The Feasibility of a 100% Renewable Electricity Mix before 2040
Abstract
According to Diesendorf and Elliston (2008), energy sector has always been regarded as “the largest contributor to global greenhouse emissions “at about “35% of total emissions” (p.318). Experts have warned that continued increase in carbon emission will lead to a rise in global temperatures and adverse effects of climate change will be inevitable. This study evaluates various literature material on the feasibility of achieving a 100 % renewable electricity mix by 2040. This review also discusses the global state of renewable energy in multiple regions such as Australia, Europe, Australia, New Zealand, USA, and the Middle East. Renewable energy is analyses through parameters such as power generation, storage and grid balancing, costs of renewable energy, environmental impact and social acceptance. From the literature, a realization of 100 % renewable energy mix is possible, however, various challenges in terms of costs, social and environmental aspects will be experienced. The overall advantage of the renewable energy mix will be eliminating greenhouse emissions, limiting climate change, improved energy efficiency and attainment of sustainable development.
Introduction
The increase in global warming has been attributed to high carbon emissions emanating from overreliance on fossil fuel use in the energy sector (Elliston, Diesendorf, & MacGill, 2012, p.606). For instance, 75.5 % of electricity generated globally comes from non-renewable sources such as coal which emits a lot of greenhouse gases (Seck, Krakowski, Assoumou, Maizi, & Mazauric, 2020, pp.2-3). In order to achieve sustainable development, there is a need for a transition towards renewable energy sources. According to Kiwan and Al-Gharibeh (2019), such “environmental concerns besides securing an” affordable energy supply has forced “many countries to seek for more sustainable energy resources, such as renewable energy” (p.423). For instance, in 2015 Paris agreement, Australia was among other countries whose leaders pledged to reduce carbon emissions by 80% before 2050 and a complete phase-out of fossil fuel use by the end of 21st century (Hansen, Mathiesen, & Skov, 2019, p.1; Elliston, MacGill, & Diesendorf, 2014, p.196; Lenzen et al., 2016, p.553; ). Moreover, the US, China, and European countries have formulated policies to increase the share of renewable energy in power generation to tackle “resource scarcity, fossil-energy dependency, and environmental issues” (Lund & Mathiesen, 2009, p.524; Seck et al., 2020, p.1). Don't use plagiarised sources.Get your custom essay just from $11/page
Power generation
Seck et al. (2020) claim that renewable energy sources only account for 24.5 % of electricity generated globally as shown in figure 1 below (pp.2-3).
Fig. 1: Estimated Renewable Energy Share of Global electricity production in 2016 (
This percentage share of renewable energy is below the target for many countries striving to achieve sustainable development goals. However, with many nations putting in place policies and systems to try and improve their renewable energy share, several studies simulating and modeling future renewable energy feasibility were analyzed based on various parameters such as power generation, storage, grid balancing, cost, and environmental impacts. Despite some nations registering a slight decline in demand, all the studies assumed that the future demand for electricity is expected to rise due rapid globalization and increase in economic activities, hence, the need for harnessing more energy from renewable sources and consolidating it to power grid systems (Hansen et al., 2019, pp.2-3; Elliston, MacGill, & Diesendorf, 2013, p.272; Heard, Brook, Wigley, & Bradshaw, 2017, pp.1123-1124).
To begin with both solar and wind power generation, the modeling assessed photovoltaic utilities, concentrated solar thermals, and wind power systems. Australia is one of the coal-reliant countries, the studies indicate that it aims at achieving 23 % of the renewable energy target of the 2020 power generation (Lenzen et al., 2016, p.5540. These studies show further that Australia needs about 100GW power generation capacity from both solar and wind power to provide 100% renewable energy that is reliable for Australia (Lenzen et al., 2016, p.554). In Denmark, wind power accounts for 20 % of the generated power (Lund & Mathiesen, 2009, p.524). Moreover, the models for Jordan in the Middle East, indicates that the country needs about “10.6 GW of concentrated solar power, 4.5 GW of wind, and 25GW of photovoltaic” to achieve 100% renewable electricity demands in future around the year 2050 (Kiwan & Al-Gharibeh, 2019, p.423). In their model Hansen et.al (2019) assumes that Germany has a capacity generation of about 250 GW onshore and 65 GW offshore wind power and 350 GW solar power potential (3). A study for New Zealand projects a 22-25% wind power generation potential (Mason, Page, & Williamson, 2010, p.3973).
