07/08 Briefing paper on clean energy supergrids
Climate scientists tell us that we need urgently to reduce the
concentration of greenhouse gases in the atmosphere. To do so, we have to emit less
carbon dioxide than the planet absorbs. That means getting off fossil fuels fast, and
saving our forests. Given the rising price of oil, gas and coal, a switch to sun, wind and
water could also save us a lot of money. Yet many people assume that renewables can
only supply a modest part of the world’s energy in the foreseeable future, and most feel
powerless to save the rainforests. In fact, if we approach the problem on a regional
scale, the following seven steps could go far towards solving the climate problem.
Build a "supergrid" linking countries within each
region, or simply linking all parts of large nations, using
high voltage direct current (HVDC) cables. HVDC lines,
which lose very little energy in transmission, can bring
solar, wind, wave, hydro or geothermal energy to
everyone from wherever these sources are abundant.
Feed into the grid cheap, reliable energy from solar
thermal power stations in deserts and other sun-rich
areas. These power stations, already operating in Spain
and the US, use mirrors to concentrate the sun's heat to
boil water and drive a steam turbine. Scaled up, they
could produce far more energy than the world uses.
Expand our capacity to store renewable energy in
mountain ranges by pumping water uphill into reservoirs,
large and small. When electricity is needed, water is run
downhill through a turbine, returning 75% of the original
energy into the grid. Many countries already use this
system, known as pumped storage.
Rapidly expand wind power. Across a wide region,
the supply is fairly steady: when the wind drops in one
place, it is blowing elsewhere. Some wind energy can be
stored in the mountains as backup to ensure 100%
reliable supply, thus allowing us to depend on wind for a
larger part of our energy.
Put solar photovoltaic (PV) panels on rooftops and
in solar farms throughout the region. The cost of PV is
falling fast, and new developments such as “thin film”
technology are about to reduce costs further. Some of
the energy generated in the daytime can be stored for
night time use, thus ensuring a steady supply.
Pay farmers and landowners to conserve forests
and other key ecosystems, and to re-forest areas where
the trees have been lost. Costa Rica had 85% forest
cover in 1900, and was down to 29% by 1987. Thanks
to innovative “payment for ecosystem services” laws,
Costa Rica is back to 51% forest cover today. The same
approach could be applied anywhere.
Switch to electric cars.Vehicles that recharge
from a normal electrical socket are already on the
road. “Plug-in hybrids” can also re-charge if necessary
from an on-board petrol-fueled generator as a back-up
power supply. The electrical equivalent of a litre of petrol
costs about US$0.25, so driving could get a lot cheaper!
Download the briefing paper on the clean energy supergrid