Stockport Metropolitan Borough Council

Hydro Feasibility Study

Final Report Water Power Enterprises

January 2008

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Contents

Introduction 3 Feasibility Study – Brief and Methodology 4 Disclaimer 6 Location of Sites 7 Criteria for Selection 8 Technology 9 Environment Agency 12 Planning Requirements 14 Potential Hydro Sites: Location 1 - City Centre 15 Location 2 – Brinksway Weir 17 Location 3 – Brabyn’s Park, Marple Bridge 19 Location 4 – Chadkrik Weir 21 Location 5 – Otterspool Weir 24 Location 6 – Strawberry Hill, Roman Lakes 28 Location 7 – Brinnington Weir 32 Location 8 – Stringer’s Weir 37 Location 9 – Castle Hill Weir 41 Financial Analysis 46 Conclusion 48 Acknowledgements 49

Appendix 1 – Map of Sites 51 Appendix 2 – Archimedean Screw Cross Section 52 Appendix 3 – Project Timescale 53 Appendix 4.1 – Chadkirk Weir Sketch Plan 54 Appendix 5.1 – Otterspool Sketch Plan 55 Appendix 5.2 – Hydrological data 56 Appendix 5.3 – FDC and HDC 57 Appendix 5.4 – Power Curve 58 Appendix 6.1 – Strawberry Hill Sketch Plan 59 Appendix 6.2 – Hydrological data 60 Appendix 6.3 – FDC and HDC 61 Appendix 6.4 – Power Curve 62 Appendix 7.1 –Brinnington Weir Sketch Plan 63 Appendix 7.2 – Hydrological data 64 Appendix 7.3 – FDC and HDC 65 Appendix 7.4 – Power Curve 66 Appendix 8.1 –Stringer’s Weir Sketch Plan 67 Appendix 8.2 – Hydrological data 68 Appendix 8.3 – FDC and HDC 69 Appendix 8.4 – Power Curve 70 Appendix 9.1 –Castle Hill Sketch Plan 71 Appendix 9.2 – Hydrological data 72 Appendix 9.3 – FDC and HDC 73 Appendix 9.4 – Power Curve 74 Appendix 10 – Financial Analysis 75

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Introduction The threat of climate change and the role of renewable energy in helping to reduce carbon emissions are now very high on the government’s agenda. Renewable energy schemes such as Wind and Biomass – which have tremendous opportunities to tackle climate change because of the large scale of their operations – receive considerable publicity. However, small scale hydro also offers opportunities for tackling climate change. In its report published in 2002, Renewables Northwest stated that if all the river weirs in the UK were used to generate electricity, they could meet 3% of the country’s electricity needs. River weirs once powered the industrial revolution. They can be re- used to help power a new green revolution. Small scale hydro has now begun to receive a higher profile as communities, local authorities and other statutory bodies respond in positive fashion to the challenges of climate change.

In December 2005 Stockport Council produced a Scoping report entitled ‘Renewable Energy in Stockport’. This report considered all renewable energy sources and their potential application in Stockport, including hydro power. The Stockport Scoping report tentatively suggested three hydro sites, namely Castle Hill, Compstall Mill and Stawberry Hill.

The Council followed this report with a consultation exercise, the results of which were shown in March of 2006 in a report entitled ‘Feedback from the two Stockport Council Renewable Energy Study Workshops’. The consultation exercise gave strong and positive feedback to Stockport Council to continue exploring the potential for renewable energy within the Borough.

Stockport Council is a signatory of the Nottingham Declaration on Climate Change. The Council’s Unitary Development Plan, adopted on 31st May, 2006, sets the framework within which renewable energy schemes within Stockport will be considered.

This report will help to provide a basis upon which Stockport Council can consider the question of how to develop what are at the moment only potential hydro sites into fully working hydro schemes that can contribute towards generating renewable energy whilst also reducing carbon emissions.

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Feasibility Study – Brief and methodology

Stockport Council made a successful application to the Energy Saving Trust in late 2008, to fund a study into the potential for hydroelectricity within the Borough. This report is a result of that funding. Interestingly, two of the three potential sites mentioned in the original Scoping report, namely Castle Hill and Strawberry Hill, are also explored in this study.

The brief for the study is shown below...

There are 8 sites identified so far as being potential hydro electricity sites in Stockport, one of which has progressed to the stage that it may well be developed shortly. Of the other eight identified, two are not under SMBC direct ownership but we would like to investigate their potential. Other sites within SMBC that are discovered during this process may be added to the list at a later date. The contractor is required to visit each site and compile/estimate data and produce a written report for stage one and one for each site on stage two. Stage one:

· Carry out detailed measurements of all structures and watercourses

· Desktop estimation of flow data and initial assessment of potential energy capture.

· Assessment of suitability of your site for the various types of available equipment.

· Calculation of system outline cost, likely revenue and economic payback time.

For any sites that have not been discounted at stage one, the following then should continue to take the scheme forward.

· Revisit site and confirm access/environmental issues.

· Initial discussions with Environment Agency and planners.

· Procurement of flow data specific to your site to generate accurate energy capture information and to size equipment.

· Budget quotations for the supply and installation of equipment.

· Sketch drawing of scheme.

· Likely project timescale.

A ninth site was added to the list prior to work commencing. Each of the 9 sites was visited on 10th November 2008. Suitable measurements, photographs and on site data were recorded to enable a decision on narrowing the 9 sites down to 5 viable sites. A Preliminary Report was produced on 28th November 2008 which discussed the criteria for selecting the 5 sites and outlined the potential

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk power outputs of the 5 sites. This report, the Final Report, will discuss in more detail the 9 sites considered and their potential for hydro electric generation.

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Disclaimer

This report has been prepared by Water Power Enterprises (h2oPE) solely for use by Stockport Council. This report is a feasibility study and does not represent a detailed system design. Any systems or equipment proposed for installation should be investigated in greater detail. In producing this report, h2oPE has relied upon information provided by third parties. Neither h2oPE nor their directors, employees or affiliated companies give any representation or warranty, express or implied, as to the accuracy, completeness or fairness of the contents of the report, nor accept any responsibility of liability for any loss, whether direct, indirect or consequential, arising from reliance on it.

Any use of this report by any third party for whatever purpose is solely the responsibility of that party who should use such due diligence to verify the report’s contents and consult its own advisers as may be appropriate.

H2oPE does not give investment advice and nothing in this report constitutes, or should be taken as a recommendation to enter into, or the giving of any advice in relation to, any investment. H2oPE and associates take no responsibility for decisions made or actions taken based upon findings of this study or the contents of this report.

The work described in this report was carried out with support from the Energy Saving Trust’s local authority One to One support programme. The views and judgements expressed in this report are those of the authors and do not necessarily reflect those of the Energy Saving Trust

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Location of Sites

The following sites were listed in the brief...

River Location Name TAME SJ 927 932 Castle Hill (Arden Mill) Goyt SJ 910 907 Vernon Park- Stringers Weir TAME SJ 906 919 Brinnington weir Goyt SJ 941 898 Chadkirk Weir Goyt SJ897 908 City Centre- Goyt at confluence with Tame Goyt SJ 967 867 Strawberry Hill (Roman Lakes) Mersey SJ 883 894 Brinksway Weir (the Co-op) Goyt SJ 93 89 Otterspool Weir Goyt SJ 96 89 Brabyns Park – Marple Bridge

Appendix 1 illustrates the geographical location of each site in relation to Stockport.

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Criteria for Selection

Each site was assessed according to a number of criteria. The criteria were applied to each of the sites visited.

1. Site Access – any potential site must be capable of being accessed by construction traffic and be capable of allowing delivery of the turbine itself. In addition, there must be sufficient space adjacent to the river weir to allow for a temporary construction site. An additional factor is the proximity of the nearest electrical substation.

2. Cost and ease of construction.

3. Potential power output – dependent upon the height and flow of the river.

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Technology

The power that can be derived from a hydro site is a function of the head – or height – of the river weir and the volume of water in the river. The bigger the head and the bigger the height, the more power can be generated.

Hydro turbines at any specific site are designed to capture the greatest possible head and the greatest possible volume of water – within the constraints of the specific site and the requirements of the Environment Agency. Turbines are engineered to turn when water goes through them and it is the turning motion which generates electricity.

There are several types of hydro electric turbines. All the turbines have a gearing mechanism that drives the generator, but they differ in the manner by which the energy is extracted from the fall of water and converted into mechanical rotation. The mechanical rotation is then converted into electrical energy.

The type of turbine considered for the small weirs explored in this report is the Archimedean Screw. There are several reasons for this choice...

