Saturday, February 16, 2013

Solar Energy Technologies

These are notes from Renewable Energy Futures Study.
  • Introduction
    • US population uses about 4,000 TWh of electrical energy each year
    • about the amount of solar energy that falls on US every few hours
    • fraction of generation is small but rapidly growing 3,400 MW in 2011
    • generating technologies began in 1970s, 80s
    • solar deployment initially dominated by CSP(Concentrating Solar Power) until PV became more popular around 2005
  • Resource Availability Estimates
    • Solar energy contains both a direct and diffuse component
    • direct accounts for 60-80% of surface solar insolation and is needed for high efficiencies for solar technologies
    • CSP is more reliant on direct components than PV or passive heating
    • Solar resource greatest in southwestern united states but generally high in most parts of the united states except alaska and pacific northwest
    • i.e. Germany is world leader in PV but has less than 40% efficiency as systems in LA
  • Technology Characterization
    • Solar Photovoltaics
      • PV convert sunlight into electricity through excitation from ground state
      • several technologies deployed at gigawatt scale
      • Emerging tech
        • Copper indium gallium diselenide thin films
        • concentrating PV
        • organic PV cells
    • Concentrating Solar Power
      • CSP uses lenses or mirrors to focus sunlight onto receiver to heat fluid
      • Parabolic trough systems, first commercialized in 1984, 96% of global deployment
        • 1 axis track linear receiver to focus sunlight
        • Dish uses 2 axis tracking
    • Other Solar Technlogies
      • water heating, space heating, cooling, and lighting, displace end use electricity
  • Technologies included in RE Future Scenario Analysis
    • PV Markets
      • grid connected residential rooftop PV
      • grid-connected commercial rooftop PV
      • distributed utility scale PV
      • central utility scale PV
    • CSP technologies
      • trough systems no storage
      • trough with thermal energy storage
      • tower systems with thermal energy storage
  • Technology Cost and Performance
    • steady trend of improvement
    • RE technology costs RE-ETI (renewable electricity evolutionary technology improvement)
      • represents more complete implementation of renewables
    • RE-ITI (renewable electricity incremental technology improvement)
      • represents only a partial achievement of potential technologies
    • Solar costs refer to bottom up estimates of materials, manufacturing, installation
    • Solar prices refer to market price of PV
  • Solar Photovoltaics Cost and Performance
    • since 1980s, factory gate module prices have decreased
  • Engineering Analysis of Advancement Potential for Solar Photovoltaics
    • PV Prices will improve from increasing module efficiencies, manufacturing throughput, reducing wafer thickness
    • PV market dominated by multi crystalline and mono crystalline PV dominates about 85% of global market
      • thin film cadmium telluride represents a significant other portion
    • Balance of systems costs for solar photovoltaics
      • BOS includes cost of inverters, transformers, support structures, mounting hardware, electrical protection devices, wiring, monitoring equipment, shipping, land, installation labor, permitting, and fees $1-4 per watt
      • Hard BOS
        • increase module efficiency, reduce size of installation
        • developing racking systems to enhance energy production and integrate them into modules
        • create standardized package systems and supply chains
        • improve inverter price/performance
      • Soft BOS
        • reduce supply chain margins
        • create standardized practices
        • expand financing plans
  • Solar cost projections in the SunShot vision study
    • in 2011 the Department of Energy launched the SunShot Initiative
    • push solar energy to become competitive with retail tech
      • PV target to reach $1 per watt for utility scale systems, and 1.25 for commercial rooftop scale PV, and $1.50 for residential rooftop
      • CSP targeted to reach $3.60 for systems with 14 hour storage
    • RE futures modeling scenarios do not reach these price and performance targets
  • Resource Cost Curves
    • curves developed for rooftop PV, distributed PV, central utility PV, and CSP
      • derived using solar resource characteristics from NREL's National Solar Radiation Database and the National Land Cover Data
    • The following table describes the supply curves for PV
    • Rooftop PV has technical potential of 700 GW in US
    • Distributed Utility PV has about 2,000 GW
    • Technical potential of central utility PV about 80,000 GW
      • land availability not likely to limit PV deployment
  • Output Characteristics and Grid Service Possibilities
    • Solar Electricity consists of 2 distinct technologies with different generation characteristics
    • PV provides DC in the range from 100-200W, then converted into utility grade power with 60 Hz frequency
    • PV fluctuation in production varies, even more than wind generation
      • Depends on cloud variability, short time variations
      • CSP systems have much less short term variability due to thermal inertia of system
      • CSP with storage viable to improve power quality, voltage, frequency stability
    • Advantages
      • PV generation curve does match peak load which occurs during the day
      • PV reduces line losses due to distributed generation
  • Technology Options for Power System Services
    • Utilize inverter's power electronics
    • reactive power, voltage control, and low voltage ride through
  • Large Scale Production and Deployment Issues
    • Environmental and social impacts
      • land area required for PV and CSP is very large
      • PV is modular, can be sited virtually anywhere, CSP has more specified locations
    • Water Use
      • CSP consumes water through evaporation, PV requires only maintenance water
    • Life cycle Greenhouse Gases
      • life cycle greenhouse gas emissions insignificant in comparison to power generation
      • 45.5g carbon dioxide for PV, 19.0g carbon dioxide for CSP 
    • Other Impacts
      • CSP often use oil or salt heat transfer fluid, which is not risk free
      • glare from PV can cause risk to nearby persons
  • Manufacturing and Deployment Challenges
    • scale up capital is necessary
    • availability of raw materials shouldn't be an issue, byproducts of electrolytic copper refining can be used for PV, cadmium telluride
    • Indium is byproduct of zinc refining
    • Material for silicon PV virtually unlimited
    • High up front costs, low operating costs
    • Human resources needed for design, manufacture, installation, and maintanence
  • Conclusions
    • fraction of solar usage is currently small but growing rapidly
    • it faces mainly the issues of high upfront cost, and regulations especially for rooftop pv, local legislature can limit growth
    • large scale deployment may cause landscape change

