The development of renewable energy and the ageing of existing electricity infrastructure means that new high voltage overhead lines, underground cables, and other electrical infrastructure is being planned and developed throughout Europe and the rest of the world. Solar developers should be conscious of the concerns that can arise during the planning process and aware of the potential issues so that they can be addressed accordingly.
Solar Panel being installed in Zurich. [1]
Technical Background
All electrical equipment emits electric and magnetic radiation. The movement of electric charge causes electric and magnetic fields to be produced in the space surrounding the charge. Human exposure to such fields can cause health problems if persistent and/or they are of high strength. The magnitude of the effects is dependent on both the field strength and the exposure time.
The strength and extent of these fields is dependent on technical parameters such as power output and also the level of shielding that exists around the electronic components. Effort is often made to minimise emissions produced by commercial equipment due to concerns over safety and electromagnetic interference. However, it is impossible to remove these fields altogether which means the potential for effects and interference always remains.
Health Concerns – Potential Effects
Power cables produce both electric and magnetic fields which can potentially affect human health. Radiation from underground cables is generally less than radiation from overhead lines because emissions from adjacent conductors within a cable tend to cancel each other out. When assessing the impacts of overhead power lines, it is important to consider the impact of both electric and magnetic fields.
Underground cables generally cause a negligible electric field above ground but can cause a significant magnetic field which is dependent on the current in the conductors.
The potential effects on human health caused by time-varying magnetic fields, such as those generated by AC [2] cables, are due to induced current on functions of the central nervous system. There are various international bodies which provide maximum safe exposure levels to time varying electromagnetic fields.
UK Guidelines for Public Exposure
The UK Policy on public exposure limits to EMF radiation is designed to comply with the 1998 ICNIRP (International Commission on the Non-Ionizing Radiation Protection) guidelines in terms of the 1999 EU Recommendation. In 2010 ICNIRP produced new guidelines but these have not yet been incorporated into UK Policy. The public exposure limits in UK policy define reference levels for electric and magnetic fields. Where field levels exceed these reference levels in significantly occupied spaces, further investigation is warranted.
Electromagnetic field level data for various underground and overground cable configurations is available from a resource produced by the Electricity Networks Association. This is an industry body for the companies which run the UK and Ireland’s energy networks. The group is understood to comprise 14 members including National Grid. The electromagnetic field levels from power cables proposed as part of a solar development can be assessed with reference to the 1998 ICNIRP guidelines to determine if any impacts on human health would be predicted and if further investigation is warranted.
Notable sources of electromagnetic radiation, other than the underground cables, include the transformers and PV inverters, and substations and BESS that may be proposed as a part of larger solar sites.
Conclusions
Pager Power has experience in assessing the potential for effects from electromagnetic emissions from solar farms, with reference to the acceptable levels for public exposure. If you are interested in an EMF or EMI assessment for a solar development, please get in touch.
References
[1] Ricardo Gomez Angel (2019) on Unsplash.com. Last accessed on 26th June 2024. Available at: https://unsplash.com/photos/two-men-carrying-a-metal-sheet-MagdWoazARo
[2] Alternating Current
