A coal mine in Wyoming, United States. Coal, produced over millions of years, is a finite and non-renewable resource on a human time scale.
A non-renewable resource (also called a finite resource)
is a resource of economic value that cannot be readily replaced by
natural means at a quick enough pace to keep up with consumption. An
example is carbon-based fossil fuel. The original organic matter, with
the aid of heat and pressure, becomes a fuel such as oil or gas. Earthminerals and metalores, fossil fuels (coal, petroleum, natural gas) and groundwater in certain aquifers are all considered non-renewable resources, though individual elements are always conserved (except in nuclear reactions).
Conversely, resources such as timber (when harvested sustainably) and wind (used to power energy conversion systems) are considered renewable resources, largely because their localized replenishment can occur within time frames meaningful to humans as well.
Earth minerals and metal ores
Earth minerals and metal ores are examples of non-renewable resources. The metals themselves are present in vast amounts in Earth's crust, and their extraction by humans only occurs where they are concentrated by natural geological processes
(such as heat, pressure, organic activity, weathering and other
processes) enough to become economically viable to extract. These
processes generally take from tens of thousands to millions of years,
through plate tectonics, tectonic subsidence and crustal recycling.
The localized deposits of metal ores near the surface which can
be extracted economically by humans are non-renewable in human
time-frames. There are certain rare earth minerals and elements that are more scarce and exhaustible than others. These are in high demand in manufacturing, particularly for the electronics industry.
Fossil fuels
Natural resources such as coal, petroleum (crude oil) and natural gas
take thousands of years to form naturally and cannot be replaced as
fast as they are being consumed. Eventually it is considered that
fossil-based resources will become too costly to harvest and humanity
will need to shift its reliance to other sources of energy such as solar
or wind power, see renewable energy.
An alternative hypothesis is that carbon based fuel is virtually
inexhaustible in human terms, if one includes all sources of
carbon-based energy such as methane hydrates on the sea floor, which are
vastly greater than all other carbon based fossil fuel resources
combined.
These sources of carbon are also considered non-renewable, although
their rate of formation/replenishment on the sea floor is not known.
However their extraction at economically viable costs and rates has yet
to be determined.
At present, the main energy source used by humans is non-renewable fossil fuels. Since the dawn of internal combustion engine
technologies in the 19th century, petroleum and other fossil fuels have
remained in continual demand. As a result, conventional infrastructure and transport
systems, which are fitted to combustion engines, remain prominent
throughout the globe. The continual use of fossil fuels is known to
contribute to global warming and cause more severe climate change.
Nuclear fuels
Rössing uranium mine is the longest-running and one of the largest open pit uranium mines in the world, in 2005 it produced eight percent of global uranium oxide needs(3,711 tons). The most productive mines however are the underground McArthur River uranium mine in Canada which produces 13% of the world's uranium, and the similarly underground poly-metallic Olympic Dam mine in Australia, which despite being largely a copper mine, contains the largest known reserve of uranium ore.
Annual release of "technologically enhanced"/concentrated Naturally occurring radioactive material, uranium and thoriumradioisotopes naturally found in coal and concentrated in heavy/bottom coal ash and airborne fly ash. As predicted by ORNL
to cumulatively amount to 2.9 million tons over the 1937-2040 period,
from the combustion of an estimated 637 billion tons of coal worldwide. This 2.9 million tons of actinide fuel, a resource derived from coal ash, would be classified as low grade uranium ore if it occurred naturally.
In 1987, the World Commission on Environment and Development (WCED) an organization set up by but independent from the United Nations classified fission reactors that produce more fissile nuclear fuel than they consume -i.e. breeder reactors, and when it is developed, fusion power, among conventional renewable energy sources, such as solar and falling water. The American Petroleum Institute likewise does not consider conventional nuclear fission as renewable, but that breeder reactor nuclear power fuel is considered renewable and sustainable, before explaining that radioactive waste from used spent fuel rods remains radioactive, and so has to be very carefully stored for up to a thousand years.
With the careful monitoring of radioactive waste products also being
required upon the use of other renewable energy sources, such as geothermal energy.
As of 2013 only a few kilograms (picture available) of uranium have been extracted from the ocean in pilot programs
and it is also believed that the uranium extracted on an industrial
scale from the seawater would constantly be replenished from uranium leached from the ocean floor, maintaining the seawater concentration at a stable level. In 2014, with the advances made in the efficiency of seawater uranium extraction, a paper in the journal of Marine Science & Engineering suggests that with, light water reactors as its target, the process would be economically competitive if implemented on a large scale.
Nuclear power provides about 6% of the world's energy and 13–14% of the world's electricity. Nuclear energy production is associated with potentially dangerous radioactive contamination as it relies upon unstable elements. In particular, nuclear power facilities produce about 200,000 metric tons of low and intermediate level waste (LILW) and 10,000 metric tons of high level waste (HLW) (including spent fuel designated as waste) each year worldwide.
