| LONDON, April 25
LONDON, April 25 Britain's most ambitious smart
grid project is being built on a housing estate in Leighton
Buzzard, a rapidly growing commuter town north of London.
UK Power Networks (UKPN), which owns and operates
electricity cables and lines across southeast England, is
installing a giant battery farm that will supply electricity to
local users at peak times.
Around 240 tonnes of lithium-ion batteries are being
installed in a specially designed building raised 2 metres above
the ground to protect it from flooding by the nearby river.
And the battery room will be air-conditioned to keep the
batteries comfortable at a steady 23 degrees Celsius to extend
their working life.
The demonstration project, which is scheduled to begin
operating in September, is jointly funded by UKPN and the Low
Carbon Networks Fund, administered by the government's Office of
Gas and Electricity Markets.
Once it is fully operational, Leighton Buzzard will have the
capacity to discharge up to 10 megawatt-hours (MWh) of power
into the local distribution network at a rate of up to 6
megawatts (MW), enough for 6,000 homes.
The aim is to test the technical and financial feasibility
of using storage to reinforce the power grid and help meet peak
loads as an alternative to the conventional approach of
installing more substations and overhead power lines.
Many analysts have written off electricity storage as
expensive and impractical. But interest in storage is growing
California has instructed utilities to install or procure
1,300 MW of storage capacity by 2020 as part of the state's
plans to increase renewable generation and reduce emissions.
Germany, Italy and China all have ambitious electricity storage
Remote island communities, where the alternative is running
expensive diesel generators, are also prime candidates for
schemes which integrate solar and wind with battery farms.
Britain's Scottish and Southern Energy has developed a
scheme in the Shetland Islands off the north coast of Scotland
to discharge 3 MW every day to help offset the evening peak.
Other island communities in the Azores, the Caribbean and
the Pacific have also been identified as promising locations for
integrated battery-and-renewables projects to cut blackouts and
reduce reliance on diesel.
Unlike physical commodities such as oil, gas and coal,
electricity cannot readily be stored, according to the
traditional textbook account. The amount of power produced by
generators must exactly match the amount demanded by customers
on a second by second basis.
For a century, the electric industry has met variable and
unpredictable demand from users by aggregating them together in
large networks (customers' behaviour in aggregate is steadier
and more predictable than individual users') and keeping lots of
spare generation and transmission capacity on hand to meet
surges in demand. Generation followed demand.
But the traditional model is being blown apart by the
government's ambitious targets to combat climate change by
electrification and decarbonisation. Over the next 30 years,
Britain will need vastly more generation and transmission
capacity and the power supply will become much more variable and
The government plans to replace gasoline and diesel-powered
cars with electric vehicles and gas-fired home boilers with
electric heaters which implies a six-fold increase in peak
demand from the current 60,000 MW to as much as 370,000 MW by
At the same time, government plans to decarbonise the system
by increasing the amount generated from renewables like wind and
solar imply much more variability in supply because they cannot
be scheduled in the same way as coal and gas-fired power
Britain's generation and transmission system is already
stretched to meet the combined heating and lighting demand on
winter evenings. Enormous amounts of spare generating and
transmission capacity are held in reserve to meet peak demand on
just 100 hours per year.
LOAD SHIFT OR STORE?
In future, as consumption grows and supply becomes more
unpredictable, it will be even harder and more expensive to meet
peak demand. Policymakers and the industry are therefore
considering how to adapt the traditional generation and
One option is to smooth out the peak in consumption and make
demand more flexible by introducing smart meters and time of use
tariffs. Every household in Britain will have a smart meter
installed by 2020. Smart meters will measure the amount of
electricity consumed in every half-hour period.
In theory, once smart meters have been installed, suppliers
could introduce higher tariffs for peak periods (generally 4 pm
to 8 pm on winter evenings) to encourage customers to shift
consumption to other times of day when demand is lower, which
would make more efficient use of generation and transmission
The other main option is to introduce more storage on the
network. Storage units would absorb excess power overnight and
when wind and solar production is especially high, then
discharge it at peak times, smoothing the demand profile.
Britain already has some limited electricity storage in the
form of pump-hydro. Dinorwig power station in north Wales, which
became fully operational in 1984, uses off-peak electricity to
pump water to an upper storage reservoir.
Electricity can then be supplied back to the grid by opening
the sluices and allowing the water to drain back into the lower
reservoir through six giant turbines. Dinorwig can produce up to
288 MW and reach maximum generation within 16 seconds, according
to its operator First Hydro.
First Hydro also owns and operates a smaller and older
facility nearby at Ffestiniog which can deliver 90 MW to the
grid in about 60 seconds.
The problem with pump-storage is that it is enormously
expensive and suitable sites are rare. Batteries are cheaper and
can be scaled to any required size. Storage batteries can be
installed at any scale - from an individual home to a street, or
even directly onto the distribution and transmission networks at
the substation level.
But batteries are still more expensive than conventional
network reinforcement. In general, distribution companies find
it cheaper to install extra lines and substations to meet peak
UKPN puts the capital cost of the battery scheme at Leighton
Buzzard at 11.2 million pounds ($18.82 million), compared with
6.2 million pounds for conventional reinforcement, with an extra
overhead power line and another transformer.
"On a pure capital expenditure basis, energy storage can
seldom compete with conventional options," the company admitted
in a presentation back in 2011.
But the company hopes that battery storage could become more
economic in future if costs come down with more experience.
Battery enthusiasts also hope their storage units can earn
extra revenues by providing a variety of additional services to
the grid, for which they would get paid.
Battery farms could earn extra revenue by providing
balancing services like fast-response and participating in the
short-term operating reserve, according to S&C Electric Europe,
which has done much of the design and engineering work on
Battery farms could also help regulate voltage, supply
reactive power to support the grid, and earn payments under
government plans for capacity markets.
There are still some problems to overcome before battery
farms can start unlocking all these extra revenue streams.
Britain's regulators consider electricity storage to be a
form of generation. Under current rules, distribution network
operators like UKPN are not meant to own "generation" assets
directly, so it has to be organised through independent third
Giant battery farms still seem outlandish. But storage will
probably play a much bigger role in the smart electricity grid
of the future. If it does, it will be thanks in no small part to
($1 = 0.5953 British Pounds)
(Editing by Keiron Henderson)