Assessing the Potential for Small Hydropower Developments...
Transcript of Assessing the Potential for Small Hydropower Developments...
Assessing the Potential for Small Hydropower
Developments on Scottish Forestry Commission Land
Aims • Establish potential hydro resources across the NFE by estimating low flows
at remote, un-gauged sites using the Low Flow Study Reports (LFSR)
derived by the Institute of Hydrology
• Compare the viability of exploiting such schemes using a theoretical
feasibility scale called the Remote Hydro Exploitation (RHE) index –
incorporating accessibility, distance from grid and remoteness from
considerable demand
• Use short case studies to highlight specific issues with energy generation at
given locations and possible options for future utilisation
Mark Calderwood - 0806582 Case Study: Allt Daidh & Allt Dabhoch, Grula, Skye • Fast flowing waterfalls located in Glen Brittle Forest. A site visit to Allt Daidh
and consultation with ‘Hydrobot’ software enabled a more detailed analysis.
• Allt Daidh: RHE Index: 3.78: Estimated demand from Eynort & Grula = 62.5
MWh/yr, potential energy surplus ≈400MWh/yr.
Overview of Results
No. Name Location Grid Ref.Area
(km2)
Annual
Runoff (mm)
ADF
(m3/s)
Q30(30)
(m3/s)
Q30(365)
(m3/s)
Net Head
(m)
Power Rating
(kW)
Energy
(MWh/year
Total Distance
(Grid + Pop.) (km)Accessibility
RHE
Index
1 Allt DaidhGlen Brittle Forest,
Isle of Skye
NG 386
2671.50 2628 0.103 0.088 0.124 168 130.1 456 8.52 0.44 3.78
2 Allt DabhochGlen Brittle Forest,
Isle of Skye
NG 383
2342.42 2628 0.166 0.141 0.201 90 112.4 394 14.92 0.44 6.62
AKinlochan, Loch
Doilet
NM 819
6730.25 2581 0.0166 0.014 0.02 270 33.2 116 10.04 0.67 6.7
BKinlochan, Loch
Doilet
NM 819
6743.58 2581 0.237 0.229 0.326 50 101.2 355 10.04 0.67 6.7
CKinlochan, Loch
Doilet
NM 819
6752.72 2581 0.18 0.172 0.246 110 167 585 10.04 0.67 6.7
4Allt na
CaillicheLoch Ailsh
NC 325
1034.41 1994 0.213 0.208 0.243 90 165 578 34.32 0.44 15.1
5Allt
Scamodale
Glen Hurich, Loch
Shiel
NM 839
7353.55 3009 0.573 0.555 0.68 95 465.4 811 20.05 0.78 15.6
6 Coire an t-Sith Argyll Forest ParkNS 130
9003.29 2379 0.193 0.188 0.249 70 116.4 408 12.07 0.56 6.71
7 Allt Criche Ben DonichNN 207
0370.75 3019 0.06 0.059 0.073 105 54.6 191 1.64 0.44 0.73
8Allt Glas-
DhoireLoch Lochy
NN 235
9382.61 2693 0.186 0.163 0.234 130 187.2 656 8.43 0.89 7.49
9Allt Camas a
ChoirceLoch Sunart
NM 765
6137.44 2581 0.498 0.494 0.696 70 305.2 1070 5.6 0.56 3.14
10Srath a
Chraisg
River Tirry, Crask
Inn
NC 525
2447.14 1423 0.216 0.234 0.249 30 62 217 19.48 0.56 10.91
3Allt Coire
Chaillich
An Option for Remote Hydro: Hydrogen Generation • Requires a drive in the hydrogen economy, and economic challenges are
reinforced by the need to understand the logistics of the technology in terms
of distributing to locations where a considerable vehicle-fuel demand is held.
• ‘California Fuel Cell Partnership’ → ‘’vehicles typically carry around 4-6kg of
hydrogen gas at a time, and can get between 50-70 miles/kg’’ [1].
• In Glen Brittle Forest, an estimated potential surplus of 800 MWh/year of
combined energy is available to produce 20,000kg of hydrogen, (using
typical electrolyser efficiency: 40 kWh of electricity ≈ 1kg of hydrogen [2]).
