Current energy generation and raw material production schemes for energy significantly impact the habitability of our planet—from coal, which has contributed about 0.3 °C of the 1 °C temperature rise observed since 1800, to oil palm production destroying forest-dependent people’s livelihoods and wildlife habitats [1
]. The extractive nature of the global energy supply system has had its negative social consequences on the planet too. These negative effects are magnified by limited consideration of the environmental consequences, human population needs, and the degree of technological advancements. Duguma et al. [2
] illustrated the prevailing vicious cycle of destruction due to lack of proper solutions to address household energy needs among rural communities. The authors demonstrated how energy extraction affects forest ecosystems, food security, climate change, biodiversity conservation, land resources management, and put societal pressure on women and girls.
To take one example, reservoirs for hydropower stations continuously suffer siltation due to soil erosion and poor land management in the watersheds. The subsequent effect of this degradation leads to the rising demand for wood fuel (i.e., charcoal and firewood) for communities that use electricity. This rising demand could generate destructive supply mechanisms that further deteriorate the ecosystem leading to biodiversity loss and ecosystem collapse. Such are the characteristics of degenerating systems, where the elements of the system are leading to a vicious cycle of energy poverty and ecosystem degradation and further complicating finding solutions to the problem [3
]. Discourses on how to solve the problem require understanding the system and identifying the right leverage points to enable significant positive change [5
So far, efforts to abate the system-wide effects of energy supply schemes [2
] have focused more on technical solutions (i.e., technological innovations such as energy-efficient systems development, nuclear power, solar energy harvesting, and others). However, the key inputs or sources of inputs for the technical solutions originate from the ecosystem. Hence, technology alone is insufficient to solve the negative impacts of energy systems. The major challenge with technical solutions to energy systems is the weak adoption levels in contrast to the high adoption [7
], the feasibility of the technologies within the socio-cultural aspects of community to use the products [9
]. Even for technologies with higher thermal efficiency, such as biogas technology with efficiency of 50–65% [10
], adoption is limited due to affordability and lack of awareness [11
Adoption alone is not sufficient as Ruiz-Mercado et al. [13
] indicated. The authors emphasized that sustained use of the adopted cooking techniques is crucial; implying that the broader impact of energy supply systems cannot be solved through technological solutions alone. Instead, there is a need for complementary interventions to boost ecosystem capacity to cater to energy raw materials coupled with efficiency improvements both in production and during use. Hence, regenerative energy supply systems that deliver benefits to the whole system [14
] are needed to limit the negative impacts arising from extractive energy uses that may lead to the collapse of the whole ecosystem.
Here we examine and elucidate the role that ecosystems play in energy supply. We then explore options for regenerative energy supply models that reduce impacts of the energy supply system and invest in the management of the ecosystems while making use of unused resources. The U.S. Energy Information Administration (EIA) [15
] indicated that even by 2040, Africa’s energy sources may not shift that significantly, in other words, biomass-based energy will still predominate. Besides technological advances, it is crucial to consider boosting the capacity for managing ecosystems to continue supplying biomass energy that the population may continue to use either as unprocessed input (e.g., firewood), semi-processed input (e.g., charcoal), or fully converted input (e.g., biomass electricity, biogas, hydropower, among others).
This paper presents a regenerative energy supply concept to move towards eco-friendly energy production options that increase the sustainability of the ecosystem. By examining and understanding the role that ecosystems play in energy supply, we explore options for regenerative energy supply models that reduce the negative effects of current energy supply models and capitalize on unused local bioenergy resources. We also propose judicious management of local ecosystems that considers the ecosystem itself, its possible future trajectories, and the social, ecological, and economic dynamics in and around it. This will aid in (1) framing proper and sustainable management strategies for energy supply sources and (2) reducing the negative environmental impacts arising from the use of ecosystems to source energy.
2. A Conceptual Framework: Towards Regenerative Energy Supply Options
Owen et al. [16
] highlighted that despite developed countries pushing for biomass energy as a renewable low carbon energy option, in Africa biomass energy is viewed as a retrogressive and environmentally damaging energy option. Irrespective of this, biomass energy is likely to remain the key pillar of the energy systems on the continent. Hence, innovative options to produce, convert, and utilize it are key. The ecosystem concept and regenerative energy are therefore crucial for the energy discourse on the continent.