Issues entirely separate from the question of the sustainability
of nuclear fuel, relate to the use of nuclear fuel and the high-level
radioactive waste the nuclear industry generates that if not properly
contained, is highly hazardous to people and wildlife. The United Nations (UNSCEAR) estimated in 2008 that average annual human radiation exposure includes 0.01 millisievert (mSv) from the legacy of past atmospheric nuclear testing plus the Chernobyl disaster and the nuclear fuel cycle, along with 2.0 mSv from natural radioisotopes and 0.4 mSv from cosmic rays; all exposures vary by location. natural uranium in some inefficient reactor nuclear fuel cycles, becomes part of the nuclear waste "once through"
stream, and in a similar manner to the scenario were this uranium
remained naturally in the ground, this uranium emits various forms of
radiation in a decay chain that has a half-life of about 4.5 billion years, the storage of this unused uranium and the accompanying fission reaction products have raised public concerns about risks of leaks and containment, however the knowledge gained from studying the Natural nuclear fission reactor in Oklo Gabon,
has informed geologists on the proven processes that kept the waste
from this 2 billion year old natural nuclear reactor that operated for
hundreds of thousands of years.
Renewable resources
The Three Gorges Dam, the largest renewable energy generating station in the world.
The production of goods and services by manufacturingproducts in economic systems creates many types of waste during production and after the consumer has made use of it. The material is then either incinerated, buried in a landfill or recycled for reuse. Recycling turns materials of value that would otherwise become waste into valuable resources again.
Satellite
map showing areas flooded by the Three Gorges reservoir. Compare 7
November 2006 (above) with 17 April 1987 (below). The energy station
required the flooding of archaeological and cultural sites and displaced some 1.3 million people, and is causing significant ecological changes, including an increased risk of landslides. The dam has been a controversial topic both domestically and abroad.
In the natural environment water, forests, plants and animals are all renewable resources, as long as they are adequately monitored, protected and conserved. Sustainable agriculture is the cultivation of plant and animal materials in a manner that preserves plant and animal ecosystems and that can improve soil health and soil fertility over the long term. The overfishing of the oceans is one example of where an industry practice or method can threaten an ecosystem, endanger species and possibly even determine whether or not a fishery is sustainable for use by humans. An unregulated industry practice or method can lead to a complete resource depletion.
The renewable energy from the sun, wind, wave, biomass and geothermal energies are based on renewable resources. Renewable resources such as the movement of water (hydropower, tidal power and wave power), wind and radiant energy from geothermal heat (used for geothermal power) and solar energy (used for solar power)
are practically infinite and cannot be depleted, unlike their
non-renewable counterparts, which are likely to run out if not used
sparingly.
The potential wave energy on coastlines can provide 1/5 of world
demand. Hydroelectric power can supply 1/3 of our total energy global
needs. Geothermal energy can provide 1.5 more times the energy we need.
There is enough wind to power the planet 30 times over, wind power could
power all of humanity's needs alone. Solar currently supplies only 0.1%
of our world energy needs, but there is enough out there to power
humanity's needs 4,000 times over, the entire global projected energy
demand by 2050.
Renewable energy and energy efficiency are no longer niche sectors
that are promoted only by governments and environmentalists. The
increasing levels of investment and that more of the capital is from
conventional financial actors, both suggest that sustainable energy has
become mainstream and the future of energy production, as non-renewable
resources decline. This is reinforced by climate change concerns, nuclear dangers and accumulating radioactive waste, high oil prices, peak oil and increasing government support for renewable energy. These factors are commercializing renewable energy,
enlarging the market and growing demand, the adoption of new products
to replace obsolete technology and the conversion of existing
infrastructure to a renewable standard.
Economic models
In economics, a non-renewable resource is defined as goods, where greater consumption today implies less consumption tomorrow.David Ricardo
in his early works analysed the pricing of exhaustible resources, where
he argued that the price of a mineral resource should increase over
time. He argued that the spot price is always determined by the mine
with the highest cost of extraction, and mine owners with lower
extraction costs benefit from a differential rent. The first model is
defined by Hotelling's rule, which is a 1931 economic model of non-renewable resource management by Harold Hotelling.
It shows that efficient exploitation of a nonrenewable and
nonaugmentable resource would, under otherwise stable conditions, lead
to a depletion of the resource. The rule states that this would lead to a net price or "Hotelling rent" for it that rose annually at a rate equal to the rate of interest, reflecting the increasing scarcity of the resources.
The Hartwick's rule provides an important result about the sustainability of welfare in an economy that uses non-renewable source.
Whether nuclear power should be considered as a form of renewable energy is an ongoing subject of debate. Statutory
definitions of renewable energy usually exclude many present nuclear
energy technologies, with the notable exception of the state of Utah.
Dictionary-sourced definitions of renewable energy technologies often
omit or explicitly exclude mention of nuclear energy sources, with an
exception made for the natural nuclear decay heat generated within the Earth/geothermal energy.
In 1987, the Brundtland Commission (WCED) classified fission reactors that produce more fissilenuclear fuel than they consume (breeder reactors, and if developed, fusion power) among conventional renewable energy sources, such as solar power and hydropower. The American Petroleum Institute likewise does not consider conventional nuclear fission as renewable, but that breeder reactor
nuclear fuel is considered renewable and sustainable, and while
conventional fission leads to waste streams that remain a concern for
millennia, the waste from efficiently burnt up spent fuel requires a more limited storage supervision period of about thousand years. The monitoring and storage of radioactive waste products is also required upon the use of other renewable energy sources, such as geothermal energy.
