uminous coal as a feedstock and produces 184,600 million Btu of liquid fuels. These two plant designs include capture and compression of slightly more than 85 percent of on-site carbon dioxide emissions. According to Gray and White (2007), the electricity required to compress the captured carbon dioxide in these cases is 53 MW.
The bituminous CTL plant consumes 17,987 tons of coal per day representing an energy input of 424,493 million Btu (HHV) per day and a carbon input of 11,541 tons per day (SSEB, 2006, Appendix D). From Table B.4, the carbon content of the ﬁnal liquid products is 3,871 tons per day, with an energy content of 181,600 million Btu. From these parameters, we estimate that the net emissions for the bituminous CTL plant (including naphtha upgrading) without carbon capture and sequestration would be 309.7 pounds CDE per million Btu (HHV) of liquid fuel produced. Assuming 90-percent capture and sequestration of plant site emissions (including those associated with naphtha upgrading), we estimate that the bituminous coal plant with carbon capture and sequestration would release 31.0 pounds CDE per million Btu (HHV) of liquid fuel produced.
For the subbituminous CTL plant analyzed by Gray, 22,988 tons of coal per day are consumed, representing an energy input of 390,796 million Btu (HHV) per day and a carbon input of 11,200 tons per day (SSEB, 2006). Using these param- eters and Table B.4, we estimate that the net emissions from a subbituminous CTL plant (including naphtha upgrading) without carbon capture and seqestration would be 303.1 pounds CDE per million Btu (HHV) of liquid fuel produced. Assuming 90-percent capture and sequestration of plant-site emissions (including those associated with naphtha upgrading), we estimate that the subbituminous CTL plant with carbon capture and sequestration would release 30.3 pounds CDE per million Btu (HHV) of liquid fuel produced.
To calculate displaced carbon dioxide emissions, we assume a carbon dioxide–emission factor of 2.09 pounds per 10,000 Btu of coal consumed, based on EIA data for 2006 (EIA, 2008d, Tables 2.1f, 12.3). For CTL plants not employing carbon capture and sequestration, we assume that the coproduced electricity will displace power from a new coal-ﬁred power plant operating at an average annual heat rate of 7,900 Btu per kWh, which is possible from an advanced IGCC plant with a design heat rate of 7,600 Btu per kWh.6 (See case 3D in Buchanan, Schoﬀ, and White, 2002). These assumptions yield a carbon dioxide credit of 1.65 pounds per kWh of electricity sold by the CTL plant.
We assume that the CBTL plant (and an associated naphtha-upgrading plant) would produce the energy equivalent of 10,360 bpd of FT diesel fuel containing 1,157 tons of carbon7 and emit (in the case with no carbon capture) 2,456 tons of carbon per day in the form of carbon dioxide. We assume that the plant, including the upgrading plant, captures and sequesters 90 percent of the carbon dioxide from all process streams, so that emissions are 900 tons of carbon dioxide per day. Relevant fuel properties used in the analysis are listed in Table B.1.
Biomass Carbon Credit. Through photosynthesis, the switchgrass converted 6,845 tons of carbon dioxide into 1,867 tons of carbon. The carbon in the switchgrass forms a closed loop with the atmosphere and reduces net emissions of carbon dioxide by 6,845 tons per day or, equivalently, 31.5 pounds per gallon of upgraded FT liquids.
This appendix documents the policy analysis that underlies the discussion in Chapter Five of how future world petroleum prices might respond to increases in production of alternative liquid fuels. It starts with a brief discussion of factors that shaped our approach to modeling the global market for liquid fuels. It then presents the model and the formulas for OPEC export revenues, consumer surplus, and producer surplus that emerge from that model. It reports numerical ﬁndings about how increases in the production of alternative fuels could aﬀect world petroleum prices, OPEC export rev- enues, and consumer and producer surpluses in the United States. It concludes with a brief discussion of the ﬁndings and their policy relevance.