1. The Archimedean Screw is designated as ‘fish friendly’. It, and the Waterwheel, are accepted by the Environment Agency as being the least harmful to fish of all the turbine types. Scientific evidence (Fish Monitoring and Live Fish Trials Phase 1, Sept 2007 and Phase 2, April 2008, Fishtek Consulting, monitored by the Environment Agency) shows the safe passage of fish down the screw whilst it is operational. The Archimedean Screw and the Waterwheel operate at normal atmospheric pressure whilst other turbines – for instance the Kaplan – operate by forcing water at high pressure into the system. In addition, the screw turns at a low velocity of approx 28 rpm. This, together with the operation of the turbine under normal atmospheric pressure, enables the safe passage of fish through the system.

2. Depletion Rate – this is measured as the distance between where the water leaves a river to enter a hydro system and where the water goes back into the river. Clearly, by taking a given volume of water out of a river, there will be an impact upon the natural ecology of the river bed. A large depletion distance may therefore compromise the ecology of the river bed. The smaller the depleted distance, the less impact there will be upon the fish and wildlife ecology. The Archimedean Screw has the lowest depletion rate because it is placed alongside a river weir – the water enters the system from just above the weir and returns to the river just below the weir. Whilst more traditional turbines such as the Kaplan can also be placed alongside the weir, the Kaplan does not have the advantage of being considered ‘fish friendly’.

3. Visibility – because the Archimedean Screw is visible, there is an educational benefit to this type of turbine. It can be readily viewed whilst in operation and the linkage

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk between the turning motion and the generation of electricity is immediately obvious. The educational aspect of the Archimedean screw ought not to be underestimated. The Kaplan system is inside the power house and cannot therefore be viewed.

4. Cost efficiency – The Archimedean screw is the most cost efficient option. A report funded by Yorkshire Forward (Archimedes’ Screw: Copley Hydro Power Generator) showed that the costs of installing a Kaplan turbine in relation to an Archimedean Screw are higher per kW installed. This conclusion is born out by the experience of Water Power Enterprises, h2oPE, in the numerous feasibility studies undertaken on potential river weir hydro sites. The difference in cost is due to two factors, namely the need to keep fish and debris out of the Kaplan turbine and the requirement to place the actual Kaplan turbine inside the power house. The ‘power house’ is where the gearing mechanism, the generator and electrical control equipment is placed. The Archimedean Screw does not have to be placed inside the power house whereas with the Kaplan, the turbine is placed inside the power house. These two effects result in increased capital cost and maintenance. The need to make sure that no fish or debris enters into the Kaplan system requires a fine mesh screen at the water inlet channel. This has to be regularly cleaned and is recommended to be accompanied by an automatic trash cleaning device. This will increase the capital costs of the project. In addition, because the Kaplan turbine is placed inside the power house, this necessitates that the actual power house is larger than that required for the Archimedean screw. This also adds to the civil cost of construction.

The Yorkshire Forward Report stated...

...the study showed a strong cost advantage for the Archimedes’ screw. For an energy output of about 15% more, the Archimedes’ screw cost about 10% less. So in terms of capital cost in £ per MWh per year, the Archimedes’ screw was 22% cheaper than the Kaplan turbine...

A further study undertaken by Western Renewable Energy on behalf of Goring and Streatley Sustainability Group, considered both the Kaplan and Archimedean screw on the same site, but the comparison work clearly favoured the screw.

It cannot always be assumed that the Archimedean Screw offers the most cost effective choice. However, it offers considerable other advantages over the Kaplan system, as described in (1) to (3) above. It is for these reasons that the Archimedean Screw is considered more cost effective for small scale hydro schemes up to about 250 – 300kW. This figure will differ depending on the peculiarities of each site.

The diagram below, reproduced with kind permission of Mann Power Consulting, illustrates the efficiency of various turbines at design flows. Whereas the Kaplan is more efficient between approx 30% and 90% of its design flow, the Archimedean Screw is more efficient at low flows. However, the cost difference per kW installed makes the Archimedean screw more cost efficient per kW installed. 10

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Reproduced with permission of Mann Power Consulting

Appendix 2 illustrates an Archimedean Screw in cross section. The photograph below shows an Archimedean Screw at New Mills in Derbyshire. The structure just to the right of the screw is a fish ladder.

New Mills, Derbyshire

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk The Environment Agency

The Environment Agency supports hydro power in principle. However, each potential site must consider a number of factors for which the EA has statutory responsibility, namely flood risk, water resources, pollution and fish protection.

1. Flood Risk

All nine sites considered within this report – not surprisingly – are in areas of 1% flood risk, ie floods are likely to occur once in every hundred years. Proposals for each site must convince the EA that they do not add to the flood risk. Hydro sites are generally placed alongside a river weir and not within the river bed. Therefore the power house, turbine and associated water channels must be shown not to increase flood risk. Generally speaking, the small size of power house required for an Archimedean Screw will not constitute an increase in flood risk, more especially so when it is above and outside of the river bed. Clearly, consideration must be given to the siting of the electrical control equipment inside the power house to avoid the risk of flood damage.

2. Water Resources

A hydro site must obtain two permissions from the EA, namely an Abstraction License and Land Drainage Certificate.

a. Under the Water Resources (Abstraction and Impounding) Regulations 2006, a water abstraction license will be required from the Environment Agency for schemes which abstract water and then return it to the watercourse. The Abstraction License is legal permission to remove a certain amount of water from the river in order to operate a hydro plant. Such licenses are given for a period of up to 10 years and are subject to renewal after that period. Licenses are given ‘with the presumption of renewal’. The License will also indicate the amount of water that is required to be left in the river to go over the weir. This is usually the Q95 level (the flow exceeded 95% of the time). The weir must always be kept wet to help its structural stability, to assist fish passage and for the aesthetics of the weir. The amount of permitted water for a hydro system is subject to a number of considerations, namely the amount left for the river weir but also the amount required for any fish passes conditional upon the hydro development and any other abstraction licenses that may exist in the river. The application fee is currently £135 and may also include advertising costs. It usually takes 4 months to obtain an abstraction license and the EA may require supporting reports – particularly for the environment and the effect on fish – in order to agree the license. However, the EA has now switched to a national licensing scheme and the effect of this upon the timescale for developing a hydro site has yet to be assessed.

b. Land Drainage Certificate – any civils works within 8 metres of the river bank will require a Temporary Land Drainage Certificate to ensure that no pollutants enter the river whilst the site is being constructed. In addition, a Permanent Land Drainage Certificate is required for the actual operation of the hydro site. This is again to ensure that no pollutants enter the water course during the operation and maintenance of the system. 12

PDF created with pdfFactory Pro trial version www.software-partners.co.uk 3. Fish Protection

At the time of writing, the EA have submitted a consultative document – Passage of Fish Regulation – which will impact on future hydro developments. At present, the EA has a statutory duty to protect fish. This duty will remain in force but will be added to after the consultation period. The consultative ‘Statement of Intent’ seeks to address obstructions to the free passage of migratory and freshwater fish. It states...

The purpose of this Statement of Intent (SoI) is to set out, in principle, the way in which the Environment Agency intends to use the new powers that the regulations will provide in respect of fish passage and screens. It may be modified as a consequence of the Defra consultation, and we anticipate that a revised Statement may be required before the regulations are confirmed.

Following consultation, the issue of fish passes and who pays for them is more likely to have tighter guidelines and will impact upon hydro development.

According to the Catchment Abstraction Management Strategy for the Tame, Goyt and Etherow rivers, the Tame and Goyt have healthy populations of fish. Brown trout are recorded in the Goyt and most of the Etherow catchment areas. Angling is widespread and theS tockport Federation of Anglers ought to be consulted about any proposed hydro developments.

Because of these considerations, it is likely that the EA would require fish passes to be constructed alongside hydro schemes to help with the migratory passage of fish. This does represent a cost saving when installing a fish pass on a ‘stand alone’ project as the civils costs of the fish pass can ‘piggy back’ on the civils costs of the hydro scheme.

Each of the 5 potential hydro sites explored in more detail below, carry individual comments about fish passage and the Environment Agency.

Data from 3 local gauging stations are relevant to this work, the EA stations at Portwood (Tame), Compstall (Etherow) and Marple Bridge (Goyt). For relevant comments see:

http://www.nwl.ac.uk/ih/nrfa/station_summaries/069/017.html

http://www.nwl.ac.uk/ih/nrfa/station_summaries/069/015.html

http://www.nwl.ac.uk/ih/nrfa/station_summaries/069/027.html

There are significant abstractions for public water supply throughout the Borough.

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Any hydro site within the scope of this report will require planning consent. This normally takes two months from the point of ‘validation’. Each scheme will need a Detailed Scheme Design drawing up which would form the basis of the planning application. There are now national guidelines concerning planning consent and the validation requirements. In order for a planning application to be ‘validated’ the application would need to supply a number of plans and reports, specifically...

a. Site plan, Location plan, Block plan and elevations. These will be required at given scales, the details of which need to be sought from the planning officer prior to submitting an application.

b. In addition, each application will need a Design and Access Statement and, depending on the site, an environmental report, economic statement and statement of community involvement. The number of supplementary reports are site specific and an early meeting with planning officers is necessary to ascertain exactly which reports will be required.

