Just to avoid confusing the innumerate among us, you are correct that if there is an excess of deaths over births that would lead to a population decaying at 7% per year, then half the initial population would be gone in about ten years. I merely pointed out that your statement could be read as saying that if B and D are birth and death rates, then you might have meant D=1.07B rather than D-B=.07 per year. It would be truly wrenching for the world to cope with a 7% per year death rate.
EROEI is an acronym for energy returned on energy invested. It sounds like a straight forward calculation to make, but there are secondary and tertiary effects that muddy the water. I just searched for "Ethanol EROEI" on duckduckgo.com and opened up the first link. It was an article posted on peakoil.com where the author discusses methodology that USDA has incorporated to produce reported results … and how the methodology has changed over time to produce improving results. This article was written in 2010, so the information is somewhat dated, but still is useful.
http://peakoil.com/alternative-energy/the-eroei-of-ethanolThe range of EROEI in the USDA reports is 1.06 to 2.34. I remember seeing other, more complete analyses that include some of the excluded inputs (e.g. mining iron ore to make tractors that farm the corn) that report an EROEI of 0.78. It is hard to estimate the cost of excess fertilizers or lost soil washing down to the dead zone in the Gulf of Mexico. If efforts to clean the runoff from farms were included, the numbers would all be lower.So if we keep the accounting methodologies consistent, here are the ethanol-only energy returns (ethanol output/total energy input) from the raw data in the USDA reports:
2002 – 1.09
2004 – 1.06
2010 – 1.42Here are the ethanol plus byproduct energy returns (ethanol plus byproduct output/total energy input):
2002 – 1.27
2004 – 1.26
2010 – 1.69Here are the ratios from utilizing the USDA’s 2002 methodology (subtracting byproducts from the inputs) across all three reports:
2002 – 1.34
2004 – 1.32
2010 – 1.93Finally, the ratios that the USDA highlighted and reported across all three reports:
2002 – 1.34
2004 – 1.67
2010 – 2.34Conclusions
That is a respectable improvement to be sure, but we should keep in mind that they have admittedly not accounted for certain inputs (the secondary inputs they mentioned in the 2004 reports). But it also begs the question of whether the USDA’s methodologies are unbiased, or whether there is a consistent pattern of favoring calculation methods that inflate ethanol’s energy return. (If the EROEI for gasoline was calculated in this manner, it would be greater than 10:1 because fuel gas is generated in the process that is fed back into the refinery).
One final word about energy allocations for byproducts. If the idea is to find a scalable replacement for gasoline, consideration must be given to the amount of byproducts that result as the scale of fuel production is increased. At some point, the byproducts can saturate the market, which can cause other unintended consequences. This is the case with biodiesel and the glycerin byproduct that results; biodiesel producers often have a hard time getting rid of the byproduct.
For that reason, when I consider ethanol as a replacement contender for gasoline, I am more interested in the expenditure of energy to produce ethanol, and less interested in how creative we can get with allocating energy inputs to byproducts. In any case, what was approximately one BTU of ethanol output for one BTU of ethanol input in 2002 is now 1.4 BTUs of ethanol out for 1 BTU in, with the caveat that secondary inputs have not been considered.
Because all US presidential elections begin in Iowa, and Iowa is a corn producer, successful candidates have to support ethanol production. Whether it is through subsidies or mandates to force incorporation into gasoline, it enriches Iowa at the expense of others. It also empowers GMO makers such as Monsanto because the corn is grown only to produce ethanol and not for human consumption.
Rather than looking at the real costs/benefits/effects of ethanol production, most people support this because it appears to make us more energy independent and appears to be a one of those partial solutions that contribute to solving peak oil and global warming. They feel like they're doing something.
From what I remember, methanol production from hemp is a much better alternative for the users and environment. (I'd search for a link, but garden work calls.) Unfortunately, the "reefer madness" hysteria continues to be promulgated by big business interests who profit enormously from corn and ethanol. Beliefs and fears (which are easy to manipulate) overwhelm real science in the political arena.