0
20
40
60
80
100
120
140
160
0 10 20 30 40 50 60 70 80 90 100
Allt Daidh FDC for 30-day and 365-day Durations
Pe
rce
nta
ge o
f A
vera
ge D
isch
arge
Percentage of Time Discharge Exceeded
0.103
Dis
char
ge (
m3/s
)
0.88
0.124
Q'P'(30)
Q'P'(365)
Conclusions • The LFSR allow useful short-term estimations of flow profiles, however
data becomes varied and unreliable as durations extrapolated
• The RHE Index method can be applied to many analysed schemes
across the NFE, and could provide an interlinked dataset that relates
magnitudes of energy with viability for exploitation
• A substantial drive in emerging technologies that involve energy storage
such as the hydrogen industry is required to fully utilise the great
potential of hydropower left ‘stranded’ across the NFE
1. Gardner, D. (2009). Hydrogen Production from Renewables. Available online at:
http://www.renewableenergyfocus.com/view/3157/hydrogen-production-from-renewables/
[Last Accessed: 24/8/14]
2. California Fuel Cell Partnership. (2013). What Do You Need to Know About Hydrogen and
Fuel Cell Electric Vehicles?
• Expanding the scheme: Incorporating Allt Dabhoch: RHE Index: 6.62,
• Additional potential energy generation ≈ 400 MWh.
Methodology 10 watercourses were identified, and the LFSR enabled design flows to be
calculated – taken as 30th percentile flows (commonly used within industry)
over 30-day durations; (Q30(30)). Q95(10) is initially derived as a starting
reference point, and is dependent on Base Flow Index (BFI), Average Annual
Rainfall (SAAR) and the proportion of a catchment area covered by a body of
stagnant water (FALOCH). Calculated from;
𝑸𝟗𝟓 𝟏𝟎 [%𝑨𝑫𝑭] = 𝟖. 𝟖𝟏 𝑩𝑭𝑰 + 𝟎. 𝟎𝟐𝟒𝟖 𝑺𝑨𝑨𝑹 − 𝟐. 𝟒 𝑭𝑨𝑳𝑶𝑪𝑯 − 𝟐. 𝟔𝟔
Average discharge (ADF) is dependent on estimations of both catchment area
and annual runoff, which is itself obtained using evaporation totals and SAAR;
𝑨𝑫𝑭 = 𝟑. 𝟏𝟕𝟏 𝒙𝟏𝟎−𝟑 𝒙 𝑨𝑹𝑬𝑨 𝒙 𝑨𝒏𝒏𝒖𝒂𝒍 𝑹𝒖𝒏𝒐𝒇𝒇
Q95(10) is converted to absolute units, and Flow Duration Curves are
formulated by firstly adjusting Q95 to a desired duration (Q95(D)), and
furthermore plotted for any percentile; Q’P’(D), using various type curves and
multiplying factors.
Flow profiles over 30 and 365 days were derived, the latter formulated to
highlight the limitations in extrapolating the estimation method over a longer
time period. SAAR and Annual Runoff highly influence the estimation
procedure - More water entering model = higher fluctuations in predictions,
especially at higher percentile flows (i.e. Q95). This results in a scenario
where Q95(365) values are often found to exceed ADF totals, results which
should be completely unattainable. Power and energy magnitudes for a given
site are obtained using Q30(30) flows and OS mapping resources that allow
head levels to be determined.
The theoretical RHE index allows the utilisation of a resource to be assigned a
degree of difficulty using the following equation;
𝑹𝑯𝑬 𝑰𝒏𝒅𝒆𝒙 = 𝑫𝒊𝒔𝒕. 𝒕𝒐 𝟑𝟑𝒌𝑽 𝒍𝒊𝒏𝒆 + 𝑫𝒊𝒔𝒕. 𝒕𝒐 𝒑𝒐𝒑𝒖𝒍𝒂𝒕𝒊𝒐𝒏 𝒙 𝑨𝒄𝒄𝒆𝒔𝒔𝒊𝒃𝒊𝒍𝒊𝒕𝒚
Where accessibility is given as a fractional value between 0.33 and 1, based
on a potential schemes score out of 9 from the following table:
Very good communications to site - A or B road running close nearby 1
Average roads leading to site, single track wide at best, a distance from A or B road and may require some alteration 2
No connecting roads suitable for vehicle transport to site, completely isolated scheme 3
Clear paths extending to essential access points at different heights of scheme 1
Some paths around construction site though extension work would be needed 2
Very few paths, considerable construction work required prior to development being deemed feasible 3
Landscape gently sloping, construction and any electrical wiring can be built to cover rural landscape with little issue 1
Mediocre terrain - some difficulties in construction and navigation but feasible to build scheme 2
Extremely steep topography making construction and navigation around site difficult, any electrical wiring must follow roads 3
/9
Connecting
Roads
Total
Forestry paths to
essential points
of scheme
Surrounding
terrain