Energy transition can’t be done only with photovoltaics on rooftops or urban land

I think that the debate that has started in recent weeks regarding the development of renewable energy in this area is about to subside and will not be closed the wrong way. The famous “renewables yes, but not like this”, the slogan of the movements that oppose the introduction of renewables in the sector, has always lacked an alternative to justify “yes”. Now, after several public posts and reports, we are beginning to see glimpses of 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 concrete. And let us be clear: This option doesn’t last.

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

The energy transition process implies that much of this final energy consumption is directly or indirectly electrified, ie we will have to generate much more electricity than those 250 TWh in the future. Even if we manage to reduce our society’s energy consumption, it would be difficult for rooftop photovoltaics to generate more than 10% of our energy needs. This is the undeniable 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 the actual potential, but a raw or technical potential, i.e. the potential that can be obtained by filling all surfaces with panels . technically enough. But as anyone working in self-consumption knows, there are a number of limitations that mean that the technological potential is never fully utilised. Limitations of material protection, adequacy of cover (many do not accept charges or contain asbestos), economic viability, connection to network, pure geometry of panels or, most importantly, limits of social use. Would you fill 50 square meters (m²) of your penthouse roof with panels? They are 50 square meters of technical capacity, but we usually use the terraces for other uses.

The reality is that we are only going to be able to capture a fraction of the technical potential with panels, however, so many insist on confusing technical potential with real. Professionals have already explained, actively and passively, that this is not the case and that persisting in confusion will only lead to failure to meet emissions reduction targets.

Renewable Plants on Urban Land

Once it is clear that the basis of the energy transition to rooftops is technically unsustainable, we must also analyze the rest of the proposals that complement that idea, such as using urban land instead of rural land. This proposal not only ignores how renewable development works, but also fails to assess the consequences of widespread development of renewable plants on urban land.

With few 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 will multiply the cost of the project by two and certainly make it impractical. If anyone tries to force renewable development to happen on urban land, there’s only one reason why almost none of it gets done. But of course this is the least of the problems. Even if we could afford it, large scale implementation of these developments on developable land would result in unwanted consequences for the population.

To begin with, the large-scale use of developable land for renewables development will make it scarce for new residential development, and could catalyze a new real estate bubble with obvious social consequences. But, moreover, it would endanger any rational urban organization. Are we going to use urban land to set up renewable energy instead of setting up hospitals, health centers, facilities, homes or schools? Are we going to send equipment kilometers away from homes, instead of putting generating plants there that don’t need to be close to the urban center? The energy transition requires massive development and it seems to me that people don’t want to understand what that means in terms of surface area or the consequences of some of the proposals.

Finally, proposals such as using degraded soil or even greenhouses are also read. Unfortunately, these are broad brushes and poorly thought out proposals. We all want development on barren land, it would be easy for developers too, but if they are not going there collectively, we have to ask ourselves why and above all, what should we do to make it so No, just look for a requirement that renewable deployments will fall short of. And about the greenhouse…

In short, I think that before launching such proposals, it is necessary to analyze their cost, what percentage of the greenhouse surface can actually be covered with panels without causing unwanted effects on plants or our traditional crops. Will accept And the same goes for proposals to cover roads or canals that have technical difficulties and high cost overruns and are therefore not developed. You can’t take a satellite image, fill the desired surfaces with panels and say it’s possible. This is not a sensible proposition.

multiply renewable energy by four

Let me be clear: To make the energy transition, Spain would need to install hundreds of thousands of renewable megawatts (MW). Yes, hundreds of thousands, we would need at least between 200,000 and 300,000 MW between solar and wind power. Now we have over 50,000 MW, so the installation has to multiply by at least four and probably more. It’s reality, it’s math, it’s physics, and you can’t negotiate with math and physics, nor can you ignore them because it’s not comfortable to accept the reality they show us.

Spanish society must recognize that, given the necessary decarbonisation, the installation of renewable energy must take place on a large scale and as quickly as possible, in order to reduce both the climate impact and the energy dependency that is plaguing Europe so much. What (renewables) and how much (thousands of megawatts we must install annually) may not be in question. When we achieve this consensus and this acceptance, we will be able to confront the struggles that the renewable energy establishment faces without being tempted to resort to outright denial so as not to admit uncomfortable contradictions to management.

And then we will be able to really debate, with undeniable data and needs, and without long excuses, how we improve the implementation of renewable energy in Spain for 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 working to improve renewable development, so that they have less environmental impact and more positive local impact, so that renewables Implementation should be responsible and socially acceptable. This is the way to negate the majority, as is being done irresponsibly from some forums.

We cannot allow the renewable installation debate to go wrong once again. These are the figures, this is the reality and this is the technical inefficiency of the proposal behind “Renewables Yes, But not like this”. You have to tell the society. And we also need to depoliticize proposals that are based on voluntarism, distorting science and evidence, because they lead nowhere but climate retardation. Voluntarism is anti-intellectual, it is anti-scientific, and if we try to reform society by turning our backs on science and reason, we won’t be much different from the worst political and social movements in history. We can’t let some magical thinking cloud climate denialism, so we don’t do what the science tells us to do, while reacting furiously to those who remind us of it. There is no progress without science, and neglecting mathematics will only lead humanity to destruction.

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