No energy answer is all green
RENEWABLE energy will be the fastest growing sector of the market over the next 20 years according to leading analysts, but the problem is that it is not actually ‘‘ green’’, says one of America’s leading environmental scientists.
Speaking in Adelaide where he addressed a major petroleum conference, Jesse Ausubel of the Rockefeller University in New York decried ‘‘ an era of mass delusion’’ about renewable energy.
Ausubel, director of the university’s Program for the Human Environment, has impeccable green credentials as one of the scientists who led the United Nations in to its work on global warming, rejects hydroelectricity, wind and solar power and biomass as ‘‘ renewable, but not green.’’
The best way to understand the scale of destruction these energy forms impose, says Ausubel, is to denominate each in watts per square metre that they can produce as a power source. A square kilometre of a hydroelectric dam, he argues, produces enough power for about 12 people while severely damaging river life, while a biomass power plant requires about 2500sq km of prime farmland to equal the output of a 1000 MW nuclear plant on a few hectares.
‘‘ Windmills, to equal the same nuclear plant, need to cover 800sq km — and that in a very favourable climate. Photovoltaics require 150sq km.’’ Ausubel says a wind energy system requires 130 times as much steel and 30 times as much concrete to match the output of a natural gas combined cycle power station.
Resolving wind and solar’s problems of intermittent supply will require a large amount of storage batteries and their heavy metals, he adds, pointing out that renewable energies also invoke high risk as supply sources in a changing climate. ‘‘ Rain may no longer fall where we build dams or plant biomass for fuel. The wind may no longer blow where we build windmills while coal, methane and uranium plants will operate reliably around the clock day after day.’’
Ausubel predicts that solar renewable power will ultimately ‘‘ become an embarrassing collection of stranded assets.’’
He is a strong advocate for dealing with energy needs under climate change by building large zero- emission power plants using natural gas initially, and then nuclear power much more widely to reach an age when pure hydrogen completes the process of economic decarbonisation.
It will probably take a century, he says, before the hydrogen age is in place, ‘‘ but the inexorable decline of carbon seems clear.’’
Ultimately, says Ausubel, the behaviour of the end user drives the energy system. ‘‘ When the end user wants electricity and hydrogen, the primary sources that can produce on the needed scale while meeting ever more stringent ( environmental) constraints will win. Dense cities will be the final arbiter of the energy system.
‘‘ My dream is 5000MW gas- fuelled, zeroemission power plants operating at high temperatures and high pressures, and thus super compact. Like the internet and computers, the energy system must become more powerful and smaller to be deeply green.’’