… molten salt/graphite block … heat stores are able to hold a decent amount of heat energy for many days (perhaps weeks) …

Depending on their volume-to-surface ratio.

But hot graphite tends to burn. Don’t assume an energy proposal makes any sense at all just because it gets attention from civil servants. As the major class of oil and gas rentier, in the race to outmode oil and gas, they have an interest in picking losers, and they’re not always subtle about it.

I suspect if the graphite-block story were sensible, it would involve magnesium oxide blocks. These, or rather, blocks whose composition is mostly MgO, have long seen high-temperature service under the name firebrick. Somehow, graphite firebrick, despite being even more refractory than MgO, has not made inroads.

(How fire can be domesticated)

While you are correct in saying that a molten salt heat reservoir can hold heat for a considerable length of time, this is not the case if heat is being drawn off to generate power,

And thanks for the reminder about compressed gases. In princial one could recapture some of the energy which went into making CNG, for example.

You may wish to consider adding that thermal energy can only be stored for a few hours. For long term storage one can use the potential energy obtained bby pumped storage or via hydrocarbons such as biomethane or fossil fuels. Note that for very long term storage, refined fuels won’t do; those degenerate with age. Methane, butane and propane will not, I believe.

You’ve touched on my only real fear about a nuclear Australia; what if it became a semi retirement job for failed politicians or it was run by Enron type creeps?

The grid connected systems being installed in the ACT do not act as UPS nor as a source of power if the grid goes down. They feed into the grid and have no storage. Off-grid systems with storage are far more costly. I suspect all those reasons you gave are invalid, although I do accept people are buying such systems thinking they can do all those things. The population is being grossly misled in many ways about renewable energy.

I cannot agree with your assessment on the avoidance cost. With the Federal Government now allowing the legal householder count and 5 MWh of RECs to sell into the mandatory market we have a six fold count this year. The net result is that we now have 4MWh less renewables for every deemed MWh created so this is actually a harm cost with the false solar credits concept. Australian electricity users are now subsidising voluntary solar panels to reduce Australias total renewable electricity, rather than just paying to achieve nothing at all, as the scheme did before July.

I am however puzzled as to why you would just drop in carbon trading scheme cost ranges. These costs are notional permit sale or secondary market costs that need to be considered in the broader context of the permits that are given out for free and the compensation that will be granted. They are numbers manipulated by governments based on what is perceived that the economy might be able to afford in the short term but they do not reflect the cost of mitigation and not at the scale that we will need to avoid disaster.

I am sure that you are aware that what you did was sell your deemed proof of generation certificates being the RECs that were probably used by liable wholesalers and retailers to meet their mandatory obligations under the Renewable Energy (Electricity) Act, or perhaps if they were sold before July this year they were turned into GreenPower and sold to a neighbour.

I think that what you are describing is that your sale was treated as if it was a subsidy which is the widespread promotion that leads people to such a decision, if they even understand enough for there to be a decision.

However, there’s another significant psychological factor, which has been a part of the thinking of those that I know of that have installed PV recently: the idea of self-sufficiency. Partly, perhaps, long-standing resentment against the utilities; partly as a partial UPS during (incredibly rare) blackouts, and partly, I suspect, as a kind of minor doomsday insurance – something that could be valuable if it all goes pear-shaped (pandemic, food crisis, …) and social services and utility networks start to fall apart.

Also, Barry, a couple of typos:

– in the third last para: “Solar panels are using described in terms of their peak kW power”: a surplus “using”?

– near the end of the second last para: “terrawatt hours”: should be “terawatt”.

I disagree with feed-in tariffs at either residential or commercial level. The rationale given by Jerome a Paris et al is that increased scale drives down average fixed costs, an argument that applies to anything. After a FiT phaseout period commercial generators of wind and solar should bid for electricity supply in 10 minute blocks at a price that covers their expected average costs. That is, higher than gas or uncarbon taxed coal and with no obligation on electricity retailers to obtain renewable credits.

An interesting perspective on Tasmanian energy is the implied subsidy from the 2c per kwh price to the State’s three electrorefiners,
http://www.themercury.com.au/article/2009/09/19/98431_opinion.html
It works out about $166,000 per employee. No doubt a touted silicon refinery will get the same deal. This could be why the island imports ever increasing amounts of coal power from the mainland; it’s buying jobs.

Barry – the flip side of the improved marginal return by including your assumed marginal tax rate is that if you were selling the power to your neighbour rather than discounting the cost off your bill then you would be subject to quite different tax treatment. Taxes such as income tax operate as a trade tariff applicable to inter household trade. They are more destructive that tariffs on inter nation trade (because the rate is typically higher and most trade isn’t international anyway). In short if you were a net producer of power the marginal return from extra panels would be different. There is an extra hidden subsidy occuring here.