Environmental Engineering Reference
In-Depth Information
are often relatively remote from centres of population. However, the resource is quite large.
The DTI/Carbon Trust has put the world's total practical tidal current turbine resource at
around 800TWh p.a., with the EU resource being around 48TWh p.a. (DTI/Carbon Trust
2004).
Tidal barrage technology, and to some extent, tidal lagoon technology, is well developed,
with the turbines being similar to those used in hydro projects. There may be some cost
cutting civil engineering innovations available in terms of barrage or causeway construction,
particularly in the case of lagoons, but otherwise these are relatively mature technologies. By
contrast, Tidal current turbine technology is at a relatively early stage of innovation, with
many rival designs and concepts emerging- much as in the early phase of wind energy
development. As with wind power, significant cost reducing improvements can be expected.
That of course assumes continuing development and continuing financial support- this is
a new technology which needs backing to reach maturity. Fortunately, that does seem to be
increasing. As indicated, the tidal current projects around the world include some in the
USA, where marine power generally now seems increasingly to be seen as a significant
option. For example, in 2007, the US House of Representatives Science & Technology
Committee backed legislation that would invest approximately $200m in federal funds for
RD&D on wave energy over four years. Representative Darlene Hooley (Democrat-Oregon),
commented 'Similar to how we helped the wind energy industry get off the ground by
providing production tax credits. Congress today made the first significant investment in what
is projected to be a promising nonpolluting energy source'. One might hope the tidal energy
might also be seen in a similar light. .
The Irish Republic has also recently shown renewed interest in ocean energy, with a Euro
26 allocation for a three years R&D and support programme, although the emphasis seems to
be on wave energy, a major potential source for Ireland. .
For the moment, the UK still seems to be well placed in the tidal field. It could take a
lead with large barrages and lagoons, if those options are backed by the new government
review, and with smaller barrages and lagoons, given the availability of support from the
Renewables Obligation system. Moreover, given that tidal current projects can also apply for
both capital and revenue support under the UK governments £42m Marine Renewables
Deployment Fund, the UK seems likely to continue to dominate in the tidal current field.
The UK's Marine Fund offers eligible tidal current turbine projects grants for up to 25%
of the capital cost, up to £5m, and 10p/kWh in revenue support for the first five years. This is
on top of the support provided by the UK Renewables Obligation, which is in the process of
being adjusted to allow new projects like tidal current systems to receive two Renewable
Obligation Certificates (ROCs) for each MWh produced- the same as has also now been
agreed for tidal barrages and tidal lagoons under 1GW. .
The value of these ROCs varies, but in effect the adjustment means that projects might
get around 8p/kWh extra for the power they produce. In addition, the Scottish government
runs a separate grants scheme, as well as its own Marine Supply Obligation support system,
for wave and tidal current projects. Scotland has the largest tidal resource in the UK, and is
the home of the European Marine Energy Centre, located on the Orkney Islands, which
provides testing facilities. It has been estimated that there are sites for Scotland which could
be used to install up to l0GW of tidal current turbine capacity, generating around 34TWh p.a..
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