Waste Heat Recovery using Supercritical CO2 turbines to create Electrical Power

See on Scoop.itGreen Building Design – Architecture & Engineering

Working fluids with relatively low critical temperature and pressure can be compressed directly to their supercritical pressures and heated to their supercritical state before expansion so as to obtain a better thermal match with the heat source.

Duane Tilden‘s insight:

>Chen et al. [1-3] did a comparative study of the carbon dioxide supercritical power cycle and compared it with an organic Rankine cycle using R123 as the working fluid in a waste heat recovery application. It shows that a CO2 supercritical power cycle has higher system efficiency than an ORC when taking into account the behavior of the heat transfer between the heat source and the working fluid. The CO2 cycle shows no pinch limitation in the heat exchanger. Zhang et al.  [4-11] has also conducted research on the supercritical CO2 power cycle. Experiments revealed that the CO2 can be heated up to 187℃ and the power generation efficiency was 8.78% to 9.45% [7] and the COP for the overall outputs from the cycle was 0.548 and 0.406, respectively, on a typical summer and winter day in Japan [5].

Organic fluids like isobutene, propane, propylene, difluoromethane and R-245fa [12] have also been suggested for supercritical Rankine cycle. It was found that supercritical fluids can maximize the efficiency of the system. However, detailed studies on the use of organic working fluids in supercritical Rankine cycles have not been widely published.

There is no supercritical Rankine cycle in operation up to now. However, it is becoming a new direction due to its advantages in thermal efficiency and simplicity in configuration.<

See on www.eng.usf.edu

Lord Lawson declares UK’s climate model ‘flawed’

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Lord Lawson is calling for an independent review of the UK’s official climate predictions as he claims the model used to make the projections is “flawed”. Based on research published …

Duane Tilden‘s insight:

>The thinktank claims predictions made by it will “always produce high estimates of future warming” regardless of the data fed into the process.

The HadCM3 model is used for official UK Climate Projections (UKCP09), which provide information to help plan how to adapt to a changing climate. It generates a virtual representation of the global climate such as the greenhouse effect, evaporation of the oceans, rainfall and sunlight. By increasing the greenhouse gases in the model, predictions on how much warmer the planet will become in the future can be made.

The UK’s climate model is also used to help make investment decisions across the public and private sectors and as estimates of future warming generated by the Government’s model are “much higher than those implied by several recent studies”, they are likely to “lead to considerable malinvestments” of public and private funds, GWPF claims.

Andrew Montford, author of the GWPF briefing paper said: “There are potentially billions of pounds being misspent on the basis of these predictions. The Government has little choice but to withdraw them pending a review of the way they are put together.”

The Met Office defended its methods and rubbished the criticism.

The organisation said in a statement: “UKCP09 used a sophisticated method that used both model projections and observations to provide a range of potential future warming which attempts to take in the uncertainties in model parameters. The GWPF article fails to note that UKCP09 also used information from many other climate models and that the projections were independently reviewed prior to publication.”<

See on www.energylivenews.com

EPA sets terms for New Power Plant carbon emissions

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Frances Beinecke: We’re already paying the costs of climate change. The new power plant emissions standards could not be more timely

Duane Tilden‘s insight:

>The carbon standards announced Friday by Gina McCarthy, administrator of the US Environmental Protection Agency, will set reasonable limits on carbon pollution from the power plants of tomorrow, those that are yet to be built.<

See on www.theguardian.com

Coal Power: One Percent Of U.S. Power Plants Produce 12 % Of U.S. Carbon Emissions

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The disproportionate greenhouse impact of a small portion of U.S. power plants shows how damaging inefficiency and inertia can be.

Duane Tilden‘s insight:

>That one percent is actually 50 plants, all of them coal-fired. In fact, America’s single dirtiest power plant — Georgia Power’s Plant Scherer — dumped over 21 million metric tons (MMT) of carbon dioxide into the atmosphere in 2011. That’s more than all the energy-related emissions produced by the state of Maine that year.