The second renewable energy source assessed by various models is hydro-electric power. Most models indicate relatively little changes in hydropower as most water resources have already been utilized. For instance, Hansen et al. (2019), states that the “Hydropower potentials” in Germany were “assumed to be constant between 2015 and 2050 as the majority of these potential are already utilized (3). Currently, France has a capacity of 12.1 % of hydropower supply and the models assume little increase to the capacity may be achieved in the future (Seck et al., 2020, p.2). Also, Rasmussen, Andresen, & Greiner (2012) states that the future growth of hydropower systems in Europe is limited (p.643). New Zealand power generation currently is dominated by hydro-electric at 60 %, fossil fuel at 32 %, and the remaining percent comprises other sources ( Mason et al., 2010, p.3973). According to Elliston et al. (2013), the model for achieving 100% renewable electricity in New Zealand was simulated by “eliminating the residual share of energy supplied by fossil fuels” while raising wind and solar supplies (p.272).
Lastly, other renewable sources include geothermal, nuclear and biomass. Several models for nuclear energy indicate that most countries will reduce nuclear power generation capacity by 2050 due to difficulties in the disposal of harmful nuclear waste. In France, nuclear power supplies about 72.5% of the total electricity generated as of the year 2016 (Seck et al., 2020, p.2). In order to reduce such a huge capacity, the models suggest that a more reliable mix of renewable energy must replace it. The model analyzed for Germany’s 100% renewable energy strategy, shows that nuclear power systems will have been decommissioned by 2050 (Hansen et al., 2019, p.2). Furthermore, the models show that geothermal power potential has not been exploited fully globally. In New Zealand, the model projects a potential geothermal power generation of about 12-14% by 2050 (Mason et al., 2010, p.3973). Nevertheless, biomass is also a renewable energy source that is being utilized by various nations for power generation. For instance, Germany has a biomass capacity ranging between 250-450 TWh per year (Hansen et al., 2019, p.3)
From the above analysis of various models reviewed, it is clear that there is potential in harnessing renewable energy and increase power generation from these sources. The only challenge facing renewable sources is that wind and solar resources have high variability which makes power generation less reliable and unpredictable (Lenzen et al., 2016, p.553; Seck et al. 2020, p.2; Elliston et al., 2012, p.607 ). Moreover, the models highlight some concerns on the effects of harsh climate conditions like winter on-peak power generation in some parts of the world (Elliston et al. 2014, p.199). Therefore, for weather-driven technologies, the models suggest the utilization of simulated generators that use metrological observations to estimate power generation (Elliston et al., 2014, p.199)
Storage and grid balancing
Rasmussen at al. (2012) argue that a “fully renewable pan-European power system” will solely depend on a large share of weather-dependent energy sources such as solar and wind energy (p.642). Their sentiments are supported by Seck et al. (2020) who claim that “renewable energy sources are dominated by variable” weather-driven “renewable energy” have “high variability and lower predictability,” hence, may jeopardize power system reliability (p.2). The storage and balancing of resources play a vital role in determining the necessary amount and optimal ratio between solar and wind power. The models for storage resources had assumptions that include “storage charge and discharge capabilities” as well as “economic aspects” were ignored (Rasmussen et al., 2012, p.642). The models indicate that 6-h storage that incorporates different storage and “time-shift technologies” such as “pumped hydro, compressed air,” may be used in the grid. Out of these storages, pumped hydro storage has been identified as the least costlier storage method (Blakers, Stocks M., Lu, Cheng, & Stocks R., 2019, p.1828). In addition, other models regarded hydrogen storage in underground caverns as the cheapest storage (Alexander, James, & Richardson, 2014, p.2).
