The energy transition cannot be done only with photovoltaics on rooftops or on urban land

I have the feeling that the debate opened in recent weeks regarding the development of renewables in the territory is here to stay and that it will no longer be closed falsely. The well-known “Renewables yes, but not like this”, slogan of those movements that oppose the introduction of renewables in the territory, had always lacked an alternative to justify that “yes”. Now, after several public positions and reports, we are already beginning to glimpse it. The alternative is summarized in the priority or exclusive development of photovoltaics on rooftops or, failing that, on urban land and degraded land. Finally you can discuss something tangible. And we must be blunt: this alternative does not hold up.

We must be absolutely blunt on one point: the energy transition cannot be done only with photovoltaics on rooftops, simply because there is not enough capacity or surface area. It is technical nonsense and, as I have stated on occasion, borders on anti-science. The best study I know of in this regard is a comprehensive European study on actual rooftop generation capacity. For Spain, it offers generation possibilities of 65 terawatt-hours per year (TWh/year), which is only slightly more than what is generated by the seven nuclear reactors in operation in our country. To give you an idea, Spain consumes around 250 TWh/year of electricity, but, and this is what is relevant, more than 1,000 TWh/year of final energy.

The energy transition process implies that the vast majority of this final energy consumption ends up being directly or indirectly electrified, that is, we will have to generate much more electricity in the future than those 250 TWh. Even if we manage to reduce the energy consumption of our society, it will be difficult for rooftop photovoltaics to generate more than 10% of our energy needs. This is the indisputable reality that the numbers show.

There are many more studies of rooftop generation potential, but unlike the study mentioned, what they are analyzing is not a real potential, but a raw or technical potential, that is, the potential that could be obtained by filling all the surfaces with panels. technically adequate. But as anyone who has worked in self-consumption knows, there are many limitations that mean that the technical potential is not fully usable. Limitations of patrimonial protection, of adequacy of the covers (many do not accept charges or contain asbestos), of economic viability, of connection to the network, of pure geometry of the panels or, most importantly, of social use. Would you fill the 50 square meters (m²) of your penthouse terrace with panels? Those 50 m² are technical potential, but we usually use the terraces for other uses.

The reality is that we are only going to be able to occupy a fraction of the technical potential with panels, however, many insist on confusing the technical potential with the real one. Professionals have already explained actively and passively that this is not the case and that persevering in the confusion would only lead to failing to meet the emission reduction targets.

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Renewable plants on urban land

Once it is clear that basing the energy transition on rooftops is technically unsustainable, we must also analyze the rest of the proposals that complement that idea, such as using urban land instead of rustic land. This proposal not only ignores how renewable developments work, but also does not seem to have assessed the consequences of widespread development of renewable plants on urban land.

With some exceptions, renewable plants of a certain size are never installed on developable land. The reason is easy to understand: the cost of developable land is almost always prohibitive, it would multiply the cost of the project by two and would surely make it unfeasible. If someone tries to force renewable developments to be on urban land, the only thing that will cause is that almost none of them are done. But surely this is the least of the problems. Even if we could afford it, the massive implementation of these developments on developable land would probably generate undesired consequences for the population.

To begin with, the massive use of developable land for the development of renewables would cause a shortage of it for new residential developments, and could catalyze a new real estate bubble with obvious social consequences. But, in addition, it would jeopardize any rational urban organization. Are we going to use urban land to install renewables instead of installing hospitals, health centers, facilities, homes or schools? Are we going to send the equipment kilometers from the houses, instead of putting the generating plants there that do not need to be close to the urban center? The energy transition needs massive developments and it seems to me that people are not wanting to understand what this implies in terms of surface area or the consequences of some proposals.

Finally, proposals such as using degraded soils or even greenhouses are also read. Unfortunately, these are broad brush and poorly thought out proposals. We all want developments on degraded land, it would be easier even for developers, but if they are not going there en masse, what we have to ask ourselves is why and, above all, what should we do to make it like that, not simply seek a requirement which would lead to the reduction of renewable deployment. And about the greenhouses…

In short, I think that before launching proposals like these, it is necessary to analyze their costs, what percentage of the greenhouse surface could really be covered with panels without generating unwanted effects on the plants or if our traditional crops would accept it. And the same goes for proposals to cover roads or canals, which have technical difficulties and high cost overruns and are therefore not developed. You cannot take a satellite image, fill the desired surfaces with panels and say that this is feasible. That is not a sensible proposition.

Multiply renewables by four

Let me be clear: to make the energy transition, Spain will need to install hundreds of thousands of renewable megawatts (MW). Yes, hundreds of thousands, we will need at least between 200,000 and 300,000 MW between solar and wind energy. Now we have just over 50,000 MW, so the installation will have to be multiplied by a minimum of four and probably more. This is reality, this is mathematics, it is physics, and with mathematics and physics you cannot negotiate nor can you ignore them because it is not comfortable to assume the reality that they show us.

Spanish society must understand that, given the essential decarbonization, the installation of renewable energies must be massive and as fast as possible, both to reduce the climate impact and the energy dependence that is doing so much damage to Europe. The What (renewables) and the How Much (the thousands of MW that we must install annually) cannot be in question. When we achieve this consensus and this acceptance, we will be able to face the conflicts that the installation of renewables obviously has without falling into the temptation of resorting to denial so as not to assume uncomfortable contradictions to manage.

And then we will be able to really debate, with unquestionable data and needs, and without protractive excuses, how we improve the implementation of renewables in Spain for all the next generations of projects. Because despite the fact that it is not known or seen in the media, there are many people and organizations that have been working to improve renewable developments, so that they have less environmental impact and greater positive local impact, so that renewable implementation is responsible and socially accepted. That is the way and not to deny the majority, as is being done irresponsibly from some pulpits.

We can’t let the renewable installation debate go wrong once again. These are the figures, this is the reality and this is the technical infeasibility of the proposal behind the “Renewables yes, but not like this”. You have to tell society. And we also need to banish from politics those proposals that, based on voluntarism, seek to twist science and evidence, because that does not lead anywhere other than climate retardism. Voluntarism is anti-intellectual, it is anti-scientific, and if we try to improve society with our backs to science and reason, we will not be very different from the worst political and social movements in history. We can’t let some magical thinking clamp down on climate denialism so we don’t do what science tells us to do, while reacting furiously to those who remind it. Without science there is no progress, and ignoring mathematics will only lead humanity to disaster.