The recent Climate Change Act of 2008 has established compliance and accountability procedures for meeting Government targets on carbon emissions. These targets will be legally binding and Local Authorities will play a role in meeting and monitoring the targets. Failure to reach the targets will mean penalties in central government funding. Stockport Council is a signatory of the Nottingham Declaration on Climate Change and has a UDP strategy favourable to the development of renewable energy. These factors, taken together, suggest that Stockport Council is fully committed to developing renewable energy schemes.

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Potential Hydro Sites

Each of the 9 sites visited are considered in turn. The rationale for rejection of 4 of the sites is explained and the remaining 5 sites are explored in more detail.

Location 1

City Centre – river Goyt and confluence with Tame

River Weir

This weir is situated just above the confluence of the Goyt and Tame rivers and is therefore only capable of using the water from one of the rivers, namely the Goyt. The weir has symbolic significance in that it marks the start of the Mersey and a hydro scheme at the site is interesting from that point of view alone.

Access to the site was not possible. The river is canalised at this point by walls at least 8 metres high on either side. There was no access down to the river itself. The height of the weir was estimated at half a metre. In addition, the weir is used by the Environment Agency as a Gauging Station. Of the nine weirs being explored, three are used by the Environment Agency as Gauging Stations. In discussion with the EA concerning this, it was stated that each potential hydro site which used a river weir also used by the EA as a gauging station would be treat on a case by case basis. However,

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk additional costs would accrue to the developer because if a hydro scheme did occur at such a weir, the EA would have to recalculate its ratings at each site.

However, even given go ahead by the EA on such a site, the capital cost of a scheme at this weir would be prohibitive.

River Weir

Environment Agency Gauging Station at City Centre Weir – note high canalised river banks making for difficult access and cost of construction.

The usual method of construction of a hydro scheme in relation to a river weir is to place it alongside the weir. This requires a large trench to be dug into which the turbine is placed. The construction of such a trench at the City Centre weir would be prohibitively expensive given the depth of the trench required – at least 8 metres. In addition, the walls of such a trench would then need to be supported. The other option would be to place the hydro turbine on top of the weir itself. However, this option is not possible because the cost of construction would be prohibitive (work on the river bed requires specialist firms with secure and expensive coffer dams). In addition, the power house would need permanent protection from the river and could be viewed as a flood risk. Indeed, even if such a scheme was not considered a flood risk, there would be a need to protect the electrical control equipment inside the power house from flood damage.

The City Centre weir is therefore not considered as an option for hydro power generation.

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Location 2

Brinksway Weir

Brinksway Weir

Situated near the Co-operative Bank ‘Pyramid’, it is unlikely this weir was ever used to generate power. There are a number of weirs in Stockport which have been used to provide water for former dye works. As such, the weirs simply needed to take water from the river for washing dye from clothes and were not therefore built with high heads for generating mechanical power. Brinksway is likely to be just such a weir used for washing dye.

The height of the weir was estimated at being half a metre. This factor alone will cause technical difficulties in installing a hydro turbine capable of taking the volume of water. The small height of weir means that the length of the screw would itself be small. Because the length of the screw is too short and therefore the number of veins of the screw are too few, the water would flow through the screw without significantly turning it and generating power.

Concerning the Kaplan turbine, a rule of thumb states that the diameter of the turbine should not be greater than the head. A diameter of turbine at less than half a metre reduces the volume of water that the system could take and therefore would result in much less power output.

Generally speaking, it is best to consider weir heads of 1 metre and above for hydro power sites. From a technical point of view, therefore, Brinskway weir is not considered viable.

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk The photograph below shows Brinksway weir after high rainfall. The weir has all but disappeared from view. The photograph is also useful from a more general point of view in showing the effect of heavy rainfall on the height of a weir. Generally speaking, heavy rainfall will reduce the height of a weir and therefore reduce the power output from a given hydro site.

Weir

Brinksway weir after heavy rainfall

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Location 3

Brabyn’s Park - Marple Bridge

Marple Bridge

The weir at Marple Bridge was measured at approx 1 metre in height. A more accurate measure was not possible due to the heavy rainfall of the previous days. However, the site is not considered suitable for hydro for two reasons.

1. The structure of the weir appeared degraded. Attempts to site a hydro scheme adjacent to the weir would have to also consider upgrading the weir. The capital investment in a hydro site requires confidence in the structural stability of the weir. Also, the weir crest needs to be level to enable an accurately measurable flow to go through the hydro system. In the case of Marple Bridge, the crest of the weir did not appear sufficiently level because of the degrading of the river weir.

2. The weir is at the bottom of a natural steep sided valley, at least 5 metres deep. The weir was originally constructed to provide power to a mill on the east bank of the river. Access to that side is limited by modern landholdings and buildings. Even if access were not an issue, the amount of construction work required to dig the necessary ditch alongside the river weir – and the heavy traffic that would be required for both the digger and removal of spoil – would make the capital costs of the civil engineering too prohibitive.

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Given that the brief for this feasibility report requires the identification of 5 out of 9 sites, there are far more favourable sites in Stockport than Marple Bridge. The photograph below shows the weir after heavy rainfall.

Marple Bridge weir – taken from the roadside and giving a sense of the height of the land above the river

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Chadkirk Weir

Chadkirk Weir

Chadkirk weir has been breached and is in a very unstable condition. The photograph below was taken in November 2008 and it is likely that the remaining structure will suffer further degradation over the winter. Chadkirk weir is also an Environment Agency Gauging Station. Questions remain as to the future of this weir. At the time of writing, the Environment Agency has stated that any reconstruction would be a cost to Stockport Council. It is understood that a bridge for cyclists is to be built across the river at this point – part of the national Sustrans network of cycle paths.

In the opinion of the report authors, Chadkirk weir is not a viable site for a hydro scheme because of the large cost of reinstating the weir and is not one of the 5 weirs that are recommended for future development. However, given the interest in the possible reinstatement of the weir and the possible juxtaposition of the Sustrans cycle bridge, we offer the following information – in good faith – to help make a rational decision about a possible hydro site at Chadkirk. It is also understood that that a nearby school is potentially interested in purchasing any hydroelectricity using a private wire direct to the school. Whilst this would enable a higher price to be obtained, the cost of a private wire and its connection to the school have not been factored into the overall budget. A working figure of at least £100 per metre should be allowed and a budget of £10,000 be added for the actual 21

PDF created with pdfFactory Pro trial version www.software-partners.co.uk connection. In addition, a private wire would need rights of easement over any private land that it had to pass through and would need legal agreements with all such landlords.

Assumptions

1. The Environment Agency agreed to reinstating the weir and that the cost was met by Stockport Council

2. The weir height after reconstruction is 2 metres

3. Cost of reinstating the weir - £175,000. This is simply an estimate based upon a visual inspection. A quotation would require a far more rigorous examination of the river itself.

4. A wholesale price of electricity at 5p per unit and ROC at 5p per unit.

The table below summarises the cost and potential income from a hydro site at Chadkirk weir.

Head Flow Installed Capacity Capital Annual Gross Running Net Return Capacity Factor Cost Power Revenue Costs Profit (m’s) Cubic Simple payback m/s kW % £000’s MWh £ £ £ on net profit in years

2 4.9 64 50 520 274 27,400 6,000 21,400 24

It should also be noted that from net profit must be deducted any debt repayments.

Appendix 4 shows a sketch map of a suggested hydro site at Chadkirk weir. At the time of writing, the report authors did not have site of any proposed sketch plans for the Sustrans bridge. Clearly, the position of the bridge and a possible hydro site would need clarifying as one would impinge on the other and alter construction costs accordingly.

The photograph below illustrates the condition of Chadkirk weir in November 2008.

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Chadkirk weir – breached and unstable

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Otterspool Weir

Otterspool weir

Otterspool weir is only several hundred metres downstream of Chadkirk weir.

Otterspool Weir

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This site is extremely low head and until recently would be unsuitable for any kind of turbine, given the fairly large flow. It is recommended that there is only one suitable technology, an Archimedes screw, and it will need to make use of variable speed control in order to achieve good capacity factor. The benefits of the site are extraordinarily good access on a currently unused site with high visibility and good grid connection. Historically, it is interesting to note that apparently this weir has never powered a mill – the weir was clearly built but the rights were never sorted out, so no abstraction was carried out.

Resource assessment

Head

Typical gross head 1.5m in low flows, reduces and is drowned in high water, head duration curve (based on model derived from measurements of the river upstream and downstream) is in appendix 5.3. Design net head 1.4m.

