Renewable energy technologies

I A pumped storage plant consisting of two 200 MW turbine units located at the Steenbras Dam, two kilometres upstream of the Kogelberg Dam on the Palmiet River near Cape Town, pumps water to the dam and generates electricity from running the water down again in peak periods. At night, excess power on the grid generated by the conventional coal and nuclear plants is used to pump water to the upper reservoir. The project was regarded as a forerunner in environmental engineering and the whole site...

Electricity supply systems

Centralised electricity supply systems are the common means of providing electricity services, whether to a small home in a city or to an energy-intensive industry. Large-scale generating plants continue to be constructed in order to feed high voltages into the grid. They are mostly fuelled by relatively low-cost coal as well as by natural gas and nuclear and gain economies of scale. In addition, hydropower currently accounts for around 16 of the total annual generation (around 19 000 TWh in...

Targets

Targets for cities aiming towards overall greenhouse gas (GHG) emission reductions (Hamburg, Kitakyushu), reducing GHG emissions per capita (Daegu, Yokohama), becoming carbon neutral (Austin, Vancouver), becoming fossil fuel free (Vaxjo, Stockholm), or aiming for sustainable development (Dubai, Freiburg), can result in a wide range of policy objectives, such as improved energy efficiency, fuel switching, development of CHP plants, installation of district cooling etc....

Smart metering

When you can measure what you are speaking about, and express it in numbers, you know something about it but when you cannot measure it, when you cannot express it in numbers, your knowledge of it is of a meager and unsatisfactory kind it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced it to the stage of science. Sir William Thompson, Lord Kelvin (1824-1907) Although the uptake of greater energy efficiency technologies in many cities has, in part, reduced...

Distributed generation

Distributed Generation Chp

Just as the distributed information technology and internet communication revolutions dramatically changed the social context as well as the economic parameters of doing business, a distributed renewable energy revolution will have a similar impact on the world. The move to a Third Industrial Revolution incorporating a social vision with an economic vision is considered by some world leaders to be essential if the future challenges of energy security and climate change mitigation are to be met....

Hydrogen

Production of this energy carrier can be achieved via a large number of processes based on renewable and non-renewable energy sources including chemical reforming of methane from natural gas or biogas gasification of solid fuels including coal or woody biomass electrolysis of water using electricity including that generated from renewable energy sources high temperature thermal using concentrating solar power bacterial fermentation of algae and other forms of organic biomass and...

Description

The move towards renewable energy sources in Indian cities has been motivated by different objectives than other cities of the world. Concerns over the stability and security of the supply of energy, as well as sustainable development, are the key issues, more so than climate change. In addition, since major cities such as Nagpur often experience daily black-outs for several hours, the general public and politicians would be particularly interested in renewable energy systems if this could help...

Small hydro and water supply systems

Hydro power is one of the oldest renewable energy systems with the first water wheels applied for irrigation purposes over 2 000 years ago and then for milling grain in the past few centuries. Smaller and faster turbines used for power generation were developed in the late 19th century. At the large scale, hydropower generation is usually based on dams that store large volumes of water on rivers some distance from cities, with the potential energy of the water passing through turbines used to...

Wind

The local wind resource varies considerably with terrain and natural and physical obstructions. This is particularly the case in a built up area where shelter, funnelling between buildings, and turbulence are high. Where the terrain and mean annual wind speeds are suitable, wind turbines can be located on the boundaries of a city or located off-shore for a city near the water. Both options can lead to planning constraints due to visual impairment of the landscape and a lack of public...

Transport resources and technologies

Fossil fuels have been essential in the development of our modern technological society. Now we must use the wisdom and wealth that have made it possible to begin to move beyond them. Energy for Tomorrow repowering the planet, National Geographic, Collector's Item, 2009 There are many good examples of recent city planning and design to encourage walking, cycling and public transport by giving improved access, more rapid transit and safer routes. Urban planning initiatives mainly aim to reduce...

Great Expectations

The transition to a new, decentralised, decarbonised energy world It was the best of times The setting The energy supply of some urban communities in the future could have a far higher dependence on renewable energy than today, even reaching 100 in some cases. It would necessitate the greater use of many technologies, distributed and decentralised energy, embedded energy storage, demand side management, electric vehicles and modern communication technologies (Fig. 3). It could also include...

Policy options

While cities are beginning to include renewable energy in urban planning, there are still relatively few explicit local renewable energy policies. Rather, renewable energy is often addressed indirectly within other themes such as sustainability, climate change, clean transportation and green or eco programmes. Often energy savings and energy efficiency are the main priorities, which makes sense due to the enormous opportunities for reducing energy demand. Reduced demand also enables renewables...

Cooling technologies

Homemade Absorption Cooling

The design of buildings in hot countries has for centuries provided cooling through thermal mass, shading by trees, reflection from white surfaces of the building, and natural ventilation. For example, the Romans used the principle of the sun warming the outside of a tall external solar chimney painted black to encourage the more rapid upward convection of hot air and thereby drawing cooler air into the building. Variations of this passive solar cooling concept are often used in modern building...

References

Urban ecosystem Europe, an integrated assessment on the sustainability of 32 European cities. www.ambienteitalia.it Asplund G, 2007. Transmission- the missing links towards a sustainable climate, ABB Power Systems, Ludvika, Sweden. Bromley C and Mongillo M A, 2008. Geothermal energy from fractured reservoirs - dealing with inducedseismicity. IEA Open Energy Technology Bulletin, 48, February. www.iea.org impagr cip pdf Issue48Geothermal.pdf Bulkeley H and Kern K, 2006....

Microgrids building integration and electric vehicles

The building sector is typically the largest user of electricity and often accounts for a significant portion of national greenhouse gas emissions. An intelligent micro-grid can incorporate buildings into the system as both electricity suppliers and energy consumers. This would enable a smooth interconnection of supply with demand and the integration of the diverse range of energy services heating, cooling, lighting, electronics, motor drives etc. that have traditionally been operated...

Ground source heat pumps

Annex 8 of the IEA Geothermal Implementing Agreement57 reports on geothermal ground source heat pumps GHPs in detail, linked with other issues relating to the direct use of geothermal heat. Small-to medium-scale GHPs can be used virtually anywhere for both heat supply in winter and cooling in summer Box C as well as to provide hot water. They use the heat storage capacity of the ground as an earth-heat sink since the temperature at depths between 15 and 200 m remains fairly constant all year...