Current research into the most efficient types of renewable energy explores sources that were well known to early mankind. They used ethanol to cook their food and energy from food to walk to work and set off on hunting expeditions. They probably spent a good deal of time out of doors absorbing heat and light from the sun.

When the British Prime Minister rides his bicycle to the Houses of Parliament he makes a statement about efficient energy. Food has powered him there cheaply and efficiently. The phenomenon of commuting from homes to work places in cities is very recent in human history, dating from the nineteenth century.

With computers and internet technology much commuting is really unnecessary and wasteful. It is possible for most jobs to be done online from home if work procedures are re-arranged. Already there are many people running large businesses from remote desert towns where they enjoy the benefits of a country lifestyle.

The phase 'that the way we've always done it' is death to innovation and progress. It is also wrong in most cases. Suburbs, cities and city centres are actually recent developments in human affairs. The billions of dollars now spent daily on commuting to work by car or train could quite easily be avoided if most people worked from home computers or lived 'above the shop' as they did not long ago.

The fact that renewable resources are insufficient to fuel extravagant energy lifestyles does not mean that they are inefficient. Inefficiency resides in extravagance. Methane gas produced from garbage and animal waste is sufficient for cooking but not an energy extravagant lifestyle involving many domestic appliances.

Many years ago ethanol was used as fuel and as a supplement to petrol. The exploding human population demanded more food and it became common for people to use massive four wheel drive vehicles to trundle around suburban lanes. As a result ethanol was considered uneconomic as fuel but a change in lifestyle could change this situation. New designs and different vehicles could make ethanol an economic renewable resource.

New urban designs that would enable people to live within walking distance of their work are quite feasible and quite unlikely to come about. This is because there are huge vested interests in the transport business that would not like to see huge reductions in numbers. They prevent progress in the same way that the oil industry has delayed the use of electric cars for many decades.

In a final analysis the most efficient types of renewable energy may be a factor of lifestyle and urban design. If urban designs require people to commute speedily over considerable distances in bullet trains and aircraft then energy from solar power and bio-fuels will be insufficient. However, if lifestyles and patterns of usage were to change, alternative energy sources such as solar power and bio-fuels could become viable again as they were through most of human evolution.