Flow

Based on gauged flow at Compstall on the Etherow and Marple Bridge on the Goyt, an accurate Flow Duration Curve (FDC) can be deduced. The catchment area is assumed to simply be the combined catchments of the Goyt at Marple Bridge and the Etherow at Compstall. The FDC is derived by adding the two daily flow figures. Data used is from approximately 1969, with some gaps. Qmean (mean flow) is 6.8 cumec s(cubic metres per second) and Q95 is 1.6 cumec. The FDC is shown in appendix 5.3.

The approach described above is appropriate for this river system, as there is significant consumptive abstraction for water supply, as well as augmentation by effluent returns at low flows, and this is accounted for in the measured flows. Comments for the individual gauging stations as mentioned earlier are relevant.

Conceptual design

Layout

See Appendix 5.1 for sketch plan.

Fairly unconstrained site, allowing easy construction. Abstraction would take place from the river in proximity of weir under arch or bridge with a short open concrete leat. Turbine would be located close to the weir, discharging into weir pool below. Reasonable space to allow construction to avoid existing parts of weir. Other bank considered impractical for turbine.

Screen

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Screen bar spacing 130mm gap or similar. Recommend 11m2 of screen area. Horizontal or vertical steel bars. Recommend bridge spanning leat of dimensions sufficient to allow mini digger access to assist with debris clearance in exceptional circumstances.

Sluice

A sluice gate will be required to control water flow into the machine, as a variable speed system is proposed. The sluice provides a method of holding back water when the system is not operating. During operational time the speed controller ensures the correct water level. The normal situation is to have a hydraulic operated gate, fully automated from turbine controller.

Turbine

The recommendation is to install an Archimedean Screw.

Leat

Short leat as shown in Appendix 5.1, namely 3.5m wide x 2m deep formed from mass concrete. Open, and fenced to 2m with anti climb fencing.

Generator

1000 or 1500rpm asynchronous generator which is resilient to turbine overspeed.

Powerhouse

Minimum 4m square for all equipment.

Control system

Standard electronic hydro control system with fully automatic control of system synchronisation and water level control. There is only one manufacturer of suitable variable speed control system. This can have an option of data logging, but it is not standard. The control system controls the speed of the turbine to maintain a constant upstream head, hence the machine runs slowly in periods of low flows, and quickly in periods of high flows.

Outfall

Concrete works for screw to include outfall and tying into existing walls with very little debris removal from river bed and little deepening of outfall is required, although the intake area is heavily silted.

Fish passage

Fish passage has not been highlighted as a problem at this site, although there may be some consideration given to improving this. It is suggested that fish pass installation would not be a condition of the development process, but it is well worth investigating if there is any desire to achieve this, since the cost of a pass can be much less if co-developed with the Environment Agency. A relevant fish pass may well be a single step bottom baffle larinier 26

PDF created with pdfFactory Pro trial version www.software-partners.co.uk pass, and this type of pass may cost around £90k if done at same time as the turbine installation. National Fish Pass Panel approval would be required, and there may be significant costs to developing the proposal.

Grid connection

A G59 grid connection is required with 350m of 415v (i.e. Low Voltage) 3ph underground SWA through fields to the nearest 11kV grid connection. 100% export of electricity is assumed. Wayleaves (permission to lay wire across private land) is assumed to be possible, The DNO can provide pole mounted transformer on current overground 11kV power line, with connection to turbine to be carried out under turbine contract.

Access

The site requires very little access improvement, and can be considered to be almost ideal. Construction will require some degree of storage space, but there is suitable ground around.

System sizing

Based on analysis earlier, design flow suggested 5.4 cumec, 45kW peak output, 49% capacity factor, 194MWh / annum. Possibly this will need to be reduced suppliers will not quote for this large volume on 1.3 or 1.4 net head.

Planning Consent

Otterspool is on the river Goyt and is within Green Belt. Any development must consider the impact upon the Goyt Valley Landscape Character Area.

The sketch plan, hydrological data and, duration curves and power curves for Otterspool are in the following appendices...

Sketch Plan Appendix 5.1

Hydrological data Appendix 5.2

Flow Duration Curve and Head Duration Curve Appendix 5.3

Power Curve Appendix 5.4

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Location 6

Strawberry Hill – Roman Lakes

Strawberry Hill

This site offers good access and a very good site in which to place a turbine. Situated in private land near a railway viaduct, the site still has the old water intake and sluice systems intact. The head of 3.7m’s referred to in the brief clearly relates to the old goit for which the weir provide the head. The goit can be traced downstream and provided power for the mill several hundred metres away. This goit cannot now be used to provide a greater head for a hydro system as it is utilised for other purposes. Therefore, only the weir can be used to provide a head.

Strawberry Hill – Roman Lakes

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Comment

This site previously powered a large mill. The history is interesting and there is plenty of evidence of use or water still existing. Given the effort being put in by the EA to improving the river in terms of Salmon migration, it is thought unrealistic to expect that a scheme following the original layout of the goit and weir would be acceptable – if this was proposed the volumes to be used would need to be reduced, so the net output would be similar. There may be a desire to improve fish passage here, and a pass could be developed alongside the turbine, as there is not space constraint.

Resource assessment

Head

Maximum gross head 2.7m measured in moderate flow, which is taken to be typical. Head duration curve (based on model derived from measurements of the river upstream and downstream) is in appendix 6.3. Design net head 2.6m

Flow

The flow has been scaled from the nearby gauging station at Marple Bridge – see appendix 6.2

Conceptual design

Layout

See Appendix 6.1. Existing intake can be reused to limit costs of the proposal. Excavation of intake as per existing site. Turbine location probably needs to be immediately downstream of railway viaduct due to space restrictions and access routes

Screen

Screen bar spacing 130mm gap or similar. Recommend 7m2 of screen area. Horizontal or vertical steel bars. Location of screen should allow good access for clearing after heavy debris deposition during high water.

Sluice

A sluice gate will be required to control water flow into the machine. If fixed speed system is employed it will control flow volume at all times. If variable speed system is employed, the sluice provides the method of holding back water when the system not operating. During operational time, the speed controller ensures water level. The normal situation is to have a hydraulic operated gate, fully automated from turbine controller

Turbine

At this size head the most realistic situation would be Archimedean screw.

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Leat

As shown in Appendix 6.1, concrete lined leat, or reuse existing walls where appropriate. Allowance for existing access track, which may make a concrete pipeline more appropriate

Generator

1000 or 1500rpm asynchronous generator, owing to resilience to turbine overspeed.

Powerhouse

Minimum 4m square for all equipment.

Control system

Standard computer based hydro control system with fully automatic control of system synchronisation, water level control, data logging and data transmission. There are two options: Fixed speed or variable speed. Fixed speed is cheaper and has greater peak efficiency. Variable speed is more expensive with lower peak efficiency, but much better part flow efficiency. Variable speed system can be considered in detailed proposals at a later date, as it can offer benefits, but currently fixed speed assumed. Variable speed tends to become increasingly economic as turbine diameter starts to exceed total system head, but it also depends on the detail of the abstraction license.

Outfall

Concrete works for screw to include outfall.

Fish passage

Fish passage may well be considered a priority, as this is a vertical weir. Whilst being potentially scaleable by a very determined fish, it is not exactly conforming to best practice. There is good space, and a two stake, Alaskan A fishway is likely to be adequate.

Grid connection

A G59 grid connection is required. The report assumes a 450m grid connection distance, with 415V 3ph SWA underground.

Access

Access is relatively good. The route has a bridge which can be avoided, so no real budget is expected

System sizing

Based on analysis earlier, design flow suggested 2.9 cumec, 53kW peak output, 51% capacity factor, 236MWh / annum.

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Planning Consent

Strawberry Hill is within Green Belt and would need to consider its impact upon the Goyt Valley Landscape Character Area. In addition, it is a Site of Biological Importance.

The sketch plan, hydrological data and, duration curves and power curves for Strawberry Hill are in the following appendices...

Sketch Plan Appendix 6.1

Hydrological data Appendix 6.2

Flow Duration Curve and Head Duration Curve Appendix 6.3

Power Curve Appendix 6.4

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Location 7 Brinnington Weir

Brinnington Weir

This is the largest weir in the Borough and is a spectacular structure. The goit that it originally fed has now long since disappeared. The weir is also used by the Environment Agency as a gauging station. The site visit showed that the site is something of a ‘conundrum’ when considering which side of the river to place a hydro turbine. The north side of the river offers a much less expensive possibility for construction as the top of the river bed is very close to the water. However, access for construction traffic is potentially difficult. However, on the south bank, although construction cost would be higher due to the elevated nature of the river bed, access is much better. It has been decided that the best site for a hydro structure would be on the north side of the river.

