Philip HOPKINS
THE requirement for extra transmission lines to cater for renewables lifts the cost of energy, but nuclear power would cut both costs and carbon dioxide emissions, an energy expert has told a Gippsland forum.
Dr Robert Barr AM, an electrical engineer and former national president of the Electric Energy Society of Australia, was a keynote speaker at a recent meeting in the Morwell to discuss the future of the Latrobe Valley as an energy powerhouse using nuclear power, and its implications for Gippsland. Up to 150 people attended the meeting.
Dr Barr, who provided a number of slides to illustrate the points in his address, said he had spent his whole working life providing low cost, reliable electricity to customers, mainly in NSW, but also in Australia and overseas. “I and many of my colleagues are very concerned at what is happening in our power system at the moment,” he said. Electricity bills were rising for homes and businesses.
In NSW, Dr Barr compared how the current system would change with the extra transmission lines required, using a simplified conceptual diagram. He apologised for the NSW example and not that of Victoria, but the principles governing the situation were the same.
Dr Barr said currently, the power stations in the Hunter Valley (Latrobe Valley) are linked to the main load centre of Sydney (Melbourne) with major transmission lines, which in turn have couple of similar lines to Canberra and one to Snowy Hydro.
In 2050, there is a planned Regional Energy Zone (REZ) at Dubbo, and added pumped storage at Snowy 2.0. The Hunter Valley power stations will be closed; double much the existing transmission would then be needed to Canberra, triple to the Snowy, and a new extra sub-transmission system will be needed in the Snowy region.
Dr Barr said the result was the need for this vast amount of infrastructure to move the electricity – a complex mixture of supplying solar to Sydney at peak midday times and redirecting energy to storage (Snowy 2.0). At nighttime, this stored energy would need to be redirected to Sydney.
He said projections showed that summer had abundant solar, where there was enough power in the middle of the day to provide power, but there was also surplus power, (renewable spillage) that can’t be used. With enough storage in the system – pumped hydro or battery storage – and despite low wind, “we get through”. “That’s what I call summer – things going well”.
However, when things were not going well, such as a particularly bad week in winter, there could be less solar and wind; pumped storage and batteries run out; there could be a big shortfall of power, with, for example, a big manufacturer voluntarily being asked to ‘load shed’, cut power use – “not ideal”.
Using modelled results for 2050, Dr Barr showed an example where the electricity system had reached a worst-case position. “The storage energy is expended, there is nothing left, the day is short, and the wind capacity is down,” he said.
“We get through to past midnight, and the wheels fall off the system; there are very large amount of unsupplied load and the same the following day.” he said.
“Scale up the resources, build more wind and solar, transmission, spend a lot more capital to supply the same amount of load – and costs keep going up and up,” Dr Barr said on managing the system.
He continued: “When AEMO (Australian Energy Market Regulator) do their costings, (basically the government’s plan), they don’t include the cost of rooftop solar PV and the cost of batteries. They use large quantities behind the meter solar PV and batteries in their modelling because they see it as free. This is where the AEMO modelling goes wrong.”
The distribution networks – “where I have spent the bulk of my career”, Dr Barr said – then come into the firing line. “When you start putting solar PV on, you get voltage changes down the distribution lines. Historically, I have designed these systems, typically on 3 or 5 kW maximum demand,” he said. “If you get the voltage drop at the end too high, it will cause disruptions to equipment in houses, so that’s how the system has been designed last 50 years.
“With a lot of rooftop solar, things change, because in the middle of the day, the houses are no longer drawing power down – they are pushing power into the system. In this localised area, within 300 metres of the substation, we get this voltage rise effect.
“A 2kW average household solar PV is generally manageable within our existing low voltage networks. When you start pushing past 3kW, 4kW and 5kW, it becomes unmanageable, and at 12kW it will be impossible. With the levels in the AEMO plan, this low voltage network has to be effectively rebuilt. It has got to have a capacity of three or four times what is there at the moment. This is not patch it up; this is knock it down and rebuild it,” Dr Barr said.
“People are scared at the costs of transmission and rightly so. With the new 500kV lines being built into Snowy 2.0 as part of the Hume Link, and other transmission lines being built in Victoria, transmission costs are on the rise. Those costs will pale into insignificance when you start augmenting the low voltage system across eastern Australia.”
Dr Barr said the real value in the power system was at the bottom end of the distribution network. “In terms of delivered electricity costs, generation is about 30 per cent, transmission about 10pc. Most of the balance in the value of the network is in the low voltage and medium voltage networks. My modelling shows the costs that will have to be met by consumers,” he said.
Dr Barr said the best power systems were those that use all the available generation systems and put them to their best use. “That’s the engineering approach; we spend time matching all the bits of pieces together, the transformers to the lines. We match generation A with generation type B to produce the best outcome overall,” he said.
Comparing the various scenarios of a mixture of renewables and nuclear out to 2050 and 2060, Dr Barr said an optimum energy mix with nuclear (74 per cent) would provide electricity at a third the cost of 100 per cent wind and solar. Fifty per cent nuclear was similar.
“Best of all, a system that includes nuclear energy has ultra-low emissions because it doesn’t need gas backup and all the embedded emissions of a grid powered by wind and solar alone,” he said.
However, renewables could be used effectively; solar can produce peaks in the middle of the day. “Put solar into the system – it’s the one that can give it the right mix – the most economic driver to supply peak power in the middle of the day. A little bit of spillage, storage – this works well.”
At the outset, Dr Barr said the Latrobe Valley’s infrastructure was a huge competitive advantage. “As an electrical engineer, driving around Latrobe, it’s like heaven – power stations, transmission lines, gas plants. One of the things that makes Latrobe attractive for a nuclear site is the high power 500kV transmission links into Melbourne. These high-capacity lines will allow the Latrobe Valley to export power to all parts of Victoria and into NSW. Latrobe is critical. It’s a great place to be if you are a power engineer, and that will continue for a long period,” he said.
“The dual 500kV lines are going to end up being one of the most strategic assets for the Latrobe Valley. High-powered connection into Melbourne will create a lot of development and jobs in this area.”