Renewable energy is derived from
natural processes that are replenished constantly. In its various forms,
it derives directly from the sun, or from heat generated deep within
the earth. Included in the definition is electricity and heat generated
from sunlight, wind, oceans, hydropower, biomass, geothermal resources, and biofuels and hydrogen derived from renewable resources.
Renewable energy resources exist over wide geographical areas, in
contrast to other energy sources, which are concentrated in a limited
number of countries.
In ISO 13602-1:2002, a renewable resource is defined as "a
natural resource for which the ratio of the creation of the natural
resource to the output of that resource from nature to the technosphere is equal to or greater than one".
Conventional fission, breeder reactors as renewable
Nuclear fission reactors are a natural energy phenomenon, having naturally formed on earth in times past, for example a natural nuclear fission reactor which ran for thousands of years in present-day Oklo Gabon was discovered in the 1970s. It ran for a few hundred thousand years, averaging 100 kW of thermal power during that time.
Conventional, human manufactured, nuclear fission power stations largely use uranium, a common metal found in seawater, and in rocks all over the world, as its primary source of fuel. Uranium-235 "burnt" in conventional reactors, without fuel recycling, is a non-renewable resource, and if used at present rates would eventually be exhausted.
A cutaway model of the 2nd most powerful presently operating fast breeder reactor in the world. The (BN-600), at 600 MW of nameplate capacity is equivalent in power output to a natural gas CCGT. It dispatches 560 MW to the Middle Uralspower grid. Construction of a second breeder reactor, the BN-800 reactor was completed in 2014.
This is also somewhat similar to the situation with a commonly classified renewable source, geothermal energy, a form of energy derived from the natural nuclear decay of the large, but nonetheless finite supply of uranium, thorium and potassium-40 present within the Earth's crust, and due to the nuclear decay process, this renewable energy source will also eventually run out of fuel. As too will the Sun, and be exhausted.
Nuclear fission involving breeder reactors, a reactor which breeds more fissile fuel than they consume and thereby has a breeding ratio for fissile fuel
higher than 1 thus has a stronger case for being considered a
renewable resource than conventional fission reactors. Breeder reactors
would constantly replenish the available supply of nuclear fuel by converting fertile materials, such as uranium-238 and thorium, into fissile isotopes of plutonium or uranium-233,
respectively. Fertile materials are also nonrenewable, but their supply
on Earth is extremely large, with a supply timeline greater than geothermal energy. In a closed nuclear fuel cycle utilizing breeder reactors, nuclear fuel could therefore be considered renewable.
In 1983, physicist Bernard Cohen claimed that fast breeder reactors, fueled exclusively by natural uranium extracted from seawater, could supply energy at least as long as the sun's expected remaining lifespan of five billion years.
This was based on calculations involving the geological cycles of
erosion, subduction, and uplift, leading to humans consuming half of the
total uranium in the Earth's crust at an annual usage rate of 6500
tonne/yr, which was enough to produce approximately 10 times the
world's 1983 electricity consumption,
and would reduce the concentration of uranium in the seas by 25%,
resulting in an increase in the price of uranium of less than 25%.
Proportions of the isotopes, U-238 (blue) and U-235 (red) found in natural uranium, versus grades that are enriched. light water reactors and the natural uranium capable CANDU
reactors, are primarily powered only by the U-235 component, failing to
extract much energy from U-238. While by contrast uranium breeder
reactors mostly use U-238/the primary constituent of natural uranium as
their fuel.
Advancements at Oak Ridge National Laboratory and the University of Alabama, as published in a 2012 issue of the American Chemical Society,
towards the extraction of uranium from seawater have focused on
increasing the biodegradability of the process and reducing the
projected cost of the metal if it was extracted from the sea on an
industrial scale. The researchers' improvements include using
electrospun Shrimp shell Chitin mats that are more effective at absorbing uranium when compared to the prior record setting Japanese method of using plastic amidoxime nets. As of 2013 only a few kilograms (picture available) of uranium have been extracted from the ocean in pilot programs
and it is also believed that the uranium extracted on an industrial
scale from the seawater would constantly be replenished from uranium leached from the ocean floor, maintaining the seawater concentration at a stable level. In 2014, with the advances made in the efficiency of seawater uranium extraction, a paper in the journal of Marine Science & Engineering suggests that with, light water reactors as its target, the process would be economically competitive if implemented on a large scale. In 2016 the global effort in the field of research was the subject of a special issue in the journal of Industrial & Engineering Chemistry Research.
Presently, as of 2014, only 2 breeder reactors are producing industrial quantities of electricity, the BN-600 and BN-800. The retired French Phénix reactor also demonstrated a greater than one breeding ratio and operated for ~30 years, producing power when Our Common Future was published in 1987.
While human sustained nuclear fusion is intended to be proven in the International thermonuclear experimental reactor between 2020 and 2030, and there are also efforts to create a pulsed fusion power reactor based on the inertial confinement principle.
Fusion fuel supply
If it is developed, Fusion power would provide more energy for a given weight of fuel than any fuel-consuming energy source currently in use, and the fuel itself (primarily deuterium) exists abundantly in the Earth's ocean: about 1 in 6500 hydrogen (H) atoms in seawater (H2O) is deuterium in the form of (semi-heavy water).