Grover
Hey Grover,
Excellent post. I began in engineering before switching over to 'science' so what you are saying resonates strongly with me. You are spot on with addressing a defined problem. Things get a bit murkier with a high risk, poorly understood situation. I was being somewhat facetious when saying to do "something, anything". The subtext should have been, 'something, anything among the many options that we have already developed'. When people talk about the IPCC reports (myself included) we are generally referring to the Working Group I, The Physical Science Basis report, but most people don't know that there are two more accompanying tomes, Working Group II, Impacts, Adaptation, and Vulnerability, and Working Group III, Mitigation of Climate Change.
In short, there has been a lot of thinking and work on the subjects of mitigation and adaptation that has been done though it is necessarily less advanced than the physical science since you need to understand what is going on to effectively respond to it. Actions can take two forms, those which are (1) generic and not location specific, and those which are (2) targeted and location dependent. Option 1 would be things like someone deciding to turn down their thermostat this winter to burn less oil and thereby help 'mitigate' global carbon emissions. It doesn't matter where this is done as the effect, however miniscule, will be globally experienced. Incidentally, we got into this situation through the cumulative miniscule actions of people around the planet so we shouldn't scoff at people making such efforts. Note, I am side stepping the whack a mole idea of potentially lowering emissions in one place yielding higher ones somewhere else. This isn't as obvious as typically assumed and has a lot to do with (dis)incentives, fodder for a different discussion.
Option 2 has much more to do with most adaptations. The effectiveness or appropriateness of what is done has everything to do with location. Building a sea wall for Miami makes no sense because of the porous substrate it sits on, while putting one on the Thames to protect London has made a difference, though it will eventually have to be replaced with a bigger one.
At the time of its construction, the barrier was expected to be used 2–3 times per year. It is now being used 6–7 times per year. (link)Any strategies undertaken require understanding of the challenges faced but decisions will be functions of location, resources and values. One cannot state categorically whether or not an action 'makes sense' based on the same flawed economic models that got us into our environmental dilemmas. Ignoring so-called 'externalities' of the uncertain or inconvenient impacts of our actions is a recipe for shortsightedness while ignoring the positive externalities of adaptation and mitigation efforts is a recipe for inaction. I work a lot with analogy because it can illustrate complicated concepts in understandable ways. In this case, take the example of a baby's first steps. Taking that first step is risky with a high likelihood of failure, pain and potentially even injury or death if not carefully supervised. If your time horizon is short, that 'investment' makes no sense, however, I think that we would all agree that it is critical to make for future success of the child. It is a no-brainer for us (parents) because we have the hindsight of experience knowing the development of those motor skills will pay of handsomely but for the child, at the time, it is nothing more than a leap of faith. We are ignorant children in terms of climate change.
We do have to get off of our collective asses and start moving. We are not 'jumping the gun' in that but we can't pretend that we have perfect knowledge of how to proceed, but then again we never will since this is the first time climate management has been necessary. I hear your fears about others claiming they have 'solutions' or a clear path that will be used to stampede the masses off the next cliff. It is a very realistic concern and I have enough knowledge of the situation to know what to fear. How many people know that geoengineering experiments are already underway, or that a single business man conducted his own unauthorized experiment to affect global climate? In part we can blame the fools who play at being gods, but we are all responsible if we are not also undertaking our own personal actions, however small. Why do I say that? Because through our collective inaction or apathy we are signaling big government or industry to 'save us'. If we are unwilling to lead by example then we will be led by others, perhaps to slaughter. We are unwilling to change and so we are therefore authorizing others to try to make sure that we do not have to. Fine print of the social contract… Put another way, if we do not make bottom up efforts at managing things, top down ones will be visited upon us that we have not necessarily agreed to.
In my teaching I open all of my courses with the statement "I can't make you think, but I will do my utmost to ensure that you do in this class". I do not see teaching as the simple conveyance of information, what I strive to do is to make students, or anyone, think critically about whatever they are being fed in this world, be it from me or anyone else. Should you accept/believe this paper or person? Why or why not? I emphasize the predicament versus problem nature of AGW from the geopolitical to the personal level. Why do the Chinese want to talk about emissions on a per capita basis while the US wants to discuss it on a per unit-GDP basis? Africa and the developing world want to talk historical emissions, the developed world does not… I am perhaps somewhat subversive in sprinkling in geopolitical commentary and infusing everything with the 3-E's but it all seems to engage people. My classes generally run 30-60 minutes long after I end the official 'graded' class because students want to keep discussing matters and wont leave. I think that there is a hunger for serious discussion and debate of issues and I have yet to be accused of inducing 'micro-aggressions' for all of my provocative questions! Knock on wood.
