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How Much Water Does it Take to Turn on a Light Bulb?

first_imgIn last week’s blog I took a look at some of the water conservation features in our new house, but I began the blog by addressing the relationship between water and energy. That got me curious, so I’ve been digging deeper into this water-energy nexus, examining the water-intensity of our different electricity sources.Some of this information is drawn from a 2012 report that I only recently came across: “Burning Our Rivers: The Water Footprint of Electricity,” by the River Network in Portland, Oregon. Low global warming and low water useIt is worth pointing out that the renewable energy technologies for power generation that are growing the quickest in implementation (photovoltaics and wind) are the least water-intensive.The only measures that do even better from a water-use standpoint are efficiency measures. Using less electricity is the place to start if the goal is to conserve water resources. Evaporative losses from hydropower plantsNearly all of our methods for generating electricity involve at least some water consumption, but the differences are huge. Producing electricity with hydropower is the most water-intensive, owing to evaporation from reservoirs. Nationwide, electricity from hydropower plants consumes about 9 gallons of water per kilowatt-hour (kWh) of electricity produced.In some parts of the world, this evaporation is a big problem. In other areas, not so much. In the arid Southwestern U.S. this evaporation is a huge issue, especially from reservoirs like Lake Mead. Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed. Water use for thermoelectric power plantsMost electricity in the U.S. (about 89%) is produced using thermoelectric power plants. These use a heat source (most commonly coal, natural gas, or nuclear fission) to boil water, creating superheated, high-pressure steam. This steam spins a steam turbine connected to generate electricity. Cooling water is then used to condense the steam back to water.center_img Comparing coal, natural gas and nuclear relative to water useOf the three primary fuels used in thermoelectric power plants, natural gas power plants have the lowest water intensity. According to Burning Our Rivers, coal power plants consume 0.69 gallons of water per kWh of electricity produced, natural gas power plants consume 0.17 gallons/kWh, and nuclear plants 0.57 gallons/kWh.With coal, according to the report, 73% (0.506 gal/kWh) of the water consumption is from evaporation, as described above, while 27% (0.186 gal/kWh) is from upstream sources (mostly mining, and transportation). Once-through cooling of coal plants results in consumptive water use (evaporation) of about 0.3 gal/kWh, while recirculating systems evaporate about 0.7 gal/kWh.Water consumption from nuclear plants is similar to that of coal though the spread between once-through and recirculating systems is even greater: 0.27 gal/kWh for once-through cooling vs. 0.76 for recirculating systems.While the water intensity of natural gas power generation is a lot lower than for coal and nuclear, there are significant differences depending on the type of power plant. Combined-cycle plants use much use much less water per unit of electricity output than do single-cycle power plants.The Burning Our Rivers report shows very low upstream water consumption for natural gas power plants, but the report did not consider hydraulic fracturing (fracking), which results in far greater water use (typically 4-5 million gallons per well) and heavily contaminates that water. An October 2013 report on the water intensity of natural gas extraction from Marcellus Shale in Pennsylvania and West Virginia by researchers at Downstream Strategies and San José University sheds some light on this issue.There are two primary ways electricity is generated from solar: utility-scale solar-thermal power plants and either utility-scale or building-scale photovoltaic power generation. Most utility-scale solar thermal is more water-intensive than coal or nuclear power plants.From the Burning Our Rivers report, parabolic trough systems are shown to consume about 0.80 gal/kWh, while linear Fresnel systems consume about 1.0 gal/kWh, solar power tower systems consume 0.63 gal/kWh, and dish Stirling Engine systems, which are far less common but do not use the heat to generate steam, consume only 0.020 gal/kWh.Adding to the challenge with large-scale solar-thermal is that these systems want to be located where there is a lot of sunlight, such as the American Southwest, and those places tend to be much drier.Photovoltaic systems use almost no water in their operation — only 0.002 gal/kWh — with most of that upstream water use for manufacturing.Finally, wind systems consume less than 0.001 gal/kWh — the lowest of any electricity source — with most of that also upstream. RELATED ARTICLES Saving Water by Conserving EnergySaving Water — Saving EnergyResilient Design: Water in a Drought-Prone EraReduce Water UseSaving Energy by Saving WaterThe Uncertain Future of Phoenix and Las VegasWater, Water EverywhereIn the West, Drought Ends ‘Era of the Lawn’ Depending on the type and age of the power plant, the cooling water is once-through (pulled from a river, for example and then returned to the river at a higher temperature), provided by a cooling pond, or recirculating. The once-through systems use tremendous quantities of water, but the vast majority returns to the water source from whence it was drawn — albeit at a higher temperature (thermal pollution can be a major problem). Some evaporates, however, and is not returned to the river; this is the consumptive use.  Recirculating cooling systems in power plants use far less water and they don’t add thermal pollution to the body of water from which the water was originally drawn, but they still evaporate considerable water — in fact, typically more than once-through cooling systems — so the consumptive water is very significant.last_img read more