Although this may seem a low proportion (about 0.015%), because nuclear
fusion reactions are so much more energetic than chemical combustion
and seawater is easier to access and more plentiful than fossil fuels,
fusion could potentially supply the world's energy needs for millions of
years.
If
nuclear power were classified as renewable energy (or as low-carbon
energy), additional government support would be available in more
jurisdictions, and utilities could include nuclear power in their effort
to comply with Renewable portfolio standard (RES).
In 2009 the State of Utah passed the "Renewable Energy Development Act" which in part defined nuclear power as a form of renewable energy.
Construction of the Salt Tanks which provide efficient thermal energy storage so that output can be provided after the sun goes down, and output can be scheduled to meet demand requirements. The 280 MW Solana Generating Station
is designed to provide six hours of energy storage. This allows the
plant to generate about 38 percent of its rated capacity over the course
of a year.
Global public support for different energy sources (2011) based on a poll by Ipsos Global @dvisor
Comparing trends in worldwide energy use, the growth of renewable energy to 2015 is the green line
The endeavor to use 100% renewable energy for electricity, heating/cooling and transport is motivated by global warming, pollution and other environmental issues, as well as economic and energy security concerns. Shifting the total global primary energy supply to renewable sources requires a transition of the energy system. According to the Intergovernmental Panel on Climate Change there are few fundamental technological limits to integrating a portfolio of renewable energy technologies to meet most of total global energy demand. Renewable energy use has grown more quickly than even advocates anticipated. As of 2019, however, it needs to grow six times faster to limit global warming to 2 °C (3.6 °F).
100% renewable energy in a country is typically a more challenging goal than carbon neutrality. The latter is a climate mitigation target, politically decided by many countries, and may also be achieved by balancing the total carbon footprint of the country (not only emissions from energy and fuel) with carbon dioxide removal and carbon projects abroad.
In 2014, renewable sources such as wind, geothermal, solar, biomass,
and burnt waste provided 19% of the total energy consumed worldwide,
with roughly half of that coming from traditional use of biomass. The most important
sector is electricity with a renewable share of 22.8%, most of it
coming from hydropower with a share of 16.6%, followed by wind with
3.1%. As of 2018 according to REN21 transformation is picking up speed in the power sector, but urgent action is required in heating, cooling and transport.
There are many places around the world with grids that are run almost
exclusively on renewable energy. At the national level, at least 30
nations already have renewable energy contributing more than 20% of the
energy supply.
According to a review of the 181 peer-reviewed
papers on 100% renewable energy which were published until 2018, "[t]he
great majority of all publications highlights the technical feasibility
and economic viability of 100% RE systems." While there are still many
publications which focus on electricity only, there is a growing number
of papers that cover different energy sectors and sector-coupled,
integrated energy systems. This cross-sectoral, holistic approach is
seen as an important feature of 100% renewable energy systems and is
based on the assumption "that the best solutions can be found only if
one focuses on the synergies between the sectors" of the energy system
such as electricity, heat, transport or industry.
Professors S. Pacala and Robert H. Socolow of Princeton University have developed a series of "climate stabilization wedges" that can allow us to maintain our quality of life while avoiding catastrophic climate change, and "renewable energy sources," in aggregate, constitute the largest number of their "wedges."
Mark Z. Jacobson, professor of civil and environmental engineering at Stanford University and director of its Atmosphere and Energy program, says that producing all new energy with wind power, solar power, and hydropower by 2030 is feasible, and that existing energy supply arrangements could be replaced by 2050.
Barriers to implementing the renewable energy plan are seen to be
"primarily social and political, not technological or economic". Jacobson says that energy costs
today with a wind, solar, and water system should be similar to today's
energy costs from other optimally cost-effective strategies. The main obstacle against this scenario is the lack of political will. His conclusions have been disputed by other researchers. Jacobson published a response that disputed the piece point by point and claimed that the authors were motivated by allegiance to energy technologies that the 2015 paper excluded.
Similarly, in the United States, the independent National Research Council
has noted that "sufficient domestic renewable resources exist to allow
renewable electricity to play a significant role in future electricity
generation and thus help confront issues related to climate change, energy security,
and the escalation of energy costs ... Renewable energy is an
attractive option because renewable resources available in the United
States, taken collectively, can supply significantly greater amounts of
electricity than the total current or projected domestic demand."
The main barriers to the widespread implementation of large-scale
renewable energy and low-carbon energy strategies are political rather
than technological. According to the 2013 Post Carbon Pathways report, which reviewed many international studies, the key roadblocks are: climate change denial, the fossil fuels lobby, political inaction, unsustainable energy consumption, outdated energy infrastructure, and financial constraints.
History
Using 100% renewable energy was first suggested in a paper in Science
published in 1975 by Danish physicist Bent Sørensen, which was followed by several other proposals. In 1976 energy policy analyst Amory Lovins coined the term "soft energy path" to describe an alternative future where energy efficiency and appropriate renewable energy sources steadily replace a centralized energy system based on fossil and nuclear fuels.
