The development of a smart, rugged, ultraefficient grid tied interface for small wind turbines

The UK’s climate change target is to reduce greenhouse gas emissions by 34% in 2020 and
80% in 2050 [DTI white paper]. Small wind turbines (SWTs) – rated up to 100kW – could be
potentially make a significant contribution towards reducing GHG emissions. The
Government has introduced a range of incentives to encourage the uptake of SWT
technologies, incl. Feed-in-Tariffs (FiT), the Green Deal and removal of the need for planning
permissions in some cases. Despite the recent increases in market uptake of SWTs, there
remains a number of challenges that restrict both the maximisation of their power output and
wider adoption of this promising renewable energy solution.
SWTs typically employ fixed-pitch blades, which facilitate simple structure, low cost, and
high reliability. However, due to the fixed nature of the blades, SWTs have a tendency to overspeed,
causing over-loading problems at excessive wind velocities. Overloading of expensive
electrical components is undesirable and often causes irreparable costly damage. An auto-stop
feature to prevent such incidences has not become commonplace due to cost and powering
supply limitations.
The nature of wind and its inherent fluctuations, mean grid connection inverters - which
convert DC current to grid compliant AC - must be oversized to deal with any excessive wind.
Oversizing is a crude way to deal with the issue, but this approach has become commonplace
since incumbent wind inverters are based on technology originally developed for generation
of stable solar energy. The result of over specified inverters is highly inefficient (30-40%)
power transfer at average site wind speed.
FuturEnergy has developed an innovative system concept to overcome these problems. If
successful, we will capture roughly 10% of our markets and generate a cumulative revenue
total of £13.7million. This revenue will result in a cumulative profit of £5.14million. With an
initial investment of £800,000, we estimate an attractive RoI of >600%.