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