of concerted kettle boiling. These smart fridges could also help iron out
short-time-scale fluctuations in wind power. The TV pick-ups associated
with the holiest acts of observance (for example, watching England play
footie against Sweden) can produce sudden increases in demand of over
2 GW. On such occasions, electricity demand and supply are kept in balance
by unleashing the full might of Dinorwig.
To provide flexibility to the electricity-grid’s managers, who perpetually
turn power stations up and down to match supply to demand, many
industrial users of electricity are on special contracts that allow the managers
to switch off those users’ demand at very short notice. In South
Africa (where there are frequent electricity shortages), radio-controlled
demand-management systems are being installed in hundreds of thousands
of homes, to control air-conditioning systems and electric water
Here’s how Denmark copes with the intermittency of its wind power. The
Danes effectively pay to use other countries’ hydroelectric facilities as stor-
age facilities. Almost all of Denmark’s wind power is exported to its European
neighbours, some of whom have hydroelectric power, which they
can turn down to balance things out. The saved hydroelectric power is
then sold back to the Danes (at a higher price) during the next period of
low wind and high demand. Overall, Danish wind is contributing useful
energy, and the system as a whole has considerable security thanks to the
capacity of the hydro system.
Could Britain adopt the Danish solution? We would need direct large-
capacity connections to countries with lots of turn-off-and-on-able hydro-
electric capacity; or a big connection to a Europe-wide electricity grid.
Norway has 27.5 GW of hydroelectric capacity. Sweden has roughly
16 GW. And Iceland has 1.8 GW. A 1.2 GW high-voltage DC interconnector
to Norway was mooted in 2003, but not built. A connection to the
Netherlands – the BritNed interconnector, with a capacity of 1 GW – will
be built in 2010. Denmark’s wind capacity is 3.1 GW, and it has a 1 GW
connection to Norway, 0.6 GW to Sweden, and 1.2 GW to Germany, a total
export capacity of 2.8 GW, very similar to its wind capacity. To be able to
export all its excess wind power in the style of Denmark, Britain (assuming
33 GW of wind capacity) would need something like a 10 GW connection
to Norway, 8 GW to Sweden, and 1 GW to Iceland.
A radical approach is to put wind power and other intermittent sources
onto a separate second electricity grid, used to power systems that don’t re-
quire reliable power, such as heating and electric vehicle battery-charging.