On the other hand, balancing an electricity grid system with a variable photovoltaic and wind power of 30-100% involves proper interconnections of high voltage transmission lines over a large geographic area that smooth out demand management, energy storage, and local weather variability (Blakers et al., 2019, p.1829). The advantage of continental-scale transmission for grid balancing ensures fewer effects of local weather and demand changes as well as it reduces the required storage capacity (Balakers et al., 2019, p.1829)
The cost of renewable electricity
It is important to factor in the cost of harnessing renewable sources, since, the existence of potential costs may pose a challenge for transitioning from “fossil fuel dominated energy systems” to renewable energy in the future (Elliston et al., 2012, p.607). While simulating costs, the models should calculate the total cost of the renewable energy system in a year (Elliston et al., 2014, p.199). Moreover, the reviewed models suggest that each generator should be assigned “capital costs, fixed operation and maintenance,” and “variable costs” for each year (Elliston et al., 2014, p.199). The models also factored in costs incurred for over a wide geographical area, types of generating technologies, location, and transmission capability costs (Elliston et al., 2013, p.280). From the simulated cost of mixed sources in Australia, Elliston et al. (2013) observed that wind power registered the lowest cost followed by “photovoltaic and dispatchable generations like CST, hydro and gas turbines” respectively (p.270). In addition, a comparative cost analysis of these models show that the annual cost of a 100% renewable electricity would be cheaper than costs incurred for replacing “fossil fuel power stations” with “modern fossil substitutes” (Blakers et al., 2019, 1828; Elliston et al., 2013, p.270). Therefore, models of cost give a clear picture of the feasibility of renewable energy sources by 2040 in which conventional systems can not meet sustainable development goals of reduced emissions and efficient power sources.
Despite renewable energy promising an overall reduction in costs of the system, Heard et al. (2017) observed that there are economical losses facing solar photovoltaic systems beyond operational knowledge (pp.1129-1130). For instance, in Germany, despite having the “highest penetration of photovoltaic systems” in the world, the grid is overloaded thus requiring additional solutions such as grid reinforcement, storage, power curtailment, and advance inverters which are costlier (p.1130). On the contrary, Blakers et al. (2019) term such views as pessimistic because over the years there has been a rapid reduction in costs and faster deployment of both wind and photovoltaic systems globally (p.1828)
Environmental impact and social acceptance
Heard et al. (2017) allude that the only “effective response to climate change is the replacement of fossil carbon fuel sources (p.1122). Most models reviewed regarding renewable energy sources are the only resources with a positive environmental impact. In his study, Sovacool (2013) claims that Denmark is the “most energy secure and sustainable country in the Organization of Economic Cooperation and Development (OECD) as shown in figure 2 (p.829). They go further to state that “Denmark leads the world in both the per capita use of wind electricity as well as the share of wind electricity as a percentage of national supply” (p.830)
Fig.2: “Energy security performance among 22 OECD countries from 1970-2007” (S0vacool, 2013, p.831)
Based on Denmark’s energy plan, there are several social, economic and environmental benefits realized. Sovacool (2013) points out that Denmark’s energy strategy helped in the reduction of greenhouse gases emissions, for instance, the renewable energy sources replaced less efficient fossil fuel sources leading to a reduction of carbon emission from 1kg to 600g per kWh electricity generated between 1990 and 2005 (p.834). On the other hand, Australia National Energy Market (NEM) still relies on highly emissive energy sources such as coal plants. The electricity sector in Australia has been identified as the largest source of emission contributing about one-third of the total greenhouse gas (190 megatons) emitted per year (Elliston et al., 2013, p.270). Such high emissions have led to global warming and climate change. Therefore, shifting from fossil fuel use to renewable energy sources has positive impacts on the environment as Heard et al. (2017) state that this will lead to 2o C drop in global temperature by 2050 (p.1122).
