eSolar’s 46MW plant allows power to be generated where it’s needed most

By CSP Today staff writer 

Project siting and permission issues remain major obstacles to utility-scale solar developments in a market like the US. 

But two-year-old start-up eSolar believes it has a solution.  

With a scalable and modular design, the company says it achieves economies of scale that shorten construction times and provide utilities and developers with further cost advantages. 

eSolar is producing scalable and rapidly deployed CSP plants, bringing down the minimum economic size of power plants to 46MW. 

“Our 46MW power plant expands the market of viable and available land — allowing power to be generated close to transmission and where it’s needed the most,” said Robert Rogan, SVP of North American Markets, eSolar.  

The plant comprises 16 towers (each with its own north-south heliostat sub-field), a turbine generator set and a steam condenser.

Unlike traditional CSP technologies that require large, flat plots of land that are difficult to secure and often located in remote areas far from existing infrastructure and population centres, eSolar claims it can generate the same amount of power with as little as half the required land.   

The industry standard for photovoltaic systems is approximately eight acres to produce one MW, while eSolar requires less than four acres, said Rogan.   

By using smaller parcels of land (a quarter square mile per 46MW power plant), eSolar’s solution overcomes difficult and time-consuming processes of siting and permission as well as enablling interconnection with existing transmission lines.  

Modular improvements

Rogan referred to the deals with independent power producer NRG Energy and an Indian technology company ACME Group to drive the point that eSolar’s modular power plants address many of the key business obstacles that delay the deployment of traditional solar power plants and prevent projects from coming online. 

“Our plants overcome the hurdles of grid impact, length of deployment, scalability and cost,” he said.  

In February this year, eSolar signed a deal with NRG Energy to build 11 solar power plants in the South-West of the US. The first plant is expected to be operational in 2011.

After this, eSolar signed a deal with ACME Group that is part equity investment and part licensing agreement. 

Through such deals, eSolar is looking at acquiring regional expertise and capabilities that accelerate the wide-scale deployment of eSolar power plants. 

The company is also currently completing its first commercial demonstration CSP plant in southern California. The facility will be the first fully functioning solar thermal power tower plant in the US.  

Computational power 

eSolar consciously decided to trade a design that needed much more computational power in return for using fewer materials.  

Rather than using bigger materials on larger pieces of land, the team decided to approach solar thermal from a different angle. 

“We saw there was a significant cost advantage in leveraging inexpensive computer software and sophisticated algorithms with smaller, pre-fabricated parts,” reasoned Rogan.  

He added that by relying on computational power for individual alignment and calibration, eSolar saves time and money on construction, implementation and capital equipment.  The highest form of concentration is achieved with mass-manufactured mirrors, each the size of a 46” LCD screen.  

eSolar creates a dynamic parabola out of the entire heliostat field by using a dual-axis tracking system where others use a single-axis tracking system.  

“This allows our mirrors to follow not only the horizontal movement of the sun, but also the vertical,” said Rogan.   

With the tracking software and calibrating technology, small commercial mirrors concentrate the sun’s heat in concert to achieve the highest level of efficiency. By utilising small mirrors, the company is also able to use flat mirrors about one-square metre in size, thereby reducing manufacturing and overall costs.  

Moore’s law in action

eSolar’s approach is to rely on software and imaging technology rather than complex hardware to concentrate the sun’s energy. 

“Our tracking software is the key to changing the economics of harvesting the sun,” said Rogan.  

eSolar’s patent-pending computer software eliminates the need for expensive surveying, ground drilling and high-precision alignment of each heliostat. Instead, it incorporates flat, small mirrors to collectively form the parabolic shape needed for the solar thermal process (rather than large, curved individual mirrors).   

By capitalising on Moore’s law, Rogan said, eSolar is able to use less steel and concrete, minimise the amount of skilled labour and create significant savings in manufacturing, transportation, assembly and operating costs.   

Cost competitive 

Earlier this year, eSolar said it had produced the first solar energy that was competitive with fossil fuels.  

Though Rogan declined to comment on the financial details, he said his company was able to produce power at a price that is competitive with fossil generation in certain markets.  

“Eventually, we’re hoping to not just be cost-competitive with peak power sources, but intermediate and baseline power as well,” added Rogan.  

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