In-Stream Run-of-River Hydropower

The term ‘In-stream Run-of-River’ (ISROR) hydropower refers to an emerging field of renewable electricity generation involving the placement of a turbine in a river current. This is usually done by mounting the turbine on the river bottom, an existing river structure or from a floating structure. ISROR technologies may operate in unidirectional or bi-directional (tidal) river flows and do not divert river flow or use dams to retain water or create an artificial head. The SRTT is ideally suited for deployment in river systems and significant potential exists for Scotrenewables to diversify into the ISROR sector.

Advantages of ISROR Hydropower

Abundant & Well Distributed Resource Close to Sources of Demand

There are many rivers all over the world of sufficient size and annual discharge to make deployment of SRTT turbines commercially viable.

High Energy Capture

If placed in a well-resourced site with steady and constant current flow ISROR systems such as the SRTT will operate at or close to rated output for a large proportion of the time – potentially achieving a capacity factor similar to conventional hydropower, nuclear and fossil fuel electricity generation. Furthermore at a well resourced site river flow will be relatively constant and will tend to vary on a seasonal rather than a daily or hourly basis.

Less Challenging Engineering Proposition

From an engineering perspective the riverine environment is generally more benign than the offshore tidal environment and will present far less of a design challenge to the tidal environment. Rivers generally have far less extreme wave action and more consistent flow speed and direction compared to tidal streams. This will result in a simplified design and significantly reduced construction costs for the turbine. The scalability of the Scotrenewables Turbine also means that different sizes of turbine may be produced for different sites - from perhaps 100kW to 2MW.

Less Site Specific than Conventional Forms of Hydropower

Conventional hydropower systems are highly site specific as they are reliant on not only sufficient water flow but also topographical features that provide head and are conducive to the construction of the necessary civil engineering structures. In contrast, ISROR systems, such as the SRTT, require little or no civil engineering and no diversion of river flow and can be deployed where there is sufficient river flow velocity, depth and width. Consequently, ISROR installations have a wider range of application and can be located closer to demand centres and grid connection points reducing transmission losses and grid-connection costs.