Brinnington Weir showing the north bank

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Comment

This site is in many ways very attractive for development, although its location is a little troublesome. The site, initially developed in 1796, previously provided a large amount of power for a mill (still extant near the new Tesco’s), and has been subject to proposals to develop as a micro- hydro scheme at least since NFFO1 in 1991. It has an excellent head of water, and the weir appears to be in good condition. It is at the top end of head size which could be accommodated by a screw turbine, and a Kaplan would be an alternative possibility, as could a Crossflow machine. Such a Crossflow machine would possibly be the most sensible alternative, since it would be more tolerant to debris than a Kaplan, but the proposal here is outlined as a screw. It would be very worthwhile investigating if there is a desire to reintroduce fish passage at this site, as it is far down the Tame catchment and will represent a total barrier to fish movement - although it should be noted that the Goyt is the priority for fish passage currently. The Tame has lower water quality.

Resource assessment

Head

Typical gross head 4.7m measured in moderate flow, which is taken to be typical, head duration curve (based on model derived from measurements of the river upstream and downstream) is shown in Appendix 7.3. Design net head 4.6m

Flow

The site is a gauging station – called Portwood - and as such the flow figures can be used directly. This may cause some degree of difficulty, since the installation of a hydro-electric system would affect the gauging of flows, but this is not insurmountable technically, as long as this is considered in the development of the proposal. The Environment Agency have stated that while in principle a hydro scheme might be accommodated at this site, the effect upon its Gauging Station is a consideration for them. Brinnington Weir is important for the EA’s Catchment Area Management System and has a low flow alarm situated on it. Any hydro system would require the EA to change its ratings at this site and the cost of this process would transfer to the developer.

Conceptual design

Layout

Appendix 7.1 is the proposed sketch plan of the hydro site. Consideration was given to construction on both banks. The Original leat – the “Portwood cut” - flowed out along the south bank. This provides generally good access to the site, but installation of a turbine on the south bank would be troublesome owing to the large amount of excavation required if a discharge into the river was required just below the weir. Consideration was given to reopening the original cut and positioning the turbine further downstream. This could be a 33

PDF created with pdfFactory Pro trial version www.software-partners.co.uk more straightforward route to installation if there were problems with the north bank. The North bank however, has the most straightforward potential installation, with a number of caveats – In times of flood, the water could bypass the weir at the point where the hydro site would be located. If this was to occur damage could be caused, so any hydro scheme would need to provide protection against this. Also the site is crossed by high voltage power lines, and this may well have implications to the installation of the machine, as a crane would need to work directly below the lines. With these points in mind a layout has been developed as shown in Appendix 7.1.

Screen

Screen bar spacing 130mm gap or similar. Recommend 6m2 of screen area. Horizontal or vertical steel bars. It is recommended that a bridge spans the leat of dimensions sufficient to allow mini digger access to assist with debris clearance in exceptional circumstances. Also, consideration ought to be given to a structure that will prevent flooding of the hydro site at high flows.

Sluice

A sluice gate will be required to control water flow into the machine. As part of the design to prevent bypassing of the weir, the sluice should be a penstock which fully seats onto a concrete wall, so that in high water the weir cannot be bypassed.

Turbine

At this head the most realistic situation would be Archimedean screw – however a conventional turbine could be considered. If the EA do not consider that migratory fish will return to this stretch of river, and the issue of the power lines is insurmountable, a south bank solution, with conventional turbine may be considered.

Leat

Short intake pipe, as shown, submerged to prevent the bypassing issue.

Generator

1000 or 1500rpm asynchronous generator, due to being resilient to turbine overspeed.

Powerhouse

Minimum 4m square for all equipment.

Control system

Standard computer based hydro control system, fully automatic control of system synchronisation, water level control, data logging and data transmission. There is no clear benefit to considering variable speed control on this site.

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Outfall

Concrete works for screw to include outfall, and tying into existing walls, very little debris removal from river bed and deepening of outfall is required, although the intake area required complete construction from scratch.

Fish passage

Fish passage is clearly a problem for the site, and while there are moves afoot within the Mersey basin to improve habitat for returning Salmon, the Tame is not a river which has been targeted. This is potentially due to the fact that little potential spawning ground may be available, and the water quality is lower than the Goyt and the Bollin, the two main tributaries for salmon in the Mersey basin. This weir is the most downstream barrier, and therefore may still be of interest for a co-development. The form of the fish pass needs further consideration, due to the large head difference, as it may need to be a substantial structure.

Grid connection

A G59 grid connection is required - 700m grid connection distance, which may be best achieved via new 11kV overhead connection to transformer at turbine location.

Access

The site requires access to be made from the West. This would be a long route, and could be expensive.

System sizing

Based on analysis earlier, design flow suggested 2.7 cumec, 88kW peak output, 58% capacity factor producing 447MWh / annum.

Planning Consent

The site is in Green Belt and any development would have to consider its impact upon the Tame Valley Landscape Character Area. It is also a local Nature Reserve and a Site of Biological Importance.

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk The sketch plan, hydrological data and, duration curves and power curves for Brinnington Weir are in the following appendices...

Sketch Plan Appendix 7.1

Hydrological data Appendix 7.2

Flow Duration Curve and Head Duration Curve Appendix 7.3

Power Curve Appendix 7.4

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Location 8 Stringer’s Weir

Stringers Weir

Located adjacent to Vernon Park, this weir offers good potential for development. A hydro system is only possible on the eastern bank, the opposite bank to Vernon Park. This is because access via Vernon Park is too difficult for construction traffic and also the river bank is too steep to permit any development. However, on the eastern bank, the land is flat, access is easy and the top of the river bank is close to the river, thus keeping construction costs down.

Stringer’s Weir

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Resource assessment

Head

Typical gross head 1.8m, reduces in high water. Head duration curve is shown in Appendix 8.3. Design net head is 1.7m

Flow

Based on gauged flow at Compstall on the Etherow and Marple Bridge on the Goyt, and using further correction for the relative sizes of the catchment, an accurate FDC can be deduced. The catchment area is 363km2. This is 7% more than the combined catchments of the Goyt at Marple Bridge and the Etherow at Compstall. The FDC is derived by multiplying the sum of the two daily flow figures by 1.07. Data used is from approximately 1969, with some gaps. Qmean is 7.3 cumec; Q95 is 1.7 cumec. FDC is shown in Appendix 8.3.

The approach described above is appropriate for this river system as there is significant consumptive abstraction for water supply, as well as augmentation by effluent returns at low flows, and this is accounted for in the measured flows. Comments for the individual gauging stations as mentioned earlier are relevant.

Conceptual design

Layout

Appendix 8.1 shows the proposed sketch plan at this site. The site is unconstrained site, allowing easy construction. Proposed to abstract from the river in proximity of weir with a short concrete leat (presumed open leat or covered pipeline). The turbine to be located close to the weir, discharging into weir pool below. Ample space to allow construction to avoid existing parts of the weir. Other bank is considered impractical for turbine.

Screen

Screen bar spacing 130mm gap or similar. Recommend 12m2 of screen area. Horizontal or vertical steel bars. Recommend bridge spanning leat of dimensions sufficient to allow mini digger access to assist with debris clearance in exceptional circumstances.

Sluice

A sluice gate will be required to control water flow into the machine. If fixed speed system is employed it will control flow volume at all times, if variable speed system is employed the sluice provides method of holding back water when system is not operating. During operational time, the speed controller ensures water level. Normal situation is to have hydraulic operated gate, fully automated from turbine controller

Turbine

At this head the most realistic situation would be Archimedean screw.

38

PDF created with pdfFactory Pro trial version www.software-partners.co.uk An alternative turbine would be the Kaplan would be possible. However, as mentioned earlier in the report, additional costs would ensue for screening 6 cumecs of water. Also, a 1.8m is very low head for Kaplan. One 1600mm diameter runner Kaplan would be approximately correct size machine, and a siphonic intake would reduce capital cost. The economics of the site would likely favour an Archimedean screw turbine

Leat

A short leat as shown in the sketch plan, 3.5m wide x 2m deep, made from mass concrete. The leat would be open and fenced to 2m for anti climb. The alternative is piped water transfer which could be cheaper if the full costs of a non climb fence were too large. Also, a fence may be visually intrusive opposite Vernon park.

Generator

1000 or 1500rpm asynchronous generator, due to being resilient to turbine overspeed.

Powerhouse

Minimum 4m square for all equipment, excluding any transformers.

Control system

Standard computer based hydro control system with fully automatic control of system synchronisation, water level control, data logging and data transmission. Two options: Fixed speed or variable speed. Fixed speed is cheaper with greater peak efficiency while variable speed is more expensive and has lower peak efficiency, but has a much better part flow efficiency. Variable speed system can be considered in detailed proposals at a later date, as it can offer benefits, but currently fixed speed assumed. Variable speed tends to become increasingly economic as the turbine diameter starts to exceed total system head, but it also depends on detail of agreed abs. license.

Outfall

Concrete works for screw to include outfall, and tying into existing walls, and degree of debris removal from river bed and deepening of outfall as this area currently on inside of river bend.

