Flicking the switch from hot air to usable heat

by Allan Jones

The 21st century has been billed as the century of the city. For the first time in history, more than half the world's population is living in cities. It is also the century of climate change and reliable science says we are already on the brink of irreversible damage to our planet.  Cities are our most profligate consumers of scarce resources and our worst polluters. Cities are the primary cause of climate change and are most at risk from climate change, but they also provide the solution to tackling it.

It makes sense, therefore, to begin finding city-wide solutions to the problems of climate change. Solutions do exist. They have been implemented and shown to work. What is needed is the political will and the co-operation of all levels of government and the private sector to implement solutions on a broader scale.

In the 1980s, I was already convinced that global warming was a reality, so when I joined the Borough of Woking in Surrey, I was determined to do something about it.

As chief engineer of this borough of 100,000 people, I introduced the energy efficiency revolving fund that led to replacing the town's electricity and heating systems with cogeneration, also known as combined heat and power generation.

In centralised power stations, two-thirds of the energy generated is dispersed into the atmosphere as heat, and further losses occur in transmission and distribution across the grid. Fifty per cent of Britain's water resources are used to evaporate this waste heat.

In Woking, we installed a gas-fired system (far less polluting than coal), which generates electricity locally. Heat from the generation process is captured and piped underground to supply heating and hot water. This is cogeneration, and in some countries such as Denmark and the Netherlands, more than 50 per cent of their energy comes from cogeneration.

In a further step - trigeneration - waste heat is converted to chilled water for air-conditioning and refrigeration. Trigeneration has a huge impact in reducing carbon dioxide emissions since it displaces electricity that would otherwise be consumed by conventional air-conditioning, generates more low-carbon electricity and does not use greenhouse gas or ozone-depleting refrigerants.

In Woking, trigeneration - supplemented by fuel cells and renewable energy such as solar panels - enabled the town to produce 80 per cent of its own power by 2004 and to drop its CO2 emissions by 77 per cent in 14 years. The power and heat was also cheaper for customers.

There is now a much greater challenge in London. Centralised energy is responsible for 75 per cent of London's CO2 emissions. The target set by the previous mayor, Ken Livingstone, was to cut emissions by 60 per cent of 1990 levels by 2025. The new Mayor, Boris Johnson, has adopted this target.

I was asked by Livingstone to set up and run the London Climate Change Agency. We are working to shift as much of London's energy use off centralised energy generation and the national grid and on to local, low-carbon sources, including trigeneration. By 2025, we aim to have a quarter of the city's energy coming from local sources and more than 50 per cent by 2050. The balance of emission savings will come through such projects as the London Array, which will be the largest offshore wind farm in the world when it is completed.

Sydney, like London, produces the greatest proportion of its greenhouse emissions from power generation. Almost 80 per cent of Sydney's emissions come from electricity supplied to homes and businesses, and less than 10 per cent from transport.

The Lord Mayor, Clover Moore, and the city's strategy, outlined in Sustainable Sydney 2030, set an ambitious target for greenhouse emission reductions of 70 per cent from today's emissions by 2030, even as the city continues to grow.

Yet this is in line with the reductions targeted in the Kyoto Protocol, and consistent with the changes that need to be made if our cities are to remain viable and productive. Already, you have developments being planned around the use of trigeneration, for both residential and mixed-use developments.

As we have learnt in Britain, privatisation of the energy supply is not necessarily an obstacle but can also be an opportunity to introduce less damaging forms of power generation and supply. But where there is no single authority able to implement these systems, a collaborative approach is essential.

Where barriers do exist, they are not technological but regulatory and, frequently, they are raised by short-sighted vested interests. They cannot be allowed to jeopardise the future of our cities, and of our children.

Allan Jones is chief executive officer of the London Climate Change Agency. He is giving a free City Talk on "Green transformers: revolutionising energy generation for a sustainable Sydney" at the Theatre Royal tonight at 6.30.