Archive for the 'Uncategorized' Category

Jul 27 2015

100% Renewable Energy is Possible!

Vancouver city strives for 100% clean energy, including electricity, heating and cooling, and potentially hydroelectric transportation. Attaining 100% renewable energy is finally possible.   “We spent 10 years arguing over whether climate change was happening and then we spent another 10 years arguing over what we should do if it is happening; now we’re getting down to the who and when.”(Reimer)The chart below displays “the price of wind and solar power continues to plummet, and is now on par or cheaper than grid electricity in many areas of the world.” (Bloomberg) -1x-1

Vancouver voted to transition to 100% renewable energy in April and has since seen a 6% decrease in greenhouse gas emissions as well as a 20% increase in number of jobs. (Shahan) “The city also has 98% greenhouse gas–free electricity, and 31% renewable electricity.” (Reimer) The city is working to reach 100% renewable by encouraging walking as the major form of transportation, adding bike infrastructure and protected bike lanes, adding incentives for electric cars, green building codes, and utilizing waste heat for energy production.
Plans towards reaching 100% renewable energy is now trending across the states and it is only a matter of time before it will be accomplished. “The technology evolution that dropped the cost of solar modules by around 75% between 2009 and 2014 is now being followed by political and financial initiatives that are further driving down costs.” (Steiner) I believe the same pattern will follow with wind and wave energy technological breakthroughs in the near future.


Randall, Tom. “ Fossil Fuels Just Lost the Race Against Renewables
This is the beginning of the end.” Bloomberg. Web. 25 July, 2015.

Steiner, Adam. “The world is finally producing renewable energy at an industrial scale.” The Guardian. Web. 25 July, 2015.

Reimer Andrea. “100% Renewable Energy: The new normal?” Huffington Post. Web. July 25, 2015.

Shahan, Zachary. “Vancouver’s 100% Renewable Energy Goal (Renewable Cities Video)” Clean Technica. Web. 25 July, 2015.

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Jul 26 2015

Azura Technology Captures the Motion of the Ocean

Northwest Energy Innovations (NWEI) designed a 20kW wave energy converter, the Azura, which began producing electricity to the grid last month off the coast of Oahu, Hawaii. (Gahran)


The Azura’s innovative design captures energy from the waves vertical and horizontal motions with its 360 degree rotating buoy. (843 Digital) “As the first grid connected wave energy device in the U.S. that will be tested and validated by an independent party, this deployment marks a major milestone for our team and the marine renewable energy industry,” said NWEI Founder and CEO Steve Kopf. (NWEI) Solar and wind power have been the most successful renewable energy sources thus far. There are several reasons wave energy is last in line including lack of open-ocean research, fluctuating wave conditions, environmental concerns, and most importantly investment cost. Azura technology allows the device to partially submerge under waves and rotate in every direction making it less susceptible to damage in rough conditions. The device has already been tested and approved on small-scale, producing 20kW of electricity and is now being tested and improved with intentions of producing 1MW energy. (Gahran)

The initial cost of wave energy systems is very high and reliant on investors. “According to the Ocean Energy Council, recent experience in the U.K. (which is more advanced in wave power testing and deployment) is about 7.5 cents per kWh at best. The industry goal is to get this down to about 4.5 cents per kwh – comparable with the cost of wind power, although still much higher than the cost of fossil-fuel generation.” (Gahran) According to U.S. Energy Information Administration, Hawaii has the highest cost of electricity production at 34 cents per kWh. Continued technology advancements in the Azura wave energy system could drive down this expense as well as provide a streamline design for future wave energy conversion installments off the U.S. coasts.

Gahran, Amy, “Wave Energy Test Rolling Forward Hawaii,” EnergyBiz, July 26, 2015. Web. 26 July 2015.

NWEI, “Norwest Energy innovations Launches Wave Energy Device in Hawaii,” AzuraWave. Web. July 26, 2015.

843 Digital. “NWEI Animation,” Youtube. October 21, 2013. Web. July 26, 2015

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Jul 25 2015

Case Study: CETO La Reunion

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What is CETO La Reunion?
CETO La Reunion is a submerged point absorber technology invented, installed, and operated by Carnegie Wave Energy, an Australian developer (Carnegie Wave Energy 2011). The CETO La Reunion project is a three stage project, with the stage 1 currently operational as a 1 unit prototype (Carnegie Wave Energy 2015). Stage 2 of the project is a 2 MW array and stage 3 expands the array to 15 MW (Carnegie Wave Energy 2015).
Reunion Island, off the coast of Madagascar, makes an ideal deep water test site for various prototypes. (EcoGeneration 2011). Reunion is also exposed periodically to high energy southern wave events, and larger, consistent waves lead to greater amounts of power generated (EcoGeneration 2011). The CETO units are installed in relatively shallow depths of 25-30 meters (ICOE 2010). This is relatively shallow when compared with other offshore wave energy technologies and this depth is even shallow when compared with other submerged point absorbers, which typically function at depths of 80-90 meters. The current stage 1 installation is about 8 kilometers off the coast of reunion, on the southwest side of the island.