Fish passage

Fish passage has not been highlighted as a problem at this site, although there may be some consideration given to improving this. It is suggested that fish pass installation would not be a condition of the development process, but it is well worth investigating if there is any desire to achieve this, since the cost of a pass can be much less if co developed. National Fish Pass Panel approval would be required, and there may be significant costs to developing the proposal.

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Grid connection

A G59 grid connection is required - 350m of 415v (i.e. Low Voltage), 3ph underground SWA through nearby fields to 11kV grid connection. Wayleaves assumed to be possible and DNO to provide transformer at current mains location. Connection to turbine to be carried out under turbine contract.

Access

The site requires an access route to be built along a similar length of route. It is assumed that is not required to be fenced and that it can be left as gravel finish only.

System sizing

Based on analysis earlier, design flow suggested 5.9 cumec, 75kW peak output, 51% capacity factor, annual energy capture 338MWh / annum.

Planning Consent

Stringer Weir is in Green Belt and the Goyt Valley Landscape Character Area and therefore proposed developments must address their impact. It is also a Site of Biological Importance. Vernon Park is a Park and Garden of Historical Interest.

The sketch plan, hydrological data and, duration curves and power curves for Stringer’s Weir are in the following appendices...

Sketch Plan Appendix 8.1

Hydrological data Appendix 8.2

Flow Duration Curve and Head Duration Curve Appendix 8.3

Power Curve Appendix 8.4

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Location 9 Castle Hill Weir

Castle Hill Weir

Located on the border of Stockport and Tameside, the site has good access for construction traffic. The site provided a head of water for a former mill much further downstream. Remains of the goit which carried the water to the mill are visible. The length of the goit and therefore the drop in the height of the river between the weir and the mill, gave an initial head – mentioned in the brief – of 6.2m’s. However, it would be extremely unlikely that the goit could ever be brought back into use due to its dilapidated state and questions over legal ownership. An added barrier to using the old goit would be the likely difficulty of obtaining consent from the Environment Agency. An operating hydro site which used the goit would have a high depletion rate in the river bed and cause potential ecological problems. The potential for power at the site is therefore restricted to the height of the weir.

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Castle Hill Weir – photo taken from Tameside bank and showing original head of goit

Comment

Historically this is was a large capacity weir with perhaps 200kW being generated from two reaction type turbines at Arden Mill at the end of long leat of about 715m. The map below illustrates the original hydro system.

Notwithstanding the issues outlined previously, which mean that migratory fish are unlikely to be present and are not going to return unless passes are installed downstream, the introduction of a

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk 715m deprived reach of the river would potentially be contentious, and for that reason a more simple screw turbine proposal has been made.

Resource assessment

Head

Typical gross head 2.4m measured in moderate flow, which is taken to be typical, head duration curve (based on model derived from measurements of the river upstream and downstream) is attached. Design net head 2.3m

Flow

Portwood is the gauging station, and as such the flow figures for Castle Hill can be assumed to be 94% of Portwood / Brinnington, based on catchment.

Conceptual design

Layout

Appendix 9.1 shows the sketch map for the proposed hydro system at Castle Hill. The existing intake can be reused to limit the costs of the proposal. Intake to be excavated as per existing. An outfall to be created close to the existing spillway channel.

Screen

Screen bar spacing 130mm gap or similar. Recommend 6m2 of screen area. Horizontal or vertical steel bars. Recommend bridge spanning leat of dimensions sufficient to allow mini digger access to assist with debris clearance in exceptional circumstances.

Sluice

A sluice gate will be required to control water flow into the machine. If fixed speed system is employed it will control flow volume at all times. If variable speed system is employed the sluice provides the method of holding back water when system not operating. During operational time the speed controller ensures water level. The normal situation is to have hydraulic operated gate, fully automated from turbine controller

Turbine

At this head the most realistic situation would be Archimedean screw.

Leat

As shown in Appendix 9.1, concrete lined leat, or reusing existing walls where appropriate.

Generator

1000 or 1500rpm asynchronous generator, due to being resilient to turbine overspeed. 43

PDF created with pdfFactory Pro trial version www.software-partners.co.uk Powerhouse

Minimum 4m square for all equipment.

Control system

Standard computer based hydro control system, fully automatic control of system synchronisation, water level control, data logging and data transmission. Two options: Fixed speed or variable speed. Fixed speed is cheaper and greater peak efficiency while variable speed is more expensive with lower peak efficiency, but much better part flow efficiency. Variable speed system can be considered in detailed proposals at a later date, as it can offer benefits, but currently fixed speed assumed. Variable speed tends to become increasingly economic as turbine diameter starts to exceed total system head, but it also depends on details of the abstraction license.

Outfall

Concrete works for screw to include outfall, bedrock at this site will make construction of outfall relatively straightforward, as limited concrete required below water level.

Fish passage

Fish passage is dependent on whether the downstream Portwood weir is ever fitted with a fish pass.

Grid connection

A G59 grid connection is required - 430m grid connection distance, 415V 3ph SWA underground.

Access

Access is relatively good, although at the actual site the crane for screw installation would be some distance from the installation site. Although access is considered reasonable a small budget is required to cover this.

System sizing

Based on analysis earlier, design flow suggested 2.5 cumec, 41kW peak output, and 58% capacity factor.

Planning Consent

Castle Hill is within Green Belt and is a Site of Biological Importance. It is also within the Tame Valley Landscape Character Area and any proposed developments would have to show consideration of these factors.

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk The sketch plan, hydrological data and, duration curves and power curves for Castle Hill Weir are in the following appendices...

Sketch Plan Appendix 9.1

Hydrological data Appendix 9.2

Flow Duration Curve and Head Duration Curve Appendix 9.3

Power Curve Appendix 9.4

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Financial Analysis

Five river weirs are recommended for development...

· Otterspool · Strawberry Hill – Roman Lakes · Brinnington · Stringer’s · Castle Hill

Capital Costs of each site (including an estimate for a fish pass) are as follows...

Strawberry Castle Brinnington Otterspool Stringer's Hill Hill Output 88 45 76 53 41 Turbine gearbox + generator at €1.1 / £1 120 69 114 87 75 Controller inc logging and remote monitoring 17 12 16 13 12 Sluice/control and ancillaries 11 12 12 9 9 Access allowance 35 5 15 5 8 Civil works 110 65 94 70 72 Installation/commissioning 20 16 20 16 16 Electrical connection 67 20 51 24 53 Turbine - Archimedean Screw 88 58.5 83.6 63.6 53.3

Total (ex fish pass) 468 257.5 405.6 287.6 298.3 £ 000's/kW 5.3 5.7 5.3 5.4 7.3

Fish pass 100 55 85 80 80 Total (inc fish pass) 568 312.5 490.6 367.6 378.3

In order to estimate income and returns on these sites, a number of assumptions are made...

1. The default price is always that obtained by selling electricity at wholesale prices to the National Grid. The working assumption is 5p per unit of electricity. The revenues obtained from selling green electricity to retail buyers – eg public buildings – can be considerable and can therefore dramatically reduce the estimated payback time. 2. The ROC price – effectively a market driven subsidy given to generators of green electricity – is 5p per unit. 3. Following the Climate Change Act of 2008, it is assumed that schemes under 50kW installed capacity will attract double ROC’s. The precise mechanism by which the new Act will administer the double ROC system has not been finalised at the time of writing. 4. The total capital cost of each site is taken to include the estimate for the fish pass.

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk The following table shows capital costs and projected returns for each of the 5 sites under consideration, as well as estimates of carbon emissions saved and the equivalent number of houses (using OFGEM statistics for the average 2 bed house) that the energy generated could supply.

Annual Number Capital Annual Gross Running Net Simple CO2 of Cost Power Revenue Costs Profit Payback Saving Households Name (£,000) MWh/yr £ £ £ (years) (tonnes/yr) Equivalent Otterspool 313 189 26,501 6,000 20,501 15 81 47 Strawberry Hill 368 232 23,205 6,000 17,205 21 100 58 Brinnington 568 438 43,817 8,000 35,817 16 188 110 Stringer's 491 328 32,837 7,000 25,837 19 141 82 Castle Hill 378 204 30,622 6,000 24,622 16 88 51 TOTAL 156,982 123,982 598 348

Appendix 10 is a fuller version of this table, expanded to include head height, flow, installed capacity and capacity factor.

A number of caveats are made with respect to these figures...

1. The figures are very price sensitive. Even a 1p difference in wholesale price can dramatically change the revenues and returns. 2. Running costs are based on knowledge of working small scale hydro schemes and include rent, rates, insurance and an allowance for maintenance. 3. The precise manner in which the double ROC’s system will be implemented has yet to be finalised. A scheme at Strawberry Hill ought to consider an installation below 50kW to capitalise on the double ROC’s. 4. No allowance is made for an increase in real energy prices which will certainly impact upon the payback period.

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Conclusion The industrial heritage of the old river weirs in Stockport Borough can be utilised to help reduce carbon emissions and generate renewable energy. Investments in small scale hydro ought to be considered as long term assets. This is because water holds more potential energy than wind and hydro schemes last much longer than wind power schemes. The returns therefore accrue in the long term.