Our choice of reservation price has no direct eﬀect on our policy-relevant ﬁndings. In the analysis that follows, we establish that reservation price by forcing our model to agree with recent EIA price projections using price elasticities that emerge from recent empirical studies. The higher reservation prices that we calculate allow us to reconcile higher absolute values of price elasticities, within the range of recent empirical estimates, with EIA’s price projections. These higher absolute values of elasticities tend to increase the level of the eﬀects we measure. But they lie well within the range of reasonable estimates of elasticity values discussed next.
Before describing the model, we oﬀer a further perspective on our assumptions about long-term oil prices. World oil prices in early 2008 were well above the range that we use in this analysis. As noted in the text, however, we doubt that such high oil prices can be persistently sustained over the future period relevant to our analysis. Though we acknowledge that crude oil prices may continue to be volatile and that, occasionally, crude oil prices might signiﬁcantly exceed even the very high levels experienced in 2008, the crude oil prices relevant to our analyses are real prices averaged over a period of at least 35 years of ongoing investment and increasing production.
9 The ranges we chose for elasticity values are based on estimates reported in Cooper (2003), Gately and Hun- tington (2002), Greene and Ahmad (2005), and Huntington (1991, 1994).
bent up in symbols known only to you.
and dark skin draped eyelids to hold in the ball.
an arrow pointing up or one pointing down.
sorrows salty like seas and easier to drown in.
sometimes invisible, but seen when you yell.
but you can.
What role should frustration have in the player’s experience of a game?
It’s a tricky question. For a while game designers assumed the answer was ‘none’, that frustration was an inherently unpleasant experience with nothing to offer, that it stood opposed to everything that players play games for. This opinion seems to have eroded over the years, as attempts to reduce player frustration ended predictably in tepid, milquetoast game experiences.
This question is made more complex because frustration is such a personal reaction The game can present the challenges and the unpleasant surprises, but whether the player finds them frustrating is a matter just as much of their personal outlook as it is of the content of the game. Some people get frustrated by even the slight puzzling challenges of a narrative adventure game, while others find the die/restart loop of ultra-hard ‘maso-core’ platformers relaxing. Sometimes these may even be the same people! In fact, being frustrated has as much to do with how hard we think something should be as it does with how hard we think it is. Thus, the unexpected challenge presented by the narrative game feels like an affront, while the repeated deaths of the hard platformer feel like, well, pretty much what the player signed on for when they booted up the game.
One reason why Dark Souls has done well from being difficult is because it’s extraordinarily up-front about being difficult. This has a number of unfortunate side effects, such as its more ignorant or obstreperous players believing that because they’ve beaten a video game they know what real adversity is or putting down players of other games as being somehow lesser gamers – or, conversely, the game’s reputation scaring away potential players who might otherwise be amenable to its patient and minimalistic, if unforgiving, approach to gameplay and storytelling. Demonstrating to people up front what they can expect from your game, what kind and what degree of challenge, is a way of nipping unpleasurable frustration in the bud, of saying beforehand “if you’re having trouble here, it’s because you’re trying to do something hard, not because there’s something wrong with you.” That is, at least, on the first playthrough: After a hiatus, I’m always dismayed when I come back to Dark Souls and find that all of the things I’d remembered being easy have suddenly become difficult again. I was supposed to be good at this, dammit!
Thus, as designers, we can reduce player frustration, not by making everything easy, but by making it clear what is going to be challenging and why. Which answers one question, but leaves another open: Players are still going to be frustrated, even if you make efforts to reduce this, but can frustration be a rewarding experience itself? I would contend so, for the same reason that it’s impossible to completely remove frustration from the gameplay experience: Being frustrated is a big part of life, and learning how to cope with that in a safe environment can be useful and interesting – even, dare I say it, fun. Working past the frustration, finding the calm within the storm, not just solving the problem but addressing the anger that is keeping you from solving the problem, these are moments of epiphany that games can offer.
Conversely, as a player – no, rather, as a person trying to solve a problem – avoiding the expectation of being great at something, avoiding the belief that something should be easy