Related Links

  • GI Energy
  • Elsevier Ltd is not responsible for the content of external websites.

Related Stories


Lessons gleaned from ‘green’ cities

Chris Davidson, Director of Development, GI Energy

Major cities are embracing renewable energy sources. But there's still plenty of room for improvement. Chris Davidson of GI Energy identifies a few trailblazers.

“The battle for life on Earth will be won or lost in cities,” says Ahmed Djoghlaf, executive secretary, Convention of Biological Diversity.

While it's true that cities may only occupy 2% of the earth's land, they account for more than 70% of its energy consumption and will house 75% of its population by 2055(1). While it is vital that we protect the planet's natural resources, it is in the cities that the real changes will take place.

Following are real-world examples of what London can learn from some of the planet's most eco-friendly cities.


This Danish city is regularly cited as one of the world's greenest, thanks to its ambitious plans to make the city entirely reliant on renewable energy sources by 2025, with initiatives that include a mandatory green roof policy for all new developments since 2010(2).

The Greater London Authority's Spatial Development Strategy recognizes the benefits of vegetated roofs, but ‘encourages developers to consider them’, rather than making them compulsory(3). A few tweaks to building restrictions could see greenery abounding on London's skyline, as its current sustainable building boom continues.

Copenhagen is also famous for its bicycle facilities, and officials hope to get as many as 50% of its citizens on wheels by 2015, by closing major roads to cars and developing even more bike lanes(4).

London is well on its way to becoming a cyclists’ paradise, with a 173% increase in bicycle traffic since 2001(5).

However, more needs to be done to prioritise bicycles over other traffic (especially since many roads in London see more bicycles per day than they do cars or buses(6)) and to reduce the risk to cyclists from heavy goods vehicles, by fitting them with mirrors and blind spot sensors, by reviewing HGV driver training, and by restricting their access to the city centre.

Mexico City

20 years ago the UN named Mexico City the most polluted city on the planet(7), with air so poisonous that birds fell dead from the sky(8). But now, thanks to the city's outstanding commitment to its ProAire programmes, it is one of the cleanest.

Mexico City has taken a diverse and holistic approach to tackling pollution, closing the most polluting factories, banning cars from the metropolitan area one day per week, and launching its Bus Rapid Transit Metro system which, in its first six years, reduced CO2 emissions by 300,000 tonnes and more than halved citizens’ exposure to particulate matter. This significantly diminished pollution-related health problems(9).

The EU's death toll for poor air quality is higher even than that for road accidents, and London faces a stiff fine if it fails to meet European targets to reduce emissions by 2020. A more radical approach is needed, with greater restrictions on private vehicles, and further investment in public transport and cycling infrastructure, to give Londoners inexpensive yet viable alternatives to running a private car.

“The target which London is looking to achieve cannot be met just by changing a few light bulbs or turning down the heating by one degree,” Davidson says.

“The game has changed.”


One of the greenest cities on the planet is Reykjavik, which gets 100% of its electricity and heat derived from renewable energy sources. This is due to Iceland's unique geology, which allows the country to rely on geothermal energy and hydropower for 85% of its electricity, rather than the traditional fossil fuels(10).

Fortunately for London's inhabitants, the city isn't located on a tectonic fault line. However, there are other ways in which the city could look to its natural environment to maximize renewable energy production. The GLA already expects architects to incorporate renewable energy technology into new developments(11), but it would be possible to go much further than this.

As Davidson states: “There are a host of factors and new technologies to consider, from carefully positioning buildings to maximise natural daylight, to selecting truly renewable forms of heating and cooling, such as Ground Source Energy Systems. The pressure to reduce carbon emissions even further will only increase – and what London does today, the rest of the country will be doing tomorrow.” 


(1) Sustainable Cities: Building cities for the future; Urban Sustainability Communication Platform 2013/14, December 2013, p.1.

(2) Green Roofs Copenhagen, The Technical and Environmental Administration, City of Copenhagen (September 2012), p. 2.

(3) The London Plan: Spatial Development Strategy for Greater London (Consolidated with Alterations since 2004), February 2008, p. 210.

(4) Top 5 Most Sustainable Cities in the World.

(5) London's Cycling Revolution, Greater London Authority.

(6) London Cycle Census Map, TFL Cycle Traffic Census, EUNOIA (April 2013).

(7) Mexico City: ProAire.

(8) Mexico City drastically reduced air pollutants since 1990s, Anne-Marie O'Connor, Washington Post (April 1, 2010).

(9) Best Practice: Metrobus Bus Rapid Transit System, New York City Global Partners, February 2010, pp. 3-4.

(10) Aska Energy – The Independant Icelandis Energy Portal. 

(11) The London Plan: Spatial Development Strategy for Greater London (Consolidated with Alterations since 2004), February 2008, pp. 205-206.

London could establish wind turbines on some of its hills as a means to boost electricity supplies to the National Grid. It might also encourage councils to replace street appliances, such as ticket machines and road signs, with solar-powered alternatives. The government should also consider proposals to build a new flood protection barrier with integrated hydropower turbines, in order to take advantage of the tidal flow of the Thames. ♦

Chris Davidson is the Director of Development of GI Energy, a renewable energy solutions company.

This article was published in the January/February 2014 issue of Renewable Energy Focus magazine.

The digital edition of Renewable Energy Focus is free of charge to readers meeting our qualification criteria. To apply to receive your copy of the magazine please complete this short registration form.


Share this article

More services


This article is featured in:
Green building