Several regions across the world are already generating reliably, with 100 percent of their annual electricity coming from renewables.
As the share of renewables being added globally is increasing year on year, a wide range of technologies is emerging to complement an entirely renewables powered world. A 100-percent global renewable energy transition is, indeed, technically possible in a short timeframe, in the range of 20-30 years. Along with a capacity to supply the same level or even more energy to society than the present infrastructure dominated by fossil fuels. Several regions across the world are already generating reliably with 100 percent of their annual electricity from renewables: eg., two north German states, Schleswig-Holstein and Mecklenburg-Vorpommern, and the Danish island of Samsoe. In 2016, Denmark as a whole and South Australia generated 42 percent and 50 percent respectively of their annual electricity from variable renewable sources, wind in Denmark and wind plus rooftop solar in South Australia.
Contrary to myth, not all renewable energy sources are variable. To achieve reliability, variable renewables are supplemented by flexible, dispatchable renewable sources such as hydro-electricity with reservoirs, concentrated solar thermal (CST) with thermal storage, batteries, geothermal and gas turbines fuelled by renewable gases or liquids. The mix of technologies to be adopted depend on the availability of resources in the region of interest.
Storage technologies will be the game-changers
New energy storage deployments demonstrate just how quickly we can overcome the limits that are presented by the intermittent nature of solar and wind. The trajectory of energy storage substituting for conventional generation can be traced from actual practices. Battery storage installed at the power plant level can take on duties that were met by conventional generators. First adopted in remote locations, battery storage paired with generation began in isolated grids in places such as islands of the US, Australia and Chile where ancillary services from very small generator fleets were unavailable or constraining grid operations. This helped establish the technical and commercial foundation for expansion into larger grids across the world.
According to the latest study by EWG, storage technologies play a critical role in enabling a secure global power supply fully based on renewable energy. The results indicate that storage technologies increase from a mere 33 TWhel in 2015 to a substantial 15 128 TWhel in 2050. Batteries emerge as the critical storage technology in the global power mix, providing a major share of the output (almost 95 percent) by 2050.
Recent energy storage deployments now demonstrate a turning point. Present state-of-the-art technology adoption includes manufacturers such as General Electric (GE) adding energy storage to improve the performance of their line of peaking power plants. Many studies find that base-load power stations, such as coal and nuclear, are redundant. In addition, they are poor partners for variable renewables, because of their relative inflexibility in operation.
Carbon capture solutions yet to take off
Carbon capture and storage (CCS) has been suggested as an option to create and maintain sinks of carbon, which aid in lowering levels of CO2 in the atmosphere. While the idea of CCS is certainly appealing, in practice, it remains unproven and uncertain as a long-term solution. Furthermore, CCS requires a long-term commitment, extending to generations that have not yet been born, towards vigilant monitoring and management of the captured CO2. The sheer magnitude of this burden, and the chance of leakage back to the atmosphere, becomes greater as stored levels of CO2 increase. As such, the more reliance on CCS there is, the greater the risk and intergenerational burden. In addition, there is yet to be a successfully demonstrated fossil-fuelled CCS power plant around the world.
Other possible options currently show more promise than fossil fuel based CCS. These are bioenergy with CCS (BECCS), CO2 direct air capture CCS (DACCS) and carbon capture and utilisation (CCU).
Renewables will provide a far more efficient power system
As suggested by the recent study, the overall energy system losses referenced to the final electricity demand decrease drastically from around 139 percent in 2015 to just about 26 percent in 2050 (equivalent to 58 percent and 20 percent of primary energy input), indicating a huge efficiency gain globally with the energy transition. The large losses during primary energy to secondary energy conversion of present power plants (mainly based on nuclear, coal, gas, oil, biomass) drastically reduce by about 88 percent.
An increasing number of jurisdictions and institutions are setting deadlines for a jump to a 100-percent renewable electricity grid or even beyond, to fossil-fuel-free heating and transport as well. Among the most ambitious national targets are those of Denmark, which aims for all-renewable electricity and heating by 2035 and zero fossil energy by 2050. The country is well on the way to reaching those goals. As of March 2017, renewables provided about 56 percent of Denmark's power, and that share will rise to about 72 percent in 2020, according to the Danish Energy Agency. More than a hundred multinational corporations have joined the RE100 effort, setting individual deadlines to source only renewable electricity. Members include Belgium-based brewer Anheuser-Busch InBev, General Motors, Google, and the likes of Unilever, based in the United Kingdom.
A majority of the people across the world want more renewable energy, as indicated by a recent survey in which 82 percent believe it is important to create a world fully powered by renewable energy. Considering transport, many countries have come up with plans to ditch petrol cars and go electric. These policies will need to join up with plans to store more energy and build more turbines and solar panels (if they do not, emissions may increase). However, they will be complemented by developments in artificial intelligence, governance, the concept of car ownership and even insurance. The ideal of replacing all fossil-fuel vehicles with electric, comfortably charging every night, may be impeded by an antiquated grid or by insurers that choose not to cover them. An optimising centrally controlled algorithm or a consumer-based dynamic pricing system could resolve these, but there are limited laws and precedents as of now – another example of technology already being far ahead of what is politically or socially feasible.
Political barriers will do more to slow that growth than any technical limitation, especially in the short- to mid-term.
Disclaimer: The views expressed by the author are his own and do not necessarily reflect that of YourStory.