Positive Energy: how renewable electricity can transform ... - WWF UK

Can storage play
a bigger role
Energy storage is a technology which can provide
flexibility, helping system security in a high renewable
energy scenario. Currently, all significant UK
storage capacity is pumped storage. This generates
hydro-electricity during hours of peak consumption
by using water that has been pumped into an elevated
reservoir during times of surplus generation.
No new storage plant has opened in the UK since the 1970s, although Scottish
and Southern Electric (SSE) do have new pumped storage in the pipeline,
providing 100GWh of storage capacity and a peak output of 60 MW. SSE are
also considering two further pumped storage projects 46 .
THE ECONOMIC
CASE FOR STORAGE
WILL BECOME
STRONGER AS MORE
RENEWABLE ENERGY
GOES ON THE GRID
A recent ENDS Report article on storage 47 highlighted that although there
is a clear benefit to building additional storage capacity, it is currently less
economic than building flexible generation or interconnection. As a 2009
House of Lords Economic affairs committee report pointed out,
“a breakthrough in cost effective electricity storage technology would help
solve the problem of intermittency and remove a major stumbling block to
wider use of renewable energy in the longer term”. 48
One likely effect of increasing how much renewable energy we use is that
electricity wholesale prices will fluctuate, with greater day-to-day price
variations. This gives storage capacity a potential opportunity to compete in
the market, as there could be significant returns on investment when output
from renewables is low. In a 2010 report addressing flexibility for the low
carbon power sector, Pöyry 49 highlighted that “dedicated storage collects its
revenues from arbitrage between prices at different times”. However, a large
volume of storage would reduce price differentials.
It appears that the economic case for storage will become stronger as more
renewable energy goes on the grid. As storage becomes more economic,
we can expect technologies such as heat and flow cells which, according to
National Grid 50 , are “the ones to keep an eye on”, to significantly improve and
their cost to substantially fall. Storage has limitations as it needs to recharge
but its role in providing flexibility could significantly increase.
WWF-UK 2011 Positive Energy page 46