In 1998 the first detailed analysis of scenarios with very high
shares of renewables were published. These were followed by the first
detailed 100% scenarios. In 2006 a PhD thesis was published by Czisch in
which it was shown that in a 100% renewable scenario energy supply
could match demand in every hour of the year in Europe and North Africa.
In the same year Danish Energy professor Henrik Lund published a first paper in which he addresses the optimal combination of renewables, which was followed by several other papers on the transition
to 100% renewable energy in Denmark. Since then Lund has been
publishing several papers on 100% renewable energy. After 2009
publications began to rise steeply, covering 100% scenarios for
countries in Europe, America, Australia and other parts of the world.
Even in the early 21st century it was extraordinary for
scientists and decision-makers to consider the concept of 100% renewable
electricity. However, renewable energy progress has been so rapid that
things have totally changed since then:
Solar photovoltaic
modules have dropped about 75 percent in price. Current scientific and
technological advances in the laboratory suggest that they will soon be
so cheap that the principal cost of going solar on residential and
commercial buildings will be installation. On-shore wind power is spreading over all continents and is economically competitive with fossil and nuclear power in several regions. Concentrated solar thermal power (CST) with thermal storage
has moved from the demonstration stage of maturity to the limited
commercial stage and still has the potential for further cost reductions
of about 50 percent.
Renewable energy use has grown much faster than even advocates had anticipated. Wind turbines generate 39
percent of Danish electricity, and Denmark has many biogas digesters
and waste-to-energy plants as well. Together, wind and biomass provide
44% of the electricity consumed by the country's six million
inhabitants. In 2010, Portugal's 10 million people produced more than
half their electricity from indigenous renewable energy resources.
Spain's 40 million inhabitants meet one-third of their electrical needs
from renewables.
Renewable energy has a history of strong public support. In America, for example, a 2013 Gallup survey
showed that two in three Americans want the U.S. to increase domestic
energy production using solar power (76%), wind power (71%), and natural
gas (65%). Far fewer want more petroleum production (46%) and more
nuclear power (37%). Least favored is coal, with about one in three
Americans favouring it.
REN21 says renewable energy already plays a significant role and there are many policy targets which aim to increase this:
At the national level, at least 30
nations around the world already have renewable energy contributing more
than 20% of energy supply. National renewable energy markets are
projected to continue to grow strongly in the coming decade and beyond,
and some 120 countries have various policy targets for longer-term
shares of renewable energy, including a binding 20% by 2020 target for
the European Union. Some countries have much higher long-term policy
targets of up to 100% renewables. Outside Europe, a diverse group of 20
or more other countries target renewable energy shares in the 2020–2030
time frame that range from 10% to 50%.
Nuclear power involves accident risks with substantial consequences (e.g., Fukushima nuclear disaster, Chernobyl disaster) and the expensive problem of safe long-term high-level radioactive waste management, and carbon capture and storage has rather limited safe storage potentials.
These constraints have also led to an interest in 100% renewable
energy. A well established body of academic literature has been written
over the past decade, evaluating scenarios for 100% renewable energy for various geographical areas. In recent years, more detailed analyses have emerged from government and industry sources. The incentive to use 100% renewable energy is created by global warming and ecological as well as economic concerns, post peak oil.
The first country to propose 100% renewable energy was Iceland, in 1998. Proposals have been made for Japan in 2003, and for Australia in 2011. Albania, Iceland, and Paraguay
obtain essentially all of their electricity from renewable sources
(Albania and Paraguay 100% from hydroelectricity, Iceland 72% hydro and
28% geothermal). Norway obtains nearly all of its electricity from renewable sources (97 percent from hydropower).
Iceland proposed using hydrogen for transportation and its fishing
fleet. Australia proposed biofuel for those elements of transportation
not easily converted to electricity. The road map for the United States, commitment by Denmark, and Vision 2050 for Europe set a 2050 timeline for converting to 100% renewable energy, later reduced to 2040 in 2011. Zero Carbon Britain 2030 proposes eliminating carbon emissions in Britain by 2030 by transitioning to renewable energy.
In 2015, Hawaii enacted a law that the Renewable Portfolio Standard
shall be 100 percent by 2045. This is often confused with renewable
energy. If electricity produced on the grid is 65 GWh from fossil fuel
and 35 GWh from renewable energy and rooftop off grid solar produces 80
GWh of renewable energy then the total renewable energy is 115 GWh and
the total electricity on the grid is 100 GWh. Then the RPS is 115
percent.
Cities like Paris and Strasbourg in France, planned to use 100% renewable energy by 2050.
It is estimated that the world will spend an extra $8 trillion
over the next 25 years to prolong the use of non-renewable resources, a
cost that would be eliminated by transitioning instead to 100% renewable
energy. Research that has been published in Energy Policy
suggests that converting the entire world to 100% renewable energy by
2050 is both possible and affordable, but requires political support. It would require building many more wind turbines and solar power systems but wouldn't utilize bioenergy. Other changes involve use of electric cars and the development of enhanced transmission grids and storage. As part of the Paris Agreement, countries periodically update their climate change targets for the future, by 2018 no G20 country had committed to a 100% renewable target.
