Plug-in solar systems plug into an electrical outlet instead of plugging into a home’s electrical panel. Although available for residential use in mainland Europe, plug-and-play solar panels are not offered in Britain due to regulations that make it illegal to plug a solar panel into a standard UK socket. These regulations (wiring regulations BS 7671) have now been amended.
Plug-and-play solar systems are small, mains-connected DIY systems that come as a complete package (panels and microinverter) that plug directly into the standard 3-pin socket in Britain and can be used to power household appliances.
Ecoflow, Lidl, Iceland and Amazon already plan to stock and sell 800W plug-in solar power systems when the new regulations come into effectwhich should happen by the summer, according to the Department for Energy Security and Net Zero.
What are plug-and-play solar panels?
Plug-in solar kits typically consist of one or two lightweight panels and a microinverter. Many of these panels are also foldable, making them suitable for all kinds of homes as they can be easily stored. The main appeal of these systems is their simplicity: they require no technical knowledge or expensive infrastructure development to power the home. They also do not require professional installation and are simply ready to use; they are plug and play.
These solar kits are installed on the balconies of an apartment or in any outdoor area of a house. The direct current electricity generated is converted into alternating current by the microinverter, which automatically synchronizes with the home’s electrical circuits so that this energy is used before additional electricity is drawn from the grid. Because these systems are connected to the socket, the power generated goes directly to the home circuit.
Plug-in solar energy technologies
There are two main photovoltaic (PV) technologies used in plug-and-play solar systems: Interdigitated Back Contact (IBC) and heterojunction (HJT) solar cells.
IBC is a PV technology that has been in development since the 1970s, where the front and back metal contacts are manufactured on either side of the cell, unlike standard cells. This provides higher output and PCE than traditional designs because there are fewer obstacles in the active area of the cell. This allows more photons to hit the semiconductor junction responsible for converting light into electricity, allowing more energy to be converted per cell surface.
Placing the contacts at the back of the cell minimizes shadow losses (as there are no metal lines at the front) and ensures maximum sun exposure. Placing the contacts on the back of the cell also allows the modules to be placed closer together, reducing the series resistance of the cell and improving module efficiency. They can also be manufactured in different shapes and sizes as there is no shading and these cells are also less affected by temperature ranges than other PV cells.
The main absorption layer in an IBC cell is a doped crystalline silicon wafer, usually an n-type wafer (doped with a Group V element such as phosphorus), because it performs better. However, both p-type wafers (doped with a Group III element such as boron) and polycrystalline silicon can also be used. The efficiency of these cells is further improved using diffusion layers, a thin-film surface passivation layer, and surface capture structures that minimize front surface recombination. The IBC cell design also includes an anti-reflective coating (often silicon oxide, silicon nitride or boron nitride). Both additional surface features improve the open-circuit voltage (VOC) and short-circuit current density (JSC) of the cell.
HJT PV cells are similar to conventional homojunction cells, but the difference lies in the composition and structure of the material layers used to form the semiconductor junction. Crystalline silicon is used to make homojunction cells, but HJT cells rely on monocrystalline silicon, amorphous silicon, and indium tin oxide (ITO). N-type monocrystalline silicon doped with phosphorus is most common, but p-type doped with boron can also be used.
Instead of being made of a single material, the absorbing layer consists of three layers, with the crystalline silicon layer sandwiched between amorphous silicon layers. On either side of this sandwich is a doped amorphous silicon layer, one of which is p-doped and the other n-doped. ITO acts as the cell’s transparent conductive oxide layer (TCO), which is layered on both sides (front and back) of the semiconductor junction. The number of ITO layers can vary and are connected to the metal contacts.
HJT cells work with the same energy generation mechanism as conventional solar cells, where the photon is absorbed in the semiconductor junction, exciting electrons, creating electron-hole pairs and generating a current. The excited electrons are collected by the terminal containing the p-doped amorphous silicon layer.
