Friday, 17 July 2015

Energy storage - our salvation ?

 Professor Win Rampen’s inaugural lecture for the Chair in Energy Storage sums up the key energy challenges facing the world, and the UK in particular:
  • Baseload electricity is presently covered by nuclear and coal, which can’t come on and off quickly (see Supply graph from Gridwatch above).
  • The main job of balancing variations in daily demand and renewable supply (wind and solar), is done by gas. The contribution from hydro is relatively small.
  • Solar photovoltaics are on the rise. Over the last few decades prices have plummeted while efficiency has crept up. Recently new cheaper materials have had rapid efficiency improvements; these may soon overtake silicon PV. Cheap PV raises the question of how other forms of generation will be able to compete for finance.
  • Photovoltaics, which count as negative demand rather than supply, is highly variable: passing clouds cause sudden generation dips. Already there is so much solar that on sunny days there is a dip around noon (see Demand graph below).
  • Prices paid by the National Grid to generators can vary by a factor of three during one day due to this variability.
  • Demand-side management is one way to deal with variability: already big companies have agreements with the grid to switch off during peak demand. In the future we will use the internet to control household appliances.
  • We need to drop fossil fuels, but how can we provide the flexibility that gas provides, given that more renewables will require even more flexibility?