Photovoltaics, Agriculture and Energy Storage
SOLAR LARGE-SCALE POWER PLANTS MEET AGRICULTURE
Today the LCOE of solar photovoltaics has reached a value that makes grid-parity PV plants independent on any form of government-backed subsidies.
Revenues are generated by the sale of electricity through Power Purchase Agreements (PPA) with top trading firms or corporations, reducing resorting to any kind of governmental support.
Avapa Energy embraces such technology that is capable of being deployed fast and operated efficiently ìn most countries around the world and is working on multiple projects with international investors in the design, development, construction, financing and management of a large pipeline of grid-parity PV projects.
When such projects are located on land that can be cultivated and farmed, Avapa Energy always designs according to the latest state-of-the-art technology to ensure the coexistence of land produce and energy production.
While it might seem as a new concept, this has been in place since centuries; our Etruscan ancestors cultivated the land to ensure they had produce for food, forage for cattle, wood for fire (energy).
Agrivoltaic works on the basis of Photosynthetically Active Radiation (PAR), part of the light spectrum of wavelengths 400-700 nm utilised by plants for photosynthesis. The ability to use incident light differs indeed from plant to plant: over a certain light intensity, the ability of plants to convert light into photosynthesis decreases (saturates). Depending on its light saturation point, a plant may be therefore better suited to grow in shaded areas, and even be able to grow in areas previously unsuited for such type of plant due to excessive solar irradiation.
Avapa Energy already has experience in agrivoltaic, having been involved in the advisory and acquisition of a now authorised large scale agrivoltaic plant in northern Italy, and has already submitted designs for other large-scale agrivoltaic plants currently in permitting in southern Italy; we have so far designed and submitted projects after having interacted with Italian universities, studied internationally peer-reviewed papers (check for instance: Agostini et al., Innovative agrivoltaic systems to produce sustainable energy: An economic and environmental assessment, Applied Energy, vol. 281, Jan 2021, DOI:10.1016/j.apenergy.2020.116102) or reports from organisations of the likes of the Fraunhofer ISE.
As per a number of agronomical studies, the following cultivations are well suited to coexist with photovoltaics: rye, barley, oats, green cabbage, rapeseed, peas, asparagus, carrot, radish, leek, celery, fennel, tobacco, onion, ebans, cucumber, zucchini, artichokes. Very well-suited cultivations, when shading has a positive effect on the product yield, are: potatoes, hop, spinach, lettuce, fava beans, citrus fruits. Obviously, also forage like alpha-alpha, clover, oats, flowers, lavender, grazing of sheep and goats, and beehives can accompany horticulture, gardening, farming by mixing areas between the module rows as a function of local irradiation levels.
Shading from photovoltaic plants have, according to Fraunhofer ISE, increased the resistance of plants to draughts and high irradiation during the summer of 2018; a reduction of 30% of the solar radiation has reduced soil temperature and evotranspiration. Since we are experiencing longer periods of drought with increasing risks of desertification in Italy due to climate change, any reduction in the water loss of the soil is extremely welcome.
Currently, the most updated attempt to norm agrivoltaic technology relies on the DIN SPEC 91434:2021-05; while this norm is not yet enforced, all position papers from Italian associations like Italia Solare, Elettricità Futura, ANIE Rinnovabili, Confindustria, base all recommendations on such pre-norm.
All our projects are designed in order maximise the land available for agriculture. According to the classifications outlined in the DIN norm, we work with structure manufactures of Category I and Catagory II Variant 2.
An example of Category I agrivoltaic is provided in the following picture.
An example of Category II Variant 2 is shown in the following, and is the strategy we adopt in most of our plants.
According to the norm, if the area is farmed and a yield of 66 % is achieved, such area is considered suitable for agrivoltaic. In this regard, the area that is no longer agriculturally usable shall be less than 15 % of the total area after the agrivoltaic system has been installed. We are more and more designing our plants in agreement to these requirements. We are working to implement larger distance from ground for our tracker-based agrivoltaic plants and ever increase the farmable land.