Friday, February 15, 2013

DnD Tower Campaign - The Beginning


Sleep, if you're not dreaming, how do you know time passes? Have you ever had a dream where you just lie down, then suddenly you wake up? There's no way to know how long you've been asleep. That's what happened to everyone in the world. You've been awake for only a short time, recently woken up in a strange room surrounded by a horde of unfamiliar people. They told you that you've been asleep for decades. They recognized that you had weapons and armor nearby, or perhaps a spell book and brought you into their halls. These people are called the Reclaimers and you're now one of their recuits. All the other recruits have a similar story some have only been awake for a few days others for a full month. Oh you get to go back to sleep, its not like your awake all the time, but you haven't fallen back into "sleep". You have been told that you must fight for a cause and today the senior Reclaimers have gathered you into an audience room to explain the history of the world. An old man walks into the room, and begins telling us some stories.

Recruits, Its time for a history lesson so gather round and listen well...
He tells you stories about the towers.
The first tower was taken down by a band of adventurers who spread the word of a being called he who sleeps that holds most of the world in thrall.

The First TowerThe second tower was taken down by a group of adventurers who found out that the towers could be warped and twisted with dark magic to serve mortals.
The Second TowerThe third tower was taken down by a group of adventurers who found out that the towers were evolving or growing in complexity, manifesting the combined dreams of an army of thousands.
The Third TowerThe old man in finishes telling his stories.

My name is Tom. I allied with some of the heroes who took down the initial towers, and created this organization. Our task is simple, take down the towers to fully awaken the world and return it to normality, defeat the dreamers who seek to either control or protect the towers, and to protect the people who have awakened from threats that have also awakened.

It is your duty to do this regardless of the affiliation you had prior to falling asleep. Not even the gods are fully able to interact with this world anymore due to He Who Sleeps, so whoever you followed before cannot guide you now. You will aid senior members as they venture out to take down towers, but your goal is to take care of the communities that have awakened. Later on when you have become more powerful you can aid in the destruction of the towers, but as of right now we know your fighting strength is not nearly enough to take them down. It would just cause your deaths. Frankly we are understaffed and we need help to take care of the villagers, and we need your help to do so.

Casts dancing lights

You four come with me. The newly formed group of adventurers ventures outside of the room and see two men and one woman. You will accompany Thrace, Theska, and Ana to the town of Tesser. Thrace will fill you in on the details.
(Thrace is duskblade, Ana is beguiler Theska is Dragon Shaman.)

Tom leaves and Thrace speaks.

There’s a tower near the town Tesser. The people there reported raids from some kobolds in the nearby area. They have someone tracking the location of them but they need help in order to wipe them out. We’ll rendezvous with you and return back here afterwards. If we take longer than a week to destroy the tower, return without us.

The group uneventfully travels to Tesser. There isn't much time so the recruits and seniors just work together on their own teamwork along the way. Upon arrival at Tesser, the town mayor greets the groups.

"Thank God you arrived, please the tower's to the south, as you can plainly see. We've also managed to locate the kobolds at a hillside a few miles east from the town, quickly I can guide you there!"

The group splits up to their assigned tasks.
Party ends up defeating the kobolds wandering the hillside and some pseudonatural bears.

Party begins exploration of the cave. They manage to defeat a few more groups of kobolds in the area but get pushed back and retreat to the town.

The weather has changed slightly, although it was previously sunny, it is now much colder and it appears that a fog has rolled in. Thao has acquired a riding dog from local residents as thanks for their work, and the townsfolk provide the party with 3 potions of cure light wounds.

