Giant Solar Thermal Steam Turbine from Siemens

Siemens is set to supply BrightSource Solar with a 123 MW solar thermal steam turbine by 2011, for the BrightSource California heliostat farm.

"Siemens is proud to be building the largest fully solar-powered steam turbine generator to date for BrightSource's Ivanpah solar power plant."

BrightSource's Ivanpah Solar Power Complex will be comprised of three separate solar plants and will produce a combined total of 400 MW of power. Upon completion, the Ivanpah Solar Power Complex will produce enough clean energy to power the homes of 140,000 PG and E customers and reduce carbon dioxide (CO2) emissions by over 500,000 tons per year. BrightSource is scheduled to begin construction on the Ivanpah site in 2009.

BrightSource Energy's solar thermal energy plants are built on the company's proven Luz Power Tower (LPT) technology.

The system uses thousands of small mirrors called heliostats to reflect sunlight onto a boiler atop a tower to produce high temperature steam. The steam is then piped to a conventional turbine inside a power block, which generates electricity. The electricity is then connected to the transmission grid for consumption. The steam is air-cooled and piped back into the system in a closed-loop, environmentally friendly process. _Source

The Power Tower technology allows for the direct heating of superheated steam, for efficient steam turbine power generation. Using the Kalina Cycle, a combined cycle power generation scheme would allow for even greater utilisation of this focused energy resource.

Biomass backup systems are likely to be used more frequently with solar thermal plants, to allow for 24 hour power generation -- with the overnight power generated on a scaled-down basis. Either biomass gasification, or the firing of "biocoal" torrified biomass (with or without coal co-firing), will allow biomass to serve as a backup power source. Unfortunately, even such high-efficiency and partially redundant renewable plants will require gas and coal backup sources to compensate for the fickle nature of nature.

Passive Cooling--Ancient and Modern

The ancients used passive cooling to maintain internal comfort when outside temperatures soared--long before the invention of air conditioning. Now an an Indian Engineer-Designer team wants to bring back passive solar cooling on a larger scale.

Jyotirmay Mathur of the Mechanical Engineering Department, at the Malaviya National Institute of Technology, in Jaipur, together with architect and urban designer Rajeev Kathpalia of Vastu Shilpa Consultants, in Ahmedabad, point out that the development of energy-efficient, and even passive, cooling systems for buildings is essential in the light of environmental pressures and costs. In the past, they point out, building designers had to rely on natural ways and means for maximising comfort inside buildings.

The team has now reasoned that two distinct technologies - the so-called solar chimney for roof-based based ventilation and a wind tower that provides a draft of air could be combined simply and effectively into a passive cooling system.

They have designed a building that incorporates a multi-storey wind tower clad with heavy stone panels which produces an upward draft of air drawn into the building passively and cooled by the massive tonnage of the stone classing. The air flows through the rooms and corridors and accumulates heat as it does so. This is then carried to the top of the building and vented with large black, thermally conducting, panels providing a way to shed the heat quickly from the top of the building. The result is a reduction in internal temperature of several degrees. The resulting temperature drop would be sufficient to improve the comfort of people in the building without the need for powered air conditioning that is both expensive to install, maintain and operate.___Source

Passive solar building design is part of the Sustainable Building approach to Green Building that has been followed loosely and sporadically for decades by a few builders. These practises are much more effective in a dry climate

Solar Tower Video--Featuring the Pilot Project in Spain

This video goes inside the solar tower pilot project that has been built in Spain. Although not as large as the tower in the previous video, this one actually exists, and generates electric power. A fascinating glimpse into what is probably one of the best large scale ways of generating electricity from the sun.

Large Scale Renewables--Fantastic Video!

While there is no doubt that human civilisation will require more nuclear plants in order to transition away from fossil fuel dependency, large scale renewables offer more sustainable energy paths for the long run.

The solar tower--particularly one of the designs that generates power both day and night--is one of the most promising ideas for large scale renewable power. Personally, I like the idea of combining the solar tower with an arcology tower dwelling--like the Ultima Tower.