Feasibility Studies

If you think you have a potential hydropower site you need to quickly find out the facts.  It's important to use a hydro consultancy company that really understands the subject.  Any company that offers feasibility advice should be able to back that up with a proven track record of designing and constructing hydropower systems.

Renewables First has been providing hydro consultancy, design and installation services for almost ten years, and in that time has worked throughout the UK on a diverse range of sites including low, medium and high head, run-of-river, storage and effluent discharge flows and just about every possible turbine type and electrical system.  We are able to draw on this core knowledge and experience to quickly establish if a site has potential for development, and if so what type of system would be most appropriate and what the project finances would look like.

Renewables First applies a structured approach to feasibility studies by breaking them into three main parts; the Screening Report (SR1) Feasibility Stage 1 (FS1) and Feasibility Stage 2 (FS2).  The diagram on the right shows the process, but the principle is simple; focus on the most important issues first, then only if the site meets the basic criteria spend time investigating the more detailed issues.  Each stage concludes with a detailed but concise report.  The same format is used but expanded to include the increased level of detail at the later feasibility stages.  The expensive initial consultations with the Environment Agency and DNO (for grid connection permission) are left until the later stages, once the site hydro resource and layout have been confirmed as suitable (though note that statutory environmental designations are checked at the earliest SR1 stage, and electrical infrastructure is checked at the FS1 stage).  The following sections describe the three main stages in more detail.

Screening Report (SR)

This is a desk-based study and aims to quickly assess the hydro potential of a site to decide whether it justifies further investigation.  A combination of web-based resources and data from the client are used to estimate the hydro resource (head of water and flow) and the power output and annual energy production.  The site layout and its suitability for hydro development are also considered, along with a check of statutory environmental designations.  From this annual revenue can be estimated, followed by a 'ball park' estimate of total project cost.  A brief report is produced summarising the research carried out and the conclusions reached, along with a recommendation of whether to proceed to the first feasibility stage (FS1).

 

Feasibility Stage 1 (FS1)

Building on the Screening Report, the Feasibility Study stage 1 starts with a comprehensive site survey to understand the site layout, measure levels across the site, identify and survey all hydraulic structures, review the options for locating the hydro system hardware (intakes, penstock pipework, turbine house, discharge, electrical connection etc.) and discuss with the client their requirements, and answer any questions.

Back in the office the data is analysed to determine the best location for the hydro system and then the head at that location is calculated from the surveyed data. In parallel we obtain the flow records from the Environment Agency (EA) and use hydrological modeling software to geographically correct the EA data back to the site.  Using the accurate head and flow data the Screening Report is used as a template to write the FS1 report with more accurate power, energy production and revenue figures. The text is expanded to recommend the most appropriate turbine, intake system and electrical system types. The cost estimate is updated and all relevant site photos annotated and attached.

Feasibility Study 2 (FS2)

No hydropower project can proceed unless it secures the relevant licenses from the Environment Agency (EA) and obtains permission to electrically connect the system to the electricity distribution network ('the grid').  To minimise financial risk we hold the initial consultations with the EA and the local Distribution Network Operator (DNO) at the earliest possible stage so that any significant issues can be identified and built into the project plan.  The initial consultation with the EA (stage EA1) and DNO (N1) are completed between the first and second feasibility study stages (see the consents page).

EA1 starts by editing the FS1 report document into a briefing document suitable for submission to the EA to assist them in their internal consultations.  Next a site meeting is arranged for all relevant parties from the EA (normally water resources, ecology, fisheries and flood defence) to meet with a Renewables First hydro licensing expert to view the site and discuss the proposed project in detail.  This gets all issues out in the open at the start and in many cases allows misconceptions to be identified and clarified. The aim is to get outline agreement in principle by the end of the meeting and to identify which licenses will apply to the proposed hydro system (abstraction and/or impoundment license, flood defense consent etc.).  After the meeting the EA are asked to produce a formal written response defining which licenses will be required and to highlight any other issues that they require to be addressed.

For the N1 stage the power output calculated in the FS1 stage is used to open discussions with the DNO to find out whether this amount of power can be connected to the local electrical network. This normally requires us to submit a draft electrical schematic and fill out a generator connection application form to define the electrical characteristics of the proposed hydro system. The DNO will then review the local electrical infrastructure maps and complete a 'network analysis' to determine whether the local grid is strong enough. The conclusion will be a written response saying either 'provisionally OK' or specifying grid upgrade measures required before connection could be allowed and an estimated cost. In each case the response can be incorporated into the project plan for review.

Once the initial consultations are complete the FS2 report brings all of the information from the previous stages into a detailed but concise document to allow a decision to be made on whether to proceed into the more complex consenting and design stages. The main sections covered are:

• Resource estimate (hydraulic head and head duration curve, flow and flow duration curve)
• Power output and annual energy production
• Main hardware specification(s)
• System size, layout and location
• Project cost estimate
• Whole-life project financial model
• Consents overview (EA, DNO and local authority planning)
• Project plan
• Appendices covering selling electricity, grid connection, site photos etc.
  

A 'made to measure' service?

Some sites have historical connections with hydropower, or another reputable hydro company may have already completed some feasibility work.  For sites like this all of the stages above might not be required, so we can tailor our feasibility services to meet your needs and ensure that work isn't duplicated.