Stepping stones: the slippery path to a clean energy future

There are several options for future energy generation. We just need to get there. waldopepper

In news today, the Greens are calling for an end to federal funding for a proposed coal- and gas-fuelled power plant in Victoria’s Latrobe Valley. Others have suggested the plant provides a source of “transition” power: a stepping stone towards renewables.

So how much should we be investing in so-called transition fuels? Or should we be investing in renewables instead? And what will Australia’s electrical energy system look like in, say, 2050?

Well, it might consist of large-scale concentrating solar plants, rooftop photovoltaics (PV) on every building, wind and wave power, carbon capture and storage, or even nuclear.

Or perhaps more likely, we could be getting our energy from a combination of these technologies.

Much of what the 2050 energy landscape looks like depends on the decisions we make in the next decade as we move toward a low-carbon economy.

One of the hurdles to overcome is the need for so-called “baseload” power – power that will be available 24 hours a day, 365 days a year.

We need to build a new energy system without disrupting this constant and reliable supply of power we currently enjoy.

The road to renewables

Finding a stepping-stone to transition from coal to low-carbon technologies may be one of the biggest challenges of the next decade.

It’s time to move beyond coal. Julian Smith/AAP

The ability to produce electricity 24 hours a day is perhaps the biggest advantage of coal-fired power. But this advantage is also a disadvantage.

It takes many hours (or even a day or two) to fire-up a coal-fired power station from cold. Because of this, coal-fired stations need customers that never switch off and a demand pattern that varies only gradually and in a predictable fashion. But this may not be the pattern of demand we have in the future.

So what does an increase in variable renewables mean for heavily-polluting coal-fired stations, even before we worry about the impact of a carbon price?

One potential pathway could involve large-scale introduction of PV and wind power. Given that environmental effects can cut the power produced by a PV array (clouds) or wind farm (no wind), fossil fuel-fired generators need to be on stand-by to pick up the slack.

Introducing such renewable generation methods will therefore increase the variability in demand on coal- and gas-fired generators.

And, in the face of more variable (but more sustainable) power generation methods, coal-fired power could become uncompetitive and might eventually be phased out.

Backup capacity would still be required and this would be met by gas-fired turbines. These can power-up and down very quickly.

But gas-fired power is more expensive (and possibly too expensive for aluminium smelting and other industries). The higher cost will certainly remove the incentives currently available for using off-peak power. Without those incentives, consumers will tend to use power during the peaks.

This would leave us with a dramatically different demand pattern of high-variability and low-overnight demand that doesn’t suit nuclear or coal.

The local angle

In Australia we have a set of technologies already well established – coal- and gas-fired power stations – with uptake of solar PV and wind power increasing rapidly but still only making a small impact in the overall generation.

There is also range of potential (but still untested) technologies such as large-scale solar thermal, carbon capture and storage (CCS) and, and at least in the Australian context, nuclear power.

Many suggest that CCS or nuclear will be our saviour, but these technologies will need to survive the transition.

Rooftop photovoltaic power could play a significant role in our sustainable energy future. AFP/Christoph Stache

The problem for yet-to-be-established technologies, especially nuclear and CCS, is they assume power consumption will continue to follow the baseload model.

This model shows that we consume power around the clock in large quantities, largely supported by energy-intensive industry that soaks up power that can’t be shut off; energy we don’t need in our homes and businesses as we sleep.

But a relatively new transition technology, know as coal gasification may change the pathway significantly.

The controversial new power plant proposed for the Latrobe Valley will showcase coal gasification. If approved, the facility - to be run by HRL electricity company - will use natural gas to dry and gasify brown coal, turning it into “syngas”.

Syngas is a combustible mixture of carbon monoxide and hydrogen that can then be burnt in a gas turbine to generate electricity.

This process of gasification enables cheap coal to be used in a fashion similar to normal natural gas, turning the power plant on and off quickly when required.

If HRL is successful, the Morwell plant could provide a lifeline to baseline-dependent industries (such as manufacturing and minerals processing), giving time for CCS and maybe even nuclear to be deployed.

While less carbon-intensive than older coal-fired power stations, the gasification process is still carbon-intensive, and will be exposed to carbon prices and environmental regulations. These factors will make it difficult to find funding for the gasification project.

If the HRL proposal fails, some other options may be available.

In the pipeline

Worldwide energy demand is on the rise. AAP/KRT

Co-burning biomass (such as agricultural byproducts) in fossil fuel generators can reduce carbon emissions, but large sources of agricultural waste (such as sugar cane bagasse) are required.

This is an already established practice in Queensland, and could potentially be expanded to other states.

Hydrogen has also been suggested as a transition fuel. It can be generated from natural gas or coal and used in fuel cells to power vehicles or to generate electricity.

But the wind seems to have gone from the sails of the hydrogen economy with electric vehicle technology dominating in recent years.

Accurate predictions of how the energy market will respond to a carbon price or increased variable renewables is difficult at best. It’s even harder to predict the electricity price at which large industrial processes – such as aluminium smelting – become unviable.

The best strategy we have is to not exclude any viable energy technologies, to keep an open mind and to keep pursuing the many options on the table.

We also need to watch how market forces and regulatory frameworks play out over the next decade.

Everything depends on everything else but one thing’s clear: our energy future is uncertain.