Towards a solar-powered future: making photovoltaic systems more grid friendly
Unobtrusive, clean, quiet, and competitive, solar photovoltaic (PV) systems play a fundamental role in achieving a sustainable Europe. They have also been identified as key to reaching sustainable targets set in the Europe Strategy 2020, which promotes higher levels of PV integration.
The challenge of ‘too much’ solar
Increasing PV deployment is, however, no easy feat. While PV technology has shown a lot of potential for high integration in both the rural and urban environment, it does face limitations. The electrical network, for one, is unable to handle ‘too much’ solar as solar generation is non-dispatchable – it cannot be turned on or off to meet fluctuating electricity needs. Added to this, there is no control over when the sun shines and solar plants are not ‘grid friendly’ so they cannot adequately support the electric grid when something goes wrong such as electrical disturbances. Understanding these limitations and with the support of the Marie Skłodowska-Curie programme, the PVCI project set out to come up with solutions. The project looked into how solar PV plants could be converted into more ‘grid friendly’ power stations, as a way to increase the solar contribution to the electricity mix. “A major task of this project was to develop control algorithms for the solar plants that allow the provision of ‘ancillary services’ to the network, for instance, to assist the electric grid during disturbances,” reports Marie Skłodowska-Curie fellow Efstratios Batzelis. In addition to this, the project studied the stability of the power system at high solar penetration to assess how much solar could be deployed. “The ambition was to provide insight on how the EU can meet its solar targets and remain a leader in the solar industry.”
Key developments
“Early on we realised that the solar plant can only become more ‘grid friendly’ if it is able to up-regulate its output on command like conventional thermal stations. But as we cannot burn ‘more sun’ like a fuel, we have two options. One is to install costly batteries or operate the solar system below capacity,” explains Batzelis. From this realisation, the project went on to pioneer a control method that allows a PV system to keep power reserves, that is, backup power which has the ability to release energy to support the electric grid during difficult times. Additionally, the project developed a modelling framework which permits the study of the PV system performance at transient and distorted electric grid conditions. This can be used to study how the stability of the power system is affected with increasing solar deployment.
Future endeavours
At the end of the PVCI project, Batzelis was awarded another prestigious 5-year research fellowship by the Royal Academy of Engineering at Imperial College London to expand his research on solar integration in developing countries. “Having explored the technical barriers of solar deployment in the EU, I decided that I should now focus on developing countries that currently face serious challenges in meeting their solar targets and United Nations sustainable development goals,” concludes Batzelis.
Keywords
PVCI, photovoltaics (PV), control, integrate, grid-friendly, power system, solar
