Does technology drive people’s behaviour or does behaviour influence technology, specifically rooftop solar photovoltaic (PV) systems? I ask this question because of the rapid development of the sector from one extreme to the other and because of a spiral towards what is perhaps the final optimum solution.
Rooftop PV, which started out as a system for reducing user demand, was the preserve of wealthier users. As prices came down, more rooftop PV was installed and the net-metering phase was entered, where “prosumers” could turn the electric meter backwards when excess power was fed into the grid. When net-metering proved not ideal (especially for distributors), the focus moved to on-site storage.
This move was also influenced by load shedding and grid failures and was followed by the appearance of “designer” home storage units. One of the most rapidly developing areas is “behind-the-meter” storage, with many smart storage units designed for residential applications. You can even access cloud-based weather systems to determine what to do with your stored energy.
Tesla has removed one of its smart storage models from the market but several other companies offer units for behind-the-meter solar systems.
This move brought the realisation that stored electricity is the property of the end-user and can be traded behind the meter and, now, over the garden fence with your neighbours, without going via the grid.
Combined with this is the appearance of community “solar gardens” and residential communal solar PV systems. The next step is likely to be community storage, as the end-user system can be connected directly via a DC link to the storage with its own metering.
The cycle of rooftop solar PV has turned utility dependent users into system owners and co-owners of larger co-operative ventures. Community solar gardens are taking hold in the USA and communal rooftop PV systems in high-density housing (HDH) units as well as retail properties are appearing. Several units already supply solar power to HDH residents in Australia.
This concept could be considered by South African residential estates where the body corporate would control the system and provide community storage with individual metering, independent of the grid. In many South African sectional title duplex complexes, the roofs and car parks are common property which could be used for communal rooftop PV.
One wonders how legislation would deal with this because no power would be sold to or wheeled through the grid, but exchanged between the residents behind the estate’s meter, surely a legislative nightmare.
One wonders whether these developments are based on pure economics or on the individual desire to be utility-independent.
At my home, I installed a very complicated solar water heating system with a control panel which allows many parameters to be set and adjusted. I will probably never recover the cost despite substantial savings, but it does give me a feeling of control.
In terms of solar, the question of net-metering still rears its head and some people believe they can accrue huge profit from it. The belief is that, if net-metering were allowed, the rooftop PV market would become profitable.
This assumption relies on the distributor paying the charged rate which, experience has shown, is not the case: this electricity has to be resold to other users at a higher rate.
I do not want to be forced to buy electricity from someone only interested in lining their pockets.
Will this be the end of the spiral or will we see even larger projects developing with whole suburbs or towns owning communal PV plant and trading with one another without going via the grid? Whatever happens with technology, it seems that behind-the-meter storage will become a feature of rooftop solar PV systems in future, and smart energy storage systems are appearing on the market like mushrooms. Maybe the obsession with net-metering may well fall away, especially if time-of-use tariffs for residential customers are introduced.
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