The article “Regenerative Economy” [17
] emphasizes that unless current business practices change, it is difficult to have a healthy planet since our current economic development approaches are not strongly considerate of the environmental consequences the built economy is creating. It argues that natural systems continued to survive to date because they are regenerative. The emphasis in the regenerative economy [17
] is the concept of “system”. There is a connection between every component of a system, and a system is as strong as its weakest link, which Meadows [6
] calls a leveraging point. A system operates with sets of universal principles and patterns: efforts to build the economy should then be able to simulate these universal principles and patterns that otherwise may damage the system structure. Liu et al. [18
] argue that Earth on its own is a system, and all other sub-systems operate under the bigger principles and patterns. The authors argue that as a system, every element is interdependent, and there is a connection between all the components. It is in this inter-relation that materials flow, and for one to understand and conserve a system, it is essential to understand the flows in each direction in specific components of the system and how each flow relates to the stability of other system components.
Among the key arguments in regenerative economy [19
] is that wealth should be considered in a holistic manner and not simply as monetary value; hence, it should include economic, social, and environmental wealth. The emphasis on GDP of our current economic thinking has led the global economy to focus on economic growth without due consideration for its social and environmental consequences [20
]. Among these consequences are child labor, environmental pollution, human exploitation, and biodiversity loss. Liu et al. [18
] contend that global sustainability challenges are interconnected and should not be treated as separate pieces. The authors argue for a system integration that looks at holistic solutions within the coupled human and natural systems so that sustainable solutions to the significant global challenges can be found.
Energy is the fundamental input to drive development. The entire earth system depends on energy to function. In any aspect of life and natural system, there is an energy aspect, particularly the biogeochemical processes. At the lowest scales, for example, smallholder households, villages, districts, and even at the national level, the context of energy changes depending on the local situation and priorities. Nonetheless, the inherent feature in systems, namely, interconnectedness, still prevails. Consequently, energy should be contextualized as an element of the broader system and not as a stand-alone issue. Within the energy sector itself, there are several relations, interactions, and flows that need to be viewed as a subsystem of the larger earth system. Therefore, we advocate strongly for the use of the concept of energy system(s) rather than referring to energy as a single piece of the issue. Figure 1
shows how the different energy sources that directly depend on the ecosystem relate to the sectors that policymakers tend to use. The conceptual representation does not show indirect linkages.
If the ecosystem elements on which energy supply depends are not appropriately managed, energy poverty is going to cripple the ecosystem and the economy broadly. Once ecosystem degradation peaks, its habitability could significantly decline as its potential to supply goods and services on which life depends gradually diminish. This creates a series of strong arguments for ecosystem-based approaches to energy production as formulated here.
Argument 1: Managing forests and woodlands for wood fuel is crucial: If forest conservation and management fail to save forests, biomass energy sources will shrink. When communities do not have alternative, affordable and accessible energy sources, they will go to great lengths to get wood for cooking and lighting. Hence, a failure in the system in one location can have subsequent adverse effects in surrounding areas [21
Argument 2: Managing forests and woodlands for hydrological services is critical. Forests and woody vegetation in general play a crucial role in the hydrological processes in a landscape. With forest destruction (deforestation or forest degradation), sedimentation (or siltation) becomes a significant challenge for dams and reservoirs. When dams do not hold enough water for hydropower plants, power generation becomes limited. Then those people who rely on electricity will divert to biomass resources which then increases the pressure on forests and woody vegetation [23
Argument 3: The high dependency on biomass energy is creating a vicious cycle of ecosystem degradation. With the current and projected high dependency on biomass energy in the next decades in Africa, unless forests and woodlands are conserved, restored, and managed, supplying energy for the wider population will remain a critical challenge. If the current state of technological advances is not improved, it will further lead to a vicious cycle of ecosystem degradation, thus, exacerbating the problem [24
Argument 4: Proper land use is fundamental [27
]. Three dimensions can be addressed here.
Argument 5: Soil management plays a crucial role. If soil is not properly managed in watersheds, incoming moisture through rainfall often flows on the surface, joining river systems. This leads to reduced water infiltration into the soil and therefore, weak groundwater recharge. Silt-loaded rivers in turn diminish power generation [30
Argument 6: Woody vegetation alone may not solve the ongoing energy scarcity on the continent [31
]. Africa’s population is growing, causing rising energy demand. If woody resources depletion is not abated, forests, savannah, and woodlands alone may not be able to sustain the supply of energy for the biomass dependent continent. Thus, there is a critical need for alternative sources of energy, proactive interventions that increase woody biomass, and technologies that enhance the conversion efficiency of energy raw materials. Residues from crops allow energy generation in forms such as biodiesel, ethanol, biowaste electricity and biogas energy to supplement the available resources [32
] and reduce the pressure on ecosystems.
