________________________________________ GURPS Vehicles 2nd Edition Additions MA Lloyd (malloy00@io.com) 9 August 1998 Modifications and Additions to Chapter 7: Power and Fuel ________________________________________ p82* Muscle Engine Table. First line is TL1-4. p82 Steam Engines. The first commercial steam turbine dates to 1885. p83 Steam turbine fuel consumptions should be (realistic values, divide multifuel consumption by 3 to compare to VE83) Steam Turbine (TL6) 0.025C/0.12M Steam Turbine (TL7) 0.017C/0.08M p83* Internal Combustion Engine Table. TL6 Standard Diesel 0.04D TL7 Marine Diesel 0.035D p83 The lines under TL7 diesels should also read 'if turbo or supercharged' p84* Gas and MHD Turbines Table. The second line under MHD Turbines should read TL 8 and $200* cost. p84 Gas and MHD Turbines Table. TL8+ Optimized Turbine should cost $25. The second line of MHD turbines should read 8 HP MHD Turbine 8xkW (0.6 x kW) + 37 $120* 0.225H p85 Fuel Cells. More realistically fuel cells take 15 minutes to start at TL7, 2 minutes at higher TLs. If you want faster startup, install a battery that will power the entire vehicle for a few minutes. p85 Nuclear Antimatter and Mass Conversion. RTG operating life is a nominal figure, the time for power to decay to 90% of its initial value. Since power drops 10% every 14 years, even after a century the RTG still puts out 47% of its original power. p86 Nuclear Table. The 14 year Pu RTG can't fall below 3.9lb/kW. Drop the TL10 and TL11 versions. p86* Nuclear Table. The missing antimatter TLs are 12 and 13. p86* Nuclear Table. The TL13 Antimatter reactor life is 5 years, not 30, to agree with the text and the weights of antimatter fuel bays. p86 Bioconverters. These are too efficient. Realistically they require 30-80 lbs of low nutrient vegetation (leaves, forage, grass), 10 lb of grain, 5 lbs of meat or 1.5 gallons of blood per kW per day. p86* Soulburner. These can be created by TL1+ mages. p87 Beamed Power. Build these as RoF 1 lasers or masers; power transmitted (in kW) equals beam output (in kJ). The power to energy relationship is currently vague. Damage should be *much* lower. Allow the designer to choose anything from /10 to /1000. p89* Fuel Tanks. Top of column 2, Table on p90 (not p89) p90 Reaction Mass and Fuel Table. * Metal/LOX fire number should agree with LOX (13) Alcohol costs $1 Cadmium weighs 72 lb/gallon Reasonably pure water costs $0.1 Liquefied Natural Gas is 3.5 lb, $0.5 and 13 Propane is 4.25 lb, $1.2 and 13 ________________________________________ Power and Fuel p81a Jet Engines and Power ________________________________________ This is poorly worded. Rephrase as: "Jet engines can produce power as well as thrust. An operating jet generates (thrust in lbs/100) kW through a simple turbine generator built into the engine. This is the usual way jet aircraft power equipment in flight. If more power is required, or if equipment must be powered when the jet is not operating, the vehicle will need an additional power plant or energy bank." ________________________________________ Power and Fuel p82a Realistic Fuel Consumption ________________________________________ Many fuel consumptions in Vehicles are seriously understated (see p82). Realistically jets use nearly 5 times as much fuel as indicated (1.75 times as much for hydrogen burners). Hydrocarbon burning internal combustion engines and turbines use about 3 times the stated volumes, hydrogen burners about 1.5 times. Fuel cell and rocket engine consumptions are about correct. The numbers in the additions in this chapter are realistic, if the existing figures in Vehicles are kept, you will need to divide these appropriately and be prepared to veto perpetual motion designs. On the other hand, in some genres fuel rarely runs low - the GM may want to divide power plant and especially reaction engine fuels by a considerable factor in a cinematic game. _______________________________________ Power and Fuel p82a External Combustion _______________________________________ In external combustion engines a working fluid is heated by the combustion of the fuel, rather than being a direct product of the reaction. The major advantages are that any heat source can be used, and since there are no design limits on the combustion it can be freely optimized, allowing cleaner and more efficient burning. The downside is heat transfer systems increase the weight. Startup time is also sometimes an issue, though even at late TL5 it is possible to add a flash evaporator which reduces starting time to 2 minutes flat - this is standard on Rankine engines and vapor turbines. *Atmospheric engines* (late TL4) are the earliest steam engines, in which the work is done by the atmosphere on the compression stroke rather than expanding steam. The first commercial versions are Newcomen engines in 1712. *Watt engines* (TL5) are condensing steam engines built under the James Watt patent, available