In lectures I have to say that the most inevitable question is, what do we do about this on a personal basis? I've been trying to answer that question in an honest and believable fashion all these years in class and in my personal life. I disappoint myself every time, but I keep trying.
Cheers,
Mark
P.S. Thank you for the kind words, they mean a great deal.
Because through our collective inaction or apathyToday I resolve to do my bit with apathy. I am going to spend Sunday in quiet repose burning a minimim of coal. Just for the kettle and for my Ipad. I could do better and read my book on Schrödinger's achievements, but the internet is far more interactive. Not being able to argue with a book is very frustrating.
The biggest problem with biofuels is that they aren't scalable, which is another "inconvenient truth" that the promoters always overlook. They are great as cute niche markets but if you try to run a global economy with them… even if you can magically get 2:1 EROEI, you will quickly find that there won't be nearly enough land, and that food vs. biofuels would become the new conflict. Those guys running biodiesel in their trucks from McDonalds french fry fryers, how many french fires would we have to eat to supply everyone with that?
The only energy sources that are scalable to run an economy are solar, nuclear and to some extent wind. I'm not placing my bets on nuclear given its arguably low EROEI when you factor everything into it, and the amount of national cohesion required to build and run such a complicated system. Wind looks nice but the future is in solar energy, if we're looking for something to fall back on to save humanity from a 95% population die-off.
I find it hard to believe that this thread has veered so far off course to be agonizing over pedantic issues such as the EROI on biofuels. To continue the population debate as an issue of paramount importance in the over all discussion, goes without saying. Mr Shermer's tacit acceptance in techno-optimism and market forces as the hopeful answer to the impending direction of collapse, leaves a good deal to be desired, as well.
Perhaps it is time to revisit Charlie Hall and friends for realistic elucidation of where we need to be on the EROI scale to have any hope of redemption for this sick planet. We don't hear much from Nate Hagens anymore, because he got tired of beating his gums to no avail and, I think, Charlie Hall is out in Montana fly fishing enjoying what life he has left. If we all got back to recognizing what the environment does for us as a species, perhaps, then we could foment realistic change. Solar thermal, yes; growing your own food, yes; riding your bike to work, yes; having chickens or sheep mow your lawn,yes.
Try measuring the total number of Joules you use on a individual basis and style your life to that metric. You will quickly find that reducing your square feet of living space or turning off the lights or turning down the thermostat can have a tremendous effect on your eco-footprint. Until we all take that seriously, we will continue to be less that good stewards of life's blessings. Put it in perspective.
Mark-BC wrote:Biofuels are simply solar energy one step removed and liquefied. Having such a liquid fuel has great utility and may be a reasonable use of 'waste' biomass but once you start growing things soely to feed into a digester you are simply taking food from someone or something (other species matter) in order to burn. Switch grass and oil palm don't just grow anywhere. The total net primary productivity of entire surface area of the United States would not provide enough biofuel to run our country, even if the energetics made sense (i.e. EROEI significantly greater than 1). There is also the little detail of having no food, forests or natural vegetation remaining even if we could do such a thing. Algae will not save us from math either. Can you imagine the logistical and energy problems of coating the SW with water to grow it? Biofuel is and will continue to be a niche market. Some locations (e.g. Brazil) can make a substantial amount of biofuel but even there 'growth' of automobile use has outstripped biofuel capacity.The biggest problem with biofuels is that they aren't scalable
All 'alternative' fuels have 'alternative' costs. Nuclear energy yields waste issues and risks of the next Chernobyl, Japan etc. Maybe if we get thorium reactors working we could scale up globally but there simply isn't enough uranium available to massively convert energy systems, even if public opinion would accept a nuclear build out. Fusion continues to be decades away from a working prototype (it was 30 years away when I worked at the MIT plasma fusion reactor 27 years ago - and it still is decades away…). I continue to hope for a breakthrough but hope is not a strategy.
Building massive wind farms starts to change surface wind fields with unknown effects on local weather patterns, as well as creating an eyesore. They are all around me these days. Recent work seems to show the effects might be small, which could be good but how this scales over space and time is still an open question.
Solar farms mean that sunlight either will not be growing something or that you are covering something bright like desert soil with dark panels. Yes, you harvest some electricity but you change albedo meaning that instead of reflecting light back to space with little climate impact you are heating the panels and transferring heat to the passing air.
