The core objective of PREFLEXMS is to enhance the predictability and flexibility of Concentrated Solar Power (CSP) generation to address the evolving needs of Regulators, Grid operators and Plant operators. Both technologies to be demonstrated can significantly improve the dispatchability of CSP plants:

  1. Molten salt steam generator based on once-through technology – Allowing fully flexible plant operation
  2. Integrated weather forecast and dispatch optimization – Allowing fully predictable energy dispatch

In addition, the merit of PREFLEXMS results will be considered in three scenarios:

  1. Operation under feed-in-tariff regime
  2. Operation under time-of-delivery regime
  3. Operation under electricity trading regime.

In all cases, participation in ancillary services will be considered as a variant.

Budget and grant

Total cost
EU Contribution

Funding scheme: IA – Innovation actionFunded under: H2020-EU.3., H2020-EU.3.3., H2020-EU.3.3.2., H2020-EU., H2020-EU., H2020-EU.

Call for proposal: H2020-LCE-2014-2; Project reference: 654984

Overall approach and methodology

The aim of the PreFlexMS project proposal is to 1) Adapt and 2) Integrate available technology into a product ready for market introduction. The project is structured along three axes:

PreFlexMS diagram

1) Technology integration – This is separated in two branches, for the adaptation and integration of

  1. a) Once-through steam generator with molten salt as heat transfer medium
  2. b) Weather forecasting and dispatch optimization

2) Technology evaluation – This include all technical, economical, business and societal evaluations

  1. a) Risk assessment
  2. b) Life-cycle analysis (environment, economy and society)
  3. c) Business case and exploitation
  4. d) Thermo/economic performance evaluation and benchmarking according to key-performance indicators

3) Technology demonstration – This includes all activities for the actual implementation of the developed technology in a pilot installation working in real conditions, which will enable the market uptake.

Work will be organized along 2 dimensions:
Work Organization
The project will first elaborate a functional specification of the final product for a utility scale, tower-based CSP power plant with molten salt storage in the 100 MWe class and develop the concept engineering (feasibility and pre-engineering). Based on this, a down-scaling exercise will be carried out to produce concept-level engineering for the pilot installation. On this basis, a detailed engineering will be carried out, ready for execution at the demonstrator site. This approach ensures that the pilot design will be relevant for the demonstration of the actual technology as applied in the full scale plant product. This is especially critical in the CSP market, where technology uptake always faces resistance if not clearly, univocally backed up by a relevant demonstration.

Benchmarks and targets

Namely benchmarks and targets will be:

  1. A state-of-the-art, tower-based CSP plant with MS storage designed for baseload operation. Typical values of CapEx, OpEx and annual electricity generation against which to compare the cost of electricity projections of PreFlexMS are given in the analysis of a Reference Plant configuration presented in the extensive report cited in the figure below41, which will be taken as basis. Against the reference cost of the TES system, a 25% reduction is expected to be brought by the MS-OTSG technology
  2. A state-of-the-art combined cycle designed for fully flexible operation. Typical start-up times, load rate of change in load following and in primary frequency support, turn-down ratio, and part-load efficiency are given in Figure 16. They will be used as terms of comparison to assess how close to this type of service the PreFlexMS technology will bring a fully flexible CSP plant with MS storage. It is expected that a MS-OTSG will enable a CSP plant to be 100% equivalent or superior to a fully flexible combined cycle power plant.
  3. Competitive LCoE compared to other intermittent energy sources: As shown in Figure 17, CSP can only achieve cost competitiveness at a certain scale of global MW installed. A predictable and flexible CSP system with integrated storage provides many additional benefits to the overall system and hence, countries with suitable solar resource would desire to increase CSP share in the energy mix. This leads to a lower LCOE compared to other intermittent energy sources