Q&A

What are the minimum requirements for an Archimedes screw turbine?

There is no exact figure for a minimum requirement. Turbines can be made to almost any size, but the smaller they are the lower the returns are. Turbines lower than 5kW are generally not economically viable as the install cost outweighs the return.
To work out how much power is available from a site you require two important figures, namely the head and the flow. The head is the difference in surface levels between two bodies of water, such as the height difference either side of a weir. The flow is described as the volume of water flowing past a given point in a given unit of time, this is measured in cubic meters per second (m3/s).

Power = Head X Flow X 7

As a rule of thumb we require a minimum head of 1m.

Hallidays Hydropower can issue you a guide on how to measure the head and flow along with other important information so that you may perform a self assessment of your site. This is issued free of charge and will save you the cost of calling out a consultant. Please contact us if you would like a copy of this document.

What is a feasibility study?

A feasibility study is a document put together as the first stage of a project. It is a study of your site that includes a site visit from us, and a 20 page document that outlines potential turbine locations, positions, sizes, power output, annual energy capture, initial hydrology studies, approximate scheme costs/revenues/returns, initial scheme design and a CAD model. We can also identify any limiting factors that may affect the scheme. This document will give you a good understanding of your site and what its potential is, and whether it is worth continuing to the next stage of the project.

Are Archimedes Screw Turbines efficient?

Yes, very. At 70%+ ‘water to wire’ efficiency, the Archimedes screw turbine is the most efficient hydro turbine at low head.  They are far more efficient than other types of domestic renewable generators, for example wind is between 12-20% efficient, and solar can be as low as 6%.
Hydro power is also far more reliable and predictable, as the water in the river flows all year round, unlike wind and solar. Power output is also in correlation to the seasonal demand, i.e. the turbine produces more power during the higher river flows in winter, when there is a higher demand for electricity. This is the opposite for solar.

How does the turbine generate me an income?

Through a combination of Feed In Tariffs (FITs), sales of power back to the National Grid and through savings of energy used on site.

How long does it take for a turbine to repay itself?

This varies on the size of the turbine. For smaller turbines, such as mill sites and small weirs, the payback is around 10 years (from a turn key package). Larger schemes tend to return quicker. There are turbine sizes that do not make economic sense due to the change in the FIT levels, namely 15-19kW systems and 101-150kW systems, as it works out that you have a higher return if you stay in the lower FIT bracket due to the increased tariff per kWh.

 

What are FITs?

As of 1st April 2010 a new government backed incentive for green energy called Feed in Tariffs (FITs) was launched to help the UK reach its 2020 targets of at least 15% of the country’s energy coming from renewable sources. The aim of this is to increase the number of renewable generators in the UK, whether they be private or corporate. These can be can be in the form of an off shore wind farm to a single solar panel to Archimedean hydro screw.

The FITs are:

  • Guaranteed 20 years from the date of installation.
  • Tax free income.
  • Index linked to inflation*.

How do I get paid from FITs?

See financing page for details

How much does an installation cost?

Prices are bespoke to each site and to the requirements of the client. Prices usually start at the £100,000 mark for a full installation (the turnkey package including design, planning, licensing, installation commission and handover). The costs are roughly spread out 20% design and legislation, 40% screw costs and 40% civil works, though this varies from scheme to scheme.

 

Can I install my own turbine?

No, for systems to be eligible to receive feed in tariffs (FITs) they must be installed by either an MCS (Microgeneration Certification Scheme) or an MCS transitional accredited installer. The turbine itself must also be manufactured by an MCS accredited manufacturer.
It is possible to install a system without MCS, but you will not receive the FITs, meaning the annual revenue could be as low as a fifth of what it would be with the FITs.

Are there any Grants available?

Grants are generally no longer available. The FITs have replaced grant funding and provide an alternate incentive for installing micro-generation systems. There are some grants available in exceptional circumstances, though if you do receive a grant, you may not be eligible to receive the FITs.

How much revenue can a turbine bring in each year?

This is totally dependent on the size of the turbine, the size and flow patterns of the river, Environment Agency requirements and FIT levels. As a rule of thumb you are looking at between 9-15% of the install cost as an annual return.


How long does it tend to take to install a turbine?

From start to finish a turbine will take approximately a year, though larger schemes can take up to three years. The majority of this time is taken up in planning, consents, and design. Installation of the turbine can take as little as 6 weeks, where as licensing can take four months. Manufacturing of the turbine can take between 16 to 28 weeks. Manufacturing should only take place once the licensing has been granted.

What licences do I need?

The main licence is called an abstraction licence. This is a licence to abstract water from a river to put through the turbine. This is required for every type of turbine. Without this licence you will not be able to receive FITs.
Consent to work in water is also required to receive this licence.

What studies do I need to have to receive an abstraction licence?

There are multiple studies required for the licence, these include ecology, hydrology, topography and more. Hallidays Hydropower will guide you through the necessary studies specific to your site.

What is the lifespan of an Archimedes screw turbine?

These turbines have an expected lifespan of 40-60 years.

Are Archimedes screw turbines high maintenance?

Due to the low numbers of moving parts, these turbines are very low maintenance compared to other forms of turbine. Hallidays Hydropower also offer maintenance packages as one of our services.