Location of Reunion Island

Location of Reunion Island

The stage 1 CETO unit is around 10 meters in diameter and acts as an anchored, submerged point absorber (Subsea World News 2013). The buoy is tethered to pump units on the seabed and moves up and down on a spar with the movement of the waves (EcoGeneration 2011). This action drives the pumps which pressurize seawater that is delivered to the shore via underwater pipelines (EcoGeneration 2011). On shore, this pressurized water is run through turbines which generate electricity, much like a hydroelectric dam (EcoGeneration 2011). An additional feature of the CETO technology, however, is that the pressurized water can be used to supply a reverse osmosis desalinization plant (EcoGeneration 2011). In reverse osmosis, pressurized water is forced across a membrane in order to overcome the osmotic pressure of water. Using CETO units in desalinization would essentially replace the electrical pumps normally required to pressurize the water, meaning greater efficiency and lower costs for the expensive process (EcoGeneration 2011).

Diagram of how a CETO unit works

Diagram of how a CETO unit works

Economics of the Project
Although it is not connected to the grid, CETO La Reunion has a power purchasing agreement under a French feed-in tariff of .22 euros per kilowatt hour (kWH) (EcoGeneration 2011). Stage 2 of the project, however, will be connected to the grid (EcoGeneration 2011). The project also received a grant of $5 million from the French government in order to finance stage 1, however, stages 2 and 3 are projected to be financially independent and profitable due the connection of the units to the grid (Carnegie Wave Energy 2015).

Environmental Impacts
In trials off the coast of Australia, the CETO system has acted like an artificial reef, attracting marine life rather than displacing it. An independent study showed that the amount of marine life increased from 7 to 27 species after deployment of the CETO unit (Carnegie Wave Energy 2015). There is minimal collision or strike risk with these units since they are not turbines and are fully enclosed, however, there is still risk of cable entanglement and operational noise with the CETO units (Week 3 Lectures). The full effects of these hazards are not fully known because the technology is relatively new.
Operability and Future Prospects
In order to be properly installed, the sea conditions and weather must be relatively calm. This led to some delays in t

One of the CETO Units

One of the CETO Units

he installation of stage 1 of the project. The undersea infrastructure was ready to go, but the buoy installation was delayed due to missing the narrow window of good weather (Subsea World News 2013). This problem could be compounded in stage 2 of the project as multiple buoys must be installed in the same narrow weather window. Currently, there is no information on the production coming from the CETO unit installed off the coast of Reunion, however, the previous generation of CETO units produced 78 kw of energy and pressurized water up to 77 bar, well above the pressure necessary for reverse osmosis desalinization (Carnegie Wave Energy 2015). The future of the CETO units, however, could be in some doubt after a cyclone with 200 km winds swept away and damaged the CETO unit operating in Reunion by snapping one of the mooring cables (RenewEconomy 2014). According to Carnegie, the unit was modified from others in that it was installed without a quick release mechanism which would have prevented such an accident. (RenewEconomy 2014). Regardless, the company claims it is not discouraged and will continue to pursue stage 2 installation (RenewEconomy 2014).


Overall, the CETO La Reunion project seems economically viable with little environmental impact. This technology could serve as a model for future wave energy projects. The fact that the point absorber is submerged takes away the controversy over NIMBY as far as aesthetics are concerned. It also helps protect the unit from the choppier more volatile waters at the surface. The environmental impact seems low: with no blades or open ducts to trap and ensnare marine life in, this unit seems less dangerous than an open axial turbine, for example. As far as the 2014 cyclone is concerned, the 200 km wind speeds recorded are atypical, even for Reunion, and I doubt any marine hydropower installation would be able to withstand those extreme conditions. The big draw with this technology, however, is the desalinization portion of it. Early testing in Australia of similar units made by the same company (Carnegie Wave Energy) indicate that these units are easily scaled up via an array format, they produce energy at a relatively high volume for marine power (78 kw per unit) and they are able to achieve more than enough pressure (77 bar) to power reverse osmosis desalinization (Carnegie Wave Energy 2015). Current desalinization processes, using electric pumps, are very expensive, and desalinization via a renewable generation system would cost even more. The prospect of emissions-free desalinization, however, is too good to not be pursued further, especially as global carbon emissions continue to rise and freshwater supplies dwindle. Overall, this is what makes the CETO technology worthy of further investment, any energy generation from the CETO units is just icing on the cake.