On the 17th November 2007, the UN body, the Intergovernmental Panel on Climate Change, produced its fourth report which stated that climate change was overwhelmingly the effect of human based activity. It also stated that by 2015, unless the rate of increase of carbon emissions began to fall, the planet will become increasingly likely to suffer the consequences of climate change.

This report presents an opportunity to use Stockport’s old industrial weirs for the purpose of generating green electricity and thereby help to tackle climate change.

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Acknowledgements

The report authors wish to thank the representatives of Stockport Council who have helped in the writing of this report.

They also wish to thank Western Renewable Energy who provided the hydrological and technical data required for this report.

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Appendix 1: Map of Sites

Castle Hill Brinnington

Brinksway

Stringer’s Chadkirk

Brabyn’s Park, Marple Bridge

City Centre Otterspool

Strawberry Hill

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Appendix 2 Archimedean Screw – Cross Section

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Appendix 3 – Project Timescale for Site Development

Task Month 1 Month 2 Month 3 Month 4 Month 5 Month 6 Month 7 Month 8 Month 9 Month 10 Month 11 Month 12 Planning Consent Discuss Apply for Planning Permission Sketch Plans Environment Discuss Apply for Abstraction License and Land Agency Sketch Drainage Certificates Plans Supporting Obtain 3rd party Information reports to support planning and abstraction license Detailed Scheme Accurate costs and Design detailed drawings Lease Agree Sign Heads of Lease Terms with Landlord Financial Analysis Process of re-iteration as more detailed data emerges Power Purchase Begin discussions Agreement Contractor Choose contractor and initiate discussions Equipment Order Turbine Assumptions...

1. Developer has been chosen 2. Construction will take place in year following successful development and within the ‘Construction window’ defined by the Environment Agency The development of a site involves all of the processes required to obtain the necessary permissions at site, including planning permission, abstraction license and a lease. 53

PDF created with pdfFactory Pro trial version www.software-partners.co.uk Appendix 4.1 – Chadkirk Weir Sketch Plan

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Appendix 5.1 – Otterspool Sketch Plan

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Appendix 5.2

Otterspool – hydrological data

Minimum Max Transmission Total Available residual Utilised Gross Net and vari- Water to % of flow flow flow flow Head Head Turbine speed Generator wire Power year /m3s-1 /m3s-1 /m3s-1 /m3s-1 /m /m efficiency efficiency efficiency efficiency /kW 1 32.320 30.749 16.946 5.400 1.500 0.514 0.843 0.890 0.948 0.712 19.4 5 19.940 18.369 10.756 5.400 1.500 0.837 0.843 0.890 0.948 0.712 31.5 10 14.829 13.258 8.200 5.400 1.500 0.980 0.843 0.890 0.948 0.712 36.9 15 11.901 10.330 6.736 5.400 1.500 1.065 0.843 0.890 0.948 0.712 40.1 20 9.924 8.353 5.142 5.400 1.500 1.123 0.843 0.890 0.948 0.712 42.3 25 8.461 6.890 5.142 5.400 1.500 1.167 0.843 0.890 0.948 0.712 44.0 30 7.276 5.705 5.142 5.400 1.500 1.204 0.843 0.890 0.948 0.712 45.3 35 6.296 4.725 5.142 4.725 1.500 1.249 0.866 0.890 0.948 0.731 42.3 40 5.476 3.905 5.142 3.905 1.500 1.290 0.864 0.890 0.948 0.729 36.0 45 4.785 3.214 4.785 3.214 1.500 1.322 0.859 0.890 0.947 0.724 30.1 50 4.207 2.636 4.207 2.636 1.500 1.348 0.848 0.890 0.944 0.712 24.8 55 3.720 2.149 3.720 2.149 1.500 1.369 0.834 0.890 0.938 0.696 20.1 60 3.331 1.760 3.331 1.760 1.500 1.384 0.804 0.890 0.931 0.666 15.9 65 3.000 1.429 3.000 1.429 1.500 1.397 0.752 0.890 0.925 0.619 12.1 70 2.675 1.104 2.675 1.104 1.500 1.410 0.660 0.890 0.921 0.541 8.3 75 2.419 0.848 2.419 0.848 1.500 1.419 0.500 0.890 0.910 0.405 4.8 80 2.229 0.658 2.229 0.658 1.500 1.426 0.326 0.890 0.900 0.261 2.4 85 2.019 0.448 2.019 0.448 1.500 1.433 0.126 0.890 0.850 0.095 0.6 90 1.791 0.220 1.571 0.220 1.500 1.441 0.000 0.890 0.700 0.000 0.0 95 1.571 0.000 1.571 0.000 1.500 1.448 0.000 0.890 0.500 0.000 0.0 99 1.287 0.000 1.287 0.000 1.500 1.457 0.000 0.890 0.500 0.000 0.0

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Appendix 5.3 – Otterspool Flow Duration Curve

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Otterspool Power Curve

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Appendix 6.1 – Strawberry Hill Sketch Plan

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Appendix 6.2

Strawberry Hill – Hydrological data

Minimum Max Total Available residual Utilised Gross Net Water to % of flow flow flow flow Head Head Turbine Transmission Generator wire Power year /m3s-1 /m3s-1 /m3s-1 /m3s-1 /m /m efficiency efficiency efficiency efficiency /kW 1 15.633 14.924 8.171 2.900 2.700 2.121 0.843 0.940 0.948 0.752 45.3 5 9.749 9.040 5.229 2.900 2.700 2.301 0.843 0.940 0.948 0.752 49.1 10 7.306 6.597 4.007 2.900 2.700 2.377 0.843 0.940 0.948 0.752 50.8 15 5.956 5.247 3.418 2.900 2.700 2.420 0.843 0.940 0.948 0.752 51.7 20 4.952 4.243 3.418 2.900 2.700 2.452 0.843 0.940 0.948 0.752 52.4 25 4.170 3.461 3.418 2.900 2.700 2.477 0.843 0.940 0.948 0.752 52.9 30 3.582 2.873 3.418 2.873 2.700 2.498 0.843 0.940 0.948 0.752 52.9 35 3.102 2.393 3.102 2.393 2.700 2.539 0.866 0.940 0.949 0.773 46.0 40 2.706 1.997 2.706 1.997 2.700 2.570 0.863 0.940 0.948 0.769 38.7 45 2.367 1.658 2.367 1.658 2.700 2.594 0.856 0.940 0.947 0.762 32.1 50 2.079 1.370 2.079 1.370 2.700 2.612 0.847 0.940 0.944 0.752 26.4 55 1.836 1.127 0.709 1.127 2.700 2.626 0.828 0.940 0.937 0.729 21.2 60 1.632 0.923 0.709 0.923 2.700 2.637 0.802 0.940 0.930 0.701 16.7 65 1.452 0.743 0.709 0.743 2.700 2.646 0.740 0.940 0.924 0.643 12.4 70 1.285 0.576 0.709 0.576 2.700 2.654 0.628 0.940 0.920 0.543 8.1 75 1.143 0.434 0.709 0.434 2.700 2.660 0.442 0.940 0.910 0.378 4.3 80 1.033 0.324 0.709 0.324 2.700 2.665 0.268 0.940 0.900 0.227 1.9 85 0.925 0.216 0.709 0.216 2.700 2.669 0.084 0.940 0.850 0.067 0.4 90 0.820 0.111 0.709 0.111 2.700 2.673 0.000 0.940 0.600 0.000 0.0 95 0.709 0.000 0.709 0.000 2.700 2.676 0.000 0.940 0.500 0.000 0.0 99 0.569 0.000 0.569 0.000 2.700 2.681 0.000 0.940 0.500 0.000 0.0

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Appendix 6.3

Strawberry Hill – Flow Duration Curve and Head Duration Curve

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Appendix 6.4

Strawberry Hill – Power Curve

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Appendix 7.1 – Brinnington Weir Sketch Plan

