Can renewables meet public and political expectations?

Energy storage

This is a field where there have been highly visible changes. Indeed, a 'revolution' in batteries has been declared, with particular reference to the Tesla Powerwall battery for home energy storage and the Tesla electric car. Both exploit the high specific energy of lithium-ion batteries. Batteries store electrical energy, and improvements in their performance and cost are seen as key to better renewables and electric vehicles.

Market success had long eluded electric vehicles, that is, until the appearance of the Tesla sports car, a 'muscle car' with an 85kWh battery and impressive performance and range. It is said to have a favorable carbon footprint but the claim is contested. Regardless, the large, heavy Tesla is hardly a prototype for environmentally benign, energy-conserving transport.

Batteries have long been used in standalone power systems but the Powerwall and competitors like the Redflow zinc-bromide flow battery have boosted expectations for applications in domestic PV systems and 'going off-grid'. The economic benefits of expensive high specific-energy lithium batteries in such systems are unclear.

There are widespread projections of falling lithium battery costs. Tesla is entering this market and building a battery 'gigafactory' in Nevada. Lithium battery production is already in the billions. It is fair, therefore, to be cautious about any further economies of scale Tesla might find.

Tesla's batteries comprise arrays of multiple small lithium 18650 cells, each slightly larger than the common AA battery. An 85kWh Tesla battery contains over 7,000 such cells. Development of larger individual cells is desirable but so far seems to have eluded success.

Tesla's products have certainly generated market appeal but it's hard to avoid the conclusion that the much-touted battery revolution is an example of marketing hype, not reflected in more sober approaches to the latest developments in battery science.

Decoupling energy and economic growth

I previously looked at the potential for saving energy through the major gains in efficiency and productivity that feature in Australia's energy policies. Energy could be saved without damaging prosperity if energy usage and economic growth could be 'decoupled'. However the observed quantitative link between energy and economic output threw doubt on the prospects of such decoupling.

Energy productivity, EP, is the ratio of GDP to energy usage. Can it really be increased by policy measures?

Economists agree that EP depends inter alia on an economy's geography (size, climate, population distribution, etc.), development stage, industry sector structure, and levels of efficiency in energy conversion and usage. Quantifying each influence seems problematic. Energy efficiency and energy productivity are often confused. There is no clear guidance on how an economy should actually go about raising EP.

Nevertheless the profile of EP has risen dramatically. An organisation has been formed specifically to see Australia's EP doubled. A conference devoted to EP was held in Sydney in 2016, even receiving coverage in the daily press. The Minister for Resources and Energy launched the Australian National Energy Productivity Plan in December 2015, with a target increase of 40% by 2030, or 2.3% per annum. The Australian Government had previously (2010) presented a report on energy efficiency that aimed to double the EP improvement rate to 3.6% and raise EP by 30% by 2020.