Caveat: This is a more technical article than most written about climate change issues, personal and corporate sustainability. It’s worth reading but you have been forewarned.
Are Renewable Energy Sources Enough?
This article addresses the question of whether wind and solar energies are capable of satisfying the world’s energy consumption demands. The general scientific consensus (Czisch, 2006; Fthenakis et al., 2009; Trainer, 2012; Jacobson and Delucchi, 2011) suggests that global supply of energy from renewables can be realized but with lower consumption levels by wealthy nations and likely, non-continuous energy flow rates we have come to expect today. This article will discuss the following: a) which technologies make-up a renewable energy ‘solution’, b) total global energy consumption demands, c) capacity allocation of renewable energy sources to meet world demand, d) infrastructure requirements, and e) the challenges and realities of supplying the world’s energy demands predominantly by wind and solar.
The Triumvirate Renewables of Wind, Water and Solar
Wind and solar are considered two of the strongest, most prevalent renewable energy sources identified that can realistically supply the world’s energy demands; substituting out energy from fossil fuel sources such as oil, coal, and natural gas. It should be noted this paper includes in its discussion water renewable energy sources as a necessary component for satisfying world energy demands. Wind/water/solar (WWS) includes the following types of renewable energy sources and technologies: wind power, concentrated solar, geothermal, tidal, solar photovoltaic, wave, and hydroelectric power. Jacobson and Delucchi (2011) offer a detailed plan that feasibly argues wind, water and solar sources have the capability to power the world’s energy demands by 2030. For all these renewable energy sources, the technologies put out minimal to no greenhouse gases (GHGs) into the atmosphere, have relatively low negative impacts on land usage and species biodiversity, have reasonably containable waste-disposal streams, and are by all accounts, “indefinitely renewable or recyclable” resources (Jacobson and Delucchi, 2011). Water renewable energy sources are added to wind and solar as a balancing mechanism to the known intermittency concerns of wind and solar.
The Concern Over Energy Intermittency
The requirements of supplying the world’s energy demands are not insignificant. Three main factors must be addressed satisfactorily by wind/water/solar renewable energy sources including: meeting future global energy demands, accommodating all modes of energy use, and providing reliability and/or consistency of energy supply. The Energy Information Administration (EIA) states the global energy consumption today is approximately 12.5 trillion watts (TW) and is currently met with energy supplied from oil (35%), coal (27%), natural gas (23%), nuclear (6%) and the remaining nine percent from a combination of biomass, solar, wind and geothermal renewable energy sources (Jacobson and Delucchi, 2011). By 2030, the EIA estimates worldwide energy demand will near 17 TW in “end-use power” (Jacobson and Delucchi, 2011). The modes of energy use globally include the adequate ability to power transportation, heating and cooling, lighting, manufacturing, motors, electronics, and telecommunications (Jacobson and Delucchi, 2011). Lastly, fossil fuel inputs have provided humanity with steady, consistent, and highly reliable forms of energy. Wind/water/solar renewable energy sources must be assessed in how well their (combined) energy can provide electric power to the world “second-by-second, daily, seasonally, and yearly” – or consistently every single day and (assumed) night (Delucchi and Jacobson, 2011).
Filling the Intermittency Gap
Wind and solar, because of their relative abundance and availability across the globe, are assumed by Jacobson and Delucchi (2011) to comprise 90% of the world’s energy supply by 2030. However, because wind and solar can be quite variable and intermittent depending on a land masses’ latitude, seasonality, and/or time of day, it is expected that other wind/water/solar renewable energy sources, specifically, geothermal, tidal and hydroelectric, will ‘fill the energy gaps’ to keep wind/water/solar renewable energy supplies stable and constant (Jacobson and Delucchi, 2011). Specifically, hydroelectric would supply 4% of future world energy supply, geothermal (4%) and wave and tidal turbines would contribute the remaining 2% of global world energy (Jacobson and Delucchi, 2011).
