According to a study, more energy is produced, and more self-consumed, if we orient the panels to the west
He is about to end up run over, his mother saves him
You have noticed that all photovoltaic panels are installed always in the same direction? Have you ever wondered why? Forget everything: the vast majority of solar modules installed in the northern hemisphere of our planet it could be misdirected.
Until a few days ago it was there only one thing for sure about photovoltaics: that you had to install it with the face of the panel facing the sun facing south east. Now there is not even this certainty: according to a study by the Pecan Street Research Institute we should orient them towards the west.
Before calling the installer saying he is incompetent, however, let's read carefully what this study says. First of all, it is a research conducted on 50 domestic installations in one city: Austin, Texas. Some of these 50 houses had panels oriented to the south, others to the west, others had a system partly oriented to the south and partly to the west.
From the measurements of the electricity produced by the three types of systems it emerged, obviously given the journey that the sun takes, that the west-facing panels produced much less energy in the morning and much more in the afternoon. And, in total, those facing west produce the 2% more of the others: 37% of the energy consumed by the house during the whole day against 35%.
But the interesting data is not so much the total amount of energy produced, but the percentage of self-consumption energy itself. If the panel produces on the roof while we consume below, then we will not buy the energy from the grid but we will use ours. The rest will be transferred to the network, with the mechanism of the Exchange on the Place better known in the United States with the term of "net metering".
The study shows that the percentage of self-consumption is higher if the panels are oriented to the west: 65% against 54% of the panels to the south and south east. This is because the peak of consumption occurs in the afternoon (during the day you are away from home to work): from three to seven.
In practice, Texan houses with west-facing panels produce 2% more electricity and transfer 11% less electricity to the network with net metering. And the latter factor should not be underestimated, given that one is underway in the United States very hard war against the Exchange on the spot (which undermines the balance of the electricity grid and ruins the profits of large companies that produce energy).
A war that has already seen a big electricity company win a first battle: in Arizona, not far from Texas and with absolutely similar levels of insolation, the electricity utility APS has obtained the taxation of photovoltaic energy sold to the grid with the net metering. Users with roof panels they will pay duty starting January 2014, XNUMX.
Peppe Croce
