Energy potentials and water requirements from perennial grasses on abandoned land in the former Soviet Union

Abstract

A ramp-up of bioenergy supply is vital in most climate change mitigation scenarios. Using abandoned land to produce perennial grasses is a promising option for near-term bioenergy deployment with minimal trade-offs to food production and the environment. The former Soviet Union (fSU) experienced substantial agricultural abandonment following its dissolution, but bioenergy potentials on these areas and their water requirements are still unclear. We integrate a regional land cover dataset tailored towards cropland abandonment, an agro-ecological crop yield model, and a dataset of sustainable agricultural irrigation expansion potentials to quantify bioenergy potentials and water requirements on abandoned land in the fSU. Rain-fed bioenergy potentials are 3.5 EJ yr−1 from 25 Mha of abandoned land, with land-sparing measures for nature conservation. Irrigation can be sustainably deployed on 7–18 Mha of abandoned land depending on water reservoir size, thereby increasing bioenergy potentials with rain-fed production elsewhere to 5.2–7.1 EJ yr−1. This requires recultivating 29–33 Mha combined with 30–63 billion m3 yr−1 of blue water withdrawals. Rain-fed productive abandoned land equals 26%–61% of the projected regional fSU land use for dedicated bioenergy crops in 2050 for 2 °C future scenarios. Sustainable irrigation can bring productive areas up to 30%–80% of the projected fSU land requirements. Unraveling the complex interactions between land availability for bioenergy and water use at local levels is instrumental to ensure a sustainable bioenergy deployment.