On 09/06/2013 16:25, Nightjar wrote:
On 09/06/2013 12:57, The Natural Philosopher wrote:
On 09/06/13 12:01, Nightjar wrote:
On 09/06/2013 09:01, polygonum wrote:
On 09/06/2013 08:49, harry wrote:
Renewable technologies are about saving fossil fuel.

What is the reason to save them?

None whatsoever, given that we already have the technology to breed
oil from algae feeding on human or animal waste. Admittedly it
currently costs $800 a barrel, but that is in laboratory conditions
and the cost could be expected to plummet were it to be done on an
industrial scale.


No. In the end synthesising hydrocarbon fuels requires energy, and that
energy costs.

You will never be able to make a kwh or electricity and make 3 kwh of
fuel from it.

If the syntheshis is algaeic, using sunlight, you are in the solar
panel/biofuel game, but at appallingly low efficiencies. Solar panels
are far better than algae, the only advantage of 'biofuels' is that they
produce an energy STORE, but you pay a high price. Conversion efficiency
is typically less than 1% compared with 10-40% for a solar panel. So
once again the need for massive solar collecting areas arises.

The expected actual yield for a simple non-concentrating sunlight system
is in the range of 40,000 - 50,000 litres, per hectare per annum,
assuming 50% oil content. The 40,000 would be at Kuala Lumpur, where the
yield for palm oil is around 5,950 l/ha/a.

Better is to use nuclear heat or electricity to fashion hydrocarbons. At
around £5-£10 a litre.

Or about $1200 - $2400 a barrel. OTOH, algal oil could probably be
brought down to near conventional oil prices, consumes waste products
and produces biomass that can be burned or converted into fertiliser.

Colin Bignell

I can imagine harry's excuses if it becomes a "home" energy product..

"sorry I can't drive to work today as I have been constipated for days
and the algae has starved to death"