Wednesday, September 7, 2011

Mr T.L. Cardwell, WHAT do you Do?

Recently there was a letter to the Editor of the Rockhampton Morning Bulletin, that bastion of Journalism! Reposted around the Interweb as:

CARBON TRADING FIASCO by someone who should know (capitals not added)

The fellow introduces himself as someone who has worked in a power station. In what capacity we are not told. Forklift driver? Boiler Attendant? Occupation unspecified.

His big claim is "Debunking the Myth" that 65-70% of the energy consumed by a coal fired power station goes "up the chimney". He then gives some numbers for boiler efficiency and for the efficiency of the particulate scrubbers, which are both well into the 90's. DEBUNKED!

Sceptics rejoice. Better, learn some thermodynamics, people.

His language is emphatic:

"First coal fired power stations do NOT send 60 to 70% of the energy up the chimney. The boilers of
modern power station are 96% efficient and the exhaust heat is captured by the economisers and
reheaters that heat the air and water before entering
the boilers."

The only trouble is, this Muppet at no time actually tells you what the conversion efficiency of his power station was.

So how much of the energy of a thermal power station is recovered from the fuel ? Its sure ain't 96%, which is the number we are left with.

His own numbers call him a liar a little later on:

"Coal-fired Power Stations are highly efficient with very little heat loss and can generate a massive
amount of energy for our needs. They can generate power at efficiency of less than 10,000 b.t.u. per
kilowatt and cost-wise that is very low"

Well, those numbers sound reasonable. Now convert the units to a common one, and divide the output (1kWh) by the Input (10,000BTU) and there you have the efficiency.

1 kWh = 1000W * 60min * 60 sec = 3,600,000J

1BTU =1055J, so 10,000BTU = 10,550,000J

N= 3.6 MJ /10.55MJ = 0.341, i.e. 34.1%

Which means that in Mr Cardwells Highly Efficient Power Station, 65.9% of the heating value of the fuel is dissipated as waste heat.

If a lay person describes this as "lost up the chimney" as opposed to " dissipated as lost heat as the cumulative losses of the equipment, plus the heat rejected into the condensers as Carnot's equation dictates that it must be" then I will not hold this against them.

Mr Cardwell presumes to teach us all about basic mathematics, but fails to teach us any basic thermodynamics. I am unsure if he knows but isn't saying, or welds for a living and avoids reading about what he welds. In either case, his argument is either ignorant or dishonest.

He then goes on with a lot of blather about renewables, which he clearly doesn't know much about, in spite of the hubris of his opening paragraph, and fails to give numbers too, other than diving the total load by the nameplate rating of a very large wind turbine.

No Renewable energy proponent that I am aware of is suggesting 100% wind generation. Its a red herring of note. 10% would be fine, and cause no hassle whatever. Isolated communities like Esperence in WA have far higher wind fractions than this, and it saves them millions of litres of Diesel, and with it millions of dollars, each an every year.

The only technology that doesn't like wind is Coal. Gas compliments it well, and buddy, Gas is coming on strong. They use Brayton cycle turbines and CCGTs to achieve higher efficiencies than your coal burning dinosaur, and they follow load, which for all customers other than aluminium refineries, is the real measure of a technologies usefulness in supporting the grid.

I don't have an aluminium smelter, and frankly I'm tired of paying the cost of orienting electrical industries towards this class of customer before then rest of us.

Wake up and smell the future, Mr Cardwell.