Dave Elliott: Most renewable energy systems are less problematic and are fully zero carbon. Most (hydro apart) only have minimal land use requirements, and offshore wind none at all. With on-land wind farms, the only area taken is that covered by the tower bases and any access roads, so they can be very compatible with continued crop farming and animal grazing. Solar PV is less so, with critics complaining that solar farms often misuse valuable agricultural land, blocking it from use for crop cultivation. In response new array layouts are being adopted, with solar modules mounted on stands, so that crops can be grown underneath, and undue sun shading of the ground plants being avoided. In fact though, some sun-shading can be beneficial for plant growth is some locations: ‘the intermittent shade cast by the PV panels in agrivoltaic systems ..does not necessarily diminish agricultural yield’. So a mix and food and energy framing may actually be best in some cases, and what we may need is an optimal agro solar farming balance. Compatibility with animal grazing is part of that, sheep being an easy option, they can keep grass and weeds down. But, even without sheep, there can be an ecological gain: PV arrays can aid biodiversity, for example allowing wild flowers and wildlife to thrive under them. That can also be the case in extreme locations like deserts, which are well suited to large PV arrays, but also have some local wildlife that needs protecting. However, there may be albedo changing issues to consider with very large arrays of black solar solar cell, although some may be positive- improving local micro climates. In some other locations, floating solar is an option, with arrays floating on pontoons on water (lakes and reservoirs) and benefitting from cooling, a big issue for PV cell efficiency in hot climates. In such locations, floating arrays of reservoirs also help to reduce evaporation. Integration with fish farming, or perhaps algae growing, might also be possible. So it there may be a range of possible agro-solar mixes, depending on location, avoiding undue land use conflicts.
Renew Extra 3rd April 2021 read more »