• RIVER FLOW AND GENERATION OF HYDRO-ELECTRICITY
On average, around 1,500 million tonnes of water flow down the River Severn through Shrewsbury every year, an average of about 4 million tonnes of water a day. In the summer, the daily flow can be only a tenth of that and at that level, there is not enough water in the river to divert any of it through a turbine to generate electricity so all the water will continue to flow over the weir. Conversely, in exceptional flood conditions, the water can’t get away fast enough below the weir, the weir becomes submerged and there is no drop or “head” left in the water level to allow electricity to be generated. Fortunately, there is a lot of time in between and feasibility studies carried out for Shrewsbury Hydro indicate that over 1½ million kilowatt hours (kWh) of electricity can be generated each year by a hydro installation alongside the weir.
• REDUCTION IN CO2 EMISSIONS
The Shrewsbury Hydro scheme should save up to 400 tonnes of CO2 emissions going up into the atmosphere each year when compared to having the same amount of electricity generated by a conventional power station. (based on government BEIS figure for 2019 of 0.23 tonnes per 1,000kWh).
• THE LOCAL ENVIRONMENT
Work undertaken into the morphology of the river has shown that a hydro scheme can be built alongside the weir which can be beneficial to fish migration whilst at the same time having no effect on flood levels. Flood Defence Consent, an Abstraction Licence and fish pass approval have been granted by the Environment Agency.