Download On the way to 20MW wind turbine

On the way to 20MW wind turbine
Written by Admins
Last Updated: Wednesday, 08 June 2011
Enerģija un Pasaule (http://85.254.195.140)
The UpWind research project has found that machines as large as 20 MW are feasible
through developing a radical new design philosophy .
Significant additional research efforts in wind energy are needed if the European
Commission's goals for wind power are to be achieved. It will mean delivering
EWEA's 'high' scenario: 265 GW of wind power capacity, including 55 GW
offshore, by 2020; 400 GW, of which 150 GW is to come from offshore, by 2030; and 600
GW, with 350 GW offshore, by 2050, meeting 50% of the EU's electricity demand.
Going offshore implies not only new technologies but also an upscaling of wind turbine
dimensions and wind farm capacities as well as new electrical infrastructure. Underlying all
research activities is a focus on reducing the cost of energy.
The industry is taking two parallel pathways towards cost reduction: first, incremental
innovation, looking at cost reductions through economies of scale resulting from increased
market volumes of mainstream products, with a continuous improvement of manufacturing
and installation methods and products; secondly, breakthrough innovation, focused on
creating innovative products, including significantly upscaled dedicated offshore turbines, to
be considered as new products.
Funded under the European Union's Sixth Framework Programme (FP6), the UpWind
project has been exploring both pathways. The UpWind project initiators realised that wind
technology disciplines were rather fragmented, in that no integrated verified design methods
were available; that essential knowledge was still missing in high priority areas, for example
in external loads; that measuring equipment was still not accurate or fast enough; and that
external factors were not taken into consideration in minimising cost of energy (grid
connection, foundations, wind farm interaction and so on).
Optimum Technology?
Rather than pursue one single 'optimum' technology, UpWind explored various
high-potential solutions and integrated them with a view to the potential reduction of cost of
energy. An optimised wind turbine is the outcome of a complex function combining
requirements in terms of efficiency of electricity production, reliability, access, transport and
storage, installation, visibility, support to the electricity network, noise emission, cost, and so
forth. UpWind's focus was the wind turbine as the essential component of a wind power
plant. Thus external conditions were only investigated if the results were needed to optimise
the turbine configuration.
In Search of the 20 MW Wind Turbine
UpWind established that 'the same, but bigger' would simply not work. Starting
with a reference 5 MW wind turbine it initially extrapolated this reference design to upscale it
to 10 MW, and then on to 20 MW.
This virtual 20 MW design was unanimously assessed as almost impossible to manufacture,
and uneconomic. It would weigh 880 tonnes on top of a tower making it impossible to store
today at a standard dockside, or to install offshore with the current installation vessels and
cranes.
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On the way to 20MW wind turbine
Written by Admins
Last Updated: Wednesday, 08 June 2011
Enerģija un Pasaule (http://85.254.195.140)
The support structures able to carry such mass, placed at 153 metres height, are not
possible to mass manufacture today. The blade length would exceed 120 metres, making it
the world's largest ever manufactured composite element, which cannot be produced
as a single piece with today's technologies. The blade wall thickness would also exceed
30 cm, which puts constraints on the heating of inner material core during the manufacturing
process, and the blade length would also require new types of fibres in order to resist the
loads.
UpWind's 'Lighthouse' Approach to Methodology
This 20 MW concept was drawn up to provide values and behaviour that could be a starting
point for optimisation. UpWind then developed innovations to enable this basic design to be
significantly improved, and therefore enable development of a potentially economically sound
design.
A means of doing this was adopting the lighthouse - a virtual concept design of a wind
turbine in which promising innovations, either mature or embryonic, are incorporated. The
lighthouse is not a pre-design of a wind turbine that will actually be realised, but a concept
from which ideas can be drawn by industry for product development. One example is a blade
made from thermoplastic materials, incorporating distributed blade control, including a
control system, the input of which is partly fed by LIDARs.
The 20 MW Innovative Turbine
While the 20 MW design was unfeasible due to issues of weight and corresponding loads, the
future large-scale wind turbine system drawn up by the UpWind project is smart, reliable,
accessible, efficient and lightweight.
It analysed wind turbine materials, optimising the micro-structure of blade materials to
develop stronger and lighter blades. Fatigue loading also needed to be reduced so that
longer and lighter blades may be built. And the aerodynamic and aeroelastic qualities of the
models were significantly improved. Significant knowledge was gained on load mitigation and
noise modelling.
UpWind demonstrated that advanced blade designs could alleviate loads by 10%, by using
more flexible materials and fore-bending the blades in the second work programme (WP).
After reducing fatigue loads and applying materials with a lower mass to strength ratio, a
third essential step is needed: the application of distributed aerodynamic blade control,
requiring advanced blade concepts with integrated control features and aerodynamic devices.
Fatigue loads could be reduced by 20%-40% (WP2).
Various devices can be utilised to achieve this, such as trailing edge flaps, (continuous)
camber control, synthetic jets, micro tabs, or flexible, controllable blade root coupling. Within
UpWind, prototypes of adapting trailing edges, based on piezo-electrically deformable
materials and SMA (shape memory alloys) were demonstrated (WP1B.3).
However, the control system only works if both hardware and software are incorporated in
the blade design. Thus advanced modelling and control algorithms need to be developed and
applied. This was investigated in WP1B3.
Powered by Elxis 2008.0 (Olympus). Copyright (C) 2006-2008 Elxis.org. All rights reserved.
On the way to 20MW wind turbine
Written by Admins
Last Updated: Wednesday, 08 June 2011
Enerģija un Pasaule (http://85.254.195.140)
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