“CETO 4 Manufactured and Delivered to Reunion Island.” Carnegie Wave Energy, 26 Sept. 2011.
“EDF EN and DCNS Deploy CETO 4 Unit on La Réunion Island.” Subsea World News. Subsea World News, 2 Jan. 2013. Web. 8 July 2015.
“FAQ.” Carnegie Wave Energy. Carnegie Wave Energy, n.d. Web. 8 July 2015.
Gautret, Laurent, and Marion Corre Labat. “Reunion Island/Indian Ocean, a French Experimental Key Laboratory for Ocean Energy.” ICOE, 6 Oct. 2010. Web. 8 July 2015.
Parkinson, Giles. “CETO Wave Energy Machine Swept Away in Cyclone, Report Says.” Renew Economy RSS. Renew Economy, 27 Jan. 2014. Web. 8 July 2015.
“Réunion Island CETO Power Project — EcoGeneration.” EcoGeneration. EcoGeneration, Mar. 2011. Web. 8 July 2015.

Image Credits:

Carnegie Wave Energy

The Swiss Rock

Renew Economy


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Jul 25 2015

Rare Earth: The Unsustainable Future of Renewable Energy

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In my first post, I discussed the future of lithium and it’s role as a catalyst towards the changing global power dynamic surrounding renewable energy. In this post, I hope to continue this trend in discussing the role of rare earth metals in the renewable energy industry and how they may serve as a limiting factor in our quest towards a fully sustainable future.

Rare Earth Elements: What Are They?

Rare earth elements are a crucial component of many green technologies, from the drivetrains of electric vehicles and hybrids to the non-abrasive gearboxes in modern wind turbines. Rare earth elements are actually a group of seventeen elements, numbers 57-71 on the periodic table, that have a set of unique magnetic, electric, and optical properties (Namibia Rare Earths 2015). Contrary to popular belief, as well as their namesake, rare earth elements actually aren’t all that rare. These elements are only called rare because they are found in scattered deposits around the planet, as opposed to the vast, concentrated reserves of other metals and fuels such as oil and natural gas (Namibia Rare Earths 2015). In total, there is an estimated 110 million metric tons of rare earth reserves in the world (Namibia Rare Earths 2015). Of the world’s rare earth deposits 55 million metric tons or exactly half of the world’s resources are located in China (Business Insider 2011). Russia and the former soviet states comes in second with 19 percent of the world’s rare earth supply, followed closely by the United States with 17 percent (Business Insider). Other than these three regions, however, the remainder of the world’s rare earths are scattered in countries such as India, Australia, South Africa, and Brazil (Business Insider 2011).

Environmental and Health Hazards of Mining Rare Earths

Although they contain half of the world’s rare earth reserves, China still controls a disproportionately large share of the global rare earth trade. The reason for this is lax environmental regulation on the part of the Chinese government (Ives 2013). China can produce rare earth minerals three times cheaper than its international competitors due to nearly non-existent environmental standards related to waste disposal from mining rare earths (Ives 2013). This economic profit, however, is not without environmental consequence: according to China’s State Council, half a century of rare earth mining has led to “damaged surface vegetation, soil erosion, pollution, acidification, and reduced food output” (Ives 2013). The Council also reported that wastewater from the plants, which is stored in large, stagnant ponds contained a “high concentration of radioactive residues” (Ives 2013). At China’s largest rare earths mining project, Bayan- Obo, there is an eleven square kilometer waste pond filled with toxic sludge that contains elevated levels of thorium, a known carcinogen (Ives 2013). These environmental and health hazards are not limited to China. The Lynas corporation is an Australian mining and refining company specializing in rare earths and in 2013 they opened a processing facility on Malaysia’s east coast only twelve miles from Kuantan, a city with a population of 600,000 (Ives 2013). The plant is receiving strong opposition from many grassroots organizations who claim that the facility is contributing to a various environmental and health problems in the region. A recent study by the Institute for Applied Ecology found that the plant was disposing of wastewater through an open channel rather than a closed pipeline (Ives 2013). In addition, the Institute found that the company refused to disclose the chemical mixture used in refining the rare earths and that the temporary waste storage facility built by the company would cause radioactive leakage “under normal operating conditions” (Ives 2013). The grassroots organizers also point to the case of an $100 million cleanup of a Mitsubishi Chemical plant that closed in 1992 after it was discovered that thorium contamination from the plant’s refining of rare earths lead to increased leukemia and pancreatic cancer rates in the inhabitants of nearby villages (Ives 2013). The opposition also claims this is just another example of a developed, western corporation passing the environmental bill off to a developing nation while their executives make a hefty profit with little to no ecological impact. On the other hand, Lynas, says that they plan to dilute any thorium produced by mixing it with lime until it is below accepted international concentrations for radioactive materials (Ives 2013). The problem, however, is that rare earth projects are often independently audited, which means that regulators are often in the pockets of the company via bribes or the government via a pink slip if they don’t pass companies who break environmental regulations (Ives 2013). As of 2015, the Lynas plant remains fully operational but as several cases wind their way through the Malaysian courts, the future is far from certain.


“High Demand for Rare Earths.” Market Demand for Rare Earths: Namibia Rare Earths Inc. Namibia Rare Earths, n.d. Web. 22 July 2015.

