A future where electricity comes mostly from low-carbon sources is not only feasible in terms of material demand, but will significantly reduce air pollution, it is claimed.
An international team led by Edgar Hertwich and Thomas Gibon from the Norwegian University of Science and Technology (NTNU) have conducted what is said to be the first-ever global comprehensive life cycle assessment of the long-term, wide-scale implementation of electricity generation from renewable resources.
The study has assembled and scaled up the assessment of individual technologies to the whole world and assessed technology implementation to 2050, taking the environmental impacts of production into account.
According to Hertwich, the NTNU-led researchers carried out the work because so little is known about the environmental costs of a widespread global shift to renewable energy technologies such as wind and solar power, and what the effect of this shift might have on material requirements.
“Would the shift to low-carbon energy systems increase or decrease other types of pollution?” the researchers asked.
Previous efforts to answer this question have typically looked at single issues, such as selected pollutants, or the effects on land use or need for raw materials, such as metals.
It is claimed that previous studies have also neglected to look at the interactions between different technologies, the researchers said.
To address these shortfalls, Hertwich and his colleagues developed an integrated hybrid life cycle assessment model.
An important aspect of the model was that “it allowed the integration of electricity produced by these prospective technologies back into the economic model,” according to Gibon.
The team looked at concentrating solar power, photovoltaics, wind power, hydropower, and gas- and coal-fired power plants with carbon capture and storage (CCS).
They also assumed that the efficiency of the production of important raw materials, such as aluminum, copper, nickel, iron and steel, for example, would improve over time.
Further, they employed two different energy scenarios developed by the International Energy Agency to assess how renewable energy would perform.
The first of these was the baseline scenario, in which global electricity production is assumed to increase by 134% between 2007 and 2050, and where fossil fuels maintain their high share in the electricity generation mix, accounting for two-thirds of the total.
Under this scenario, coal-based generation is 149% higher in 2050 than in 2007, accounting for 44% of all power generation.
The other was the “Blue” map scenario, which assumes that electricity demand in 2050 is 13% lower than in the baseline scenario because of increased energy efficiency, and that the power sector emits less pollutants from fossil fuels by reducing their use and adopting carbon capture and storage technologies, along with an increase in the use of renewable energies.
Low carbon technologies can demand much more use of raw materials per unit of power generation than conventional fossil fuel plants, the researchers noted. For example, photovoltaic systems need 11-40 times more copper than fossil fuel production, while wind power plants need 6-14 times more iron than fossil fuel production.
The researchers characterised these material demands from a broader perspective as “manageable but not negligible”.
For example, the amount of copper needed to build out photovoltaic systems by 2050 represents just two years of current copper production. The demand for iron and steel would increase by a mere 10%, while the demand for aluminum should decrease.
The shift across will also decrease air pollution and reduce fossil fuel extraction.
“Energy production-related climate change mitigation targets are achievable, given a slight increase in the demand for iron or cement, as two examples, and will reduce the current emission rates of air pollutants,” Gibon said.
The human health benefits are clear, Hertwich said. “Pursuing climate mitigation will limit the human health impacts from air pollution, while continuing with business as usual will increase it.”
Meanwhile, fossil fuel subsidies totalled $550billion last year – more than four-times those to renewables – and are holding back investment in efficiency and renewable energy, the International Energy Agency has warned.
Global subsidies to renewables reached $121billion last year, up 15% on 2012, and will increase to approximately $230billion in 2030 in the New Policies Scenario, before a lack of support for recently deployed capacity will likely cause a subsidies decrease to $205billion in 2040.
In its just published World Energy Outlook 2014 (WEO-2014), the Paris-headquartered IEA suggests that international primary energy demand is set to increase by 37% by 2040.
However, were it not for efficiency measures helping slow the growth of energy demand, pressure on the global energy system would be even higher.
WEO-2014 states that fossil fuels continue to dominate the power sector, although their share of power generation drops from 68% in 2012 to 55% in 2040, while the share of renewables in total production increases from 21% in 2012 to 33% in 2040.
The report suggests that by 2040, demand for gas will be more than 50% higher; coal demand will be 15% higher, but growth will have slowed to a near halt in the 2020s; and world oil demand will have slowed to a near halt.
Nuclear generation capacity will rise by 60% to 624GW in 2040. However, its share of global electricity generation, which peaked almost two decades ago, will rise by just 1% to 12%.
Environmental benefits.
The Global Renewable Fuels Alliance (GRFA) reacted to the report, saying that renewable fuels such as biofuels offer both environmental and economic benefits, but require the right policies to be endorsed by governments to increase their production and consumption.
GRFA spokesperson Bliss Baker said: “It seems counter-productive to subsidise the most profitable industry on Earth that contributes the majority of global greenhouse gas emissions, especially when biofuels are growing and are the only commercial alternative to transport fossil fuels.”
In the IEA central scenario, the entire carbon budget allowed under a 2C climate trajectory is consumed by 2040, which stresses the need for an ambitious agreement at the COP21 meeting in Paris in 2015.
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