And the disproportionate contribution of the dirtiest plants to greenhouse gas emissions continues on down the scale: in 2011, half of all the power sector’s carbon emissions came from the 100 dirtiest plants (98 of which are coal-fired). And 90 percent of all those emissions came from just the 500 dirtiest power plants. That’s out of almost 6,000 electricity generating facilities — renewable and fossil-fuel-powered alike — in the country.<

See on thinkprogress.org

Coal opposes Senate Energy Commission Nomination

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Ronald J. Binz, nominated to lead the Federal Energy Regulatory Commission, is opposed by the coal industry because of his efforts to promote renewable energy.

Duane Tilden‘s insight:

>At the Electricity Consumers Resource Council, which represents large industrial customers, Marc Yacker, a vice president, said that the coal industry had some reason to be worried. The industry believes, he said, that “the whole idea of socializing the cost of new transmission necessary to get wind to population centers is anti-coal.”<

See on www.nytimes.com

Water-Smart Power: Strengthening the U.S. Electricity System in a Warming World (2013) | UCSUSA

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This report shows how the U.S. can build an electricity system that protects our water resources and dramatically reduces global warming emissions.

Duane Tilden‘s insight:

>The country stands at a critical crossroads. Many aging, water-intensive power plants are nearing the end of their lives. The choices we make to replace them will determine the water and climate implications of our electricity system for decades to come.

Today’s electricity system cannot meet our needs in a future of growing demand for power, worsening strains on water resources, and an urgent need to mitigate climate change.

[…]

Energy-water collisions are happening now, and are poised to worsen in a warming world

  • The heat waves and drought that hit the U.S. in 2011 and 2012 shined a harsh light on the vulnerability of the U.S. power sector to extreme weather, and revealed water-related electricity risks across the country.
  • When plants cannot get enough cooling water, they must cut back or completely shut down their generators, as happened in 2011 and 2012 at plants around the country.
  • Nationally, the 2012 drought was the worst in half a century. Amid soaring temperatures in the Midwest, several power plant operators got permission to discharge exceptionally hot water rather than reduce power output.
  • Electricity-water collisions are poised to worsen in a warming world as the power sector helps drive climate change. Extreme weather conditions that have historically been outliers are expected to become standard fare.<

See on www.ucsusa.org

Water in Crisis: A New Paradigm in Power Generation

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The US can affordably and sustainably meet its energy and water needs by pursuing a “renewables-and-efficiency” path, according to a new EW3 report.

Duane Tilden‘s insight:

>The current system of power generation in the U.S., according to EW3, “clearly cannot meet our needs in a future of growing demand for electricity, worsening strains on water resources, and an urgent need to mitigate climate change.”

What’s urgently needed, they assert, is a system of power generation that is much more resilient – one that is not only much less dependent on water, but one that can operate sustainably in a warming climate and, at the same time, help mitigate climate change. With the release of its second report, EW3 advocates making decisions today that puts U.S. society firmly on such a path. […]

EW3′s research team constructed two long-term scenarios in order to better understand and analyze the implications of decisions made today regarding electricity production in the U.S. in terms of water usage and greenhouse gas emissions.

Pursuing a business-as-usual path that would see natural gas combustion growing to account for 60 percent of U.S. power generation in coming decades “would fail to reduce carbon emissions, and would not tap opportunities to safeguard water,” EW3′s research team found. In sharp contrast, both water usage and carbon emissions in the power sector would drop much further, and faster, under a “renewables-and-efficiency” scenario.

Under the renewables-and-efficiency scenario, both water withdrawals and consumption by the power sector would be less than half of today’s levels by 2030. By 2050, water withdrawals would be 97 percent below today’s levels while water consumption would drop 85 percent – nearly 80 percent below the business-as-usual scenario.<

See on www.triplepundit.com

China’s Coal-Fired Economy Dying of Thirst as Mines Lack Water

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Coal industries and power stations use as much as 17 percent of China’s water, and almost all of the collieries are in the vast energy basin in the north that is also one of the country’s driest regions.

