We have a statutory duty to secure the proper use of water resources and use the licensing process to do this. On rare occasions there have been competing licence applications to abstract the same water for separate hydropower schemes. In these situations, we need to consider the merits of each scheme including their impacts on the environment and the efficiency with which they use water. We use this information to make a licensing judgement which we consider to be in the interests of responsible water resources management and environmental protection. This judgement can be complex and is made on a case by case basis. This guidance is provided to help applicants understand what we consider when doing this.

Approach to Competing Schemes

Where two or more applicants (current or prospective) seek to develop hydropower schemes at a single site, options include

  • a shared scheme
  • a split scheme
  • a decision from NRW

Shared scheme

Applicants may work together to propose a shared scheme, agreeing between themselves such issues as how investment in the scheme, and any associated income is to be split. They will then be able to seek the necessary licences from us for the shared scheme and these will be considered through usual licence determination.

Split scheme

It may be possible to develop a split scheme using a single weir structure, with applicants reaching agreement on sharing water at the site and each submitting their own licence application. This will not be possible at all sites and may involve the need for each party to accept a lower abstraction rate than that possible with a single applicant. It will also normally entail the need for cooperation and agreement between the parties.

NRW decision

If neither a shared scheme nor a split scheme is possible, it will become necessary for us to decide which (if any) of the proposed schemes should be permitted to proceed using the factors shown below. Where considered by us and the applicants to be feasible, agreeing to a shared or split scheme may, subject to our approval, allow both parties to pursue a hydropower scheme at the location of interest. In the absence of agreement, there is a risk that neither scheme, or at most only one scheme, will be licensed. We therefore encourage parties to reach agreement outside of the licensing process.

Several points should be understood by applicants who are unable to reach agreement:

  • In reaching a decision as to whether to licence a scheme, we will consider applications on their merits having regard to any other (actual or potential ) competing applications of which we are aware concerning the same water resource. The timing, order or status of an interest in a potential abstraction will not normally be relevant. We will consider which scheme, if any, is most desirable and in the public interest, as informed by our legislative duties and policy aims.
  • We do not operate a ‘first come first served’ policy in relation to competing hydropower applications. We will consider the merits of each application regardless of which application is received first.
  • We will not necessarily licence one of two or more competing applications. There may be circumstances where we deem it inappropriate to grant a licence for any application, for example where a scheme is likely to have a significant effect on a site designated for nature conservation under the Habitats Regulations.

Split schemes

In many cases, hydropower developers will seek to use the maximum amount of water available under our abstraction licensing standards. It will normally be impossible for two schemes to abstract at the maximum allowable rate.

Where the applicants express an interest in pursuing the possibility of a split scheme, we will consider with the applicants whether a split scheme – two hydropower schemes each utilising a proportion of the available flow – is feasible at the site in question. Such consideration may include the following factors, where relevant:

  • the potential impact on statutory designated sites and legal requirements that must be considered in any permitting decision;
  • the physical location and the feasibility, desirability and impact (including visual impact), of installing two hydropower schemes.
  • the available flow at the site and the available flow for each of the two schemes.
  • the viability – both in practical and economic terms – of the two schemes with a share of the available flow.
  • the enforceability of licence conditions for the two schemes. In particular, a feasible means of apportioning the available flow between the two schemes and of enforcing a ‘Hands Off Flow’ licence condition independently for each scheme will be needed. It is likely that control systems for two schemes will require shared elements, for example one system to monitor flows and/or water levels. The details are likely to be site specific.
  • any agreement which the applicants have made, or propose to make, in relation to the split scheme – including any agreement as to, for example, shared costs, monitoring, operation of scheme and fish pass, and mutual co-operation.

In some cases, we may conclude that a split scheme is not acceptable for environmental reasons, or is not in the public interest, at the site - for example, where there will be unacceptable impacts upon notified features of designated sites, fish passage, weir pools or increased flood risk. In such cases, if both applicants still wish to proceed with schemes at the site, the applicants may wish to consider proposing a joint (shared) scheme. Failing this, it may fall to us to asses both applications.

Shared schemes are likely to be preferred to split schemes for environmental reasons, especially in relation to fish passage. On split schemes a single fish pass may not be effective, leading to the need for two fish passes to utilise the attraction flow from each scheme.

Factors to be considered when assessing competing schemes

If we decide that only one of two or more competing schemes is appropriate at a site, we will then consider which of the schemes, if any, will be licensed. In doing so, some or all the factors set out in paragraph 17 below may be relevant, depending upon the characteristics of the site and all other relevant circumstances. It is emphasised that the list below is non-exhaustive: other factors may be relevant and may be of equal, or greater, importance.