Verrastro, Frank A. “The Geopolitics of Energy.” The Geopolitics of Energy. Center for Strategic and International Studies, Oct. 2010. Web. 22 July 2015.

Ives, Mike. “Boom in Mining Rare Earths Poses Mounting Toxic Risks.” Yale Environment 360. Yale University, 28 Jan. 2013. Web. 22 July 2015.

Jones, Nicola. “A Scarcity of Rare Metals Is Hindering Green Technologies.”Yale Environment 360. Yale University, 18 Nov. 2013. Web. 22 July 2015.


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Jul 25 2015

Lithium: Changing Global Power

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Lithium: Fuel of the Future

From Tesla Roadsters to iPhones, laptops to golf carts lithium-ion batteries are an essential component of 21st century society. Current estimates project that by 2020, there will be over 1 million electric vehicles (EVs) on the roads, spurred by the rapidly decreasing costs of lithium-ion batteries which are becoming 6- 9 % cheaper with every doubling of production (Hunt 2015). Lithium-ion batteries are over three times more efficient and half the weight of lead- acid cell batteries (Fletcher 21). This makes them the ideal power source in hybrid and electric cars due to this reduced weight. Out of all the elements on the periodic table, lithium is far and away the most efficient for electrochemical storage. Lithium is incredibly light at 6.941 atomic mass units (amu) whereas lead is over thirty times heavier at 207.2 amu (Fletcher 20). Lithium is also incredibly willing to shed its outermost valence electron which contributes to its conductivity and ultimately allows it to pack so much power in such a small package (Fletcher 20).
Who (Literally) Holds the Power?

Most of the world’s most easily accessible lithium can be found in the region known as the Lithium Triangle- the area where the borders of Chile, Argentina, and Bolivia meet (Fletcher 177). This area is dotted with salt flats, whose briny pools hold massive quantities of easily accessible lithium (Fletcher 176). The Salar de Uyuni in Bolivia is home to the largest lithium resources in the world, over 8.9 million metric tons (Fletcher 176).When considering the world’s supply of lithium, there are two ways of measuring the mineral: one is the amount of lithium reserves, which is the amount of mineral sources that can be legally and economically extracted today, and the other second is identified resources, which is simply known mineral deposits (Fletcher 217). In terms of reserves, Chile is dominant with around 7.5 million metric tons of lithium that could be accessed and mined today (Fletcher 217). China comes in second at 3.5 million metric tons followed by Argentina with 830,000 metric tons (Fletcher 217). The United States, on the other hand, is pretty far down the list with only 38,000 metric tons of reserves (Fletcher 217). The measures of identified resources, however, tell a much different story. Chile and China remain leaders, clocking in at second and third respectively, however, the overall global leader in identified resources is Bolivia with 9 million metric tons of lithium (Fletcher 217). Even more surprising, however, is that the United States, a developed country that had minimal reserves of lithium, is fourth in world with 4 million metric tons in identified resources (Fletcher 217). This is because in the United States, most of the lithium is located underground, which is much more expensive to extract than lithium carbonate located in salt pools on the surface. Meanwhile, in Bolivia there are different reasons for why an abundance of easily accessible lithium resources has not resulted in economic prosperity for the country. For one, Bolivia’s nationalized mining companies are too poor to build the infrastructure necessary for any kind of large scale mining operation and although there are many projects in the pipeline, none have come to fruition thus far (Fletcher 190). Bolivia’s government is also extremely wary of foreign exploitation, so they have banned all foreign mining operations in the Salar de Uyuni (Fletcher 190). Bolivians point to the fate of sub-Saharan African nations such as Nigeria that allowed foreign companies to come in and extract their natural resources, leaving behind environmental destruction while lining their own pockets (Fletcher 190). If Bolivia, can find the capital necessary to finance large scale mining operations in the Salar de Uyuni, they would be thrust immediately into the driver’s seat of the international lithium trade.
The New Lithium Economy

Lithium, however, could provide a significant counterweight to the current western dominated alliance of power, a leftover relic brought about by the Bretton Woods Institutions post World War II. As lithium-ion batteries become cheaper and more desirable, and as fossil fuels become more and more depleted, countries such as Bolivia, Argentina, Chile, and China will become the largest stakeholders in the new lithium driven economy (Hunt 2015). These countries, by controlling a precious resource, could form an alliance, not unlike OPEC, and dominate the global lithium trade, leaving countries with significantly less resources, such as the United States, sitting on the fence (Hunt 2015). Lithium could be the catalyst these countries need, much like oil was for the Middle East, to catapult Bolivia and Chile into the global market and solidify China’s rise as the dominant global superpower.


Fletcher, Seth. Bottled Lightning: Superbatteries, Electric Cars, and the New Lithium Economy. New York: Hill and Wang, 2011. Print.

Hunt, Tam. “The Geopolitics of Lithium Production.” Green Tech Grid. Green Tech Media, 30 June 2015. Web. 24 July 2015.

