Engineering facts about batteries

I am writing in response to Dr Chris Cole’s recent letter regarding the Narrabri Community Battery. Misinformation about how batteries and our energy system work can cause unnecessary fear, so I would like to share some engineering facts. I am an electrical engineer with more than 30 years of experience in Electrical Power Industries and a supporter of Geni.Energy.

Narrabri is not alone in facing the future of energy. In Australia there is now more solar power being generated in the middle of the day than is being used by the grid. This means household and solar farm output must be turned down (or constrained). This is already happening locally, likely to your solar. A community battery will help by soaking up that extra solar when the sun is shining and then supplying it back when people need it most, in the evening. That means we get better use of the solar we have already paid for on our rooftops and in our community.

Lithium batteries are highly efficient. Including the charging and inverter infrastructure, they can return close to 90 per cent of the energy they store. Lead acid batteries, the type used as starter batteries in cars, only reach around 75 per cent efficiency. Battery and solar technology has rapidly improved and become much, much cheaper over the past decade. It is now usually cheaper to install a standalone solar and battery system than to make a new connection to the grid.

Dr Cole raised the Broken Hill blackout as a battery failure. It was caused by a freak storm that blew over several towers in the single transmission line that supplies Broken Hill – and the failure of the diesel backup power station. Even though they were not designed to be connected, the Broken Hill battery and Silverton wind farm were connected and successfully powered the town. The delay in doing so was caused by regulatory settings, not a problem with the battery technology.

He also mentioned the Waratah Super Battery transformer issue. Transformers can fail anywhere including at coal power stations and on poles in our streets. That does not mean coal or the electricity system does not work. Engineers are currently investigating the cause of the failure of the brand-new transformer. These transformers were made in Australia by an Australian company which has supplied thousands of transformers across Australia. The failure is not the fault of the batteries, which are performing as designed.

Coal power plants only convert around 30 to 40 per cent of coal’s energy into electricity. The rest becomes waste heat. More power is lost through long transmission lines, especially in rural areas. Sometimes less than half the energy generated reaches the farm gate. By producing and storing energy locally in a battery, we avoid those losses.

Coal also brings enormous waste. One coal unit can burn ten semi loads of coal every hour and create half a semi loads of ash every hour. In NSW there are 12 of those units. That continues day and night. Contrast that with quietly charging a battery from our own sunshine.

The Narrabri Community Battery will improve the performance of the existing solar, keep more value locally, and help manage peak demand. In the long term in a bigger picture, it can also help households lower bills by allowing more clean power to be used when it is needed.

We all want reliable power. We all want local benefits. Community batteries are a practical step toward both. Narrabri can lead the way rather than be left behind.

Change is never easy, but this is not a risk. It is an opportunity. Let us base our decisions on facts and make smart choices that support our community now and into the future and ask what benefits the community can gain from technology.

Trevor Woolley, Denman