Weighing the advantages of combining solar, wind and gas

By Andrew Williams

Hybrid renewable energy plants, which generate electricity from more than one source of renewable energy, have the potential to help developers in their ongoing battle to lower costs and extend operating hours, particularly during periods of cloud cover or inclement weather. 

The perceived advantages have led some companies to establish such plants – one notable example being the joint GE, MetCap and eSolar ‘Project Dervish’ power plant in Turkey (highlighted in part one of this article), which combines power from a variety of sources, including CSP power towers, wind turbines and a combined cycle gas turbine (CCGT) in a purpose-built 530MW plant. 

However, what might be the constraints for this type of project, particularly in terms of siting, permitting and resource availability?  Moreover, are such approaches really cost competitive when compared with ‘traditional’ plants?

Permitting pressures

One concern relating to the establishment of hybrid plants is the idea that they might face greater challenges in obtaining the necessary permits to operate, particularly since they make use of multiple renewable, and sometimes other, energy sources - meaning that developers may sometimes have to deal with more than one permitting agency or authority.

Dale Rogers, Senior Vice President - Projects at eSolar explains that, when seeking to establish a new hybrid renewable energy plant, eSolar would need to apply for two separate kinds of permit. 

The first kind would be the standard permits associated with fossil fuel based plants and the second kind would relate to the solar energy component of the planned facility – relating to aspects such as tower height, water and land usage.  However, he is confident that such an arrangement would not lead to unnecessary delays and other associated difficulties.

“The permitting process would be run in parallel.  There’s nothing more [or] less because of the combination [of the two energy sources],” he says. 

“In the case of converting an existing plant into an ISCC plant, only the solar piece would need to be permitted,” he adds.

Meanwhile, Dr. Celal Metin, Chairman of Met Capital Partners, one of eSolar’s partners in the Project Dervish venture, argues that, far from being a problem, the utilisation of several energy sources may in fact help developers to make better use of existing resources.

“Hybrid plants need more land but that doesn’t complicate the issues.  On the contrary, it optimises resource allocation by getting the most out of what we have,” he says.

Cost competitive

So, is the development of hybrid renewable energy plants cost competitive; or do factors such as the perceived complexity of the permitting process, site selection and contract management process render it too time-consuming or costly?

According to Rogers, the approach to hybrid plants adopted by eSolar is ‘extremely’ cost competitive.  His view is that by ‘bolting on’ several sources of energy within a single plant configuration, developers are able to reduce the costs associated with operating hardware, as well as balance of plant, operations and maintenance (O&M) costs.

“In addition, solar as a power source—a free power source—protects against market volatility and rising natural gas prices,” he says.

Metin agrees, arguing that hybrid renewable plants currently represent the most competitive approach to the supply of power to consumers.  In his view, such plants will ultimately become more and more price competitive – particularly in light of the general trend for increasing oil, coal and gas prices and market disruption.

He also explains that such ‘integrated’ plants, with their associated economies of scale, can help developers to reduce costs in a variety of other ways.  To begin with, he says, they optimise the amount of natural gas being burned - leading to lower fuel costs.  Secondly, by helping to reduce CO2 emissions, they enable operators to cut the carbon levies or taxes they face - or might even help to generate ‘carbon income,’ perhaps via trading schemes.

“In addition, off grid wind energy supplying auxiliary power to the plant maximises the electricity pushed onto the grid and shared infrastructure reduces investment costs,” says Metin.

“This is a winning approach of multi-resource utilization for the years to come,” he adds.

Rogers also agrees that hybrid energy plants could well become an effective means for developers to navigate the increasingly choppy global economic waters.  In his view, there is a ‘huge market demand’ for hybrid plants, especially in the face of rising wholesale fossil fuel prices and concerns over market volatility and energy security.

The early evidence from schemes such as Project Dervish demonstrates that the technology and know-how for such an integrated approach already exists.  As the cost pressure on coal, oil or gas fired power plants continues to grow, this type of hybrid energy plant looks set to emerge as an increasingly credible alternative. 

To respond to this article, please write to the Editor:

Rikki Stancich: rstancich@csptoday.com