Until 2018 there were 181 peer-reviewed papers on 100% renewable
energy. In the same year, 100% renewable energy was also mentioned in
the Special Report on Global Warming of 1.5 °C as a potential means to "expand the range of 1.5 °C pathways", if the findings can be corroborated.
Recent developments
The Fourth Revolution: Energy is a German documentary film
released in 2010. It shows the vision of a global society, which lives
in a world where the energy is produced 100% with renewable energies,
showing a complete reconstruction of the economy, to reach this goal. In
2011, Hermann Scheer wrote the book The Energy Imperative: 100 Percent Renewable Now, published by Routledge.
Reinventing Fire is a book by Amory Lovins released in October 2011. By combining reduced energy use with energy efficiency
gains, Lovins says that there will be a $5 trillion saving and a
faster-growing economy. This can all be done with the profitable
commercialization of existing energy-saving technologies, through market
forces, led by business. Former US president Bill Clinton says the book is a "wise, detailed and comprehensive blueprint". The first paragraph of the preface says:
Imagine fuel without fear. No
climate change. No oil spills, dead coal miners, dirty air, devastated
lands, lost wildlife. No energy poverty. No oil-fed wars, tyrannies, or
terrorists. Nothing to run out. Nothing to cut off. Nothing to worry
about. Just energy abundance, benign and affordable, for all, for ever.
The Intergovernmental Panel on Climate Change
has said that there are few fundamental technological limits to
integrating a portfolio of renewable energy technologies to meet most of
total global energy demand. In a 2011 review of 164 recent scenarios of
future renewable energy growth, the report noted that the majority
expected renewable sources to supply more than 17% of total energy by
2030, and 27% by 2050; the highest forecast projected 43% supplied by
renewables by 2030 and 77% by 2050.
In 2011, the International Energy Agency has said that solar energy
technologies, in its many forms, can make considerable contributions to
solving some of the most urgent problems the world now faces:
The development of affordable,
inexhaustible and clean solar energy technologies will have huge
longer-term benefits. It will increase countries' energy security
through reliance on an indigenous, inexhaustible and mostly
import-independent resource, enhance sustainability, reduce pollution,
lower the costs of mitigating climate change, and keep fossil fuel
prices lower than otherwise. These advantages are global. Hence the
additional costs of the incentives for early deployment should be
considered learning investments; they must be wisely spent and need to
be widely shared.
In 2011, the refereed journal Energy Policy published two articles by Mark Z. Jacobson, a professor of engineering at Stanford University,
and research scientist Mark A. Delucchi, about changing our energy
supply mix and "Providing all global energy with wind, water, and solar
power". The articles analyze the feasibility of providing worldwide
energy for electric power, transportation, and heating/cooling from
wind, water, and sunlight (WWS), which are safe clean options. In Part
I, Jacobson and Delucchi discuss WWS energy system characteristics,
aspects of energy demand, WWS resource availability, WWS devices needed,
and material requirements. They estimate that 3,800,000 5 MW wind turbines, 5350 100 MW geothermal power plants, and 270 new 1300 MW hydroelectric power plants will be required. In terms of solar power, an additional 49,000 300 MW concentrating solar plants, 40,000 300 MW solar photovoltaic
power plants, and 1.7 billion 3 kW rooftop photovoltaic systems will
also be needed. Such an extensive WWS infrastructure could decrease
world power demand by 30%.
In Part II, Jacobson and Delucchi address variability of supply,
system economics, and energy policy initiatives associated with a WWS
system. The authors advocate producing all new energy with WWS by 2030
and replacing existing energy supply arrangements by 2050. Barriers to
implementing the renewable energy plan are seen to be "primarily social
and political, not technological or economic". Energy costs with a WWS
system should be similar to today's energy costs.
In general, Jacobson has said wind, water and solar technologies can provide 100 percent of the world's energy, eliminating all fossil fuels. He advocates a "smart mix" of renewable energy sources to reliably meet electricity demand:
Because the wind blows during
stormy conditions when the sun does not shine and the sun often shines
on calm days with little wind, combining wind and solar can go a long
way toward meeting demand, especially when geothermal provides a steady
base and hydroelectric can be called on to fill in the gaps.
A 2012 study by the University of Delaware
for a 72 GW system considered 28 billion combinations of renewable
energy and storage and found the most cost-effective, for the PJM Interconnection, would use 17 GW of solar, 68 GW of offshore wind,
and 115 GW of onshore wind, although at times as much as three times
the demand would be provided. 0.1% of the time would require generation
from other sources.
In March 2012, Denmark's parliament agreed on a comprehensive new
set promotional programs for energy efficiency and renewable energy
that will lead to the country getting 100 percent of electricity, heat
and fuels from renewables by 2050.
IRENEC is an annual conference on 100% renewable energy started in 2011 by Eurosolar Turkey. The 2013 conference was in Istanbul.
More recently, Jacobson and his colleagues have developed
detailed proposals for switching to 100% renewable energy produced by
wind, water and sunlight, for New York, California and Washington states, by 2050. As of 2014,
a more expansive new plan for the 50 states has been drawn up, which
includes an online interactive map showing the renewable resource
potential of each of the 50 states. The 50-state plan is part of The Solutions Project, an independent outreach effort led by Jacobson, actor Mark Ruffalo, and film director Josh Fox.