in 1769. Early steam engines (VE82) are the fully developed form of the low pressure condensing steam engine, as available after 1830. *High pressure steam engines* (TL5) were experimented with from quite early, but metallurgy wasn't up to production models. The forced draft engine (VE82) is the fully developed high pressure steam engine as available after 1860. Successful experiments date to as early as 1798, but are up to 10 times heavier and 100 times as expensive. *High pressure compound engines* (TL5) were also experimented with early, but between the pressure problem and theoretical errors weren't too successful. The triple expansion steam engine (VE82) is the fully developed form, as available after about 1880. *Steam turbines* (TL6) use a jet of steam to turn a turbine. The first commercial models produced in 1885 were about 5 times heavier and used 12 times as much fuel. By 1895 they were down to twice as heavy and 5 times the fuel use. By 1910 the full TL6 version (VE82) is widely available, and becomes the standard method of electrical generation, a role it still holds, since no more efficient large scale combustion engines have become available. *Rankine (or vapor cycle) engines* (TL6) are closed loop external combustion engines where the working fluid is recondensed and recycled. Where the fluid is water this is basically the Watt engine design with a pipe connecting the condenser to the boiler. For a time automobiles and even aircraft were built with closed cycle steam engines, and a great deal of effort went into rapid startup and lowered weight, but in the long run internal combustion won out. The most common alternate working fluids are halobenzenes. *Vapor turbines* (TL6) are use a jet of vaporized working fluid to turn a turbine. Small steam turbines are less efficient than their larger cousins, but significantly lighter. *Stirling cycle heat engines* involve two pistons - the working piston and a displacement piston separating the hot and cold ends of a cylinder. In the combustion engine configuration an external burner heats the hot side. This provides the multifuel capability, quiet operation (no detonations) and high economy, low pollution fuel use (burn optimization is independent of cycle constraints). In modern designs the pistons are sealed and filled with 100 bar hydrogen or helium as the working fluid, Stirling's original design used low pressure air, which hurt efficiency significantly. External Combustion Engine Table 5 Atmospheric engine 1800 x kW (1000 x kW) + 4000 $5 0.7C/3.0M 5 Watt engine 800 x kW (400 x kW) + 2000 $2 0.35C/1.5M 6 Rankine 35 x kW (15 x kW) + 100 $2 0.15M 7 Rankine 20 x kW (10 x kW) + 50 $4 0.12M 8 Rankine 15 x kW (8 x kW) + 45 $4 0.10M 6 Vapor Turbine 50 x kW (20 x kW) + 150 $2 0.12M 7 Vapor Turbine 20 x kW (12 x kW) + 40 $4 0.10M 8 Vapor Turbine 15 x kW (10 x kW) + 25 $4 0.08M 7 Stirling 20 x kW (15 x kW) + 25 $10 0.06M/0.0125C 8+ Stirling 10 x kW (8 x kW) + 16 $5 0.04M/0.0085C Open cycle steam engines, which include all Atmospheric, Watt, Early Steam, Forced Draft, Triple Expansion or Steam Turbine engines, also consume water. Multiply the coal consumption in cf by 20 to find the number of gallons of water required. ________________________________________ Power and Fuel p85a Fuel Cells ________________________________________ *Regenerative Fuel Cells* are hydrogen fuel cells that retain the water exhaust, and can operate in reverse to regenerate the hydrogen if power is available from another source. Essentially this modification converts the fuel cell and tankage into a rechargeable battery. Multiply the weight and volume by 1.5 and the cost by 2.0. *Hydrocarbon Fuel Cells* are fuel cells that consume hydrocarbon fuels and atmospheric oxygen, and exhaust water and carbon dioxide, though there is usually some intermediate chemistry involving catalytic water to convert the hydrocarbon to hydrogen, methane and carbon monoxide. Hydrocarbon fuel cells will run on high grade multi-fuel, but not cheap ones like diesel, or even most standard gasoline or alcohol mixtures. Multiply fuel consumption by 0.8 if using aviation gas, 1.2 if alcohol, 1.5 if propane or hydrazine, 2.0 if methane. The cell can even run on hydrogen, using 1.2 times as much as a hydrogen fuel cell of the same TL. Fuel Cell Table 7 HC Fuel Cell no (30 x kW) + 200 $25 0.10M 8 HC Fuel Cell 15 x kW (5 x kW) + 50 $10 0.05M 9+ HC Fuel Cell 15 x kW (5 x kW) + 50 $5 0.04M ________________________________________ Power and Fuel p85a Nuclear Antimatter and Mass Conversion ________________________________________ *Radioisotope Dynamic Generators* (TL6): use a decaying isotope to heat a working fluid turning a conventional generator. Use the statistics for RTGs, but multiply the power output by 1.5, and remember moving parts wear out. *Unshielded Fission* (TL7) any fission reactor (or rocket or air-ram) can be built with minimal shielding. This halves the