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Jul 26 2014

Desalination in Dare County – More on the Water-Energy Nexus

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In the past forty years, the Dare County has seen tremendous growth. From 1970 to 1980, the permanent population growth rate was 6.7 percent and approximately 5.5 percent in the following decade (Dare County, 2011.) Moreover, the profuse influx of tourist during peak summer months draws the total population to exceed 268,000 people (Dare County, 2011.)  Fluxes in seasonal population coupled with a constant growth rate of permanent residency has lead to drastic increases in fresh water demand since the incorporation of a county wide water management body in 1962 (Hardee, 1989.) Moreover, limited supply of fresh surface water and aquifer resources caused the county to explore brackish water sources to be used in desalination.  In 1988, Dare County opened its first reverse osmosis desalination plant in Kill Devil Hills. I had the opportunity to visit the plant, known as the North Reverse Osmosis Facility (NRO), and speak with Ken Flatt, the director of the Dare County Water Department. Through this experience, I was able to better understand how Dare County continues to evolve their water resource management strategy with attention to energy efficiency.

Please note that all data concerning water and energy efficiency were given by Ken Flatt unless otherwise noted

Energy Basics 

Although the NRO is powered by fossil fuels via grid connection, many of its internal technologies are among the most efficient processes available to desalination facilities. The plant operates with five purification devices, each containing approximately twenty reverse osmosis membranes. Each device is powered by a generator that contains a variable frequency drive. A variable frequency drive makes the generator more efficient by converting AC to DC in two stages. During the second stage, DC is inverted back to AC which allows the generator to regulate frequency and thus speed of the current, allowing the device to increase or decrease the speed based on purification needs (Youtube, 2014.) The membranes have a recover rate of 75 percent, meaning for every one gallon of raw water input that passes through the system, ¾ of a gallon of fresh water is produced. Moreover, each set of membranes contains an energy recovery device to help reduce grid electricity needs for purification. The energy recovery devices utilize the brine (waste water) produced after the raw water passes through the first set of membranes to subsequently power a turbine that boosts pressure in the next membrane chamber (Figure 1.) This is an important facet of energy efficiency when considering that each purification device has a total of 430 square feet of membranes and operate using a pressure between 260-280 pounds per square inch (Figure 2.) At first I was surprised to quantify the operating pressure with such a large unit, but after seeing how thick each membrane was I realized that this is indeed energy efficient (Figure 3.)

Figure 1: Energy Recover Device, the turbine is featured in the bottom right

Figure 1: Energy Recover Device, the turbine is featured in the bottom right


Figure 2: Membrane Devices

Figure 2: Membrane Devices

Figure 3: A view of the membrane where filtered water passes through the tube in the middle

Figure 3: A view of the membrane where filtered water passes through the tube in the middle

Since the facility’s first operations in 1989, the market for reverse osmosis membranes has become increasingly more competitive. Consequently, desalination in the Outer Banks has become just as cost efficient as treating the county’s only fresh water aquifer. Furthermore, in the case of decreased water quality, the facility can easily switch out membranes without taking a huge economic toll on operations. The plant draws its water from the Yorktown aquifer, a brackish aquifer that gains salinity content from deep fossil saltwater. The aquifer has naturally large reservoirs of arsenic, which calls for a minimally energy intensive post-desalination treatment process (Vengosh, 2011.) The treated water is passed through vats filled with iron silt that absorb the arsenic. This process adds very little to the energy needs of the facility Lastly, the brine is either discharged into the Atlantic or into the Croatan Sound. The discharge process has negligible environmental impact, as concluded by Duke researchers. This substantially cuts down on the plants energy consumption as it minimizes the need for long distance pipelines or storage facilities.

Political Obstacles for Improving Energy Efficiency

When asked about areas in which the facility can improve in areas of energy efficiency, Mr. Flatt responded by explaining the political hindrances that prevent more cost and energy efficient water management strategies. Rooted in historical economic policies, the towns of Nags Head and Kill Devil Hills resolved to separately deliver their residences with clean, fresh drinking water. As funding difficulties prevented the municipalities from sticking to their goal, Dare County became the primary governmental unit for regulating and treating drinking water (Hardee, 1989.) This interlocal agreement remains today with both Nags Head and Kill Devil Hills buying the water from the county and distributing to residences with separate resources. Mr. Flatt explained that Dare County pumps water from their ground storage units to each municipality’s ground storage units where they bring the water to elevated storage (Figure 5.) Logically, treated drinking water is usually treated and then pumped to elevated storage before direct distribution. Mr. Flatt admits this increases water costs, but claims that “consolidation is unfriendly word around here” seeing that both towns collect revenue from water distribution.

A view of the elevated storage for Nags Head (left) and Kill Devil Hills (right) from Highway 158. The two storage facilities are so close to one another they separated by only a strip mall.

A view of the elevated storage for Nags Head (left) and Kill Devil Hills (right) from Highway 158. The two storage facilities are so close to one another they separated by only a strip mall.