The ultimate question in every case will be which of the proposed schemes, if any, is environmentally acceptable and in the public interest, for us to licence. Our role will be to make decisions about the appropriate use of the site for the benefit of existing and future generations, bearing in mind the long-term impacts of many hydropower schemes and our statutory remit. That includes contributing to sustainable development, community benefit, managing and protecting designated sites, conserving and enhancing the natural beauty and amenity of waterways and associated land, conserving the aquatic environment, protecting fisheries and securing the proper and efficient use of water resources.

Our overall aim in making a decision will be to ensure the development of the best possible sustainable hydropower schemes both now and in the future. If faced with two or more competing schemes, only one of which might be licensed, we will choose between the schemes on their merits by deciding which scheme is most environmentally acceptable and offers the greatest public benefit by reference to the factors set out below (this list is not exhaustive – see paragraph 14 above), including in particular the need for efficiency in the use of water resources and the need to protect the environment.

In deciding which scheme should be licensed, if any, we will normally give weight to the following issues:

  • The optimum use of available water resources considering for example (i) the amount of water used; (ii) the reasonable requirement for water (iii) the amount of power proposed to be generated and (iv) any adverse impacts in water resources terms.
  • Whether there are any likely significant effects on designated sites (SAC, SPA, Ramsar and SSSI) and whether the proposals meet the requirements of the Conservation of Habitats and Species Regulations 2017 and S.28 of the Wildlife and Countryside Act 1981.
  • Local and wider environmental impacts of the proposed scheme. Such effects could be positive or negative, and might include, for example: changes in hydromorphology, changes to the ecological status of a water body, changes to fish passage through inclusion of a fish pass, provision of appropriate screening and scheme design to enable best measures for fish protection/passage.
  • Assessment and mitigation of flood risk of the proposed scheme both where a scheme requires consent for works and in our role as adviser on flood risk with a duty to exercise a general supervision over all matters relating to flood risk.
  • Impact on other water users of the proposed scheme in terms of effects on protected rights of existing abstractors and lawful uses of water by others for agricultural, industrial, public supply or recreational purposes including fishing and on requirements of fisheries, navigation or land drainage.
  • The impact of the scheme in renewable energy terms, including both (i) carbon emissions saved by electricity generation, (ii) the amount of renewable energy generated and (iii) embedded carbon and the lifecycle carbon footprint of the scheme.

We summarise issues at the end of this section which will usually be considered in reaching the decision on which proposal (if any) to licence. To undertake a comparison of potentially relevant factors including local ownership we will need to be provided with information in the environmental report accompanying each scheme application.


Every hydropower application will be decided on its own merits. We will seek to grant those hydropower applications which are most environmentally acceptable and of greatest public benefit, bearing in mind their short and long-term impacts on the environment and the overall desirability of any scheme in the public interest, when considered against all other actual or potential proposals at the site.

Summary of issues

When determining competing licence applications for hydropower we will assess applications against the following design, operation and mitigation standards:

  • The scheme has been designed to avoid the need for a new impounding structure or to minimise modifications to an existing weir unless those modifications will lead to an environmental improvement
  • The intake weir, penstock and outfall have been sited and designed in line with our guidance to minimise impact on site geomorphology and sediment transport
  • There is provision of effective upstream and downstream fish passage including fish and eel passes and easements
  • There is effective fish and eel screening of the turbines and protection against fish entrainment or impingement
  • Scheme design has involved assessment and design to mitigate impacts on the weir pool morphology/ecology
  • Turbine type is appropriate for the proposed location considering environmental factors and aesthetic/amenity issues
  • The proposal has been fully assessed for effect on flood risk and meets standards set out in national policy and guidance
  • The arrangement of the proposed scheme has least impact on the river environment by having the shortest length of flow depleted or influenced river reach
  • The proposal can demonstrate a reasonable requirement for and efficient use of abstracted water
  • The hydropower abstraction regime is consistent with our guidance on protection of river flows and/or provides other environmental benefits in terms of residual flow protection
  • The proposed scheme fully meets all legislative requirements for the protection of designated sites for nature conservation, protected habitats, features and rare species
  • The potential impacts of the scheme on other water users, landscape, heritage and amenity have been fully assessed with appropriate mitigation measures developed where necessary
  • The scheme can demonstrate the best design life carbon reduction benefits in terms of both construction and long-term operation
  • The scheme has least environmental impact in development of site access, construction and electricity grid connection
  • The scheme has an element of local ownership and can demonstrate community benefit
  • The licence holder has complete legal authority to construct and operate all components of the proposed hydropower scheme

Read about hydrological reporting for hydropower schemes

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