weight, volume and cost, but makes the device very dangerous. It is safe until turned on, but while operating it gives off a lethal radiation flux (6000 rads/second at 1 hex, decreasing with the inverse square of distance). Once used it remains highly radioactive for the next few thousand years, though the worst waste products decay after a few weeks of disuse, dropping the flux at 1 hex to a mere 2000 rads/hour. This is seldom considered for anything but unmanned probes, though there were early proposals to build cruise missiles with unshielded fission air-rams. *Experimental Fusion* (TL8) is intended to model various near term fusion designs (the ones that have been 15 years away from being commercial since about 1950). They are very heavy and very expensive, but sometimes seriously proposed for spacecraft. Minimum cost is $100 million. *MHD Fusion* (TL9) a consequence of the incredible performance of the standard Fusion Rockets (p36). The exhaust from a fusion rocket is used to vaporize a working fluid in a MHD generator instead of a high temperature combustion reaction, and the working fluids are condensed and recycled. Nuclear Power Table 8 Experimental Fusion no (2x kW) + 2 million $50 0.5yr. 9 MHD Fusion no (0.5 x kW) + 100 $65 200yr 10+ MHD Fusion no (0.4 x kW) + 90 $50 200yr ________________________________________ Power and Fuel p86a Concentrated Solar Power ________________________________________ *Solar Dynamic Engines* (TL5): use focused sunlight to vaporize a working fluid, which drives a piston or turbine. They consume no fuel and recycle the working fluid. Like steam engines there is a startup time to heat the working fluid reservoir: 5 minutes + 1 minute/kW at TL5, half that at TL6, 2 minutes flat at TL7. *Solar Thermionic Generators* (TL7): use focused sunlight to heat the hot side of a thermoelectric junction. Focused Solar Energy Table Weight if output is TL Type under 5kW more then 5 kW Cost Power 5 Solar Dynamic Engine 200xkW (100xkW)+500 $0.2 12.0 6 Solar Dynamic Engine 40xkW (20xkW)+100 $2 6.0 7 Solar Dynamic Engine 20xkW (8xkW) +60 $20 3.0 8+ Solar Dynamic Engine 10xkW (2xkW) +40 $30 1.5 7 Thermionic Generator 40xkW (20xkW)+200 $100 10.0 8+ Thermionic Generator 15xkW (5xkW)+ 50 $50 5.0 Power is the light power required per kW generated; install a mirror array to supply it. If the mirror array can not supply the needed light, usually because it is in lower sunlight than designed for, the engine produces proportionally less power, down to a minimum of 30% of its rated output at TL 5 or 6, 10% at TL7+. Below that it never gets hot enough to work at all. *Mirror Array* (TL2): A system of mirrors for focusing sunlight. Select an area in square feet; the light power focused is 0.1 kW x area. To determine weight decide on a structural strength and consult the Vehicle Structure Table to compute the weight of the frame. Add the mirror itself as expensive metal armor. DR0 glass is also available with the statistics of DR1 metal at TL6; at TL7+ DR0 metallized film (0.001 lb and $1 per square foot) can be used instead. The frame has 0.2 hit points x area, modified by the frame strength. The area of an extended array adds to D to determine aerodynamic drag (p134). For double weight and cost the array can retract into weight/50 cubic feet. Retracted arrays provides no light power, but do not affect streamlining and are less easily damaged. Like solar panels, mirror array power levels assume Earth-normal sunlight. Around another star multiply by the relative luminosity of the star. At a distance other than 1 AU divide by the distance (in AU) squared. ________________________________________ Power and Fuel p86a Wind Generators ________________________________________ *Wind Generators* (TL5) generate power from the wind. At TL7 1 kW and smaller units are a common method of recharging batteries aboard small boats. The nominal output determines statistics. The actual output at any moment is the nominal output times the wind Beaufort number (see p30). In non-terrestrial atmospheres multiply the output by the relative density of the atmosphere. Weight if output is Wind Generator Table under 5kW 5kW or more Cost Blade radius (ft) 5 Wind Generator (80xkW)+30 (40xkW)+230 $5 20 x SQRT(kW) 6 Wind Generator (60xkW)+20 (30xkW)+170 $5 15 x SQRT(kW) 7+ Wind Generator (40xkW)+15 (20xkW)+115 $10 12 x SQRT(kW) Wind generators must be mounted so the blades can rotate. This is usually done by mounting them on a mast higher than the blade radius, other mounting methods are subject to GM approval. _______________________________________ Power and Fuel p86a Waterwheels _______________________________________ Waterwheels generate power from moving water. This is usually not a vehicle system, though there have been moored floating waterwheels in some rivers. It is possible to extract energy from a moving watercraft - if rather dumb aboard anything but a sailboat. Subtract 100 x