Agri-voltaics, an opportunity for sustainable development in rural areas
Mondo Macchina interviews Nicola Colonna, from the Sustainability Department, Biotechnology and Agroindustry Division of the ENEA Casaccia, Research Centre, who analyses the new landscape of photovoltaic technologies, which represent a development driver for primary sector companies and an important source of sustainable supply
The subject of the environmental and economic cost of energy has been at the centre of public debate for decades, but in the past year we all have the feeling that the issue has moved from a mid-level position to the top. In this dynamic, the conflict between Russia and Ukraine has played a prominent role, bringing to the surface the countless critical issues related not only to energy production systems, but also to the often irrational use of energy. Theoretically, the way out of this impasse has been identified at a strategic level - and with the full support of science and technology - in the massive recourse to renewable energy sources and energy efficiency. With this in mind, it is necessary to quickly exit the era of fossil fuels and find the most sustainable and realistic alternatives for each production sector in relation to energy needs and the availability of renewable sources. On the subject of so-called agro-energy, an interesting point of view can be provided by Nicola Colonna, a researcher at ENEA who has been studying the subject for years and who also disseminates it to stakeholders at events such as EIMA International and Agrilevante.
How heavy is the national agricultural sector in terms of energy consumption?
Statistics from the National Energy Balance Report show us that the primary sector (agriculture, animal husbandry and fishing) has a significant weight in terms of consumption at about 2.3% of the total, and that the sector consumes mainly diesel fuel, used mostly for traction and to power irrigation pumps, while the second most important source is electricity, and the other fuels are negligible. If we broaden our view to the agro-food sector, the situation changes as natural gas and electricity are the most used sources. As we know, natural gas of fossil origin can be replaced by 100% renewable biomethane, which can be obtained - for example - from the fermentable waste from the production cycles of the agro-industry. Electricity generation can be replaced in increasing percentages by RES (renewable energy sources) that can be implemented in the agricultural sector in different applications.
How can the primary sector, in its multifunctional vocation, contribute to reducing climate-changing emissions?
The sector's emissions are related to the three main greenhouse gases included in the Kyoto Protocol: methane (CH4) mostly originating from rice fields and the livestock sector, nitrous oxide (N2O) originating from soils due to nitrogen fertilisation, and carbon dioxide (CO2) emitted, for the most part, from diesel combustion. It is on this last gas that we focus our attention because through alternative energy choices, including photovoltaic production, significant emission reductions can be achieved to curb the climate change phenomenon with all its attendant criticalities.
Among agroenergy options, the biomass resource plays a central role, but how does agrivoltage fit into a short to medium-term scenario?
The current Italian targets (PNIEC) indicate an additional photovoltaic power of about 30 GW by 2030, but this target will have to be revised upwards by virtue of the recent REpowerEU Plan, introduced to cope with the consequences of the energy crisis linked to the war in Ukraine, which increased the European targets significantly. Some of the new photovoltaic power will be installed on roofs (NRRP's Agrisolar Inventory Programme), in industrial or otherwise non-agricultural areas and on the surfaces of lakes and reservoirs (floating photovoltaics), also by virtue of recent regulatory interventions that have simplified some types of measures. But a significant part will have to be built on agricultural land in the new Agrivoltaic implementation version, i.e. systems that integrate agricultural production with energy production. Many projects are underway and many others under authorisation throughout the country with large-scale systems, and with very different types and solutions.
How does ENEA support these new technological systems?
ENEA, aware of the technological evolution of photovoltaics and the opportunities that arise from the potential synergies of crops and photovoltaics, has moved ahead of the times by setting up a multidisciplinary task force in April 2021, coordinated by architect Alessandra Scognamiglio. The intent of the task force is to promote an integrated vision of the three main aspects that must coexist in an agrophotovoltaic project: landscape, agriculture and energy. In launching the project, ENEA has promoted an Italian Sustainable Agri-Voltaic Network by launching initiatives and dissemination seminars that have so far been attended by thousands of users and many farms, testifying to the great interest in the topic.