Can smart cities protect their IoT Achilles heel from hackers?

first_imgLast year’s headline-grabbing security breaches of Internet of Things (IoT) technology was the opening salvo in a new cyberwar where smart cities are firmly in the crosshairs.Smart city security vulnerabilities were a recent topic of discussion with Paul Williams, SADC Country Manager with cyber security software firm Fortinet.Williams says that 2016’s high profile IoT cyber-attacks exposed how vulnerable this new technology is to hackers.“As was seen recently in a series of IoT-based denial of service attacks, IoT devices can be compromised and hijacked into a Shadownet and controlled by a command and control center run by hackers,” he says. “Alternatively, these devices and services may be attacked in order to deny services to legitimate users.”And considering that global smart city strategies hinge on connecting massive numbers of IoT devices and sensors, this boosts the attack surfaces targeted by smart city hackers.“The increase in the size of a smart city’s IoT device footprint corresponds to an increase in the size of its attack surface,” he warns.In light of how quickly IoT technology is being integrated into vital systems of smart cities, considerable damage can be done by malicious hackers.Some examples of possible smart city attacks could include: disrupting traffic by hijacking traffic lights or misdirecting vehicles; causing sewage system floods or disrupted access to drinking water; or remotely operating alarm systems and temperature control systems.But rather than hitting the panic button, Williams recommends smart cities begin a systematic approach to tackling their IoT security threats.“While it’s not possible to secure every possible security breach in a totally connected environment… it’s possible to take some key initial steps to strengthen the smart city’s security posture and architecture,” he says.Using strong encryptionAmong these initial steps would be the usual advice of using strong encryption, designing tamper-resistant systems and implementing strong system access control.Beyond these steps he says that complex smart city networks need to implement segmentation to boost security. He suggests, for example, that smart transportation networks be logically segmented from other networks like user services or energy networks.“This aids in isolating an attacks, and allows for the advanced detection of data and threats as attacks and malware move from one network zone to the other,” says Williams. “This also divides the smart city network into security zones, which aids in compliance, monitoring internal traffic and devices, and preventing unauthorized access to restricted data and resources.”He also recommends that smart cities develop specific mitigation strategies to counter distributed denial of service (DDoS) attacks. These strategies could include overprovisioning the city’s bandwidth to withstand the overwhelming nature of DDoS attacks.“This may be comprised of either an over provisioned appliance solution, or a hybrid solution consisting of appliances combined with a cloud based scrubbing center,” he says. Tags:#cybersecurity#Fortinet#IoT#Smart Cities#smart city Donal Power How Connected Communities Can Bolster Your Busi… For Self-Driving Systems, Infrastructure and In…center_img Related Posts How IoT Will Play an Important Role in Traffic … Surveillance at the Heart of Smart Citieslast_img read more

Mamata Banerjee moots ‘return black money’ protests

first_imgWest Bengal Chief Minister Mamata Banerjee on Sunday directed Trinamool supporters to hold “return black money” demonstrations as a counter to the allegedly BJP-backed “return cut money” protests raging across the State.She was addressing the annual July 21 mega martyrs rally. “I am asking you to raise slogans demanding return of black money. There will be meeting in blocks and at booths demanding that the BJP return black money,” Ms. Banerjee said.During her hour-long speech, she raised several issues, including allegations of Central agencies threatening her party leaders over chit fund scams and the attack on the Vidyasagar statue during the Lok Sabha election. She proposed shunning electronic voting machines (EVMs) and holding polls for all civic bodies and panchayats using ballot papers. However, the BJP State unit called the rally a “flop show”. BJP State president Dilip Ghosh said his party was not involved in the “return cut money” protests. “It is her party people who are gheraoing their own leaders,” he said.last_img read more