Desalination in Dare County presents overall net benefits to citizens through striving to keep the most up to date and energy efficient technologies.  Although some obstacles to greater efficiency are beyond technical solutions, desalination is the most logical avenue for producing fresh water along the northern outer banks.


Special thanks to Ken Flatt and the Dare County North Reverse Osmosis Facility


Works Cited

Dare County (2011). Existing and Emerging Conditions.

Hardee, J.E. (1989).  Dare Beaches Water Supply: Fresh Pond to Reverse Osmosis.

YouTube. (2014). What is a VFD (Variable Frequency Device/Inverter)?.

Vengosh, A. (2011). Rising Salinity in N.C. Coastal Aquifer Traced to Fossil Seawater.

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Jul 25 2014

Blue Carbon – Economic Impacts from Environmental Degredation

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This section will address the methods by which carbon deposits are stressed to emission, along with the ways in which these coastal ecosystems vary. For reference, it should be stated that the brunt of the disturbances is felt by the top one meter of sediment, and therefore the following regards near-surface carbon.

Seagrass ecosystem degradation often results from a decline in water quality that occurs because of over-exposure to nutrients and organic sediments released by various organisms, and less frequently results from the anthropogenic activities of trawling, dredging, and dropping anchors within these networks. The aforementioned disturbances lead to the release of carbon deposits from the underlying sediments to the surrounding water network or atmosphere (Orth RJ, 2006). Tidal marshes suffer from conversion to arable land usable for agricultural practices, thus heavily effecting underlying sediments because of extensive oxidation that occurs as a result of diking and draining efforts that disturb these ecosystems (Barbier EB, 2011). Finally, mangroves owe their decline to the common transformation of these networks into aquacultures. This causes the near-surface range to be almost entirely disturbed as a result of digging activities, which in turn leads to further oxidation of exposed sediments. The detrimental effects of maintaining these aquacultures can become even longer lasting if not maintained properly, as over-harvest and expansion practices can increase the extent of erosion and subsequently increase exposure of underlying sediments to oxidative environments (Kristensen E, 2008).


Seagrass Beds

Of the three types of vegetated coastal ecosystems, it was observed that mangroves contribute the largest portion of carbon dioxide release, as they possess the greatest withheld carbon stock per-hectare and are thus responsible for about half of these emissions. Coming in second for global blue carbon emission totals, seagrasses contain the least amount of carbon per-hectare, yet contribute the next largest amount due to their greater global presence in terms of area covered. Tidal marshes then contribute the least to these CO2 emission totals because they occupy the smallest global area, even though they possess a mid to upper carbon stock (Simon Thrush, 2012).


Tidal Marsh

The “social cost of carbon”, or SCC, as defined by the U.S. government, places the global economic expense at $41 per ton for each subsequent unit of carbon dioxide added to the atmospheric carbon pool (according to the value of the U.S. dollar in 2007) (United States Government, 2010). At this rate, the study by Simon Thrush et al places the estimated global cost resulting from degradation of vegetated coastal ecosystems at a range of $6.1 to $42 billion per annum, which relies on conservative measures (United States Government, 2010). Taken on any side of this range, this figure displays that there is a high economic stake to maintain the underlying sediments in these coastal regions, proving that conservation and monitoring of habitat conversion and land-use of these ecosystems is of greater economic benefit (and of greater ‘scientific importance’) than restoration attempts that are being conducted currently, which generally are not capable of sequestering as much carbon and preventing cycling into the atmosphere.






  • Barbier EB, Hacker SD, Kennedy C, Koch EW, Stier AC, et al. (2011) The value of estuarine and coastal ecosystem services. Ecological Monographs 81: 169–193.
  • Kristensen E, Bouillon S, Dittmar T, Marchand C (2008) Organic carbon dynamics in mangrove ecosystems. Aquatic Botany 89: 201–219.
  • Orth RJ, Carruthers TJB, Dennison WC, Duarte CM, Fourqurean JW, et al. (2006) A global crisis for seagrass ecosystems. Bioscience 56: 987–996.
  • Simon Thrush, et al. “Estimating Global “Blue Carbon” Emissions From Conversion And Degradation Of Vegetated Coastal Ecosystems.” Plos ONE 7.9 (2012): 1-7. Academic Search Complete. Web. 19 July 2013.
  • United States Government (USG) (2010) Technical Support Document: Social Cost of Carbon for Regulatory Impact Analysis Under Executive Order 12866. United States Environmental Protection Agency website. Available at: http://www.epa. gov/otaq/climate/regulations/scc-tsd.pdf.

