Renewables prove their power

Renewables prove their power

Do we really need base-load power stations?

The electricity industry is being transformed. In 2017, global investment in renewable energy – mostly wind, solar and hydro – was equivalent to US$310 billion, more than double global investment in fossil-fuelled and nuclear electricity combined. Numerous detailed scenario studies suggest that 100-per-cent renewable electricity is technically and economically feasible.

Coal and nuclear  producers  spread false claims that  we can’t reach 100-per-cent renewable and reliable energy.

Coal and nuclear producers spread false claims that we can’t reach 100-per-cent renewable and reliable energy.Credit:Jessica Shapiro

The rapid growth in wind and solar photovoltaics (PV) has triggered a reaction from incumbents – especially the supporters of coal and nuclear power – who are disseminating the incorrect claim that 100-per-cent renewable electricity is impossible and that base-load power stations will always be needed. In the absence of base-load power stations, they claim that vast amounts of expensive storage would be needed to balance the variability of wind and solar.

Base-load power stations can operate at full rated power 24/7, except when they break down or undergo planned maintenance. They are mostly coal-fired in Australia, nuclear in France and a mix of nuclear and coal in the UK.
While base-load power stations can offer nearly continuous operation at rated power and can supply the majority of annual electricity generation in a traditional system, they are inflexible.


They take up to a day to power up from cold to rated power and most are very slow to respond to large changes in electricity demand of an hour or two. That’s why they must be supplemented by flexible peak-load power stations such as hydro and open-cycle gas turbines. The latter reach full power within 10 minutes and, when hot, can vary their output within seconds. Hydro can respond within seconds.

In an electricity grid where most generation is provided by variable renewables, a small proportion of flexible “dispatchable” renewables incorporating storage can supply power at short notice. Batteries charged with renewable energy can also play a valuable role because of their very fast response to changes in supply and demand.

Scores of computer simulations of electricity grids show that 100-per-cent renewable electricity systems can be reliable. Already places such as Denmark and South Australia have already operated entirely on variable renewables for periods of hours to days. Base-load power stations are unnecessary!

Response: Dr Mark Diesendorf

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