by Peter Ravenscroft, Matthew Bates, Lee Pooley, Jill Topp and
Turbine installed May 2017 - Courtesy of MWH Treatment
Reservoir is the first of three reservoirs owned by Severn Trent
Water in the Upper Derwent Valley. The reservoir is bounded at
its southern end by Howden Dam which impounds the River Derwent
and overflows to Derwent Reservoir which in turn overflows to
Ladybower Reservoir. Work commenced on the dam’s construction on
16 July 1901 and was completed in July 1912. The works involved
constructing a temporary village at Birchinlee (or ‘Tin Town’)
for the workers, a temporary railway line from the main line at
Bamford and a link aqueduct to Derwent Dam. The dam is of solid
masonry construction, is 36m tall and 330m long. A catchment
area of some 21km2 drains into the reservoir which holds 8,600
million litres of water. The Upper Derwent Valley is a very
popular tourist attraction for walkers, runners, cyclists and
birdwatchers. It has two visitors’ centres, Fairholmes at
Ladybower and Hatherdene at Derwent.
Harnessing the power
There are two existing
pipes which run from Howden Dam to Bamford WTW. These were
installed c1910 to convey water direct from Howden Reservoir to
Bamford WTW, bypassing Derwent Reservoir. These have long been
abandoned and it was realised that they could be used to feed a
new turbine to generate renewable electricity.
MWH Treatment conducted
extensive surveys on both pipes to establish if the scheme was
feasible and these were found to be in very good condition.
Working in conjunction with Severn Trent Water, MWH Treatment
designed and constructed a mini hydroelectric scheme to harness
the available energy from the 28m head difference between Howden
and Derwent Reservoirs.
As part of their energy
efficiency commitment, Severn Trent Water has a target of
generating by 2020 renewable energy equivalent to 50% of their
own consumption, and this project contributes to this target.
The cross-flow turbine,
installed by MWH Treatment and manufactured by Ossberger in
Germany, is rated at 300Kw and will generate 1,45GWh per annum
of electricity, resulting an annual carbon saving of 760 tonnes
of carbon dioxide. The electricity produced will be exported to
the national electricity distribution network.
Turbine house under construction
Courtesy of MWH Treatment
Courtesy of MWH Treatment
The idyllic location next
to Howden Dam required careful consideration of the materials
and appearance of the new turbine house. The use of locally
sourced larch cladding has provided benefits in cost, carbon
reduction and benefited the local community economics. There are
a number of key benefits:
Larch is a locally grown sustainable product sourced as part of
holistic forestry management.
Hundreds of miles of road transport were saved reducing the
overall embedded carbon footprint of the project.
The timber was processed in the local regional economy.
To blend the turbine
house into the surroundings, a choice of using natural wooden
cladding was made in agreement with the local planning
Typically, larch cladding
is sourced from either Scotland, or Siberia which inevitably
entails significant transport cost and associated carbon impact.
At Howden however, the team worked with Severn Trent Water’s
local site supervisor to arrange for the trees off their own
estate to be used. Suitable trees were felled and transported to
a nearby mill to be sawn and treated, thereby reducing cost,
saving carbon and producing a quality product.
Prior to construction,
the banks of the reservoir were a popular breeding ground for
sandpipers and little ringed plovers. To avoid disturbing their
nests and general well-being during construction, MWH Treatment
laid out black geotextile membrane to dissuade the birds from
nesting in the working areas. These nesting birds have been
restored as part of the landscaping. MWH Treatment worked very
closely with the Forestry Commission and other agencies during
the design and construction phases of this project.
Howden mini hydroelectric scheme under construction -
Courtesy of MWH Treatment
The construction site was
located a mile up a track alongside Derwent Reservoir. The track
is part of a circular walking/cycling route around Howden and
Derwent reservoirs and is very popular with the public. MWH
Treatment undertook some extra measures on this site to mitigate
the impact on both the local visitors and the wider community:
fencing: The site was close to a steep slope and the use
of yellow Heras fencing rather than the standard dull grey
fencing made it easier for the cyclists to distinguish it,
especially in the low light in winter and close to and under
deliveries: With a mile of single track stone road to
the site, the safety of pedestrians and cyclists was a key
concern. To minimise and control the interface with transport
every delivery was collected and accompanied in both directions.
This ensured that the risk to the public was minimised.
The site cabin area
was fenced in close boarded timber: This helped reduce
the visual impact of work. The cabins themselves included the
use of an Eco-cabin which was totally solar powered.
The Howden Mini
Hydroelectric Project is an excellent example where Severn Trent
Water and MWH Treatment have worked together, utilising their
expertise to harness a small scale local renewable energy
The scheme has been
designed and delivered taking all stakeholder requirements into
account. The completed asset will provide many years of
renewable power to the grid and contributes towards Severn Trent
Water’s renewable energy target.
All installation work was
completed in May 2017 and commissioning work will be completed
in August 2017. The turbine will be generating power to the grid
from September 2017.
Turbine house - Courtesy of Severn Trent Green Power
and publishers would like to thank Peter Ravenscroft, Asset
Creation Manager with Severn Trent Green Power, Matthew
Bates, Senior Solution Engineer with Severn Trent Water, Lee
Pooley, Solutions Engineer, Jill Topp and Vicky Gillibrand,
Marketing Manager with MWH Treatment, for providing the
above article for publication.