In HJT cells, all three semiconductor layers absorb photons. The first photons interact with the outer amorphous silicon layers, but most of the photon conversion takes place within the crystalline silicon layer. The remaining photons are converted into electricity by the rear amorphous silicon layer. Because multiple layers absorb photons, fewer photons are missed during capture and absorption, leading to higher conversion efficiencies. Efficiency is also high because the doped amorphous silicon layers also help reduce surface recombination (the recombination of excited electron-hole pairs at the surface of a material that prevents the electrons from collecting and flowing in the circuit) by acting as a buffer layer that optimizes the movement of charge carriers.
The main advantages of HJT are that the optimized material layers lead to high PCE and the efficiency can exceed 26%, which is useful for smaller cells such as plug-and-play cells. Like IBC cells, they are also less affected by temperature than conventional cells.
Legislation and regulations that make plug-in solar energy possible
The conversation about plug-and-play solar in Britain is only happening because of regulatory changes by the UK government. According to BS 7671 wiring regulations, it is illegal to connect a solar panel to a wall socket in Great Britain.
However, this is going to change. Until recently, plug-in solar systems were considered unsafe as they could cause fires as they were not compatible with electrical systems in Britain. There was also no proper certification to cover the risk of electric shock and fire when connecting a solar panel directly to the house’s main wiring system.
The new amendment, BS 7671 Amendment 4, will make plug-and-play solar energy legal in Britain from summer 2026, provided the products meet new safety standards. The new amendment is a set of electrical wiring regulations that will set new safety requirements for electrical installations in Britain and covers plug-in solar energy systems, among other small-scale electrical installations.
An important aspect of the new amendment is that the wattage of the systems will be limited to 800W. This prevents the household wiring systems from overheating, but is still large enough for the solar installation to provide sufficient power. The UK government is also updating the G98 distribution code to include plug-in solar kits, so anyone purchasing and using plug-and-play kits should notify their District Network Operator (DNO). This will help keep local electricity grids in balance as many households adopt plug-and-play solar energy and will ensure that the solar kits are connected safely to the electricity grid.
The new regulations are part of a wider effort by the UK government to support cleaner energy, including the new Future Homes Standard (FHS) is being developed by the British government. The FHS will ensure that new homes (with exceptions such as high-rise buildings) will be built using on-site renewable energy sources, mainly solar energy. However, because apartments are unlikely to be installed with solar energy, the new regulations support high-rise buildings towards cleaner energy by offering plug-and-play as an alternative.
Possible problems with plug-and-play solar
Although there is much debate about the potential benefits of plug-and-play solar for certain households, not all industry experts are convinced. One of the main concerns is that the BS 7671 regulations apply to actual installations, and not to the internal design of plug-in systems. It is stated that once the device exports energy to an electrical installation it becomes a source of power and falls within the scope of Section 551 of BS 7671: IET Wiring Regulations. In this section, Regulation 551.7.2(ii) states that a generating set shall not be connected to a final circuit through an electrical socket. This is because the final circuits in domestic electrical installations are designed to originate from a single point of supply to the consumer unit.
Therefore, all protection devices and isolation procedures depend on this arrangement and are not designed for plug-and-play systems. This can lead to localized overloading of the ring terminal conductors due to current injected at multiple points, altered residual current device (RCD) behavior, conflicts with grounding depending on the inverter setup, and there is a chance that the plugs will still be live for a while after the solar cell has been disconnected – and this residual electricity can pose immediate safety concerns for anyone using plugs in the home.
There is also a chance that system owners will not inform grid operators as prescribed in the regulation, which could lead to more safety and grid problems than expected due to incorrect information. There is also the risk that suppliers, especially online suppliers, will sell panels that do not meet the required safety standards, which could pose safety risks for some people. So while there is a lot of interest and benefit in the systems, we will have to see if they also pose safety concerns that may have been overlooked.
