Oliver Schmidt

Grantham Institute - Climate Change and the Environment

​South Kensington Campus

Imperial College London

London SW7 2AZ, UK

tel: +44 79 345 487 36

e-mail: o.schmidt15@imperial.ac.uk

LinkedIn: www.linkedin.com/in/oliver-schmidt/

Integration of renewable generated electricity

We analyse the amount of renewable power supply that can be integrated for energy consumption, i.e. utilised, and the role of electricity storage to enhance it. We use hourly wind and solar generation and demand data for the UK, vary the ratio of wind and solar power, and scale their combined output over the modelled timeframe as a function of demand (Renewables penetration). The amount of unused hourly oversupply indicates the degree of successful integration of the renewable power (Renewables utilisation).

The figure below reveals four useful insights for the UK:

  • Top left: 80% wind and 20% solar represent the optimal ratio to integrate renewable power supply with demand in the UK. Example: If renewables generate the same amount of energy as demanded (over a certain timeframe), then around 75% of this energy can actually be utilised to satisfy demand. The remainder is oversupply in situations where renewable power output is higher than demand.

 

  • Top right: There is a linear relationship between energy storage efficiency and increased utilisation. Example: If renewables generate the same amount of energy as demanded (over a certain timeframe), 20% efficient infinite storage increases utilisation to 80%, 40 % efficient infinite storage to 85%, 60% efficient …

 

  • Bottom left: A storage device of 6.16 TWh capacity (two weeks of average UK demand) and 100% efficiency, enables nearly full utilisation of renewably supplied power. Example: While a 70 GWh storage device (two hours of average UK demand) increases utilisation by 5%, a 6.16 TWh device increase utilisation by >15%, from 80% (no storage) to >95%.

 

  • Bottom right: While small, efficient storage is beneficial at renewable penetrations <80% of demanded energy, large and less efficient storage is more beneficial for the integration of renewably generated energy above 80% of renewable penetration.

Figure – Renewables utilisation (share of renewable energy in energy consumption) as a function of renewables penetration (share of renewable generation relative to energy demand) without energy storage (top left), with infinite energy storage (top right), with finite storage (bottom left) and two options of storage (bottom right) in the UK. Axes denote renewable fraction of energy demand. av.l.h – average load hour

 Project in progress. Please contact us directly for more preliminary results.