Duane Tilden‘s insight:

>About half of China’s rivers have dried up since 1990 and those that remain are mostly contaminated. Without enough water, coal can’t be mined, new power stations can’t run and the economy can’t grow. At least 80 percent of the nation’s coal comes from regions where the United Nations says water supplies are either “stressed” or in “absolute scarcity.” […]

Geneva-based Pictet Asset Management’s $3.17 billion global water fund doubled its exposure to stocks offering water services in China to 10 percent since 2007.  […]

Beijing Enterprises has risen 55 percent this year to HK$3.10 and Deutsche Bank sees it reaching HK$3.20 within a year. China Everbright is up 81 percent to HK$7.10 and JPMorgan Chase & Co. estimates it will reach HK$7.60 by mid-October.

Severe Pollution  “The best opportunity is in industrial water re-use, and for the mining industry, it is of the utmost urgency,” said Junwei Hafner-Cai, a manager of RobecoSAM’s Sustainable Water fund. “Water that has been released from the coal mines and from petrochemical plants has resulted in severe pollution on top of the water scarcity.”

A shortage of coal because of the lack of water to mine and process the fuel may force China to increase imports, pushing up world prices, according to Debra Tan, director at research firm China Water Risk in Hong Kong. China, which mines 45 percent of the world’s coal, may adopt an aggressive “coal-mine grab” to secure supplies, said Tan.<

See on www.moneynews.com

Water Stress Threatens Future Energy Production

See on Scoop.itGreen Building Design – Architecture & Engineering

When we flip on a light, we rarely think about water.  But electricity generation is the biggest user of water in the United States.  Thermoelectric power plants alone use more than 200 billion gallons of water a day – about 49 percent of the…

Duane Tilden‘s insight:

>Large quantities of water are needed as well for the production, refining and transport of the fuels that light and heat our homes and buildings, and run our buses and cars.  Every gallon of gasoline at the pump takes about 13 gallons of water to make.

And of course hydroelectric energy requires water to drive the turbines that generate the power.  For every one-foot drop in the level of Lake Mead on the Colorado River, Hoover Dam loses 5-6 megawatts of generating capacity – enough to supply electricity to about 5,000 homes.

In short, energy production is deeply dependent on the availability of water.  And, as a report released last week by the U.S. Department of Energy (DOE) makes clear, as climate change brings hotter temperatures, more widespread and severe droughts, and lower river and lake levels, the nation’s energy supply is becoming more vulnerable. […]

One particularly interesting figure in the report compares the water requirements of seven different types of electric power facilities – nuclear, coal, biopower, natural gas combined-cycle, concentrated solar, photovoltaic solar and wind.  The last two come out as by far the most water-conserving electricity sources.  In contrast to the 20,000-60,000 gallons per megawatt-hour needed for nuclear and coal plants with “once-through” cooling systems, PV solar and wind require only negligible quantities.<

See on newswatch.nationalgeographic.com

Nuclear Plant Closures Forecast for New York and Chicago regions

See on Scoop.itGreen & Sustainable News

Nuclear reactors that light New York City and Chicago with carbon-free electricity face possible extinction before they can reap the benefits of President Barack Obama’s proposed climate rules.

Duane Tilden‘s insight:

>A slump in power prices, increasing maintenance expense as plants age and stricter safety regulations following Japan’s 2011 Fukushima nuclear disaster may prompt the industry to retire as many as five plants before the end of the decade, according to research firm UBS Securities LLC. That would eliminate enough generating capacity to power 2.4 million U.S. homes. […]

Reactors such as Indian Point are combating critics that want to shut them down over safety concerns. New York, for example, has solicited bids to replace the plant with natural gas-fired generators and authorized a transmission line to deliver hydropower from Quebec.

Retired nuclear units would likely be replaced by gas plants built by operators such as NRG Energy Inc. (NRG), which would have the result of increasing overall greenhouse gas emissions. That may complicate Obama’s longstanding goal of slashing U.S. emissions 17 percent from 2005 levels by 2020, and echo challenges faced by countries such as Japan and Germany as they phase out nuclear power, said Chris Gadomski, an analyst for Bloomberg New Energy Finance.<

See on www.bloomberg.com