The prosperity of our ecosystems depends on how they are managed. If the different sectors indicated to have a strong linkage with energy (Figure 1
) are not part of the whole planning process of energy supply strategies, the trade-offs among the sectors will increase, as observed across the tropics where agriculture remains the main cause of deforestation. It is important to note that no single sector stands alone. They are all linked, and part of the whole, the sustained management of which whose sustained management needs to embrace regenerative energy supply. Figure 2
, building on the principles described in [17
], shows pathways to a regenerative supply schema that could be widely beneficial. Due to limitations in space, not all pieces of the schema are dealt with in detail.
Reaching a desired future state of regenerative energy supply options requires a shift from the conventional way of thinking about and managing energy to a more holistic one. Sourcing energy must be considerate of the ripple effects it causes on the other components of agroecosystems as indicated in Figure 1
. This can only be achieved if actions are taken to transition from the status quo (current modes of energy use) to a desired sustainable future condition (Figure 2
). Several pathways could help.
Technologies to improve on efficiency: The energy production and use system in Africa is characterized by huge wastage of raw materials and very low raw material to energy conversion ratios. For instance, the most widely used cooking method on the continent, the three-stone fire, has an energy efficiency of less than 20% [34
Technologies to transition to new forms of energy sources: Most of Africa’s population still relies on firewood and charcoal for energy generation. However, with appropriate technologies, a shift to solar and wind energy, which are among the cheapest energy raw materials, can be possible. To date, the access rate of such technologies in Africa is exceedingly low.
Understanding the lifecycle analysis (footprints) of energy supply options: The energy that we use at every moment of our daily life comes at a significant environmental cost. For instance, generating one gigajoule (GJ) of energy from charcoal comes with a water footprint of about 53 m3
]. Similarly, generating the same amount of energy from firewood (non-coniferous) comes with a water footprint of 21 m3
. Even further, the extraction of charcoal and firewood often causes deforestation and forest degradation, which subsequently threatens the habitat values of ecosystems and hence damages biodiversity.
3. Materials and Methods
3.1. The Scope of the Research
The current analysis focuses on Africa, particularly sub-Saharan Africa. In some instances, comparative examination was given to Latin America and Asia, both of which have similar sociodemographic and agroclimatic contexts—all three are tropical and subtropical regions. In the three regions, biomass energy and hydropower, to a large extent, dominate energy sources for households. The three regions are also the most affected by poverty and population growth, but particularly Africa and Asia. Hence, in some cases, a comparative insight looking at the three regions is presented although the major emphasis of the analysis is on sub-Saharan Africa.
3.2. Estimating the Ecosystem’s Role in Supplying Energy
We estimated the contribution of an ecosystem to energy supply by focusing only on energy sources that are directly driven from land and water. In Africa, most studies have found that the biggest share of energy sources comes from land resources such as biomass. Hydropower is a growing energy supply means. Waste (both household and agricultural) was included in this assessment as it results from ecosystem management and affects the ecosystem too. In this study, we have excluded solar, wind, and geothermal power sources because these are not directly affected by the current and likely future contexts of ecosystem management. Though wind energy may be affected by the global circulation systems and seasonality, coherent and consistent data and evidence on this is scanty. Therefore, despite its relevance, we excluded it from the current analysis. For any specific period assessed, the energy supply potential of an ecosystem is the sum of the biomass tree-derived energy (firewood and charcoal), other biomass (e.g., stems of grasses, manure), hydropower, energy from waste, and biogas where data was available.
Data for biomass resources was obtained from a report on forest products from the United Nations’ Food and Agriculture Organization [36
]. Data for hydropower capacity was obtained from the International Hydropower Association [37
]. Data for energy supply and production in energy units at country level for biofuels, waste, charcoal, and hydropower was collated from the United Nations Statistics Division [38
]. Data availability for long-term analysis was a challenge, as available data is limited to short time frames. For the data we used, we advise readers to consult the sources provided for any assumptions, caveats, and other considerations as to how the data was produced.
3.3. Estimating the Potential of Landscape Restoration to Boost Energy Supply in Africa
To estimate the potential of restoration for boosting energy supply, we collated data on the sparsely vegetated area (areas with low vegetation density) for each country in Africa from FAOSTAT [39
]. We extracted data on areas of barren land, which currently have no vegetation cover. For this, we assumed half of it could be restored to grow woody biomass, which in turn affects the hydrological processes affecting the water flow into the river systems connected to hydropower reservoirs or dams. We assumed that there is a potential to restore all sparsely vegetated areas and that barren lands could be restored to produce biomass to the optimum capacity, which may vary by local agroecological contexts. This is not without recognizing the fact that some of such lands could be severely degraded and may require significant investments. Here, we use restoration scenarios with different restoration options having different biomass stocking potentials (Table 1
We derived dry biomass equivalents for the emission values presented in Bernal et al. [40
]. For conversions, we used an average wood fraction of 0.47 from the total biomass [41
]. Potential biomass harvestable for energy from restoration options was computed using the area data for each country. The biomass was then converted into energy equivalents to estimate the potential. As this analysis is largely at the national level, final energy units generated may differ slightly as different countries may adopt a context-specific approach of restoring degraded vegetated areas and barren lands probably due to variations in agroclimatic zones resulting in different biomass production.
