Renewable gas: energy of the future

A Tasmanian-based engineering firm is helping the City of Sydney develop a sustainable energy supply. [30 July 2013 | Peter Boyer]

Biogas plant in Europe. PHOTO KLAUS LEIDORF <http://www.leidorf.de>

Tasmania is the source of some great applied thinking in humanity’s huge quest for a more sustainable existence. Think Bill Mollison and permaculture, Nigel Tomlin and river-run hydro, Frank Strie and biochar, to name a few.

But I can’t think of a more original or a more satisfying enterprise than the current project of Attilio Pigneri, an Italian-born engineer now working out of Hobart, who has spent most of his professional life studying high-yield, low-carbon sources of energy.

Pigneri, who worked in Europe, the United States and New Zealand before making Tasmania his home, runs a consultancy group with the engaging title of Talent with Energy (TWE). What they’ve come up with could turn out to be a game-changer in the Australian energy scene.

For the past couple of years, TWE has been engaged by the Sydney City Council to help work out how it can get energy from garbage, sewage and biomass, and how this energy source can help to reduce or even eliminate the dependence of Sydney’s inner city on grid electricity.

Major Australian urban centres rely heavily on electricity from fossil fuels. Making the transition to a renewable, sustainable energy supply has been achieved by cities elsewhere – in Germany and Scandinavia, for instance – but coal-free power would be a huge step for cities here.

Attilio Pigneri

TWE was charged with identifying the potential for renewable gases given off during the treatment of waste to meet the energy demands of inner Sydney. The brief involved investigating energy sources across metropolitan Sydney and surrounding areas.

The TWE study explored Sydney’s existing plans for renewable energy and trigeneration (combined production of electricity, heating and cooling) and came up with the idea of decoupling waste conversion and energy recovery.

Under this scenario, renewable gas generated from a network of conversion plants for residual waste and biomass is upgraded and piped to a distributed network of trigeneration facilities.

All key components including waste or biomass conversion plants, gas upgrading and delivery are commercially available, so there’s no need to reinvent the wheel. What’s unique is the network-level integration of the components to provide high-volume, reliable supplies of usable gas.

TWE calculates that the renewable gas produced by the network, while already commercially viable, will become even more competitive in coming years as sales of Australian natural gas to an energy-hungry world drag up its price within the country.

By 2030, it’s estimated the scheme would generate 2.28 terawatt hours (TWh) of renewable electricity, more than double the city’s target of 1 TWh by 2030, and substantially help it to meet its ambitious greenhouse gas emission reduction target of 70 per cent by 2030.

What appeals about TWE’s Sydney project is that it takes an existing problem – our insatiable appetite for food, clothing and other consumer goods and all the waste this generates – and turns it to advantage in the very place where the waste is created.

Like solar power, energy from waste is produced in or near urban centres where it’s most needed, but unlike solar it’s available all the time, not just when it’s sunny. And for all its increasing take-up, urban rooftop solar can meet only a fraction of a city’s commercial and industrial demands.

The TWE scheme captures biogas and landfill gas that would otherwise escape to the atmosphere while also rendering inert and harmless potentially damaging waste chemicals and heavy metals.

Other side benefits include greater material recovery, reduced landfill and generally improved waste management practices. The waste gasification process focuses on waste left over after recycling, on the basis that by 2030 all suitable material will be routinely recycled.

The project had a setback last month when plans for the “Green Square” precinct in the southern part of the municipality were shelved because the operation went over budget, but three other trigeneration plants in the city’s CBD are going ahead.

Sydney is far from alone. A survey of cities around the world released last month by the Carbon Disclosure Project found that over 90 per cent of them believed that their efforts to cut carbon emissions would be good for their businesses and lift their economies.

In the United States, San Francisco is already powering many municipal buildings wholly from renewable sources and currently gets 41 per cent of its electricity from renewable energy in pursuit of a 100 per cent renewable target by 2020.

Australian cities need changes to electricity distribution to enable smaller-scale plants to share energy and provide power to discrete areas, one of the issues being looked at by the Australian Energy Market Operator in a current review of national market reforms.

Faced with such constraints, as well as increasing energy costs and carbon mitigation obligations, every municipality in Australia is increasingly alert to energy-saving opportunities. Melbourne is a case in point, if anything even better suited than Sydney to the kind of solution proposed by TWE.

Such issues in Tasmania are much smaller in scale and less concentrated, but they are still there to be addressed. The need to find alternative local sources of energy becomes more pressing with every passing year.

This is a place where local government can really come into its own, leading by example where other levels of government are struggling to find direction. Right now, municipalities across Tasmania are looking actively at their energy options. Watch this space.