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Jul 24 2014

Salinity Gradient Technologies, a Technology with Natural Influences

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The production of energy from the creation of an ion gradient is a method which is far from new or original—this process is the foundation of energy generation in cellular respiration and photosynthesis. Humans, however, did not conceive the idea to generate electricity from the creation of an ion gradient until the 1970s and this technique was not pursued until recently. The production of electricity from salinity gradients is based on the natural tendency for freshwater to mix with saltwater. This technique relies on the use of a semi-permeable membrane and water’s osmotic properties. Currently, two methods of membrane technology are being pursued—pressure retarded osmosis (PRO) and reverse electrodialysis (RED).

Pressure retarded osmosis relies on the diffusion of freshwater across a semi-permeable membrane to a chamber containing seawater cause an increase in the water volume inside the seawater chamber and, consequently, pressurizing the water (IEA, 2009). The pressurized water then turns a turbine which generates electricity. The products of PRO are electricity and brackish water resulting from the mixing of freshwater and saltwater (IEA 2009).

Visual of a PRO system

Visual of a PRO system

Reverse elctrodialysis is also a membrane-based electricity generation method but it relies on electrochemical reactions instead of osmotic pressure. This method utilizes a series of stacked membranes. Half of the membranes are permeable to sodium ion and half are permeable to chloride ions. Freshwater and saltwater flow alternately between each pair of membranes. The controlled diffusion of sodium and chloride ions in the water causes oxidation and reduction reactions at the iron ends of the device—otherwise known as the anode and cathode. The reverse elctrodialysis technique has been tested only at relatively minute scales with capacities around 100mW (IEA, 2009).

Visual of a RED system

Visual of a RED System

One limiting factor of osmotic electricity production is that it is an entirely location-specific technology. Because this method relies on the mixing of freshwater and saltwater, osmotic power plants must be placed where a river meets saltwater. Other limiting factors of osmotic electricity production exist in the water properties. The salinity, volume, and turbidity of the water influence the effectiveness of electricity production. The higher the salinity gradient, the greater the pressure, and greater pressure leads to a higher rate of electricity generation. Similarly, a greater volume of water will yield more electricity. A major concern of salinity gradient device installments is the accumulation of biofouling. The accumulation of organisms on the water collection pipes would reduce the pressure of the collected water and hence reduce the amount of electricity produced. Therefore, the devices would need to be regularly cleaned and maintained in order to maintain optimal efficiency. Fortunately, the two major components necessary for osmotic power generators, the membrane and pressure exchanger, are fairly commercialized (Sandvik & Skihagen, 2008). Thus, this technology has the potential for widespread installation in the near future.

Norway PRO Installation

Norway PRO Installation

A PRO project exists in Norway and has a capacity of 4kW. This project was installed primarily as a test project and for experimental research on the PRO technology (OES-IA, 2009). One of the main objectives of this installation is to improve the efficiency of the PRO technology. As previously mentioned, RED technology has been tested at small scales. One of these small-scale installations exists in the Netherlands and its main purpose is to study the environmental impacts and improve the existing technology (OES-IA, 2009). Currently, salinity gradient electricity generation is expensive due to installation and operation costs. Moreover, the capacity is extremely low in comparison to other coastal and offshore energy devices and their installation prices. As investment in renewable energy increases, however, the price of salinity gradient energy technologies will likely decrease as the efficiency and capacity increase.



  • IEA, 2009. Ocean Energy: Global Technology Development Status. International Energy Agency Implementing Agreement on Ocean Energy Systems Annex I: Review, Exchange and Dissemination of Information on Ocean Energy Systems. IEA-OES document No.: T0104 available at:
  • OES-IA, 2009. International Energy Agency Implementing Agreement on Ocean Energy Systems Annual Report 2009. OES-IA document A09. Available at:
  • Sanvik, S.O., Skihagen, S.E., (2008). Status of technologies for harnessing Salinity Power and the current Osmotic Power activities. Article to the 2008 annual report of the International Energy Agency Implementing Agreement on Ocean Energy Systems Annex I: Review, Exchange and Dissemination of Information on Ocean Energy Systems. Available at:


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Jul 24 2014

Italian Energy Reforms

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The Italy National Renewable Energy Plan was commissioned in April of 2009, as part of an update to the European Union’s directive in 2001. The 2001 directive produced a set of national targets from individual member states. Italy was supposed to have 25 percent of its power generated from renewable resources by 2010 but, falling short of that, the country’s target was substantially reduced to 17 percent by the year 2020 (Renewable Energy, EC).