At the same time, ENEA participates in European and national projects that test and analyse agri-voltaic systems with a view to assessing which systems and combinations are the most efficient. Moreover, thanks to the level of know-how achieved, some members of the task force have been involved in specific working tables for the development of technical standards.
What are the strengths and weaknesses of agri-voltaics?
Like all initiatives related to the deployment of innovative technological systems, the development of agrophotovoltaics presents both elements of opportunity and criticality. However, as already mentioned, there are numerous, even enthusiastic endorsements, but these must be tempered by some important considerations. The possibility for farms to self-produce the energy they need and to sell their surplus are certainly positive elements, thus creating a vital income supplement, useful for maintaining high competitiveness. All of this is made possible by the evolution that photovoltaic technology has undergone in recent years with the development of better performing modules, double-sided panels and solar tracking systems. These factors make it possible to create plants that are decidedly more efficient and more productive than those of just 10 years ago. In an evolving and positive scenario, however, we cannot forget that the creation of a true agri-voltaicsystem, which truly integrates cultivation and energy production, which preserves the landscape and generates income for agricultural enterprises, has too short a history and the experiments are too fragmentary and of limited duration to offer adequate choices to farmers. There are few experiments available to date, carried out on different crops in different settings and with different agri-voltaic models. For example, we currently call very different solutions and combinations by the same name, and this certainly does not help the interpretation of the results. This is precisely why we need a coordinated network of research experimentation in order to create a framework that is truly useful for farms.
How do agri-voltaics fit in with agricultural production and modern mechanisation?
The issue of mechanisation is also fundamental in this specific production orientation. A multifunctional approach of farms that intend to produce energy without abandoning food and feed production for the market cannot disregard it, but this means making rational choices in the design phase of the agri-photovoltaic system to allow the machines to operate safely for the operators, and to preserve the crops and structures between which they manoeuvre. There are very high agri-voltaic systems that do not place any operational limits on the machines even if they are large, but their cost is made higher due to a greater investment in support and reinforcement structures. The heights from the ground of the panels, the movement, and the distance between the support poles and any tensile structures are all elements that must be carefully evaluated during the design phase in relation to the cultivation system to be adopted. Attention must also be given to some typical aspects of the operational phase, such as the potential production of dust and the distribution of pesticides. All these elements are connected to the use of operating machinery and that may temporarily decrease the efficiency of photovoltaic modules. The Italian mechanical sector, which is so dynamic and innovative, will certainly only be able to offer solutions to these problems if it plays an active part in the development phases of agri-voltaics, also providing solutions to the needs of the operators involved. Lastly, I would like to point out that the mechanical sector must play a leading role in training to ensure the safety of operators. We are talking about complex and expensive installations where one works in the presence of low- or medium-voltage electrical cables, and therefore in order to reduce the risk of accidents as much as possible, the personnel employed need specific training.
In conclusion, can we already refer to some good practices in Italy
The first initiatives started a decade ago in the Piacenza area with elevated installations equipped with a two-axis tracking system capable of orienting the photovoltaic modules with reference to the position of the sun and the specific needs of the plants. This, for example, allows for wider shading on certain summer days when high levels of solar radiation, temperatures and windiness can cause physiological stress for the plant. The photos clearly show the level of infrastructure required for this type of system. There are also simpler system s with a lesser impact on the landscape that take advantage of the traditional staking of permanent crops (such as vineyards) to produce energy, partially shade, and still allow mechanical harvesting. We can refer to many different solutions capable of providing useful services to the crops and the farm, integrating into the farm's production model. So we must look at these systems, which are born in agriculture and for agriculture, with interest.
The Italian sustainable agri-voltaic network
In 2021, given the novelty and implications of the topic, ENEA promoted a network of stakeholders interested in debating, comparing and sharing information and ideas on agri-voltaic applications. The network is implemented together with ETA FLORENCE, which handles its website and operational management, organises webinars, periodically produces a newsletter and makes information available to users. Participation is free of charge, subject to registration on the website www.agrivoltaicosostenibile.it. At present, over 900 companies, professionals, farms and associations are registered.
