What contribution do "small power plants" in private residential construction make to the desired energy- and heat-transition?
On
the weekend I had another nice conversation with someone who was interested in
installing a solar system on his roof. A conversation which animated me to this
article.
In
the course of the conversation, a question was asked again and again:
"What is the point of my small system, if we strive for a global energy-
and heat- transition?"
Well,
the answer should be simple. Any system that ensures that we do not need a
combustion process to generate heat or electricity is an asset.
To
put it in rough figures, let's say 1 million roofs are equipped with a 3 kWp PV
system and a 5 m² solar thermal system.
With
PV this would be about 3 million KWp or 3 GWp of power that would be installed,
which corresponds to an annual output of about 3 TWh of electricity that would
be generated.
Yes,
I estimated 1000 kWh/KWp. In the south it will be a little more, in the north
less. It is a milkmaid's bill, no question, but not far from reality.
And
if you now add to this the fact that a solar thermal system in summer can help
to avoid burning oil or gas to generate hot water, I would say that this, taken
as a whole, is no small contribution to the energy- and heat-transition.
But
I have now focused only on solar. If we spin this idea further, then we come to
heat pumps that can convert electricity into heat many times over. Depending on
the type of system, it is possible to turn 1kWh electric power in up to 4 kWh
of heat. How nice if most of the electricity or additional heat would now also
come from the roof. ?!
Unfortunately,
in such conversations, you come across a factor that is at the forefront of
such considerations. "What does such a system cost me and when will my
investment pay off?" A perfectly understandable question. But even here,
just pull out the calculator and think about what e.g. the electricity from the
grid costs and what e.g. the electricity generated by my PV system costs.
Especially with regard to the low-interest loans that are currently granted for
the construction of such a system.
And
if you now add the subsidy programs for the use of "renewables" in
general, the answer should not be difficult.
Here
is an additional example from the past: "What, 10,000 EUR for a solar
thermal plant, that's too expensive for me..." A few months later it
sounded like this: " What 12,000 for a solar thermal plant with a subsidy
of 2,000 EUR, ... I am interested".
Well, everybody can think about that on his own...
Another
sentence that got stuck in my memory: "The energy-transition is more
likely to be achieved with large solar and wind parks. Well, of course, a large
plant concentrated on one area is able to generate more power than a plant on a
private roof. BUT, on the one hand, such plants are more reserved for investors
who want to generate a quick profit.
On
the other hand, we have to ask ourselves to what extent a large plant, for
which forests are cleared, agricultural areas are sealed, or natural areas
destroyed, can still be called "sustainable".
It
is not about demonizing these plants, whether wind or solar parks, but about
not losing sight of the thoughts "environmentally friendly, nature
conserving, real sustainable etc.", just because one concentrates on the
fast profit.
Especially
in regard to the fact, that there are already applications in the solar sector
available that allow the occupied area to be used in a multiple way. Keyword
"Agro-PV", here an agricultural area is used to generate electricity,
but is still available for the cultivation of agricultural products. In combination
with e.g. semi-transparent modules in the field of PV, even the cultivation of
sun-sensitive agricultural products is possible.
In addition, even a reduction in water consumption can be achieved through partial shading.
In addition, even a reduction in water consumption can be achieved through partial shading.
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| Picture: Solidenergie GmbH - https://www.solidenergie.com/ |
We
have to start looking a little bit more beyond the horizon. On the one hand,
with regard to the effect of "many small systems from the field of
renewables" in private or small commercial applications and, on the other
hand, with a view towards "real sustainability" instead of
"quick profitability", at least if we want to implement a truly
environmentally friendly energy and heat turnaround in a globally sensible way.
And this NOW!
Just
a simple thought.
06.2020
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