Five Trends Powering Renewables

 

Trend One: Next-Gen Batteries

What’s holding renewal energy back? One major factor is storage. Energy is often created during peak energy hours but is needed later, such as during nighttime hours. There have been recent advances in batteries used to store such power. They are based on a range of materials such as sodium, aluminium and zinc.  For example, the World Economic Forum (WEF) reports:

Fluidic Energy announced an agreement with the government of Indonesia to deploy 35 megawatts of solar panel capacity to 500 remote villages, electrifying the homes of 1.7 million people. The system will use Fluidic’s zinc-air batteries to store up to 250 megawatt-hours of energy in order to provide reliable electricity regardless of the weather. In April, the company inked a similar deal with the government of Madagascar to put 100 remote villages there on a solar-powered mini-grid backed by zinc-air batteries.

Such batteries could potentially transform electrical usage of remote communities all over the world.

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Trend Two: Beyond Batteries

Organizations have been working on perfecting alternative storage devices as well. There are a variety of storage techniques, but here are two of the most promising:

  • Compressed air energy storage: When power is abundant, plants with this technology use it to power a large air compressor that pushes pressurized air into an underground geologic storage structure. When energy is scarce or more expensive, the stored air is released and heated so that it turns turbines to generate electricity.  These plants can re-generate up to 80% of the electricity they take in.
  • Molten salt storage: This requires the use of a solar “power tower” design. A field of sun tracking mirrors called heliostats concentrate solar radiation onto a receiver, through which molten salt is circulated. The salt is then routed to an insulated storage tank. Later, when power is scarce again, the hot molten salt is routed to a heat exchanger, producing steam that powers a conventional steam turbine.
solar_power_tower_2

Wikipedia photo by Alejandro Flores: Solucar PS10 is the first solar thermal power plant based on tower in the world that generates electricity in a commercial way.

Trend Three:  Perovskite Solar Cells

Perovskite has three big advantages over silicon, the material normally used to create solar cells. First, perovskites are considerably less expensive and resource-intensive to make. They represent a broad “class of materials in which organic molecules, made mostly of carbon and hydrogen, bind with a metal such as lead and a halogen such as chlorine in a three-dimensional crystal lattice.” Second, liquid solutions can be used to deposit perovskites as thin films on virtually any type of surface. This makes perovskites cells lighter and easier to install than solar panels. Third, researchers have much greater success boosting the efficiency of perovskites. The WEF reports:

By 2016, perovskite solar-cell efficiencies were above 20 percent—a five-fold improvement in just seven years and a stunning doubling in efficiency within just the past two years. They are now commercially competitive with silicon PV cells, and the efficiency limits of perovskites could be far higher still. Whereas silicon PV technology is now mature, perovskite PVs continue to improve rapidly.

perovskite_structure

Wikipedia image by Christopher Eames et al. : CH3NH3PbI3 structure

Trend Four: Exponential Growth?

Futurist and computer scientist Ray Kurzweil stated at a recent presentation:

In 2012, solar panels were producing 0.5% of the world’s energy supply. Some people dismissed it, saying, ‘It’s a nice thing to do, but at a half percent, it’s a fringe player. That’s not going to solve the problem. They were ignoring the exponential growth just as they ignored the exponential growth of the Internet and genome project. Half a percent is only eight doublings away from 100%. Now it is four years later, [and solar] has doubled twice again. Now solar panels produce 2% of the world’s energy, right on schedule. People dismiss it, ‘2%. Nice, but a fringe player.’ That ignores the exponential growth, which means it is only six doublings or [12] years from 100%.

I’m not sure where Kurzweil is getting that data, but Wikipedia also reports that “worldwide growth of photovoltaics has been fitting an exponential curve for more than two decades.”

expoential doubling_time_vs_half_life.svg

Wikipedia image by Cmglee: Graphs comparing doubling times and half lives of exponential growths (bold lines) and decay (faint lines), and 70/t and 72/t approximations.

There’s a major difference in the official prediction of the Energy Information Administration’s (EIA) International Energy Outlook and the radical prediction of Kurzweil. The EIA predicts that energy consumption from renewables will grow an average of 2.6 percent a year through 2040. That’s fairly impressive, being the largest growth in consumption for all energy sources, followed closely by nuclear.

Still, if we assume that 10% of the energy the US consumes is from renewables and that there will be a 2.6% growth per year, that only gets us to about 18.52% of energy consumed by 2040. That also assumes relatively stable energy usage trends.

Kurweil says we are only “eight doublings” (that is, 16 years) from meeting 100% of humanity’s needs with solar. If he’s right, then it would happen even faster in the U.S. If 1% of U.S. energy comes from solar (which is only a fraction of renewable energy), then it would double to 2% in 2018, 4% in 2020, 8% in 2022, 16% in 2024, 32% in 2026, 64% in 2027, and 100% by 2029.

So, that means only seven doublings in the U.S. alone. This sounds unlikely to me, as Kurzeil’s exponential-based predictions often do, but we should find out pretty quickly (that being a relative term) whether his projections have any validity. If the EIA predictions hold true, then all renewables will account for just 12.55% of US energy in 2026, but if Kurzeil is right, then we’ll already be at the 32% mark for solar alone. It should be an interesting real-world experiment.

Trend Five: Germany Now Gets Most of Its Power from Renewables

In May 2016, Germany met nearly all its power demands through renewable energies. This is a remarkable achievement considering Germany is Europe’s largest economy, the third largest exporter in the world and  has the fourth largest GDP. However, there is a catch to this historic event. That is, renewables were only able to meet Germany’s demand because of the nation has a strong export capability. Even when solar and wind peaked, conventional power plants were still supplying 7.7 gigawatts, but this energy could be exported. This has led to questions about energy oversupply and costs in Germany.
german solarGIS-Solar-map-Germany-en

Wikipedia image by SolarGIS © 2011 GeoModel Solar s.r.o.: Solar Radiation Map: Global Horizontal Irradiation Map of Germany

Analysis

So much is happening in the world of renewable energy that it’s difficult to gauge the future. Will we be attain a solar economy over the next two decades, as Kurzeil projects, or will this take at least until the late 21st century? Yes, the fast-moving technologies themselves make such a forecast difficult, but so do shifting economic, political and environmental trends. The case of Germany makes it clear that the world–or at least, the developed nations–could move to a solar economy quickly if it had the political will. However, there are many entrenched business interests that would resist such a global initiative, and there are convincing economic arguments against moving to a solar economy as long as other, less expensive sources of energy are available.

And then there are competing energy technologies, especially nuclear. If nuclear fusion ever becomes a viable technological and economic reality, there’s no telling how that would effect the solar trend. For now, however, we should at least expect renewables to provide a growing proportion of of global energy. It’s the speed of such growth that is the primary unknown.

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