3.4. Estimating Energy Potential from Sparsely Natural Vegetated Areas
To estimate the potential of restoration for boosting energy supply, we collated data on sparsely naturally vegetated areas (areas with low vegetation density) for each country within Sub-Saharan Africa from [42
]. For this, we assumed that restoration of half of these areas could grow a considerable amount of woody biomass, which in turn would affect the hydrological processes affecting the water flow into the river systems connected to hydropower reservoirs or dams. It is also important to note our assumption that all degraded vegetated areas may not be applicable or at least may require massive investment to restore the land. We assumed that all sparsely vegetated areas could be restored to accommodate biomass to the optimum capacity, which may vary according to the local agroecological and agroclimatic contexts.
The total biomass that can be utilized for energy is computed using the average annual biomass production of 4.3 tonnes/ha/year and half the sparsely naturally vegetated area in the country. The average annual biomass production is considered an average figure for all the countries due to the variety in the state of regions from total degradation to sparsely vegetated areas [43
]. With the amount of biomass produced, the energy that can potentially be generated is computed using 20 GJ/tonne of energy production from dry biomass [44
]. To analyze the potential number of people that can be adequately supplied with energy from this source, we used the per capita annual consumption in Sub-Saharan Africa of about 28.76 GJ.
3.5. Estimation of the Potential of Crop Residues to Boost Energy Supply in Africa
To estimate the energy potential of crop residues, we assembled data from [39
] on the production quantity of various crops within Africa. The top 19 crops with an annual average production quantity above 1,000,000 tonnes were chosen in the years 2013–2018. The annual average production quantity is then used to compute the average residue amounts for each crop with the crop to residue ratio (CRR). We collated CRR values from various literature sources. Once the residue amounts were obtained, we used these values to compute the potential energy that can be generated from these crops annually with the energy content of each crop. The energy content of the crops was also derived from various literature sources as presented in the later sections of this paper (Table 4). We assume that all crop residues can generate energy without any further processing. For each crop, the potential energy generated is used to compute the number of people it can adequately supply with energy with the average annual per capita consumption of 28.76 GJ.
Sub-Saharan Africa, despite its deteriorating state of ecosystems, is still highly dependent on biomass for energy generation for domestic consumption. Around 87% of the continent’s energy supply is directly ecosystem dependent. In 2016 alone, the continent generated about 2917 billion kWh of energy from firewood, charcoal, and hydropower.
Nevertheless, with proper technical and policy support, ecosystem-based energy production holds great potential. The total energy generation potential from ecosystem-based energy sources is 27 billion GJ (restoring of degraded forest and savannah), 22.80 billion GJ (restoring of sparsely vegetated areas), 11.44 billion GJ (promotion of agroforestry in degraded farm areas), and 10.50 billion GJ (use of main crop residues for energy). This indicates the substantial potential restoration has for fulfilling the energy needs of the continent for domestic use at least. Investing in such interventions will not only secure energy for population but also sustainably enhance the supply of ecosystem services that are crucial for human survival. At an implementation level of 50% (i.e., if the continent commits to invest in 50% of the potential identified), Sub-Saharan Africa can supply energy to its population even if technologies with low biomass to energy conversion potentials are used. Restoring ecosystems while generating sufficient bioenergy has the potential to drive a transition from the current extractive mode to regenerative approach. Achieving this would reduce rates of forest and woodland losses from clearing and selective logging. The regenerative aspect of these energy supply options is also that at any point in time there is no full harvest of the main stock but rather the bioenergy supply depends on the mean annual increments of the restored ecosystems.
This study looked at continental scale of energy issues. It is undoubtedly necessary to contextualize the options proposed to suit local country or field level contexts to achieve the best outcome. It is also important to note that estimates of areas available for ecosystem-based bioenergy supply are broadly optimistic, relying largely on previous studies. Under local conditions, what may seem to be degraded pastureland may be providing critical ecosystem services that the local community may not want to forgo to increase woody biomass production for use as energy. In summary, the estimates are based on best available material but may not be so precise. Despite such assumptions and limitations, this study should ignite the discourse on why it is crucial to look at energy issues as a multisectoral issue and as a potential driver of a regenerative economy. The indicated pathways in the study provide national governments with the win-win scenarios to directly fulfill global targets on sustainable development goals (SDG) such as SDG 7 (affordable energy), SDG 13 (climate action) and SDG 15 (life on land).