purpletigron

Last night, I heard Paul Mobbs speak.

Energy beyond Oil

http://www.fraw.org.uk/ebo/

What are the scientific estimates of future energy availability? Energy sources can be limited by many factors: e.g. scarcity of mineral resources; land area required; the 'net' energy output (considering energy needed in production); the effects on global environmental stability (e.g. climate) etc.

In 2004, the world consumed nearly 10,000 Mtoe[1], or about[2] 400 EJ. Currently, we source about 75% of our energy from fossil fuels.

This is the crux: Non-renewable resources follow a peaked, Gaussian supply curve; we are nearing the peak of oil and natural gas supply. So, demand for energy will soon rapidly out-strip physical supply of fossil fuels - oil and gas will be too scarce and expensive to meet our energy needs. Energy drives the global economy - without huge alternative energy supplies and efficiency gains, the world economy will have to contract significantly.

Mobbs' conclusion is that, by 2050 the UK will have access to only 25% of our current primary energy supply. He argues that nothing can replace conventional oil for 'business as usual'.

How do we currently use energy? The UK in 2003 had a 'primary energy supply' of 10 EJ, having exported 5 EJ. Transport uses 2.4 EJ, industry, commerce and the public sector, 2.3 EJ, and we use 2 EJ in homes - the energy industries used 1 EJ, and another 2 EJ goes as waste heat. For the past 30 years, oil has supplied about 30% of the UK energy budget - increases in industrial use of natural gas, and efficiency, have been offset by increased motor vehicle use.

What about future energy supply? Nuclear fission reactors can supply 30% of the current world energy budget for only 20 years on known U-235 reserves. Commercial fast breeder reactors could meet current demand for 100 years, but may take 50 years to develop. Global coal could last 100 years, but would cause catastrophic climate change. Biodiesel is too land intensive to replace mineral diesel on large scales. Wind power is unpredictable, and would require a massive turbine building programme. Hydrogen is not a primary energy source. Commercial nuclear fusion is 50+ years away.

Solar energy is a special case. The Earth intercepts about 5 million EJ of solar radiation annually. Roughly, 35% is reflected back, 40% warms up the atmosphere and land, 25% drives the hydrological cycle, and 1% drives the winds. Just 0.02% is captured by plants. If the Earth is in thermal equilibrium, that energy must all be re-radiated into space as waste heat. Can we extract more useful work from solar energy without disrupting the natural processes that it also fuels, and without raising the global equilibrium temperature?

"It is up to us all, on the basis of how we view the evidence about an 'energy crunch', to plan 'beyond oil'."

[1] 1 Mtoe is 1 million metric tonnes of oil, equivalent
[2] 1 Mtoe ~= 4.2 x 10^16 J or 0.04 exajoules [EJ] http://www.grida.no/climate/ipcc_tar/wg3/477.htm

Oil has driven the world economy for decades. The solar and geothermal energy input to form oil was made ~ 100 million years ago. Now, 'the market' needs to put in place substitute energy sources, which are reliable, convenient, affordable and annually produce tens of exajoules more energy than they use. My expectation is the market will not produce a miracle - there will be a global interruption in economic growth whilst the energy industry rushes to adapt. Locally produced renewable energy could be a useful 'stop-gap' that communities can provide for themselves.

Apparently, the British National Party are already planning to politically exploit the mass consumer frustration that economic disruption will cause.