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Appendix 7.2

Brinnington Weir – Hydrological Data

Minimum Max Total Available residual Utilised Gross Net Water to % of flow flow flow flow Head Head Turbine Transmission Generator wire Power year /m3s-1 /m3s-1 /m3s-1 /m3s-1 /m /m efficiency efficiency efficiency efficiency /kW 1 19.500 18.230 10.385 2.700 4.600 4.072 0.843 0.940 0.948 0.752 81.0 5 10.600 9.330 5.935 2.700 4.600 4.275 0.843 0.940 0.948 0.752 85.0 10 7.440 6.170 4.355 2.700 4.600 4.349 0.843 0.940 0.948 0.752 86.5 15 6.050 4.780 4.540 2.700 4.600 4.382 0.843 0.940 0.948 0.752 87.2 20 5.120 3.850 4.540 2.700 4.600 4.405 0.843 0.940 0.948 0.752 87.6 25 4.490 3.220 4.490 2.700 4.600 4.420 0.843 0.940 0.948 0.752 87.9 30 3.990 2.720 3.990 2.700 4.600 4.432 0.843 0.940 0.948 0.752 88.1 35 3.590 2.320 3.590 2.320 4.600 4.460 0.867 0.940 0.949 0.773 78.4 40 3.290 2.020 3.290 2.020 4.600 4.480 0.865 0.940 0.948 0.771 68.3 45 3.020 1.750 3.020 1.750 4.600 4.496 0.862 0.940 0.948 0.768 59.2 50 2.820 1.550 2.820 1.550 4.600 4.507 0.856 0.940 0.947 0.762 52.2 55 2.620 1.350 2.620 1.350 4.600 4.518 0.850 0.940 0.945 0.755 45.1 60 2.440 1.170 2.440 1.170 4.600 4.526 0.843 0.940 0.941 0.746 38.7 65 2.280 1.010 2.280 1.010 4.600 4.534 0.822 0.940 0.936 0.723 32.5 70 2.160 0.890 2.160 0.890 4.600 4.539 0.804 0.940 0.931 0.704 27.9 75 2.040 0.770 2.040 0.770 4.600 4.544 0.776 0.940 0.927 0.676 23.2 80 1.920 0.650 1.270 0.650 4.600 4.548 0.724 0.940 0.923 0.628 18.2 85 1.790 0.520 1.270 0.520 4.600 4.553 0.628 0.940 0.920 0.543 12.6 90 1.600 0.330 1.270 0.330 4.600 4.559 0.326 0.940 0.900 0.276 4.1 95 1.270 0.000 1.270 0.000 4.600 4.568 0.000 0.940 0.500 0.000 0.0 99 0.983 0.000 0.983 0.000 4.600 4.576 0.000 0.940 0.500 0.000 0.0

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Appendix 7.3

Brinnington Weir – Flow Duration Curve and Head Duration Curve

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Appendix 7.4

Brinnington Weir – Power Curve

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Appendix 8.1 – Stringer’s Weir Sketch Plan

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Appendix 8.2

Stringer’s Weir – Hydrological Data

Minimum Max Total Available residual Utilised Gross Net Water to % of flow flow flow flow Head Head Turbine Transmission Generator wire Power year /m3s-1 /m3s-1 /m3s-1 /m3s-1 /m /m efficiency efficiency efficiency efficiency /kW 1 34.582 32.901 18.132 5.900 1.900 1.423 0.843 0.940 0.948 0.752 61.8 5 21.336 19.655 11.508 5.900 1.900 1.581 0.843 0.940 0.948 0.752 68.7 10 15.867 14.186 8.774 5.900 1.900 1.647 0.843 0.940 0.948 0.752 71.6 15 12.734 11.053 7.208 5.900 1.900 1.685 0.843 0.940 0.948 0.752 73.2 20 10.619 8.938 5.362 5.900 1.900 1.711 0.843 0.940 0.948 0.752 74.4 25 9.053 7.372 5.362 5.900 1.900 1.731 0.843 0.940 0.948 0.752 75.2 30 7.785 6.104 5.362 5.900 1.900 1.746 0.843 0.940 0.948 0.752 75.9 35 6.737 5.056 5.362 5.056 1.900 1.774 0.867 0.940 0.949 0.773 68.0 40 5.859 4.178 5.362 4.178 1.900 1.799 0.864 0.940 0.948 0.770 56.7 45 5.120 3.439 5.120 3.439 1.900 1.817 0.858 0.940 0.947 0.763 46.7 50 4.501 2.821 4.501 2.821 1.900 1.831 0.847 0.940 0.944 0.752 38.0 55 3.980 2.299 3.980 2.299 1.900 1.842 0.828 0.940 0.937 0.729 30.3 60 3.564 1.883 3.564 1.883 1.900 1.850 0.802 0.940 0.930 0.701 23.9 65 3.210 1.529 3.210 1.529 1.900 1.856 0.740 0.940 0.924 0.643 17.9 70 2.862 1.181 2.862 1.181 1.900 1.862 0.660 0.940 0.921 0.571 12.3 75 2.588 0.907 2.588 0.907 1.900 1.866 0.500 0.940 0.910 0.428 7.1 80 2.385 0.704 2.385 0.704 1.900 1.869 0.268 0.940 0.900 0.227 2.9 85 2.160 0.479 2.160 0.479 1.900 1.873 0.126 0.940 0.850 0.101 0.9 90 1.916 0.235 1.681 0.235 1.900 1.876 0.000 0.940 0.600 0.000 0.0 95 1.681 0.000 1.681 0.000 1.900 1.879 0.000 0.940 0.500 0.000 0.0 99 1.377 0.000 1.377 0.000 1.900 1.883 0.000 0.940 0.500 0.000 0.0

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Appendix 8.3

Stringer’s Weir – Flow Duration Curve and Head Duration Curve

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Appendix 8.4

Stringer’s Weir – Power Curve

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Appendix 9.1 – Castle Hill Sketch Plan

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PDF created with pdfFactory Pro trial version www.software-partners.co.uk Appendix 9.2

Castle Hill – Hydrological Data

Minimum Max Total Available residual Utilised Gross Net Water to % of flow flow flow flow Head Head Turbine Transmission Generator wire Power year /m3s-1 /m3s-1 /m3s-1 /m3s-1 /m /m efficiency efficiency efficiency efficiency /kW 1 18.330 17.136 9.762 2.500 2.400 1.868 0.843 0.940 0.948 0.752 34.4 5 9.964 8.770 5.579 2.500 2.400 2.076 0.843 0.940 0.948 0.752 38.2 10 6.994 5.800 4.094 2.500 2.400 2.154 0.843 0.940 0.948 0.752 39.7 15 5.687 4.493 4.388 2.500 2.400 2.188 0.843 0.940 0.948 0.752 40.3 20 4.813 3.619 4.388 2.500 2.400 2.211 0.843 0.940 0.948 0.752 40.7 25 4.221 3.027 4.221 2.500 2.400 2.227 0.843 0.940 0.948 0.752 41.0 30 3.751 2.557 3.751 2.500 2.400 2.240 0.843 0.940 0.948 0.752 41.2 35 3.375 2.181 3.375 2.181 2.400 2.264 0.866 0.940 0.948 0.772 37.3 40 3.093 1.899 3.093 1.899 2.400 2.282 0.865 0.940 0.949 0.772 32.8 45 2.839 1.645 2.839 1.645 2.400 2.297 0.862 0.940 0.948 0.768 28.4 50 2.651 1.457 2.651 1.457 2.400 2.308 0.858 0.940 0.947 0.763 25.2 55 2.463 1.269 2.463 1.269 2.400 2.317 0.850 0.940 0.945 0.755 21.8 60 2.294 1.100 2.294 1.100 2.400 2.326 0.843 0.940 0.941 0.746 18.7 65 2.143 0.949 2.143 0.949 2.400 2.333 0.822 0.940 0.936 0.723 15.7 70 2.030 0.837 2.030 0.837 2.400 2.338 0.806 0.940 0.932 0.706 13.5 75 1.918 0.724 1.194 0.724 2.400 2.342 0.776 0.940 0.927 0.676 11.2 80 1.805 0.611 1.194 0.611 2.400 2.347 0.724 0.940 0.923 0.628 8.8 85 1.683 0.489 1.194 0.489 2.400 2.351 0.628 0.940 0.920 0.543 6.1 90 1.504 0.310 1.194 0.310 2.400 2.358 0.326 0.940 0.900 0.276 2.0 95 1.194 0.000 1.194 0.000 2.400 2.367 0.000 0.940 0.500 0.000 0.0 99 0.924 0.000 0.924 0.000 2.400 2.374 0.000 0.940 0.500 0.000 0.0

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Appendix 9.3

Castle Hill – Flow Duration Curve and Head Duration Curve

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Appendix 9.4

Castle Hill – Power Curve

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Appendix 10

Financial Analysis

Design Annual Number Net Design Installed Capacity Capital Annual Gross Running Net Simple CO2 of Head Flow Capacity Factor Cost Power Revenue Costs Profit Payback Saving Households Name (m's) (cumecs) kW (%) (£,000) MWh/yr £ £ £ (years) (tonnes/yr) Equivalent Otterspool 1.4 5.4 45 49 313 189 26,501 6,000 20,501 15 81 47 Strawberry Hill 2.6 2.9 53 51 368 232 23,205 6,000 17,205 21 100 58 Brinnington 4.6 2.7 88 58 568 438 43,817 8,000 35,817 16 188 110 Stringer's 1.7 5.9 75 51 491 328 32,837 7,000 25,837 19 141 82 Castle Hill 2.3 2.5 41 58 378 204 30,622 6,000 24,622 16 88 51 TOTAL 302 156,982 123,982 598 348

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