Why my former neighbour did not put all his solar panels on the sunniest side of the house

// Translation of my 'How hard can it be?'-column in this weekend's edition of the Dutch newspaper de Volkskrant

I spoke to my old neighbour and he was very pleased with his new solar panels. 'I've put some facing the east, almost northeast,' he beamed. Now I'm no solar panel expert, but I thought solar panels should always face south because that's when the output is greatest.

'Well, with the newer generation of more efficient panels, east-west roofs will work just fine too. But it also becomes less favourable if all the panels are on the side with the most solar yield when the Dutch government will phase out the net-metering scheme ('salderingsregeling').' Oh, I forgot to mention: my former neighbour works on the sustainability of buildings. So he came well prepared when installing his own panels.

Currently, the net-metering scheme still applies, which allows solar panel owners to at the end of the year deduct the electricity they delivered back to the grid when their panels produced too much from the electricity, from what they took in when their panels did not produce enough. The plan is to phase out that scheme, which regulator ACM wholeheartedly encourages, but the house of representatives is opposed for the time being for various opportunistic reasons. However, this is very similar to the mortgage interest deduction scheme: abolishing it is going to hurt a bit, but basically everyone knows that that it is not fair anymore and has to be phased out.

Under the current net-metering policy, your goal as a solar panel owner is: generate as much electricity as possible, no matter what time of day. Because when you deliver back to the grid, you get the same price for it as when you buy electricity at a later time. That leads to an overload of the electricity grid at peak times. The new rules of the game change that. You can still deliver back, but the price will be low if everyone does so, say in the middle of a sunny spring day. So the new goal will become to generate your electricity as much as possible at times when you need it yourself.

And then there are two options: either you adjust the time of consumption, or that of generation. If you want to adjust your time of consumption, you can, for example, run the dishwasher and washing machine and turn on your heat pump at the times when your panels are generating a lot and your electricity is 'free'. But you can also spread the generation. And that is why my former neighbour does not want all his panels on one side of the house (be it south, east or west), but on different sides.

This nicely shows how product design is driven not only by our needs and available technology, but also by revenue models and pricing. The phasing out of the balancing scheme and the associated shuffling of panels is part of the transition to an electricity grid in which, due to variable energy sources such as solar and wind, balancing supply and demand will play an important role and prices are therefore likely to be increasingly dynamic.

Read the full column in Dutch on the website of de Volkskrant.