There is no free lunch. None of this means we shouldn't ramp up alternative energy but we should be cognizant of the associated costs. The only way that these sources can rapidly become a large fraction of the energy that we use nationally/globally, in the relatively short term, will be if we dramatically reduce demand for energy at the same time.
Energy efficiency gains will continue to be the most cost efficient investment we can make. That is not the same thing as saying that it is the only approach we should be taking.
What I like about solar is it's scalable, from drying your clothes on the line to a solar hot water heater on your roof to a huge solar farm in the desert. The reason solar works is because it is the primary source of energy for all the others, except nuclear. So why take the hit and harvest energy one or two steps down? Doesn't make sense.
I love solar, especially as a distributed system on as many roofs as possible. It isn't a panacea but it could go a long ways toward making our power grid more robust and resilient. There will continue to be questions about associated resource use and long run sustainability but it is viable and scalable now. What I was alluding to are the giant solar farms. They may still be viable but there are associated externalities, though hopefully less than those associated with the fossil fuel systems they would replace.
The issue is that distributed intermittent power sources decrease stablity and resiliency:
-
Solar and wind power can have large swings in power output. For instance passing clouds and storms can cause panel output to drop by 50% or more with in a very short period. Unfortunately loads can not be changed abruptly which can cause brownouts, voltage spikes, and other electriical problems. Power Plants cannot not increase or decrease output as rapidly as a distributed PV/Wind systems can.
-
Regions with a large number of independent power sources can cause phase noise which can cause problems for transformers, electrical motors and other devices that require smooth and consistant power. A Grid tied invertor uses sampling from the grid to synchronize ouput to match the 60hz (or 50hz in Europe) as well as the signal phase. Since inverters are electronic switching devices, they tend to drift in frequency and in phase makeing the inverter output slightly offset from the grid. The more grid tied inverters connected the noiser the grid becomes as the noise makes it more difficult for the inverters to properly sync. This can cause transformers and motors to overheat. The phase noise introduced by a collection of inverters creates a feedback loop. As the phase noise increases the inverters have a more difficult time locking on the correct phase & frequency, causing the problem to gradually increase, even if no additional inverters are connected.
-
Grid was not designed for distributed power. The was designed to transfer power from large power plants to end users. Feeding power back into the grid can cause problem as transformers can saturate leading to overheating and transformer failures.
Tertiary delta wound transformers help a lot with noise (odd harmonics), and good old fashioned synchronous generators absolutely kill poor phase angles.
But you are right, the distribution grid is one complex machine. It's all about feedback loops. Perhaps AI can help replace very slow (poorly coupled) and error prone wetware.
TechGuy,
That is great information! So what do we do about it? It seems that if whatever output to the grid, from a house or business, is passed through a battery or other storage device that the rapid fluctuations can be managed to some degree. Basically each home should have a capacitor or equivalent to prevent massive swings in load. What specifications would be needed to reduce the problem substantially? A ramp of a millisecond, minute or hour?
In a world of aging infrastructure we can be assured of little other than increased outages in the future. Having recently experienced one myself, I think that having some home power for critical items at a minimum would be a lot more sensible from and individual point of view. It would also reduce desperation and potential riots if widespread enough when the inevitable large outages do occur.
With talk of smart grids, EMP pulses and what not, it would seem that we have plenty of incentive to build a more distributed and resilient grid. What do you think would really be entailed in doing it well? Obviously it is not plug and play for net metering as implied.
Interested in your thoughts on the matter.
TechGuy is correct about the present technology.
However, all the problems are easily solved at the local level by making self regulating, local resilience DIY grids at the local level.
I developed and am building DC electric grids that you basically do yourself. Build (or buy from me) a fairly small box that you plug in: a. your own solar panels, b. some appliances to be powered like coffee pots, electric grills, water heaters, computers, lights,etc. c. utility power back up, d. optional batteries for backup if desired, and e. connect to your neighbor via simple wire that you can buy at Home Depot.
I am commercializing this with some other guys in Chicago. (I walked away from my successful law firm in order to focus on this extremely hot area in technology that provides an energy escape plan from the present paradigm). I have published patent applications and (if you contact me directly and indicate confidentiality) possibly can even show a business plan. I plan to start selling next year but have prototypes to show off now. If you go to the solar expo in Las Vegas next month I can show you in person.