Italian regulations are also recognising agrivoltaic plants as a viable technology and are granting access to subsidies (https://www.bosettiegatti.eu/info/norme/statali/2012_0027.htm#65). Law decree 27-2012 states that agrivoltaic plants may be granted subsidies (in Italian) if "(...agli impianti agrovoltaici) che adottino soluzioni integrative innovativa con montaggio dei moduli elevati da terra, anche prevedendo la rotazione dei moduli stessi, comunque in modo da non compromettere la continuità delle attività di coltivazione agricola e pastorale, anche consentendo l’applicazione di strumenti di agricoltura digitale e di precisione."
Following a vision that Avapa Energy had in place long before March 2021, we design and develop nowadays agrivoltaic plants according to the following principles:
elevated, rotating or fixed photovoltaic structures that leave room for a large portion of the land to be farmed or grazed;
upgrade of previous cultivations, if possible, to premium produce (i.e. D.O.P.);
introduction of advanced monitoring technology to improve control of quality and quantity of production;
collaboration with universities in pilot studies to introduce novel cultivations, extend farming periods, reduce water needs, optimise production.
RENEWABLE ENERGY STORAGE
Nearly all our PV plants are designed with energy storage to enhance flexibility, improve operational performance, and facilitate the addition of more and more renewable energy in the national electricity grid.
Solar photovoltaic plants convert renewable energy during daytime, but tend to be uneven in nature when solar radiation is low or absent during bad weather conditions or night time.
Energy storage is then the key to enable decisions about when to use the energy converted from natural sources that cannot be time-controlled. Energy storage systems for large-scale applications are therefore considered an important medium-term development of energy networks.
Storage can be employed for power-intensive applications, where power is delivered for relatively short periods of time, or energy-intensive applications, where energy is delivered to the load for relatively long periods of time; the number of available applications made possible through the adoption of energy storage technologies are myriad and all of them, taken singly or combined, provide enormous benefits to the energy infrastructure.
Energy Storage Systems (ESS) are the solution to this problem and, if combined with the conversion of energy from renewable sources, grant the
chance to drastically reduce, or eliminate altogether, dependence on the fossil fuel infrastructure.
Centralized electric storage power plants or distributed installations (i.e. for residential, community, industrial applications) would facilitate and increase the introduction of large shares of renewable energy connected to the grid: if the grid needed increases in energy supply, decentralized
ESS could provide part of the capacity by discharging in conjunction with other decentralized storage units or, on the contrary, by absorbing part of the surplus energy when supply is larger than demand. This way, even with varying power injection, the grid would still remain stable and reliable.
By combining ESS to a high penetration of RES in the power-generation mix and a new paradigm in energy-management smart technologies, base-loading can be covered by technologies that do not resort to fossil fuel usage. Entire regions with varying energy availability and demand needs can be interconnected with smart power backbones that can make energy flow consistent with supply-demand logic. ESS at 4 or more hours of storage already represent a viable solution for base-load fossil fuel substitution.
Even power-peaking can be managed more effectively by ESS coupled with renewable energy sources. A study by the California Energy Storage Association has shown that by using 100 MW of ESS instead of a 100 MW gas turbine peaker plant, the benefits following benefits could be gained:
600 times faster ramp up of power supply;
4 times the flexibility of its range of use;
3 times more available operating hours;
6500 gallons/hour of water usage saved;
90% GHG emission reduction.
ESS possible uses are many and outlined in the following. It is evident how resilient the grid can be made by clever design and placement of energy storage systems.
Green Electrical Energy Storage
Science and Technology for Total Fossil Fuel Substitution
Environmental concerns, together with the diminishing availability of traditional fossil fuels, have spurred the adoption of green energy conversion technologies and
increased their penetration in many countries all around the world. Green energy is most often converted to electric energy, since electricity is one of the most usable forms of energy.
As unevenness of many forms of large-scale renewable energy plants have impacts on the management of electric energy distribution grids, energy storage
technologies can be adopted to filter out spikes and troughs and stabilize the grid itself, while at narrower scale energy storage is already used to optimize users’ energy consumption and increase their independence from the grid.
Many are the possible revenue streams that can come from well-designed plants embedding energy storage as a central component, alongside the many non-monetary benefits that storage brings along in terms of exploitation of the renewable energy source itself.
Energy storage is a viable technology that can prominently contribute to the substitution over time of most of the fossil fuels and give access to an era of a carbon-free energy infrastructure.
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