Towards a green economy

4 Greening urban sectors 4.2 Buildings

Having illustrated the general economic, social, and environmental benefits of greening cities, this section looks at examples of how the greening of specific sectors – including transport, buildings, energy, water, waste and technology – can be achieved at the city scale. Most of these sectors are addressed more broadly in the respective chapters of this report, and some of the examples below are referenced elsewhere in this chapter to support broader, cross-sectoral strategies to aid the transition to green cities.

4.1 Transport

Most green transport policies that follow the “avoid- shift-improve” paradigm outlined in the Transport Chapter can be found in

cities. While “avoiding

transport” is mostly covered by structural adjustments to the shape of cities introduced earlier, classic green transport strategies in cities primarily

focus

on reducing car use or at least slowing its growth. In Central London, for example, the congestion charge reduced daily vehicles trips by 65,000 to 70,000 (Transport for London 2004 b) and CO2

Tackling the energy demand of existing building stock is a priority for cities, and urban green building strategies also include more efficient use of other resources such as water and materials. As outlined in the Buildings Chapter, three principal green building strategies can be differentiated: design, technology, and behaviour- related. Particularly in a developing world context, passive design solutions to improve environmental performance are by far the most cost-effective approaches. For example, housing projects on the coast in Puerto Princesa City, the Philippines, have been designed to reduce energy demand through increased natural light, improved ventilation, the cooling effect of the roofing material, and strategic planting (ICLEI, UNEP and UN-HABITAT 2009).

emissions by

19.5 per cent (Beevers and Carslaw 2005). Singapore’s Electronic Road Pricing and Vehicle Quota System slowed increasing car use and motorisation (Goh 2002). Bogotá’s BRT system has contributed to a 14 per cent drop in emissions per passenger (Rogat et al. 2009). It is encouraging, therefore, to see that the BRT system has been replicated in Istanbul, Lagos, Ahmadabad, Guangzhou, and Johannesburg.

In Europe, cities are following Zurich’s example of investing in a tram system as the backbone of urban transport in preference to an expensive underground system (EcoPlan 2000). Emission standards and car sharing schemes (Schmauss 2009; Nobis 2006) have reduced car dependency while low-emission zones and timed delivery permits have helped reduce congestion and pollution (Geroliminis and Daganzo 2005).

In recent years, some cities have led efforts to electrify road-based transport, even though walking and cycling are still the greenest forms of transport. Copenhagen, Amsterdam, London, and New York are investing in pro-cycling and walking strategies. Cycle- hire schemes have changed attitudes towards cycling in London and Paris. In South America, cities such as Bogotá, Mexico City and Rio de Janeiro have instituted regular car-free days or weekend street closures (Parra et al. 2007).

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Stringent building codes, mandatory energy certificates, tax incentives and loans, have had a measurable impact on energy demand in a number of European and US cities (C40 Cities 2010b). Toronto’s revolving energy fund and Austin Energy’s Power Saver Program have imposed higher energy efficiency standards for new buildings and are leading to a comprehensive retrofitting programme of existing building stock (C40 Cities 2010c, Austin Energy 2009). Berlin requires a solar- thermal strategy for all new buildings and Freiburg’s energy efficient housing standard has reduced average household energy consumption for space heating by up to 80 per cent (von Weizsäcker et al. 2009). As owners of large amounts of public property, municipal authorities are able to set an example by implementing green strategies on their own public building stock with beneficial effects on the development of a local green building market.

4.3 Energy

Cities uniquely concentrate energy demand and rely on energy sources beyond their boundaries. But cities have the potential to either dissipate the distribution of energy or optimise their efficiency by reducing energy consumption and adopting green energy systems including renewable micro-generation, district heating, and combined heat and energy plants (CHP). Rizhao, China has turned itself into a solar-powered city; in its central districts, 99 per cent of households already use solar water heaters (ICLEI, UNEP and UN Habitat 2009). In Freiburg, PV systems, encouraged by Germany’s generous feed-in tariff, now supply 1.1 per cent of the