Mots
Get into reality…settle your mare…brown outs mean nothing to…third world countries… Or…
Da man… what you are doing is exactly what folk need. A good draft with harness, a miller and tanner would be of long term benefit.
Mark Wrote:
"That is great information! So what do we do about it? It seems that if whatever output to the grid, from a house or business, is passed through a battery or other storage device that the rapid fluctuations can be managed to some degree"
Well I don't see Grid tied inverters being the solution. At best a self reliant system that allows the home to either run completely off the grid or off-grid capable of using the grid as a source. The issue is that most solar systems are sold without a battery system due to the added cost and higher maintaince. Solar companies also are promoting grid tied systems so that the home-owner can sell power back into the grid on the assumption that it will reduce the payback time. Unfortunately Power companies buyback power at a substantianly lower cost then the cost the consumer is charged and most homeowners looking at Solar don't understand that.
The only way I can think of at the moment to support large scale distributed power grid, is if the Grid frequency was a Radio broadcast that could be used to constantly syncronized every inverter via Phase Lock Loop method, Although balancing Loads with supply will still remain a challenge. Every Applicance would need to be converted as a smart appliance and be able to recieve a broadcast do dial back loads, but that could still be a problem, if the load suddenly drops when too many devices turn off, or if terrorists rebroadcast false signal that cause all applicances to turn on or off suddenly. A Radio broadcast to control smart devices probably won't work since loads need would need to ramp up slowly. To summarize: its complicated!
I don't thnk alternative power systems would really prevent widespread and frequent blackouts in a failing economy. The reliably of the grid is an economical issue. The problem I see is that as a nations economic continues to decline there is less and less income to support an maintain the grid infrastruture. If a significant number of households switched over to solar, i think it would speed up the degration of the grid since their would be fewer people consuming power from the grid or consuming less power. The Grid is supported by consumption and not distributed power sources.
There are some other issues not discussed that involves the labor pool for electrical grid workers. Most of the grid workers are boomers which are retiring over the next 10 to 15 years, and they are likely to retire faster than replacements can be hired. Perhaps shortages can be accomidated by immigration of skilled power workers, but I suspect there is likely a global shortage of skilled power workers.
I really don't think we will see wide spread use of Solar or alternative power systems due to cost. Even if Solar prices continue to fall, most people won't have the money to spend for a solar system. In the US, Home ownership is now at a 40 year low and continues to fall as people can no longer afford their own homes. In the US & Europe, the middle class is shrinking due to a combination of outsourcing and automation. There are less and less middle class jobs as we can see the majority of millienials with college degees end up in low paying retail jobs. It think we will see the number of househood shrink and the number of people per household increase as people pool their declining wages together to support a household. The biggest economic hit to power companies is the loss of demand from industrial and commerical business as industrial production continues to move overseas and automation reduces the number for workers leading to less office space demand. We are already seeing large number or power plants being shutdown due to lack of demand.
Mark Wrote: "What do you think would really be entailed in doing it well? Obviously it is not plug and play for net metering as implied."
In my opinion, I am looking at solar as an option to maintain a high standard of living for as long as possible. I am building myself a homestead "lifeboat" and working on becoming self-reliant. But I don't plan to rely on just solar for off-grid power, as I will have access to the grid, a backup generator and I am working on micro-steam power system.
To give you some idea, of cost for a basic Solar system that can run appliances (ie dishwasher, washer, refrigerator, well pump, furnance, etc), you'll need about an 8 KW system, which will cost about $30K for the panels, chargers, Inverter, batteries, switch gear, and installation. I think this is out of the budget for most folks. It can be done cheaper, but few people have the skills need to implement a whole house DIY Solar system. It be done with a smaller system, but it will require dramatic lifestyle changes for most people (ie hand washing dishes and clothes, being mindful of running applicance when flushing the toilet, and so on. Even with an 8kw system a household will need to make signifcant changes. Even if none of your applicance uses 8kw, if it has a large motor it likely will require a large startup current. an undersized inverter will likely fail under repeated motor start ups.
