Case Studies / Concentrated Solar


Mirror, a 250 MW portfolio of five concentrated solar power plants with parabolic trough technology in Spain.

Project Overview

Investment Year: 2019
Ownership Stake: 49%
Technology: Concentrated Solar Power with Parabolic Trough Collectors
Industrial Partner: ContourGlobal

Energy Infrastructure Partners co-invests in Mirror alongside ContourGlobal, a global power utility with a strong focus on renewables and thermal power generation.

ContourGlobal is an excellent partner as this technology requires expertise from two different sectors: steam turbine power plants, which they independently operate in the North of Spain, as well as renewable energy sources.

ContourGlobal and Energy Infrastructure Partners have previously worked closely together on a number of projects, including Sunscreen. ContourGlobal has the experience and team necessary to ensure Mirror runs efficiently for decades to come.

Benefits from proven technology and an experienced industrial partner

Commissioned between 2009 and 2012 and equipped with best-in-class electricity generators from original equipment manufacturers Siemens and GE, Mirror faces a long remaining life; the first CSP plants built in the mid-1980’s in California continue to operate to this day.

In addition, Spain is an excellent location for solar powered plants; along with its stable regulatory framework and supportive public acceptance for renewable energy, it has the highest direct irradiation levels in Europe – required for efficient energy generation from CSP technology.

Takes advantage of some of the highest irradiation levels in Europe

Geography is a primary factor when considering the location of CSP plants, because a slight latitudinal difference can make a tremendous impact when it comes to potential energy production in terms of solar irradiance. Solar irradiance, or irradiation, is the power per unit area received from the sun in the form of electromagnetic radiation. It works best as an energy source when skies are clear and sunny, which is why the plants comprising Mirror are located in Extremadura and Andalusia, areas averaging just over 3,000 hours of sunshine per year.

To put this into perspective, Spain’s average yearly solar irradiation in terms of KWh per square meter is more than 30% higher than irradiation levels in southern Germany. In addition, studies have shown that solar radiation in Spain has increased over 2% per decade since the 1980’s. This is linked to a decreased presence of clouds, reaffirming CSP technology as an excellent form of power generation in Spain for decades to come.

Transforming solar irradiation into electricity

The CSP plants at Mirror use parabolic trough technology to concentrate direct solar irradiation onto a receiver tube. The collectors, which are essentially parallel rows of glass mirrors, are equipped with sensors to follow the sun from east to west.

Thermal oil is used in the collectors as a heat transfer fluid, reaching temperatures of approximately 390° C. The thermal oil moves through an interconnected piping system to a power block where it generates hot steam. This mechanical energy is then converted into electricity using a turbine and subsequently exported to the grid.

Spain’s renewable energy framework offers stability to investors

In 2013, the Spanish electricity system began a major transformation with the introduction of several changes to balance the overall structure of electricity regulation. This intervention was primarily driven by a rising tariff deficit accumulated over the years prior, caused by a mismatch between the income collected from end grid users and fixed system costs.

The new laws modified support schemes applicable to electricity generation from sources such as renewables, in addition to implementing tolls under certain conditions.

Regulation RD 413/2014 calculates returns using average yields on the secondary market of the Spanish 10-year Government bond during a certain period, as well as a set spread amount.

This return is due to be updated every regulatory period, or 6 years, with the same formula. The calculation is made according to a number of parameters, including the regulatory life of the asset, operating hours, pool electricity prices, and so on. There are also protective mechanisms in place to cope with fluctuations in pool electricity prices.

Ultimately, these regulations mean that investments like Mirror offer predictable, stable cash flows with a very limited level of risk.