The party hears a loud drum at the side of the town, a
lizardfolk accompanied by two elemental grues walk in holding a human prisoner. “You dare attack our coalition! Filthy Humans! We captured this human snooping around our camp and we know there were others that came from this village! Bring them forth so that we may exact retribution!” After some banter the lizardfolk commands his elementals to attack but he himself gets quickly dispatched with one sapphire nightmare strike from Sablefox.

“My name is Gil, thanks for saving me! I was the one who found the location of the cave, and informed the mayor, but I didn’t think he’d send you there so quickly! I haven’t finished scoping out the full force of what we have to deal with.

“The problem is far worse than I originally thought. Something has organized the monsters in the wilds and they’ve been preparing for an assault on this village for a long time already. How do you want to deal with it?”

  1. There’s a small summoning shaman they’ve been using to summon elementals, they’ve amassed a small force that could be devastating to the village. This is within the cave.
  2. Attack a separate group of pseudonatural lizardfolk to the north of town of the town.
  3. The main force of kobolds are amassing near the west of town directly attack them.
  4. Arrange a defense, prepare for a stand in the center of the village, gather civilians into buildings near the center of town.

The party meets a weapon smith named Zur who gave them all access to his smithy and gave them masterwork weapons.

Thursday, February 14, 2013

DnD Towers Campaign - Third Tower

The Third Tower

The story of the third tower is both grand and simple. It serves as a warning to always be vigilant of what towers are capable of. In this case a band of powerful warriors ascended to slay a tower. When the entered, they saw something truly amazing. The interior of the tower was not limited to the size seen from the outside, they arrived in the middle of a gigantic battlefield in an open plain next to a forest. They became part of the dream world created inside this tower and became members of the losing army. A few hundred against a horde of thousands.

Through deception and trickery they managed to isolate the generals of the opposing army away from one another and assassinate them. Even though their bluffs weren’t always successful, through luck and coincidence everything worked out to let them fight in small skirmishes instead of facing the might of the entire army working against them. In the end the sheer battle strength of this group of adventurers proved too much for the dream army and they emerged victorious, defeating the tower and destroying it.

This goes to show that you never know what to expect inside a tower, the possibilities are endless, and you must rely on your wits and teamwork in order to have any hope of prevailing against these towers.

Thank you for your patience young Reclaimers. My name is Tom the Bard and I wish you luck in your travels! Now we shall split you into teams in order to address some urgent situations at hand.

DnD Towers Campaign - Second Tower

The Second Tower

The tale of the second tower is a bit different from the first. Why do we call it the second tower? Was it the second tower to fall? In fact, it wasn’t. Heroes were taking down towers left and right, freeing more and more people from their sleep. Many towers fell before this one. Its called the second tower because it is the second most significant tower that was destroyed. 

A group of adventurers different from the first woke up to a town under siege. A small group of demons were attacking the townsfolk and the adventurers rushed out to fight them. Luckily, they were so strong that the demons were defeated with ease. The townsfolk told them about how one day these attack just started happening, and it seems that the demons emerge from the tower floating nearby. Again this tower was different from the first, normally a tower is seen just hovering above empty ground, but this time it floated above a gigantic magical glyph.

The heroes went up to the tower and found the entrance charred and partially destroyed, which was odd since the tower seemed in no danger of falling despite the damage. The heroes cautiously entered into the tower and were greeted by a well organized team of adventurers. Although individually weak, they worked extremely well in tandem and nearly defeated our heroes. However when they were defeated they did not fade into mist, they simply died. The enemies in this tower were not figments of dreams, they were real people!

As they approached the entrance to the next level in the tower, they heard the sounds of a corpse being dragged across the ground. They entered in and found two swordmages, one which drew power from the shadows and another who drew power from his draconic heritage. They were disposing the bodies of a group of adventurers that they had just defeated, and so our heroes were able to take advantage of their fatigue and overwhelm them. Once again their corpses remained.

In the final level of the tower the heroes took down a powerful necromancer who summoned undead dragons to fight against them. It turned out that this necromancer perverted the tower to his own uses in order to summon demons and send the dream beings out of the tower to attempt to conquer the surrounding areas. Luckily, he didn’t have very much time to practice this power before the heroes defeated him so his control over the tower was still weak despite the massive amounts of work put into the glyph below and on the walls of the tower. The other people in the tower were all disciples of the necromancer and were following orders to help set up the controlling glyphs and defend against intruders.

This was the first recorded attempt of someone using a tower to his own ends instead of trying to destroy it, and others would follow his example. Some folk even formed cults in order to keep the towers standing in the hopes that they would be drawn back into the magical sleep of the tower. We named these people collectively as dreamers. There isn’t an organization of dreamers yet, but these madmen have grown in number over the years and pose a significant threat to the goals of the reclaimers. This is our second enemy.

