40 percent of Europe's total wind energy.
- Cuts carbon footprint: wind electricity is renewable energy.
- Lowers fuel bills: The Energy Saving Trust is reporting on a range of micro wind systems discovers how much energy well-sited wind turbines with good wind resource can generate.
- Earn Feed-in Tariffs (FITs): Micro and small wind turbines are eligible for FITs <50kWs, and above 50kWs for either FITs or ROCs <5 MW from 2010.
Wind turbine certification
At micro-level (<50kW), there are MCS standards for wind turbines for installer companies and products. MCS installers and products are mandatory for FITs and installer companies must belong to a consumer code of practice. At the moment there is only one, the REAL Assurance Code .
At the moment there is no other certification scheme considered ‘equivalent’ to MCS which is an EN45011 scheme but if there were, it would also have equal access to FITs.
Grants
There are no Government grants for micro or small wind turbines.
Permitted Planning
Getting planning permission can be a barrier to householders wishing to install microgeneration technologies. In England and Scotland, changes to permitted development rights were introduced on 6th April 2008 and 12th March 2009 but excluded wind turbines, for reasons of possible noise and amenity issues.
Last year the Department of Communities and Local Government (DCLG) consulted on proposals to extend permitted development rights (PDR) to various categories of renewable energy technology, including domestic wind turbines. The consultation suggested at 45 decibel noise limit for permitted planning (PDR).
Permitted Development Rights (PDR) removes the requirement to submit a planning application to the local planning authority for developments meeting specified conditions, saving costs and time. But in the case of wind turbines, potential impacts such as noise, vibration, appearance and public safety all need to be carefully addressed. The consultation setting out the details and the Government’s proposals can be found at on the National Archives version of the Communities & Local Government website.
Wind turbine installations are now eligible for permitted planning, if they meet criteria set out in the MCS planning standards available on the MCS website.