Tipping Points for Solar Energy

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coal, energy economics, natural gas, photovoltaics, renewable energy, tipping point, wind

Below is a recent article in Bloomberg that has a bunch of good facts about the state of solar energy. Among them:…..

-“The world …. is adding more capacity for clean energy [solar & wind] each year than for coal and natural gas combined”

-“it’s likely that the total amount of solar photovoltaics added globally [in 2016] will exceed that of wind for the first time”

-“Half the price of coal”- It is noted that a record deal on a PV plant in Chile signed in August of this year came in at $29 /MW-hr – “roughly half the price of competing coal power “.

Here’s the link to the full article: https://www.bloomberg.com/news/articles/2016-12-15/world-energy-hits-a-turning-point-solar-that-s-cheaper-than-wind

World Energy Hits a Turning Point: Solar That’s Cheaper Than Wind

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Renewable Energy Intermittency in Hawaii

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energy storage, hawaii, intermittency, Oahu, smart grid, solar, wind

Hawaii is in a particularly unique position in terms of renewable energy production because it has abundant renewable resources (solar, wind, geothermal), lacks in-state fossil fuels, and is comprised of a series of islands that have their own isolated electric grids.  This isolation, combined with the fact that Hawaii now gets 21% of its electric power from intermittent solar and wind, creates large challenges for grid operators who are constantly trying to balance the supply and demand of electricity: http://www.wsj.com/articles/hawaii-wrestles-with-vagaries-of-solar-power-1435532277 The solution(s)?  Currently, the state utility is starting to implement smart grid components while also telling many customers to hold off on installing new residential  PV systems. They are also seeking bids for installing 300 MW of energy storage on Oahu, the biggest island in Hawaii.

Power-to-gas and NG infrastructure for H2 storage

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canada, Germany, grid scale energy storage, hydrogen, intermittency, natral gas, pipelines, power-to-gas, solar, wind

When we think about hydrogen and the future “H2 economy”, we tend to think about the production of H2 for use as a fuel in a fuel-cell based transportation system.  However, there are many opportunities for H2 use beyond transportation, including grid-scale energy storage.

One concept that has received increasing attention in recent years is that of “power-to-gas”, the idea of converting excess electricity into H2 through water electrolysis. Power-to-gas could play an important role in grid-scale energy storage thanks to its ability to quickly absorb large amounts of excess electricity produced by intermittent renewable resources such as solar or wind.

In Germany, which currently gets a higher percentage of its electricity from solar and wind than any other country, the government has initiated 20 power-to-gas demonstration projects:

http://www.technologyreview.com/news/530331/germany-and-canada-are-building-water-splitters-to-store-renewable-energy/

Many of these projects will be based on polymer electrolyte membrane (PEM) electrolyzers, which use electricity to electrochemically split water into H2 and O2 at very high current densities, typically 2-4 A/cm2. A leading company in the application of PEM electrolyzer-based systems for power-to-gas is Hydrogenics, a Canadian company.

After being produced, the H2 from power-to-gas plants must be stored until electricity prices go back up. Presently, many demonstrations seek to leverage the existing natural gas infrastructure for this purpose.  This can be achieved by reacting H2 with with CO2 in a methanation reactor for direct production of CH4, or, as is being done in a number of the German demonstration projects, the H2 can be input directly into the current natural gas piping infrastructure.   H2 is compatible with CH4 at low percentages, and can therefore be stored in the existing infrastructure at minimal cost, and the mixture can then be burned in a natural gas power plant to be converted back into electricity.

For a full list of power-to-gas pilot plants for stationary applications, see this article:

http://www.sciencedirect.com.ezproxy.cul.columbia.edu/science/article/pii/S0360319912026481#