Why only using batteries to store renewable energy is a missed opportunity.

The problem with renewable energy is its intermittency. Solar panels require sunshine, and wind turbines need a healthy breeze to generate electricity. When the conditions are right, the capacity to exceed demand already exists in parts of Australia. When they are not, we have to look to fossil-fuelled generators to keep the lights on.

Putting something aside for a rainy day.

It is widely acknowledged that for renewable energy to become the backbone of the nation’s power supply, we need to be able to store it for dispatch at a time where generation can’t meet demand. For precisely that reason, more than 40 battery systems have been built or are in the planning stage for use across Australia.[1]

Though they are a good solution, these batteries are capital intensive. And if we merely use them to store energy for later dispatch, I see it as a missed opportunity. It’s a little like pouring your entire life savings into an everyday transaction account so that you always have access to them. A wise investor would make at least a proportion of their money work much harder.

The power to create a new market.

When you pay money into a bank, it doesn’t just sit there. The bank makes money by investing it elsewhere or lending it to others. At the same time, the money is still available for you to withdraw whenever you need it.

We can do the same with renewable energy by converting it to chemical energy. By storing electrons from large-scale renewable energy projects as hydrogen or ammonia, we can widen the reach of renewable power and repurpose it for use in other sectors while still maintaining stability in the grid.

We call this Power to X (P2X). It relies on the use of renewable energy to power electrolysis, which makes the process green—run electrolysis on water, and you obtain hydrogen (H2) and Oxygen (O2). It’s a simple process to produce an important energy carrier, yet it is an approach used to make less than 1 percent of the world’s hydrogen. Instead, we rely on heating fossil fuels to generate the 115 million tonnes of hydrogen used every year across the globe, two-thirds of which goes to making ammonia or refining petrol.

One of the reasons hydrogen isn’t produced through electrolysis is cost. At present, it costs more than twice as much ($5-6/kg) to produce it this way as through carbon capture. However, our modelling at UNSW shows that using solar PV as a source — and with the right cost of and return on capital—a price of $2/kg is achievable.

Renewable energy provides us with the opportunity to kick-start the hydrogen economy. And the economic benefit of doing so is not to be sniffed at; the current estimate is that, by 2050, the hydrogen economy could generate $26 billion each year in revenue for Australia, as well as up to 16,900 direct jobs and tens of thousands of indirect jobs.

The power to decentralise and decarbonise.

P2X isn’t just about producing hydrogen. We can use renewable energy to power electrolysis and produce many other chemicals for primary or secondary use, including ammonia, methanol, and hydrogen peroxide. All have historically been made in large, centralised industrial sites where capital costs and emissions are high. They then have to be transported.

Power to X allows the production of these chemicals to be decentralised. For example by producing H2O2 at the point of consumption we can substantially reduce greenhouse gas and toxic waste. In other words, we can produce it with zero emissions and zero waste.

It’s a similar situation with ammonia. Traditionally, it has been produced using the emissions-intensive Haber-Bosch process and then transported to where it will be consumed. But a recent collaboration between UNSW and the University of Sydney has led to the development of a hybrid process to convert air and water to green ammonia at ambient conditions, using renewable energy to power an integrated plasma reaction.

Export power.

Perhaps the most significant opportunity for P2X is to supply a new export market for hydrogen. The European Union, Japan, and South Korea have all recognised the potential in hydrogen and included it in their roadmaps and strategies. Indeed, Germany is already in a bilateral partnership with Australia to explore the potential for importing hydrogen. The project, known as HySupply, is looking into the feasibility of exporting hydrogen as liquid H2, ammonia, methanol, or LOHC (Liquid Organic Hydrogen Carrier). It is funded by DFAT and led by a team at UNSW with partners Deloitte and Baringa Partners.

At this point, ammonia looks like a strong candidate. The National Hydrogen Roadmap outlines ammonia as a key vector in enabling the storage and transportation of hydrogen for export. It is a very efficient carrier of hydrogen, is easy to compress and transport as a liquefied fuel, and has a long history of being shipped across the world. It also has a higher energy density than hydrogen and may even be used directly as a fuel in marine shipping.

Within our power.

There are, of course, obstacles that need to be overcome for Australia to lead the field in Power to X. Although we have abundant resources to generate renewable energy, one thing we lack is water. To generate 1kg of hydrogen through electrolysis requires 9-10 litres of water. Therefore, developing efficient ways to recycle, reclaim and even desalinate water will be important. However, sourcing it is unlikely to contribute to more than 2 percent of the overall cost of generation.

Make no mistake, Power to X is changing the way we see renewable power. Five years ago, when we talked about developing renewable generation, it was to decarbonise the electricity industry. Today, renewable energy has a far wider reach. In addition to solving our climate change issues, it offers access to a new, green economy.


[1] https://www.smh.com.au/national/what-are-big-batteries-and-how-could-they-reshape-the-electricity-grid-20210211-p571qm.html

Scientia Professor Rose Amal (based on her invited talk at the Australian Renewable Energy Zone Conference)

Professor Rose Amal has been working on harnessing solar energy and converting it to chemical energy for more than 20 years. Previously, her focus was solely on solving environmental issues. But today’s renewable technologies offer much more: unlocking their power will help decarbonise our industries and pave the way to a new, green, and sustainable economy

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