EnviroMission are seeking to construct a Solar Tower, a world’s first in large-scale solar thermal power generation.

EnviroMission are seeking to construct a Solar Tower, a world’s first in large-scale solar thermal power generation, which would deliver renewable energy and also be a tourist destination and engineering icon.

If completed the Solar Mission Project would realise a world’s first large-scale solar thermal producing clean green renewable energy. It’s estimated the Solar Tower will generate 200 megawatts, enough electricity to power 200,000 homes, and will keep 830,000 tons of greenhouse gases out of the atmosphere annually.

History of the Technology

In 1903, Isidoro Cabanyes, published the idea in the magazine “Electrical Energy", a proposal for a solar chimney. In 1982 German Ministry of Investigation and Technology, in collaboration with Spanish Power Company Union Fenosa, promoted and financed the construction of a solar tower prototype. The project was based on Isidoro Cabanyes principle and was bulit 150 km south of Madrid, in the town of Manzanares.

This medium-scale working model was built under the direction of German engineer Jörg Schlaich. The chimney had a height of 195 metres and a diameter of 10 metres, with a collection area (greenhouse) of 46,000 m² (about 11 acres, or 244 m diameter) obtaining a maximum power output of about 50 kW. During operation, optimisation data was collected on a second-by-second basis. This pilot power plant operated for approximately eight years, but “encountered severe structural instability close to the tower due to induced vortices”, and was decommissioned in 1989.

Jörg Schlaich is now a senior partner with Schlaich Bergermann Partners (SBP), who are leading consulting engineers from Stuttgart, Germany. The firm is the world leader in lightweight construction of towers, roofs, bridges and “suspended" buildings, including the Munich Olympic Stadia and the Ting Kau Bridge in Hong Kong. SBP in developing the Solar Tower has devoted in excess of 25 years of research to the concept. In parallel with SBP’s input, over $75M (Australian) has been invested to bring the technology to commercialisation.

How it Works

The design is based on three well-known and robust thermal principles:

1. The use of the sun’s radiation to heat a large body of air (greenhouse effect lets light in, direct and diffuse, but does not let heat out);

2. Hot air rises (as through a chimney); and

3. Movement of air as energy source to drive large turbines to generate electricity (basic engine).

The reinforced concrete chimney will cover approximately one square kilometre at its base and will be surrounded by a “greenhouse” of glass, polycarbonate and polymer. The tower is hollow in the middle like a chimney. The sun’s radiation will be collected and trapped under the transparent canopy, creating a massive force of air heated to around 35°C greater than the ambient temperature.

This large body of hot air moves at 15 metres per second towards the cold air at the top of the tower which is located in centre of the canopy. The heated air mass moves as a powerful updraft, forcing air through 32 large turbines to generate electricity. A solar thermal power station using Solar Tower technology will create the conditions to cause hot wind to flow continuously through its turbines to generate electricity.