EPIC’s helical wind turbines were installed on October 19th 2008. The 5m tall turbines, mounted on top of their 9 m masts, are clearly visible above the roof of the exhibition halls. The option to mount them directly onto the roof would have provided an even better performance but the particular planning restrictions that prevail at the EPIC site would not allow this.
These are the first helical wind turbines to be installed in Lincolnshire and are numbers 29 & 30 in the UK.
The Helical wind turbines installed at EPIC were chosen as micro wind power demonstrators. The blades activate at wind speeds from 4.0 to 21 m/second and can spin up to 300 rpm before a safety brake operates automatically. Their minimum performance is expected to be about 5,000 kW hours saving about 2,900 kg of CO2 per year. The original aim was to mount the turbine units on 15 metre masts which would have increased the performance to around 8,500 kW hours thus saving over 4,900kg of CO2.
The location of all wind turbines is an important factor in their performance. Wind is not a constant resource. Buildings can exert a wind shadow and can change the direction and intensity of the wind.
Wind speed and direction varies all the time and the graph belopw indicates wind speed and direction experienced by the two turbines between October 10 and November 11 2011.
Unusually the past 30 days have been dominated by easterly winds and the profile of wind speeds shows some similarities to the predicted wind resources for the location of the turbines. However it is obvious that 52% of the wind movements yield no generation at all.
Overall the energy yield of the site has disappointed. Wind runs measured by the met station 5 m above EPIC’s roof give average wind speeds twice that experienced by the turbines themselves. If the original 15 heoght application had not been reduced to 9m due to planning restriction by MOD the overall output of the turbines would be treble.
Reliability has also been a challenge as can sometimes be the case with first-to-market technology. After one year of activity vibration sensors began to shut down one or both of the turbines with increasing frequency. Problems were then detected with metal fatigue in some of the rotors attachments and the turbines were shut down for many months. Energy consumption during start up at low wind speeds ate into overall output performance and the system’s sofware has undergone several upgrades. Quiet Revolution have worked with EPIC through all these deve;opmental issues and we remain confident that the turbines will improve.