Environmental Engineering Reference
In-Depth Information
number of technical solutions, ranging from special-purpose FACTS devices to
enhanced WTG control. Solutions are likely to be dictated by economics and to be
system-specific. It may be cheaper to accept some curtailment.
Power systems have always been prone to dynamic instability. The solution
has often been to install 'power system stabilisers' at influential generators. High
wind power penetration may tend to displace some of these generators. The con-
sequent loss of inertia exacerbates the problem. Hence the wind sector may have to
provide equivalent solutions to avoid curtailment. Co-ordinated control of inverter-
connected wind generation could provide a low-cost solution, but the design is
likely to be challenging. It will probably be necessary to replace the missing syn-
chronous inertia with pseudo-inertia from variable-speed wind generation.
Co-existence with other forms of low-carbon generation
The main concern here has been with wind energy development in power systems
where fossil-fuel fired thermal generation is the prevailing technology. However,
wind power may also have to co-exist with other low-carbon generation technol-
ogies. In particular, nuclear power has been the main source of low-carbon elec-
tricity for the past half-century, notably in France and the United States. The cost of
nuclear power has generated as much debate as the cost of wind power. The
planned new nuclear power station in Britain - Hinckley Point C - will be paid
£95/MWh. That is comparable with most feed-in tariffs for wind. Nuclear gen-
eration has a low running cost and is invariably run as base-load plant. New nuclear
plant is claimed to be flexible, and is therefore less likely to constrain wind pene-
tration compared with traditional nuclear generation.
Although nuclear power is essentially emission-free, it is not renewable. The
main source of renewable electricity is hydro-power, as has been the case since
the early days of power supply over a century ago. The hydro-electricity potential
in the developed world has been largely exploited, and is often dwarfed by the
subsequent development of fossil-fuel and nuclear generation. However, where
hydro-power is plentiful, it can complement wind power. Essentially, hydro-power
is used to generate at peak times. If wind power is available, hydro-power potential
is stored for later use. A good example is the way in which Danish wind power is
balanced against hydro-power in the Nordic countries. Much the same argument
applies to pumped storage. The pumping/generating regime needs to be flexible
to take account of wind generation. The aim is to use the pumped storage to max-
bearing in mind
70-75 per cent.
North-western Europe has abundant marine energy resources. Tidal and wave
energy resources have now been well researched (MacKay, 2009), and several
demonstration projects are in operation. Unfortunately, they suffer from the same
deficiencies as wind energy - variability and low capacity factor, albeit a com-
pletely predictable variability in the case of tidal power. They therefore tend to
compete with, rather than complement, wind energy.
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