However, some of these renewable sources are raising concerns on social acceptance. In Denmark, there is social opposition and protests against large wind turbines. Despite Danish people having positive attitudes toward wind power than other nations, Sovacool (2013) argues that many groups of people are opposing due to obstruction of environmental viewscapes, excluding locals from participating in it (p.836). Moreover, Heard et al. (2017) argue that the maximal exploitation of biomass and hydroelectricity in developing countries may threaten social justice, social cohesion, and environmental sustainability (p.1130). Blakers et al. (2019) support this observation by stating that more often social and environmental opposition from local communities encounters the construction of new hydroelectric projects (p.1829). Despite some opposition to some types of renewable sources such as hydro, Winter and Ericson (2012) allude that the general perception of renewable energy among people in the USA and European countries is good as most of them expressed positive interests, attitudes, and willing to pay for renewable energy(p.2).
Renewable electricity mix
Based on the above evaluation and analysis of renewable energy sources, the achievement of a 100% renewable electricity mix by 2040 is viable. This should comprise of dispatchable resources and non-dispatchable resources. On one hand, the dispatchable resources which supply power for the baseload demand of electricity include hydropower, geothermal and biomass. All these types of dispatchable resources have advantages and disadvantages. The hydropower is considered the cheapest, however, future expansion of hydropower is limited due to resources that have been utilized globally (Blakers et al. ,2019, p.1828). Moreover, climate change and fluctuating weather patterns have affected the rainfall amount and consequently power generation from hydro systems (Blakers et al. ,2019, p.1828). At the moment, the potential of hydropower is around “616,000 promising sites” with a “storage capacity of 23 million GWh,” but exploiting further these resources is expected to encounter social opposition (Blakers et al. ,2019, p.1828). Biomass can also be deployed as the dispatchable source, however, Mathiesen et al. (2014) argue that “biomass is a limited resource” and cannot be used to replace fossil fuels (p.140). Geothermal energy is another potential resource, however, it is limited to given locations hence its exploitation is constrained (Droege, 2009, p.19).
On the other hand, non-dispatchable resources which comprise of solar photovoltaic, wind power and concentrated solar thermals can be used to power intermittent load. These energy sources are readily available around the world, but, the only disadvantage of these sources is weather-driven hence have high variability characteristics (Droege, 2009, p.211). Moreover, a study done by Blakers et al. (2019) shows that wind and solar photovoltaic have global capacity potential additions of about 60% (p.1828)In addition, storage and balancing resources are required to ensure energy security, reliability, and stability of this energy mix. Mathiesen et. al. suggest the use of large-scale electricity storage technologies which include “pumped hydroelectric energy storage (PHES) and compressed air energy storage (CAES) for implementation (p.142). Despite both the storage resources offering power storage greater than 100MW, they have low energy efficiency at 85% and 65 % respectively (Mathiesen et al. 142).
Therefore, from the reviewed models, the feasibility of 100% renewable energy mix combining energy sources such as “solar, wind, hydro, biomass and geothermal resources” is viable for the achievement of sustainable development goals in the future (Bogdanov & Breyer, 2016, p.1).
Discussion and conclusions
To conclude, Lund and Mathiesen (2009) assert that three technological changes are involved in designing a “100% renewable energy system” that is energy saving on the consumer side, efficiency energy generation and replacing fossil fuels with renewable energy (p.524). The literature reviewed in this paper indicates transitioning to renewable energy is possible since therein still potential in various renewable resources that have not been fully exploited. The impending barriers to the realization of 100% renewable electricity by 2040 are the existence of costs for transitioning from fossil plants to renewable sources. However, over time gradual improvement in technology has caused a reduction in costs of most photovoltaic and wind systems. Other challenges include environmental, social opposition, and efficiency of technology in generating and storage of power (Hansen et al. p.3). This paper asserts that the future of sustainable energy development lies in renewable energy resources such as photovoltaic, hydro, wind and geothermal power. The paper recommends further research and improvement in technology of energy storage, solar, wind and geothermal sources for improved efficiency in energy generation and storage.
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