Re: Between a rock and a hard place
I hope I am note repeating what someone else has said, I have only read about 5 of the answer pages !
One of the main problems with wind and solar renewables is that none can provide a consistent and 24/7 supply. This is compounded by the problem in northern climes that during winter the day is at its shortest and often during the coldest periods there is little wind. Backup supply is therefore needed and whilst continuous output gas turbines are efficient, they can only be reduced by about 10%. To have a gas turbine that can by varied to cope with the variation of renewables the units used are much less efficient and the latest idea of using diesel powered generators as ultimate backup makes it very inefficient and puts lots of CO2 into the atmosphere. Altogether the inefficiencies add up to very little saving, if any, from using all high efficiency continuous gas turbines.
I will not go into the farcical situation of paying wind turbine owners money to turn them off when the power is not needed or to windy !
If we could get wave power or similar to work, it would be far more useful as the tide times are known, there are 2 per day and change times round the coast, so a set around the coast could provide a consistent output 24/7. How much is an unknown ?
This really leaves us with nuclear.
I know to many this is a horror story, but as has been stated the death rate due to nuclear is small compared to most industries. The Japanese problem was not the earthquake or really the tsunami, but the security feature of turning off the power plant in the event of an earthquake. This caused a loss of power to the cooling pumps. Compounded of course by not putting the standby generators inside the protective building. Thus the generators were destroyed. The nuclear building survived the tsunami and earthquake. The problem was human.
So to be safe we need a ‘safer’ version of Nuclear – Thorium.
The Thorium cycle was one of the generating proposals looked at by the Americans in the early days and was the favourite. However not by the military as it did not produce very much plutonium, which they wanted for weapons. This now is a very good reason to use Thorium. It cannot sustain a nuclear reaction and needs a neutron source to supply enough neutrons to keep the reaction going. We have lots of this – High level nuclear waste and plutonium.
So an ideal reactor would have liquid lithium salts fed by neutrons from nuclear waste, which if something went wrong and the neutron source could not be withdrawn quickly enough, a thermal plug would melt and dump the whole thorium salt liquid into a sump. I could only solidify as it could not continue its nuclear reaction. Very simple mechanical fail-safe.
The Thorium cycle produces the majority of its breakdown products with half lives of 50 years or less. Only a small amount of Plutonium is produced and could be processed and used as a neutron source. As the process is based on a liquid cycle – it is however possible to use a similar process as is used in existing nuclear power plants, but a lot of the advantages are lost – allows the liquid to be processed to remove ‘impurities’ without shutting down the plant for months.
It is estimated there is enough Thorium for about 1000 years.