Avoid the grid! Although the national grid is the preferred source of electricity in most countries and the aspiration in others there are now powerful forces pushing the other way. So called self-healing, self-organising networks like the internet, the airport system across the world and national grids were thought to be just that – very resilient against failures from poor maintenance, terrorism and natural disasters – but network theory tells us nodes form and they are very vulnerable. Take out Heathrow and Chicago O’Hare and you largely cripple global air travel for quite some time. Take out just two major power stations in a country and you cripple electricity supply.

With an increase in extreme weather events caused by mankind, houses and businesses were grateful to have diesel gensets or solar with battery to fall back on and this has become more of the selling proposition though increasingly there are cost benefits as well. Indeed, the situation is being turned on its head with the grid being used merely as backup. 70% of people will soon be in cities with 80% in prospect by 2050, so this becomes an urban story and the focus is now how to make your own urban electricity. Further impetus comes from inadequate maintenance of many national grids due to cost and the fact that, increasingly often, it is becoming cheaper to create off grid supply instead of extending a grid to more of a sprawling city.

Needless to say, the focus is now on zero emission production of this electricity. Wrongly, the initial impression is of ugly retrofit photovoltaics on grid-connected houses and small wind turbines that are stationary most of the time. It is rare for the mightily publicised Tesla solar roofing with their Powerwall battery to give a good payback, so what is really possible to give at least some independence from the national grid or at least zero emission backup for it? Are we talking only of trivial amounts of energy like kilowatts? Is it not just a case of invisible Building Integrated Photovoltaics BIPV consisting of unaffordable options such as solar wall cladding and integral roofing viable one day and only when incorporated from the start of new designs?

No on all counts. The choice is enormous and power levels already run up to over ten megawatts per installation and there is more city electricity to be made away from urban buildings that on them. There is a huge Saudi Aramco car park in Dharan Saudi Arabia. The 10.5MW of solar car shelters shade the cars, keeping them cool and the power provides all the electricity needs of the huge office complex next to it plus charging electric cars. In cities, solar roads are half as efficient as roof top panels because of the ruggedization surface and obscuration by traffic but they will make 2-10 times the power because the parking areas, walkways and roads in a city have that much more area. Currently, just parking in a city takes at least 10% of the area of a city. Las Vegas casinos have saved a great deal of money by starting to make all their electricity from nearby solar farms they own.

The new IDTechEx report, «Electricity Generation by Urban Infrastructure: Zero Emission 2018-2050» has a host of new infograms, forecasts, roadmaps and technology comparisons embracing activities of 241 organisations. This report is intended for urban planners, legislators, architects, electricity utilities, technology developers and users. It shows how we have entered a golden age where beautiful and sometimes invisible Building Integrated Photovoltaics BIPV is a practicality rather than an expensive dream. A host of new technologies are appearing, some invisibly retrofittable like solar window coating and glass that powers its own electrically-operated darkening for privacy and climate control. This hugely increases the addressable markets. We show how this can be on a national grid, simply using the grid as back up or fully off grid.

This report starts with a comprehensive Executive Summary and Conclusions, sufficient in itself for those in a hurry as it explains definitions, microgrids to megagrids, good and bad practice, technology preferences and futures with 12 pages of detailed forecasts at the end. After the introduction chapter putting it all in contest, there are chapters on urban wind energy including a full appraisal of Airborne Wind Energy to be first commercialised in 2018, urban photovoltaics including how we shall achieve transparency and doubling efficiency, BIPV in action then self powered multifunctional windows and glass. The seventh chapter appraises electricity generating roads, paths, fences, lamp posts and the report closes with a good look at urban blue energy. The emphasis is in on commercialisation and emerging options with real depth. Indeed, it is the first to give a twenty year roadmap of the whole picture, importantly also embracing the campus, not just the buildings, because, for example, solar paths, fences, road furniture (bus and vehicle charging shelters, signage, lamp posts) and roads must also be considered as a major part of the electricity generating package.

The emphasis is analytical not evangelical. Consequently, although we appraise the many new forms of photovoltaics from that three times as efficient to flexible and/or transparent PV for windows. We also look at complementary technologies coming along. For example, a solar road can also capture movement using piezoelectrics and vertical wind turbines down the centre of a road can harness wind from traffic. These are all development programs not just dreams but we throw in some dreams as well because this is a subject where dreams today become practicality tomorrow. Do you want to help emerging nations to prosper without pollution? Do you desire freedom from national grid problems and prices? These and other questions are answered from the point of view of what buildings and their immediate environs can contribute.

Although there are over one million small wind turbines generating electricity across the world, most are a disappointment because low level wind, particularly in the urban environment, is usually weak, very intermittent and turbulent. By contrast, on an urban island, even the largest wind turbines with integral energy storage by water make great sense. More speculatively, Airborne Wind Energy using tethered drones may usefully generate 30kW-1000kW from the top of a high rise building if someone can make it safe for passing aircraft and those on the ground. Most cities are on a river or by the sea so they and urban islands will make electricity from many promising new forms of «blue energy» under development as we describe in this report. Overall the major trends are identified as being off grid and integration.

Off grid

Many new technologies make zero emission electricity production very attractive for off grid use by individual buildings up to the city as a whole. For more on this see the IDTechEx report, «Off-grid Zero-emission Electricity 2018-2038: New Markets, New Technology Roadmap». Other options include geothermal which is not necessarily zero emission and not usually urban.


Structural electronics is the replacement of dumb load-bearing and protective structures with ones that serve two purposes or more such as load-bearing/ protective skin (mechanical) plus electronic/ electrical. See IDTechEx report, «Structural Electronics 2017-2027». Integrating wind turbines into buildings has been a failure but integrating water turbines into river bridges, jetties etc is practicable. Most important is building integrated photovoltaics BIPV which is now a viable reality in many forms. Tesla says its solar roof can be the same installed cost as a regular roof. Transparent solar windows are being widely installed not just photovoltaic wall cladding. Trials of solar roads and barriers look promising. Motion harvesting roads are more of a maybe and they will be piezoelectric or electrodynamic if successful. They might be combined with solar road technology.

Only the new report, «Electricity Generation by Urban Infrastructure: Zero Emission 2018-2050» critically covers the whole urban electricity generation picture focussing only on zero emission and looking forward all the way to 2050. It is a very exciting story, assessed and predicted by the many multi-lingual, PhD level analysts at IDTechEx who travel the world on your behalf. Our approach is creative, based on our industrial and academic background in this subject and best practice in other industries that can be transferred to urban infrastructure. The report is complementary to our energy harvesting, off-grid and other reports.