STE Plants: Beyond Dispatchability Firmness of Supply and Integration with VRE

Abstract

Abstract The Solar Thermal Electricity (STE) community is certainly concerned about the difference in the deployment trend when compared with Variable Renewable Energies (VRE). The installed capacities in wind and PV have reached 350 GW and 160 GW respectively while STE plants have only achieved 4 GW. The explanation is easy: the current generation costs of wind and PV plants are lower than those of STE plants and a large majority of installations were sited in industrialised countries – where no additional backup was required. Large shares of VRE bring significant reductions on the operation time of flexible conventional plants and even lead to curtailments on renewable energy sources as well. In developing countries, the situation is quite different. These must not only increase, but mainly multiply their installed capacity in the next years for meeting the demand needs at all times. Therefore, this increase of installed capacity power cannot be exclusively based, e.g. in PV and/or wind plants, as the evening peak has to be covered every day. Such investments in VRE must then be backed up by new combined cycles. This also why STE could already be selected as the best choice in several Sun Belt countries. However, the main challenge for STE plants is not only to offer some flexible dispatch features, but also to be able to respond to the requested dispatch profile under any circumstances. Achieving this goal with huge solar plans and storage systems will be certainly not cost competitive in the short term. Therefore, “smart” combinations between storage and hybridisation solutions will need to be developed. In this paper, different conceptual alternatives for firm supply features of STE plants are analysed and the advantages of high-performance hybrid solutions combined with storage capabilities are featured. Nevertheless, a fruitful coexistence and the reaping of synergies with VRE at large regional and seasonal scales are also addressed. Although there is still a large potential for further VRE plants deployment, policy makers everywhere will realise sooner rather than later, that the true market value of firm supply as delivered by the last generation of STE plants –besides their substantial positive macroeconomic impacts in the countries’ economy. And so will hybrid STE plants with storage be the prevailing concept in the future.