Our Current and Future Reality Realized
In one future scenario suggested by Jacobson and Delucchi (2011), global energy demand by 2030 could be met with the following wind/water/solar renewable energy technology infrastructure in place:
|Wind/Water/Solar Energy Source|
|Global Infrastructure (# of units)|
|Energy Output |
|2030 Global Energy Supplied |
(% of Total)
|Wind turbines||3,800,000||5 Mega Watts (MW)||50%|
|Concentrated Solar power plants||49,000||300 MW||20%|
|Solar Photovoltaic power plants||40,000||300 MW||14%|
|Rooftop Photovoltaic systems||1,700,000||3 Kilo Watts||6%|
|Geothermal power plants||5,350||100 MW||4%|
|Hydroelectric power plants||900||1,300 MW||4%|
|Wave devices||720,000||0.75 MW||1%|
|Tidal turbines||490,000||1 MW||1%|
Note well: this proposed scenario does not rely on any future technology advancements to develop the necessary infrastructure capacity requirements for today. It also assesses material resource needs and acknowledges that although some rare materials currently used in the production of, for instance, solar photovoltaic technology, may have to be substituted in the future, material demands are viable at this point in time to realize this wind/water/solar renewable energy scenario by 2030.
Tackling Intermittency Issues and Building Distributed Energy Grids
The crux of this discussion on the viability of wind/water/solar renewable energy sources to realistically supply 100% of the world’s energy demands turns on putting in practice the currently, theoretical application of this argument. There is no doubt the potential energy supplied by wind and solar is great and could, theoretically, supply future global energy demands multiple times over, if harnessed efficiently. That said, significant solar, wind and water energy infrastructure would have to be built. The single greatest concern related to solar and wind renewable energy sources is their variability. Practically, solar and wind’s variation “does not match the demand pattern [globally, by continent or nation-state] over the same times scales” (Delucchi and Jacobson, 2011). These same authors (2011) propose several solutions, applied in-conjunction, to mitigate wind and solar intermittency issues. The six mitigating factors to smooth energy variabilities include: 1) interconnecting wind, solar and wave farms that are geographically disperse, 2) supplementing wind and solar with geothermal and hydroelectric sources, 3) using ‘smart’ demand-response management systems to direct high energy demands with high energy availability and vice versa, 4) storing excess energy for future demand, 5) building wind/water/solar infrastructure to provide the globe with ‘oversized’ capacity, and 6) forecasting weather systems better to more effectively plan energy demands (Delucchi and Jacobson, 2011).
The Necessity of Investment, Infrastructure and Local Micro-Grids to Power Economies
Trainer (2012) points out several flaws in Delucchi and Jacobson’s (2011) argument that 100% of the world’s energy demands can be realistically met with wind/water/solar energy sources. Trainer (2012) first argues wind and solar intermittency need to be assessed at their minimum occurrences (not average) to provide a more realistic assessment of power plant requirements. Second, peak (versus average) energy demand levels much be analyzed to correctly build the necessary redundant (two-to-three times) capacity required to smooth energy variability. Third, Delucchi and Jacobson (2011) fail to take into consideration embodied energy costs, excess capacity costs, and cost of capital to develop, maintain and renew wind/water/solar energy infrastructure every couple of decades (Trainer, 2012). Lastly, Trainer (2012) believes Delucchi and Jacobson (2011) severely underestimate the total annual global energy investment necessary; even at the estimate $5 trillion per annum, is 11 times greater than actual total global energy investment numbers ($450 billion) in the early 2000s.
Trainer (2012) is in agreement with Jacobson and Delucchi (2011) that global energy demands can satisfactorily be met with renewable energy sources. He suggests that world energy consumption levels, particularly for the richest nation-states, will have to drop significantly and that a renewable energy-driven world will more likely be localized with steady economies versus inter-connected globally powering growth-driven nation-state policies.
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Czisch, G., Giebel, G., 2007, Realisable Scenarios for a Future Electricity
Supply based 100% on Renewable Energies, unpublished manuscript, Retrieved from http://www.zonnekrachtcentrales.nl/assets/files/files/Gregor%20Czisch%20Realisable%20Scenario-s%20for%20a%20Furure%20Electricity%20Suppy%20%20based%20on%20Renewable%20Energies%20ris-r-1608_186-195.pdf
Delucchi, M.A., and Jacobson, M.Z., 2011, Providing all global energy with wind, water, and solar power, Part II: Reliability, system and transmission costs, and policies, Energy Policy, 39, p. 1170-1190.
Fthenakis, V., Mason, J.E., Zweibel, K., 2009, the technical, geographical, and economic feasibility of solar energy to supply the energy needs of the US, Energy Policy, 37, p. 387-399.
Jacobson, M.Z., and Delucchi, M.A., 2011, Providing all global energy with wind, water, and solar power, Part I: Technologies, energy resources, quantities and areas of infrastructure, and materials, Energy Policy, 39, p. 1154-1169.
Trainer, T., 2012, A critique of Jacobson and Delucchi’s proposals for a world renewable energy supply, Energy Policy, 44, p. 476-481.