Technology for the next generation of wind turbines
The Norsetek wind turbine technology is more than incremental adjustment of the previous solution. Our approach to large size design resulted in as follows: Material weights, fabrication cost as well as levelled cost of wind energy will be significantly reduced.
In addition the technology facilitates for up to 100% increase of wind turbine unit sizes
We have also resolved handling and transport restrictions related to component dimensions and weights on multi-megawatt wind turbine blades and tower sections. Each blade is sectioned near mid length by bolted interfaces. The blade is assembled at site of erection.
Aluminium can be used in major items and (fatigue issues are resolved) at a cost reduction. The rotor tilt angle is greatly reduced which will increase power producton as well as fatigue lifetime.
The Norsetek wind turbine technology also bring along options with five slim rotor blades. We expect this improves architecture and appearance and reduces the noise emissions because of a reduced optimum rotor speed.
The technology is protected in all major markets and patent is achieved in several large countries including China and USA.
The technology may well be utilized on medium size wind turbines but weight and cost saving will grow with turbine size to well beyond the largest multimegawatt machines.
Rotor
- Considerably lighter, stronger and more cost effective rotor structures (blades + hub), estimated to 30% cost reduction.
- Aluminium in the inner part of the rotor is also very promising (and yes, fatigue is considered small problem).
- Small blade tip deflections and more space for tower and also a reduced rotor tilt angle.
- Slight increase of rotor efficiency.
- Reduced rotor tip speed, less blade passing noise and subsequent noise reduction.
- The rotor blades are divided in two by bolted junction, and easy to transport.
Tower
- Layout which provide for more cost efficient and taller towers.
- Tower with three feet spread and a considerably more material efficient foundation.
Total solution
- More material efficient and significant increase of optimum size of wind turbines. 5-10 MW onshore and 12-15MW offshore is expected.
- Cost-, weight- and aero-efficient 5-bladed rotors consisting of slimmer blades. Less noise emission and improved visual appearance expected.
- Logistics in line with other industries: Items are made in handy sizes for smoother sourcing and fabrication. Even large rotors are easy to ship globally and road transport on narrow and bendy roads is easy. The blade parts are then bolted at site and assembled with the rest of the wind turbine.
- There is only one movable item in the blade, the extra blade bearing. Which is a sliding bearing near the mid of the blade.
- The Norsetek wind turbine technology is applicable to both onshore and offshore wind industries.
- Any technical disadvantages are considered to be of minor importance.
A large Norstek wind turbine installed in a landscape (3D model).
Background of the Norsetek Light Rotor structural design:
Other industries and structures like bridges, houses and factories are transported on the road in parts. The first small bridges and ships also consisted of just few parts, until they grew bigger. This will also be necessary for wind turbines and our solution shown down right in fig 3 is a sound response to the need for large and cost efficient wind turbines. Each of our wind turbine blades has structural similarities with a sail boat mast, where pretentioned stays are necessary in order to have a sufficiently light and rigid rigging.
The technology development started when the founder of Norsetek saw the need for large offshore turbine units. 10-15MW unit sizes were defined as key targets. Conceptual studies on large turbines combined with regular”maritime” approaches provided interesting results. Later studies, improvements, analyses and application of wind energy knowledge resulted in the Norsetek Light Rotor and our light wind turbine tecnology.
A 5MW rotor has been analysed and compared with a light reference rotor by Garrad Hassan and Partners Ltd. They consent in the approach and in our calculations, for instance related to the light weight.
Conceptual approach: When structures become large, air separation between tensioned and compressed members are used in order to provide executable solutions and far better cost efficiency. The Norsetek Light Rotor (down right) is similar solution for large wind turbine structures.
Side view of a Norsetek Rotor with a multilegged tower. The stiff performance of the rotor provides space for a stable and light tower structure and even a reduced rotor tilt angle.