Image of Italian minister of economic development, Flavio Zanon, the day of his conference.
Reforms have been recently made to Italy’s renewable energy incentives. The minister of economic development, Flavio Zanon, has announced that there will be an altered cap on renewable incentives. The change aims to change solar energy incentives spending at 9 billion euros annually for a 20 year period, as opposed to the previous 18 year period. Essentially, this creates a 3 billion euro savings which will assist households and businesses with electricity bills (Woods, 2013). However, the change has been criticized by many analysts, who state that this will scare off investors and trigger costly legal actions (Jewkes, 2014). Solar technology in Italy took off at the end of 2010 when production subsidies skyrocketed, increasing from 750 million euros to 6.7 billion euros in 2013. Over the last 5 years, investments of roughly 50 billion euros have been made in solar energy and, as a result, solar energy capacity has increased significantly. Italian Prime Minister Matteo Remzi has been criticized for his government’s changes, stating that the subsidy cuts were not planned properly and have the potential to affect long-term investment in renewable resources (Jewkes, 2014).

solar farm

A 1 megawatt solar farm in Italy
Similar trends in cutting funding for projects has been seen in Spain, Greece, and Bulgaria. Some analysts state that energy companies should have seen this coming; it is an ongoing trend in Europe that countries invest too heavily in renewable energy and then are forced to cut the budget for one reason or another. In 2013, Spain had a comparable change in renewable tariffs that triggered a wave of multi-billion euro lawsuits, ultimately giving compensation to energy companies based on the fact that they were misled by the government (Jewkes, 2014).
Due to economic factors within the country, Italy has to balance the pros and cons of investment in renewable energy at this time. While immediate cuts to subsidies may improve the economy in the short-run, it will eventually come back to hurt the country if energy investors are unwilling to continue on with their projects.



Renewable Energy. European Commission. <>

Jewkes, Stephen. Italy’s planned solar subsidy cuts risk scaring off investors. June 23, 2014. <>

Woods, Lucy. Update: Italy reforms renewable energy incentives. September 2, 2013. <>

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Jul 24 2014

Blue Carbon – Understanding the Decline

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Based upon the present data, it appears that the most immediate effect of vegetated coastal region degradation will be an increase of GHG emissions, as projections hold that these rates of release could be up to 50 times that of carbon sequestration, given the ecosystems were still intact (McLeod E, 2011). Luckily, the mechanism by which blue carbon acts to seize emissions is readily understood through scientific explanation.


Ocean’s Involvement in the Carbon Cycle










In these vegetated coastal regions, there exists an underlying layer of sediments that is organic-rich and therefore capable of withholding carbon, due to a relatively low presence of oxygen and other inhibitory compounds that relate to decomposition at depth below the surface. Although terrestrial ecosystems have also been observed to perform the same mechanism, it is notable that the efficiency and capacity of these ‘blue carbon’ sequestration sources is much greater, and thus stocks of stored carbon are much more abundant in the marine environments. When habitat conversion and land-use of these ecosystems occurs, the carbon residing in these deep sediment sinks becomes exposed to oxygen or is destabilized through another chemical reaction, and following microbial actions act to release the stored greenhouse gases to the above aquatic environment or atmosphere (Kristensen E, 2008). This process does not have a limiting factor. This means that the rate and amount of carbon released into the environment, generally occurring in the form of CO­2 or CH4 among other carbon species, is dependent upon the nature of land use and the type of underlying sediment.

Recent experiments have allowed for the production of data sets and figures that display the rate of carbon sequestration by the vegetation and top one meter of sediment in these areas. This is a major development because it reveals the emission rates for this so called ‘near-surface carbon’, which is the portion of the sediment that is most vulnerable to the subsequent effects of ecosystem alteration. In one study conducted by Simon Thrush et al, it was found that near-surface blue carbon became oxidized after disturbance and was then converted into the chemical species of CO2, as well as into bicarbonate and carbonate ions, which equate to an increase of the active carbon dioxide occurrence in the ocean-atmosphere system (Simon Thrush, 2012). As this system relies on an equilibrium of partial pressure produced by differential levels of CO2 existing between the atmosphere and oceans, the amount of carbon dioxide persisting in the atmosphere can be altered either through direct circulation between the two, or by the declining ability of the oceans to sequester carbon.

The study by Simon Thrush, et al. presents some of the most current estimations and projections resulting from habitat conversion and land-use of coastal vegetated ecosystems, but these are still conservative figures. This means that they remove uncertain variables from their calculations such as: deep sediment release, high-end area estimations, further speculative assumptions as to the ability of converted regions to retain at least 75% of near-surface carbon, and ambiguous measures of the effects of ecosystem distortions in producing new sediments that could further efforts of carbon sequestration. Given the above parameters, this study attributes an amount of 0.15 to 1.02 billion tons of carbon dioxide released to the atmosphere from blue carbon sinks each year, with the mean value lying at 0.45 billion tons.



  • McLeod E, Chmura GL, Bouillon S, Salm R, Bjork M, et al. (2011) A blueprint for blue carbon: toward an improved understanding of the role of vegetated coastal habitats in sequestering CO2. Frontiers in Ecology and the Environment 9: 552–560.
  • Kristensen E, Bouillon S, Dittmar T, Marchand C (2008) Organic carbon dynamics in mangrove ecosystems. Aquatic Botany 89: 201–219.
  • Simon Thrush, et al. “Estimating Global “Blue Carbon” Emissions From Conversion And Degradation Of Vegetated Coastal Ecosystems.” Plos ONE 7.9 (2012): 1-7. Academic Search Complete. Web. 19 July 2013.

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