Friday, February 8, 2013

Energy Water Nexus

These are notes from Energy Water Nexus.

  • Water: a new vulnerability in the energy system
    • Through looking at the world from space we think we have an abundance of water
    • less than 3% of water is fresh
      • 2.5% of fresh water frozen in glaciers
      • only .5% easily accessible in aquifers, lakes, rivers, or wetland
    • Freshwater is unevenly allocated
    • 60% of Earth's water controlled by
      • Brazil, Russia, China, Canada, Indonesia, USA, India, Columbia, and the Democratic Republic of Congo
      • Australia faces water scarcity
      • Developing nations also pose an issue
    • Potential inability to match water demands
    • Water is consumed in industry for high income countries
    • One billion lack access to fresh drinking water
  • Linkage between water and energy
    • energy is used to pump, move and treat water
    • water is often used for energy, from water mills to hydro dams
    • global population and economic growth continues, despite water shortage
  • A more water-constrained future
    • huge urbanization rates of Asia, Latin America, and Africa
      • energy and water security national level problems
    • Climate change due to global warming adds to water stress
    • approach to preserve present level of comfort while improving energy efficiency in developed nations
  • Water requirements in the energy sector
    • freshwater required for many steps of energy generation
      • extraction, production, refining, processing, transportation, storage and generation
      • North america consumes 1/4 of world's energy
  • Fuel Production
    • water consumption varies with energy utilization
    • developing nations often use biomass and solar in ways difficult to measure
    • Crude Oil
      • highest energy production rate
      • 1.058 m3 water needed per Gigajoule of energy from oil
      • oil accounts for 34% of current energy production
      • hope to decrease to 22% by 2050
      • Asia accounts for more than 40% of worlds water consumption due to oil 
    • Natural Gas
      • gas production due to double over the next 40 years
      • Water consumption due to gas is low
      • 0.109 mof water needed per GigaJoule
      • Horizontal drilling and other extraction techniques making gas more viable
      • water used is recoverable but contains contaminants
    • Coal
      • Energy from coal below oil but likely to rise
      • 0.164 mof water needed per GigaJoule
    • Uranium
      • Energy accounts for only 6% of energy production in world
      • 0.086 mof water needed per GigaJoule
    • Biomass
      • considered "fuel for the poor"
      • inefficient and highly polluting
      • wood, agro, municipal by products
  • Electricity Production
    • Thermoelectric Plants
      • all fuel types need cooling and process water
      • differentiated between once-through and recirculating systems
      • wet recirculating systems about 40% more expensive than once through
      • dry cooling is 3-4 times more expensive than wet
      • once-through loses 1%
      • recirculation, less than 1% drawn from source, lose 70-90% lost through evaporation
      • recirculating system consumes 10 times the amount of water
      • Subcritical and Supercritical types of Pulverized Coal plants
        • supercritical more efficient
        • subcritical older and more commonly used
      • Integrated Gasification Combined Cycle
        • turns coal into synthetic gas then uses that gas to heat water
      • Combined Cycle Gas Turbine
        • gas turbine generates electricity, waste heat used to make steam to generate more electricity
      • Natural Gas Combine cycle
        • majority of water used for cooling, lowest in comparison with other fossil fuel techniques
      • Nuclear Plants
        • have higher cooling tower, water consumption high
    • Carbon Capture and Storage
      • development of carbon capture and storage technologies used to meet climate change standards
      • reduces emissions by 80-85%
      • requires more water
    • Hydroelectric Power Plants
      • largest generator of renewable energy
      • water not really lost but reservoir creation can cause additional evaporation
        • significant for smaller power plants
    • Electricity from wind and solar
      • minor amounts for both PV and Wind power mainly for cleaning and maintenance
      • Water consumption to generate electricity may double in the next 40 years as we move to cleaner technologies

Wednesday, February 6, 2013

EPA Coal Plant Regulations

These are notes from EPA Emission Regulations.
  • Proposed emission rules for EPA spell gradual demise of coal power generation
    • set a standard within capabilities of gas fired plants but impossible for coal w/o carbon capture and storage technology
    • transitional exemption to make change gradual
    • makes coal more expensive
  • Natural Gas has recently had a boom
    • EPA wants to entrench current advantage of gas
  • Limiting coal is part of a larger scheme to remake energy industry
  • EPA picks fights with coal-state democrats
    • aggressive pushes to control emissions
    • multiplying congressional enemies
  • Most promising technology integrated gasification with integrated carbon capture and storage
    • nowhere near commercial use
  • Dangerous powers for an organization to have
    • through the use of regulations, EPA has controls on which industries can succeed or fail in the energy industry
    • EPA has the ability to bypass Congress
    • however the powers currently being used are done with forewarning