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For nearly a century electricity has been
generated in Scotland by harnessing the power of
water and this has been highlighted by recent
publicity given to the start of construction of
Scottish and Southern Energy’s Glendoe Hydro
Electric Scheme at Fort Augustus. The scheme is
similar in size to some of the major hydro
schemes built 50 years ago in Scotland, however
it may be one of the last of these large scale
schemes to be built in the UK.
It is however acknowledged that there is still
significant potential for smaller scale hydro
schemes in Scotland, where the main resource,
water, is in plentiful supply. Micro to small
scale schemes of 50 kW to 5MW (5,000kW) in
capacity can provide landowners with steady
revenue for at least 50 years or more.
These smaller schemes are often “run of river”
schemes, where water is extracted and passed
downstream to the powerhouse, where the water
will pass through turbines, generating
electricity, before flowing back into the river
or burn. These schemes usually take one of two
forms; ‘high head’ or ‘low head’. This describes
how much fall is available. High head schemes
tend to take the form of a small diversion weir
higher up a hill side where the water is
abstracted and passed down to the turbine via a
(buried) pressure pipeline. Low head schemes
tend to be typically located about existing
weirs where the use of larger volumes of water
compensates for the lack of head. Old mill sites
often lend themselves to this type of scheme
where much of the original infrastructure, (i.e.
the weir and perhaps the millrace), is still in
place.
The scale of such hydro schemes depends on the
type and area of the catchment, precipitation
over that area and the head of water available.
Larger capacity schemes are usually connected
directly to the grid and the electricity is sold
into the electricity distribution system. Very
small projects are often still grid connected
but are used for self supply with the surplus
being sold into the electricity network, (e.g.
at night when there is little or no on-site/home
demand). In more remote locations, small scale
hydro installations are often a most efficient
and secure means of providing local power when
there is no public electricity supply.
Graham Lumby FRICS
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Whilst such schemes are seen as having minimal
impact on the countryside, environmental
constraints will determine the success of a
scheme. Projects proposed in rivers with
migratory fish will attract much scrutiny and
(probably) constraints. In the planning process,
Environmental Impact Assessments (EIA) are not
required for the smaller size schemes and if a
proposed installation is scoped properly during
the consenting process, even some larger sites
may not require an EIA. This is an area which is
clearly site specific. Schemes of below 1MW will
be consented via a normal Planning Application
through the Local Authority, but schemes of over
1MW will require an application to the Scottish
Executive. In general the major generator’s
interest is limited where schemes are below 1MW,
primarily due to their company’s higher
overheads, but there are a number of smaller
developers who are keen to take on schemes of
below 1MW where their lower overheads can make
small schemes more cost effective.
If landowners have the financial resources to
build a scheme themselves, consultants can be
brought in to give guidance in the planning
process and to assist in procurement and
building the scheme if required. Depending on
the size and constraints of a scheme, it will be
hoped to achieve a return on capital invested
within 10 years of a scheme being constructed.
Bell Ingram are advising landowners on a number
of hydro schemes throughout Scotland, including
the Glendoe project at Fort Augustus. On one
small scale scheme near Aberfeldy, which has
been generating for over two years, we assisted
during the planning phase and currently
administer the finances for the scheme on behalf
of the owner.
Camserney, near Aberfeldy
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