There are potentially serious health issues with grid-tie solar panels and even off grid systems that incorporate an inverter.
The best way to use solar is with a DC (direct current) 12 or 24 volt system. (There are a lot of 12 or 24 volt appliances on the market as they are used in yachts, caravans and motor homes. People with a 12 or 24 volt based house often have a gas fridge (although you can get 24 volt fridges) and a gas stove and/or cook/heat their home and/or hot water with wood and/or use passive solar for water heating. A house would usually need to be re-wired to accommodate a DC system, unfortunately.)
Using solar panels with a grid-tie system means that an inverter has to be used (to transform the DC electricity produced by the solar panels to alternating current (AC) electricity for export to the grid or for use within the house by conventional appliances). Inverters can create high electric and magnetic fields. The NZ legal limit for magnetic fields associated with electrical equipment is literally hundreds of times higher than the level of these magnetic fields that are potentially carcinogenic.
Inverters also have the potential to create a lot of “dirty electricity” (high frequency transients and harmonics) that are potentially carcinogenic or may exacerbate many chronic health conditions. It is generally accepted that these transients and harmonics cannot economically be filtered from the electricity supplied from the inverter but possible ways to achieve this are being investigated. The high magnetic and electric fields from the inverter cannot be remediated in any way that I know of (other than placing the inverter as far away as possible from living and sleeping areas in the house where people spend most of their time.)
Often dirty electricity is the main issue that can be measured and there are quite a few videos on dirty electricity at this link: http://www.safespace.net.nz/resources.html
Also, as solar panels in a grid tie system are often connected up in series (rather than in parallel) the high DC voltages can potentially pose a serious electrocution and fire risk if wiring is faulty. (This is because DC runs continuously. By contrast with alternating current (AC) there is an instant at which the current effectively stops flowing as the current reaches the “zero” on the sine wave; at this time it may be possible to let go of a live wire as long as the current is not too strong.)
The technology may improve in time but without having access to test data from a trustworthy source on primarily the dirty electricity and also the magnetic and electric fields from the inverter and other components of a solar system, I have recommended to friends who want to go solar against using any solar power configuration that includes an inverter at the moment. I don’t think the potential increase in cancer risk and many other chronic health conditions, which could be substantial, is worth the saving on electricity bills.