Friday, August 13, 2010

The path to sustainability

Researchers in Australia have laid out an ambitious plan to transform Australia's electricity supply from primarily coal-based to 100% renewable energy within a decade:

Under the plan, 60 per cent of the nation's electricity would be sourced from 12 huge solar thermal power plants, which use Australian-developed technology to store heat in molten salt, allowing them to operate for long periods when there is no sunshine. The remaining 40 per cent of the power grid would be filled by about 6500 wind turbines at 23 large-scale wind farms dotted mainly around the coast. The plan would generate 325 terawatt hours of electricity a year, meeting the nation's entire power demands in the year 2020, if a comprehensive energy efficiency plan is also factored in. Any shortfalls could be made up by biomass energy generation, using a portion of the stubble from the nation's wheatfields.
The cost? A$37 billion a year for a decade. That sounds staggering, and it is - its about 3% of total GDP. But that's the sort of price you pay when you replace a country's entire electricity infrastructure in a short space of time. Not pursuing a crash program and extending the time period would reduce the cost substantially (as well as avoiding any costly block-obsolescence problems further down the track). Doing it over the lifetime of the infrastructure with a "no new fossil fuels" policy (meaning old stations get replaced with renewables as they retire) would effectively reduce it to zero.

I don't expect Australia to pursue this plan, but it shows the sort of challenge the world is facing. In order to deal with climate change, we need to decarbonize our energy infrastructure. And if we want it to happen in time to make a difference, we need to start now.

Nominally, the New Zealand government is already starting, with a target of 90% renewable electricity generation by 2025. But we don't actually have any policies to achieve that goal, and the construction of a single large gas or coal fired power plant will make it unachievable (as well as spiking electricity prices due to high carbon costs). The lowest-cost option is clearly gradual replacement and requiring new generation to be renewable, but that's not something we can leave in the hands of the market. If we want to meet that target, rather than being forced to abandon it or start an expensive crash program, we need to reinstate the thermal ban now. Otherwise, it may cost us all a lot more in the future.