I know some people are using DC applicances designed for off-grid homes, but I my opinion they have major drawbacks. Low voltage DC applicance need heavier gauge wireing. A 1kw appliance needs about 8.8 Amps at 120VAC, and about 21 Amps at 48VDC. In a failing economy its probably going to be impossible to find parts or replacement DC applicances, but AC applicances will likely available and widely salvagable from abandon buildings if necessary. It can also be difficult to find DC electronics (it TV, computer equipment, power tools, Window fans, Vacuum cleaners, etc. We live in world of AC tools and Applicances.
As far as EMP, Solar systems are "NOT" EMP hardened. and will likely fail in a NEMP (Nuclear EMP) or a solar CME. Its possible to protect your system by disconnecting the equipment and shielding it. With a CME event you likely have a 3 day notice to prepare since it usually takes about 3 days for a CME to reach Earth. A NEMP event might be tricky since likely make occur without notice or little time. Of course to to shield your Solar system you will need it set up for quick disassembly.
If you are planning for an EMP event then you also need to be food reliant as its very likely food distribution would fail and might not recover. Storing a few weeks or months of food, may not work if the EMP causes a Roman era type collapse. Odds are that an EMP event would result a failures of several Nuclear power plants triggering mass evacuations and leaving large areas un-iinhabitable. I think most of the distribution systems, including food distribution is too dependent on electronic systems and the Just-In-time model. I think it may be exteremely difficult to restart food & energy distribution after a major EMP event. Riots, fires, blocked roads, and lack of spare parts for damaged electronics would make recovery very difficult. The longer the distribution system remains off-line the more difficult it will become to restart it. Water could also be come a major problem for people relying on municiple water systems or have deep wells.
My guess that at some point the US will face rolling backouts as the economy continues to deteriate. But I don't think we will see widespread rolling blackouts in the next few years. I would suspect that more frequient localized outages happen, as utilities cut back on personel which result in repair delays. . The Sun appears to be in abnormally quiet, and does not appear to be producing a large number of CMEs. At this time an NEMP strike from a terrorist group or a rogue nation seems unlikely. From the research I've done, at this time, only the US, Russia and China have the means to perform a contiental scale NEMP attack. If any of these three nations did use an NEMP weapon it likely means the start of WW3. At this time I am not worried about an NEMP attack from North Korea, or Iran. I don't think either has the missile or nuclear bomb capable of causing a large scale NEMP event. I think if Iran was going to attack the US, it would smuggle a nuclear bomb into a major US City using its network of terrorist.
If you are limited to solar only, you’ll probably want to ride out a three-day storm, so you’d want a five-day storage system, at least. That’s prohibitive. However, if you were to have a combination of solar/wind, then storms aren’t a problem.
Therefore, I’d suggest a combo of solar wind, with about a day and a half of storage, two days tops.
A small house requires 12 kW of power, or about 600 kW-hr of storage. 600(3600)=2160000=2 MJ of energy storage available to use; since you don’t want to spin things down completely, you might want to buy a 4-MJ system.
Looking on the web, I see this:
http://www.activepower.com/UKen/flywheel-technology/#flywheel-our
That’s a 4-MJ flywheel; it should be buried in a concrete bunker underground to be made safe.
See Point #2.
One way, is to have your cell-phone clock, synchronized with GMT. Then, at a given location, read the current offset over a long time (60 hz x 3600 s/hr x 24 hr = 5M samples, good enough). Then coordinate your phase with that, and keep locked in to that.
another way, to do it live, is to simply average the time-based phase offset over the last thousand cycles, and base your target peak on that.
Either way, timing will handle itself.
A bigger issue is to have a proper ground, to avoid the main network from blowing up your units. Also to have super-loads from destroying your generators.
Flywheel systems are not designed for battery replacement. they are used in UPS system to provide a short period of power until the backup generator takes over. Flywheel system provide between 30 to 90 seconds of power. They can't provide a steady amount of power over hours.
A deep cycle 600Kwh battery bank would likely cost around $100K, and batteries don't last forever.
A practical option would be a modest battery bank coupled with a backup generator to recharge batteries. I don't think a pure solar/wind solution will be viable because its possible that you have a snow storm that will cover your panels and not generate much wind. Wind can also be very intermittent or insufficent depending on your location.
The problem with generators and wind turbines they will attract attention to you in a major crisis. People can hear your generator or see your wind turbines and might just show up at your door. Ideally you won't want a crowd of desperate people come knocking.