A 100% worldwide renewable future

A 100% worldwide renewable future

A new study into the intermittency of renewable energy and how to resolve the issue has concluded that there may be three methods by which consistent power could be achieved. The research was carried out by Mark Jacobson, a professor of civil and environmental engineering at Stanford University, with additional input from colleagues at California University, Berkeley, and Aalborg University in Denmark.

Mr Jacobson said: “I can more confidently state that there is no technical or economic barrier to transitioning the entire world to 100% clean, renewable energy with a stable electric grid at low cost. This would go a long way toward eliminating global warming and the 4-7million air pollution-related deaths that occur worldwide each year, while also providing energy security.

“There are multiple solutions to the problem. This is important because the greatest barrier to the large-scale implementation of clean renewable energy is people’s perception that it’s too hard to keep the lights on with random wind and solar output.”

The research looked the amount of energy required to supply full unbroken demand in 2050. To achieve this 139 were grouped into 20 regions based on geography and then matches supply and demand in 30-second increments for 5 years (2050-54) to account for the variability in wind and solar power as well as the variability in demand over hours and seasons.

A computer modelling system then predicted global weather patterns which in turn predicted the amount of energy that would be generated from weather based renewable sources, in particular wind and solar.

This estimated output was then compared to more stable renewable energy generation methods such as geothermal power plants, tidal and wave devices, and hydroelectric power plants, and of heat, like geothermal reservoirs. The second model also included ways of storing energy when there was excess, such as in electricity, heat, cold and hydrogen storage.

By comparing these the group was able to predict both how much energy could be produced through more variable sources of energy, and how well other sources could balance out the fluctuating energy to meet demands.

This led them to conclude that there are three methods by which consistent power via renewable energy can be attained at low cost for all 20 geographical regions by 2050.

This therefore goes against the long-held view that power supply can be consistent using only renewable energy generation. The research also predicted for each method, costs would reduce to approximately 25% out what they are now by 2050.

In addition, energy saving would be gained by avoiding the energy needed to mine, transport and refine fossil fuels, converting from combustion to direct electricity, and using heat pumps instead of conventional heaters and air conditioners.

Berkeley’s Mark Delucchi said: “One of the biggest challenges facing energy systems based entirely on clean, zero-emission wind, water and solar power is to match supply and demand with near-perfect reliability at reasonable cost.

“Our work shows that this can be accomplished, in almost all countries of the world, with established technologies.”

However, this still leaves the issue of cooperation across political boundaries: “Ideally, you’d have cooperation in deciding where you’re going to put the wind farms, where you’re going to put the solar panels, where you’re going to put the battery storage. The whole system is most efficient when it is planned ahead of time as opposed to done one piece at a time,” Mr Jacobson continued.

Energy storage therefore becomes vital in making this model successful and there is various research in this field currently taking place throughout the world.

In the USA, at Northwestern University, Prof Sossina Haile’s team has created a new ceramic fuel cell with exceptional power densities and long-term stability. “For years, industry has told us the ‘Holy Grail’ is getting fuel cells to work at 500-degrees Celsius and with high power density, which means a longer life and less expensive components,” Prof Haile said.

“With this research, we can now envision a path to making cost-effective fuel cells and transforming the energy landscape.”

The ceramic fuel cells high electrolyte conductivities failed to produce enough power. Her team has overcome this challenge by combining a high-activity cathode with a chemically stable electrolyte to produce exceptional power density and stability at intermediate temperatures.

“We solved multiple problems simultaneously by changing out the electrode, improving the electrolyte and creating good contact and communication between the two materials,” Prof Haile said. However, it should be noted that in order to make this method viable a reduction in manufacturing costs must be achieved.

At the other end of the of the spectrum researchers in Shanghai have developed a battery with organic compound electrodes that can function at -70C. Traditional lithium-ion batteries rapidly lose their ability to conduct and store energy when subjected to extreme low temperatures, so this technology will be especially useful in our harsher climates.

The Shanghai team have developed an ester-based electrolyte using organic compounds which has a low freezing point, enabling it to conduct a charge at extremely low temperatures. Although this is a positive step in battery technology Yong-yao Xia the team’s chief researcher has admitted that more work is required before it will be able to be used commercially.

Another new battery storage method currently at the development stage is taking place at Rochester and Buffalo Universities. Lead researcher Ellen Matson and her team are developing battery technology with increased redox performance.

A redox flow battery uses excess solar and wind energy to charge chemicals that can be stored for use when sunshine and wind are scarce. The key to this technology, called a redox flow battery, is finding chemicals that not only “carry” sufficient charge, but can also be stored without degrading for long periods. By making a simple molecular modification the team was able to expand the window during which the cluster of chemicals is stable, doubling the amount of electrical energy that could be stored.

The Rochester and Buffalo teams have applied for a US National Science Foundation grant as part of an on-going collaboration to further refine the clusters for use in commercial redox flow batteries.

As renewable energy and wind energy in particular became more prominent intermittency of generation and stress on the grid were debated throughout the world and were often used as sticks to beat it with. However, as capacity continues to increase neither of these have been a major issue.

If we are to aim for 100% renewable generation however we must look at viable storage solutions. At present we have the more traditional options such as industrial lithium batteries and pump storage hydro and as necessity is often the mother of invention new technologies such as those discussed above will start to become more feasible as their consistency increases and costs decrease.

Worldwide 100% renewable energy generation may seem like a pipe dream but it is a must. Our other options are either dirty, dangerous, or finite and in some cases all three. The advances in technology will benefit everyone and while we may not be there yet with them we can keep progressing in the knowledge they we will be ready when required.




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