The first of February this year was a red-letter day for the State government-owned high voltage business, TransGrid.
This was when the intricate planning that holds together the backbone of power supply in the largest demand region met reality head-on.
On the hottest day of the summer, peak demand at 4pm required delivery of a 14,820MW load.
Ensuring the supply chain functioned required input from 8,300MW of available coal-fired power stations, 3,300MW of hydro-electricity, 1,600MW of of gas-fired plant and the variable contribution of 120MW of wind power.
Delivery included use of 1,300MW of supply located in Victoria and Queensland – and had to take in to account overall line losses (exacerbated in high temperatures) of 680MW.
“The system operated within its capability,” says TransGrid primly in its annual review of its operations.
If it hadn’t, on the eve of a State election, you would still be hearing the howls of unhappiness from customers and politicians today.
In particular, hanging on this reliable delivery are consumers in the coastal corridor from Wollongong to Newcastle, whose requirements account for 75 per cent of the State’s demand and a third of the whole supply on the east coast.
Dominating this load is Sydney itself, with a peak requirement of 7,100MW, followed by Newcastle with 2,200MW.
The TransGrid system involves 91 sub-stations and 12,600 kilometres of high voltage cables. It transports more than 75,000 gigawatt hours of energy each year.
Maintaining it and expanding it to meet this decade’s supply is one of the highest priority infrastructure requirements in Australia.
The regulator-approved capital works outlay on this task for 2009 to 2014 is $2.6 billion
Obviously engineering skills are a major issue, but so too is the science of estimating where demand is going and getting out ahead of it – which requires finding a way through the thicket of regulators, permanently out-of-countenance industrial consumers, the media in continuous heat over power prices and, of course, the politicians.
To which can now be added a bit more uncertainty about what demand will be.
The latest annual planning report from the network, released in August, shows some of the challenges involved in coping with an environment over the next decade in which the impact of rising power prices and of decarbonisation policies creates new uncertainties.
From modelling undertaken for TransGrid by KPMG, it can be seen that two key factors in planning ahead are just how big the NSW population will be and how far and how fast the State economy will grow under a new government.
The population in 2010-11 is calculated at 7.6 million and gross State product at $438 billion. Population scenarios for 2020-21 all exceed 8 million, but vary by 500,000. GSP projections all exceed a half trillion dollars but vary by $90 billion.
For the first time, also, the actual generation mix for the State is open to question. What will carbon policies deliver in power station construction? When will new plant be built? Will any existing plant be forced to close?
TransGrid CEO Peter McIntyre told a forum held this month to discuss the network’s 2011 planning report that a more moderate increase in average electricity consumption in NSW is now being forecast.
“The growth shows signs of slowing down,” he said.
But the big, big issue, of course, is whether this reflects the current global economic uncertainty, a slower economy – the boom times are elsewhere in Australia – and/or changing consumer behaviour in reaction to rising power bills.
NSW power supply has risen from just on 10,000 GWh a year in 1961 to 75,000 GWh now – and annual demand has increased by 15,000 GWh since 1991. On current modelling, it could exceed 84,000 GWh by 2020-21.
On present trends, demand in 2021 could be five per cent below the forecast that was being put forward even a couple of years ago – or it might be higher.
The summer peak is always the wolf prowling the paddocks.
The variation in the TransGrid modelling for the summer of 2020-21 is as much as 3,600MW, with a high likelihood that the peak will have risen to about 16,300MW and the potential for it to go as far as almost 19,000MW.
This poses challenges for both the generators and the overall network system, including distribution – and always for the politicians. Bear in mind that the Coalition government recently elected in a landslide will be at the polls in March in 2015 and 2019.
What end-user prices will be and what NSW energy security will be at the decade’s end unquestionably are as big a challenge for the politicians as the power suppliers.
There is at least no lack of investment interest in building new generation in the State, although whether or not interest can be translated in to action, and when, is another matter.
TransGrid says it has on hand inquiries about transmission links for wind farms with a capacity exceeding 4,700MW – and another 5,120MW of possible gas generation.
The system at the moment contains 12,000MW of coal-based capacity, 1,900MW of gas plant, 210MW of wind generation and access to 4,200MW of hydro-electric power, mostly the Snowy system.
Notwithstanding the continuing fast rise of demand in Queensland, NSW is where the major supply action is – and can be expected to still be so in 2020.