The debate over the feasibility of 100% renewable energy systems is heating up, with a number of papers, reports and surveys emerging in the last few weeks with divergent takes on the matter.
A United Nations-backed survey of renewable energy experts from academia, industry, government and green NGOs found that 70 percent feel that a completely renewable global energy system is achievable by mid-century. The poll, performed by the Renewable Energy Policy Network for the 21st Century (REN21), did however note that in some regions, especially Africa, the United States (US) and Japan, experts were more sceptical—their doubt being driven by the vested interests of the fossil fuel sector, plus the absence of a stable renewables investment structure in most countries.
Separately, a new report out from Clean Energy Canada this week argues the plummeting price of renewable energy will make a fossil-free era inevitable, regardless of the efforts of US President Trump to reverse US climate and energy policies. The generation cost for large-scale solar photovoltaic energy is expected to decline by 57 percent by 2025, the report says, with the price of onshore and offshore wind energy to also enjoy substantial declines by then; 26 percent and 35 percent respectively.
Each year since 2012, more renewable energy capacity has come online than from fossil fuels, and solar in particular had a record-breaking year last year, adding some 73 GW of new capacity—nearly half all the new renewable capacity added, while wind had its second best year ever. Competitive auctions for contracts to build new renewable energy projects are pushing prices down to record levels that are increasingly undercutting their fossil fuel rivals, the report continues.
It is not all good news however. Canadian investment in renewable energy dropped in 2016, reflecting a wider global trend. Earlier that year, analysis from Bloomberg New Energy Finance had found that global investment in renewables had declined 18 percent on 2015. The main reason for the tumble was something of a pause in China and, secondarily, in Japan, both of which are currently focused on better integrating their large investments in intermittent renewables into their electricity grids.
Meanwhile a freshly published systematic review of multiple studies that show that 100 percent renewable systems are possible, found that all such articles published to date are deficient in key areas. Specifically, the review found they lack realistic projections of the electricity demand required for deep decarbonisation or offer insufficient detail about system reliability, as well as the requirements of enhanced transmission in high-renewable-penetration systems, or what are known as ancillary services. These support services include voltage and frequency control, reserves used to maintain reliability when there is an unexpected imbalance between supply and demand, and the ability to ‘reboot’ the system in case of a blackout.
As noted in an explainer article in the US online publication Vox on the sometimes-prickly debate, the dispute over the feasibility of “100 percent renewable energy” revolves around a simple fact: The most abundant sources of carbon-free power, wind and sun, are variable. Therefore the question lies in how to best fill those gaps.
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