As of 2014, many detailed assessments show that the energy
service needs of a world enjoying radically higher levels of wellbeing,
can be economically met entirely through the diverse currently available
technological and organisational innovations around wind, solar,
biomass, biofuel, hydro, ocean and geothermal energy. Debate over
detailed plans remain, but transformations in global energy services
based entirely around renewable energy are in principle technically
practicable, economically feasible, socially viable, and so realisable.
This prospect underpins the ambitious commitment by Germany, one of the
world's most successful industrial economies, to undertake a major energy transition, Energiewende.
In 2015 a study was published in Energy and Environmental Science
that describes a pathway to 100% renewable energy in the United States
by 2050 without using biomass. Implementation of this roadmap is
regarded as both environmentally and economically feasible and
reasonable, as by 2050 it would save about $600 Billion Dollars health costs a year due to reduced air pollution
and $3.3 Trillion global warming costs. This would translate in yearly
cost savings per head of around $8300 compared to a business as usual
pathway. According to that study, barriers that could hamper
implementation are neither technical nor economic but social and
political, as most people didn't know that benefits from such a
transformation far exceeded the costs.
In June 2017, twenty-one researchers published an article in the Proceedings of the National Academy of Sciences of the United States of America rejecting Jacobson's earlier PNAS article, accusing him of modeling errors and of using invalid modeling tools. They further asserted he made implausible assumptions through his reliance upon increasing national energy storage from 43 minutes to 7 weeks, increasing hydrogen production by 100,000%, and increasing hydropower by the equivalent of 600 Hoover Dams. Article authors David G. Victor called Jacobson's work "dangerous" and Ken Caldeira emphasized that increasing hydropower output by 1,300 gigawatts, a 25% increase, is the equivalent flow of 100 Mississippi Rivers.
Jacobson published a response in the same issue of the PNAS and also
authored a blog post where he asserted the researchers were advocates of
the fossil fuel industry.
Another study published in 2017 confirmed the earlier results for a
100% renewable power system for North America, without changes in
hydropower assumptions, but with more realistic emphasis on a balanced
storage portfolio, in particular seasonal storage, and for competitive
economics.
Grid integration simulation
In
2015, Jacobson and Delucchi, together with Mary Cameron and Bethany
Frew, examined with computer simulation (LOADMATCH), in more detail how a
wind-water-solar (WWS) system can track the energy demand from minute
to minute. This turned out to be possible in the United States for 6
years, including WWS variability by extreme weather events.
In 2017, the plan was further developed for 139 countries by a team of 27 researchers
and in 2018, Jacobson and Delucchi with Mary Cameron and Brian
Mathiesen published the LOADMATCH results for 20 regions in which the
139 countries in the world are divided. According to this research, a
WWS system can follow the demand in all regions.
The program LOADMATCH receives as input estimated series, per half minute during 2050-2055, of
the energy demand
the intermittent wind and solar energy supply predicted with a 3D global climate / weather model GATOR-GCMOM
the hydropower, geothermal, tidal and wave energy
and specifications of
the capacities and maximum loading / unloading speeds of the different types of storage
losses due to storage, transport, distribution and maintenance
The program has been carried out for each region 10-20 times with
adapted input for the storage capacities, until a solution was found in
which the energy demand was followed, per half minute for 5 years, with
low costs.
The WWS system is assumed to connect in the electric network
geographically dispersed variable energy sources, concentrated solar power (CSP) and hydro power
storage facilities: pumped hydro, as heat in CSP plants, in batteries, as hydrogen by electrolysis of water, or as compressed air underground.
Some places have high percentages, for example the electricity sector in Denmark, as of 2014, is 45% wind power, with plans in place to reach 85%. The electricity sector in Canada and the electricity sector in New Zealand have even higher percentages of renewables (mostly hydro), 65% and 75% respectively, and Austria is approaching 70%. As of 2015, the electricity sector in Germany sometimes meets almost 100% of the electricity demand with PV and wind power, and renewable electricity is over 25%.Albania has 94.8% of installed capacity as hydroelectric, 5.2% diesel generator; but Albania imports 39% of its electricity. In 2016, Portugal achieved 100% renewable electricity for four days between 7 May and 11 May, partly because efficient energy use had reduced electricity demand. France and Sweden have low carbon intensity, since they predominantly use a mixture of nuclear power and hydroelectricity.
Although electricity is currently a big fraction of primary
energy; it is to be expected that with renewable energy deployment
primary energy use will go down sharply as electricity use increases, as
it is likely to be combined with some degree of further
electrification. For example, electric cars achieve much better fuel efficiency than fossil fuel cars, and another example is renewable heat
such as in the case of Denmark which is proposing to move to greater
use of heat pumps for heating buildings which provide multiple kilowatts
of heat per kilowatt of electricity.
100% clean electricity
Other
electricity generating sources are considered clean, though not
necessarily renewable, as they also do not emit carbon dioxide or other
greenhouse gases. The largest of these is nuclear energy which produces
no emissions. Carbon capture and storage
projects may still use coal or natural gas but capture carbon dioxide
for storage or alternative uses. Pathways to eliminate greenhouse gases
may include these in addition to renewable energy so as to avoid
shutting down existing plants and allow for flexibility in designing a
carbon-free electric grid.
