Much debate today in Melbourne Age about power systems

Letters in today’s Melbourne Age.

We need to redesign our electricity systems

South Australia, which has substantial wind power, recently experienced a crisis in electricity supply, requiring a gas-fired power station to be reopened. Thomas Hogg (Letters, 22/7) uses this example to suggest that rhetoric about renewable energy does not match reality. The reality is that we must stop using fossil fuels urgently. We have no choice – unless we want to bequeath future generations a much hotter world.

Certainly this transformation is difficult. Our electricity systems are designed around large, centralised, coal and gas-fired power stations sending electricity radially to consumers. Renewable energy is diffuse and site-dependent and typically the electricity output is variable.

We could embrace nuclear power and bequeath nuclear waste and the risk of devastating accidents to future generations. Or we can embrace renewables and redesign our electricity systems accordingly. This means a stronger grid, including more interconnections between states, distributed storage facilities, and more use of solar thermal (which can better match demand). It also means managing electricity demand to better match the output of renewable power stations. Rather than dismissing renewables, let us redesign our electricity systems to make them work with renewables.

Andrea Bunting, Brunswick.

The flexibility of pumped hydro-electricity

Thomas Hogg correctly argues that power grids have supply and demand problems. This balancing act is as old as the grid itself and as individual as the market in which it operates. All generating assets need to be shut down for routine maintenance, suffer breakdowns and are strained by unusual high demand or supply limits (eg coal mine fires, drought, low wind or sun). The most flexible solution is pumped hydro-electricity as was incorporated into the Snowy Hydro Scheme in 1949. Pumped hydro responds within minutes to consume excess electricity to pump water from a low to a high dam. When there is a supply shortfall, the stored power can be quickly recovered.

Pumped hydro has fast and controlled two-way response at much lower cost and pollution than batteries. It needs very small water volumes as they fill and empty daily or weekly (rather than annually like combined irrigation/power dams), and requires established technology often easily applied to existing grid systems. Our lives will depend on a renewable future, including solar and wind. The new multi-sourced grids need to expand pumped hydro to manage the ever-changing community demand and means of supply.

Robbert Veerman, Wandin North.

The gradual transition to renewable energy

In South Australia, when the wind didn't blow and Victoria's electricity link was down, they did use gas (a fossil fuel) to produce electricity. But when the wind was blowing, fewer tonnes of carbon dioxide were put into the atmosphere. Also, because South Australia bought electricity sourced from gas, less carbon dioxide was emitted than if it had bought it from coal. Maybe this is an acceptable outcome whilst we are in transition to renewable energy sources. In terms of emissions saved, it is already certainly better than coal-based electricity. Let's look at the bigger picture, please.

Jill Dumsday, Ashburton.

Environment cost of building turbines

When wind farms are under discussion, a significant factor is conveniently overlooked – the hundreds of thousands of tonnes of greenhouse gases which are produced in manufacturing and installing the wind turbines.

Roy Barclay, Frankston South.