Hydroelectric power

By Andrew VerneyNBS-MO16

Courtesy Queen Mary University of London

t

The hydrological cycle

Hydro Power Potential

3 Types of Hydro Power

Run of River schemes – use the natural flow of the river and there is continuity of flow.

Storage – water is stored behind a dam and released through the plant

Pumped Storage – the plant can be reversed to pump water uphill when surplus power is available

Source: DECC

Scales of Hydro Power Pico:   <5kW

Micro:  5kW  – 50kW

Small / Mini: 50kW – 20MW

Large:  >20MWSource: DECC

Hydro Power: UKGeneration

In 2008, hydro power using natural flows generated approximately: 18.6 PJ of electricity, or 24 % of electricity generated from renewables in the UK

Hydro power from pumped storage generated approximately: 19 PJ of electricity, or 1.11 % of all electricity sold in the UK in 2008

http://www.decc.gov.uk/en/content/cms/statistics/source/renewables/renewables.aspx

Advantages of Large-Scale HEP

Once the dam is built,the energy is very cheap Water ‘energy’ can be stored above the dam Much more reliable than other renewables No waste or pollution produced “Switch off and onable” Reservoirs are multi-purpose amenities – leisure;

irrigation; flood control and wetland habitats

Constraints of Large-Scale HEP

Dams are very expensive Dams cause environmental upheaval upstream

and downstream The UK is running out of suitable sites Siltation reduces life expectancy Pumped storage requires available ‘baseline’

power and is not renewable

Small Scale Resource and Limitations

675MW of unexploited hydroelectric power in Scotland alone according to recent survey

Design life is high, investment cost relatively low Generate electricity for 3p/kWh Short construction times cf Large Scale Requires a suitable watercourse Initial capital cost is significant Environment Agency may not be supportive Multiple ownership of land, fishing and water

abstraction rights causes confusion and delay

Assumptions – Large Scale

Used Declared Net Capacity (DNC) figures from DUKES 2008

Load factor will improve slightly as control management systems improve

Changes in rainfall are ignored Glendoe online in 2009 Pumped storage is a management tool

not additional capacity

Projections – Large scale

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Assumptions small scale

Government incentives such as feed-in tariffs promote small-scale development

Planning and environmental restrictions do not counteract Government incentives

Current improved load factors remain at 38% Three Scenarios – Current rate of growth –

Doubled rate of growth or halved rate of growth

Projections – Small Scale

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2004 2009 2014 2019 2024

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Optimistic

Pessimistic

Conclusions

Large Scale development promoted by the Scottish Government could see one or two more large power stations come online.

Small scale pant could see a significant increase in percentage terms but remains a small sector.