In 2018 California passed SB 100, which will mandate 100% clean,
carbon-free by 2045, including a 60% renewable electricity goal by 2030. 2019 legislation in Washington will also require 100% clean electricity by 2045, eliminating coal by 2025.
Further states and territories that will require 100% carbon-free
electricity are Hawaii, Maine, Nevada, New Mexico, New York, Puerto
Rico, and Washington, DC.
Obstacles
The most significant barriers to the widespread implementation of
large-scale renewable energy and low carbon energy strategies, at the
pace required to prevent runaway climate change, are primarily political and not technological. According to the 2013 Post Carbon Pathways report, which reviewed many international studies, the key roadblocks are:
NASA Climate scientist James Hansen discusses the problem with rapid phase out of fossil fuels
and said that while it is conceivable in places such as New Zealand and
Norway, "suggesting that renewables will let us phase rapidly off
fossil fuels in the United States, China, India, or the world as a whole
is almost the equivalent of believing in the Easter Bunny and Tooth Fairy."
In 2013, Smil analyzed proposals to depend on wind and solar-generated
electricity including the proposals of Jacobson and colleagues, and
writing in an issue of Spectrum prepared by the Institute of Electrical and Electronics Engineers, he identified numerous points of concern, such as cost, intermittent power supply, growing NIMBYism,
and a lack of infrastructure as negative factors and said that "History
and a consideration of the technical requirements show that the problem
is much greater than these advocates have supposed." Smil and Hansen are concerned about the variable output of solar and wind power, but American physicist Amory Lovins has said that the electricity grid can cope, just as it routinely backs up nonworking coal-fired and nuclear plants with working ones.
In 1999 American academic Dr. Gregory Unruh published a
dissertation identifying the systemic barriers to the adoption and
diffusion of renewable energy technologies. This theoretical framework
was called Carbon Lock-in
and pointed to the creation of self-reinforcing feedbacks that arise
through the co-evolution of large technological systems, like
electricity and transportation networks, with the social and political
institutions that support and benefit from system growth. Once
established, these techno-institutional complexes
become "locked-in" and resist efforts to transform them towards more
environmentally sustainable systems based on renewable sources.
Lester R. Brown founder and president of the Earth Policy Institute,
a nonprofit research organization based in Washington, D.C., says a
rapid transition to 100% renewable energy is both possible and
necessary. Brown compares with the U.S. entry into World War II and the
subsequent rapid mobilization and transformation of the US industry and
economy. A quick transition to 100% renewable energy and saving of our
civilization is proposed by Brown to follow an approach with similar
urgency.
The International Energy Agency says that there has been too much attention on issue of the variability of renewable electricity production. The issue of intermittent supply applies to popular renewable technologies, mainly wind power and solar photovoltaics,
and its significance depends on a range of factors which include the
market penetration of the renewables concerned, the balance of plant and
the wider connectivity of the system, as well as the demand side
flexibility. Variability will rarely be a barrier to increased renewable
energy deployment when dispatchable generation
such as hydroelectricity or solar thermal storage is also available.
But at high levels of market penetration it requires careful analysis
and management, and additional costs may be required for back-up or
system modification.
Renewable electricity supply in the 20-50+% penetration range has
already been implemented in several European systems, albeit in the
context of an integrated European grid system.
In 2011, the Intergovernmental Panel on Climate Change,
the world's leading climate researchers selected by the United Nations,
said "as infrastructure and energy systems develop, in spite of the
complexities, there are few, if any, fundamental technological limits to
integrating a portfolio of renewable energy technologies to meet a
majority share of total energy demand in locations where suitable
renewable resources exist or can be supplied". IPCC scenarios "generally indicate that growth in renewable energy will be widespread around the world".
The IPCC said that if governments were supportive, and the full
complement of renewable energy technologies were deployed, renewable
energy supply could account for almost 80% of the world's energy use
within forty years. Rajendra Pachauri,
chairman of the IPCC, said the necessary investment in renewables would
cost only about 1% of global GDP annually. This approach could contain
greenhouse gas levels to less than 450 parts per million, the safe level
beyond which climate change becomes catastrophic and irreversible.
In November 2014 the Intergovernmental Panel on Climate Change came out with their fifth report, saying that in the absence of any one technology (such as bioenergy, carbon dioxide capture and storage,
nuclear, wind and solar), climate change mitigation costs can increase
substantially depending on which technology is absent. For example, it
may cost 40% more to reduce carbon emissions without carbon dioxide
capture. (Table 3.2)
Google spent $30 million on their RE
Seasonal Energy Storage
Hydropower
is currently the only large scale low-carbon seasonal energy storage.
In countries with high variation in energy demand by season (for example
the UK uses far more gas for heating in the winter than it uses
electricity) but lacking hydropower electrical interconnectors to countries with lots of hydropower (e.g. UK - Norway) will probably be insufficient and development of a hydrogen economy will likely be needed: this is being trialled in the UK and 8 TWh of inter-seasonal hydrogen energy storage has been proposed.
In Australia as well as storing renewable energy as hydrogen it is also proposed to be exported in the form of ammonia.
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