kW generated from the motive thrust of the ship. An ideal undershot waterwheel transforms 8/9 of the kinetic energy of the water flowing through it (0.44 x rwp v^3), an ideal overshot waterwheel also converts the potential energy of the water falling over it (r^2 wpgv) where r is the wheel radius, w is its width, p is the water density, v is the speed of the current and g is the local gravitational acceleration. By TL5 real undershot wheels reach 30% efficiency and overshot wheels about 70%. By mid TL7 hydropower turbines routinely exceed 90% of the theoretical efficiency. A typical system weight is 1200 lb x kW, volume is 650 cf x kW and cost is $1/lb, though variations span an order of magnitude or more. ________________________________________ Power and Fuel p86a Exotic Power Plants ________________________________________ *Orgone Engines* (TL 9): use a technology distantly related to the Soulburner to convert orgone (life-force, and the blue color of the sky, see W23p106) to electricity, expelling Deadly Orgone Radiation as exhaust (treat as 1.5 rads/hour per kilowatt to nearby living things and see W23p106 for the risks of 'emotional plague'). The output of the engine assumes a living environment (such as Earth); UFOs will also need an energy bank since space contains little or no Orgone. 9 Orgone Engine no (0.005 x kW) $500 infinite ________________________________________ Power and Fuel p87a Broadcast Power ________________________________________ *Field-Based Electrical System* (TL6): a low TL precursor to Broadcast power, replacing wiring over short distances. It is common on UFOs and in worlds based on the experiments of Nikolai Tesla. Realistic versions can't handle high power demands, require antennas heavier than the wires would be, waste power by heating anything metallic or otherwise conductive aboard and are very sensitive to interference. The cinematic UFO version suffers none of these problems and is immune to EMP or an MPD field disruptions, but long exposure causes cancer in earthly mammals (this may also be true of the realistic version - probably not, but not all studies of the risks of electromagnetic fields have been discredited.) *Broadcast Power* (TL12): is the next step beyond beamed power. It does not require line of sight and involves no hazardous beams. A broadcast power receiver weighs 0.25 lb, occupies 0.005 cf and costs $5 per kW it can pick up. A transmitter weights 0.5 lbs, occupies 0.01 cf and costs $5 per kW, plus $500. Select a maximum range for each transmitter, up to 0.05 miles x kW transmitted. Broadcast receivers operate on specific channels, and pull power from any available transmitter in range operating on that channel. If the total power drawn by all receivers in an area exceeds that available on their channel, the system browns out. Legal receivers have a built in comm link and GPS and talk to a scheduling computer to prevent overloads. Military and emergency vehicles rarely use broadcast power because of the risk something will take down the network. ________________________________________ Power and Fuel p87a Energy Banks ________________________________________ For some applications discharge time is critical, short high power loads such as firing energy weapons or initial FTL drains. Many energy banks can't be discharged that quickly; several systems below have lousy energy densities and shelf lives, but remain in use because they discharge in microseconds. The systems capable of near-instantaneous discharge are capacitors, explosive generators, pulse generators, spinning inductors, superconducting loops and ultracapacitors. Flywheels, clockwork and anaerobic biocells take a few seconds to discharge, lead acid batteries and thermal systems 15 minutes, high capacity storage batteries take 30 minutes, advanced batteries, air breathing biocells, cryogens and thermal storage take an hour. *Advanced Batteries* (TL6) batteries with higher energy densities than lead-acid are available in 1901. The TL6 versions are nickel-zinc or nickel-iron (Edison batteries); at TL7 nickel-cadmium, zinc chloride and silver-zinc are typical, at TL8 most are lithium based - lithium chloride or lithium organic electrolyte. Advanced batteries are normally rechargeable, but half cost versions are available which are not. *Biochemical Cell* (TL10) the energy bank equivalent of a bioconverter, a living machine that stores energy as energetic biomolecules. The air breathing biocell uses sugar molecules, requires oxygen to extract the energy, and vents carbon dioxide. The anaerobic cell stores phosphoenolpyruvate, and recovers energy by hydration, it operates completely independent of the environment. Install a bioconverter if they are to be recharged. In settings with advanced biotechnology both biocells and bioconverters may be TL8. *Capacitors* (TL5) store energy as separated electrical charge. They are heavy and quickly lose stored energy (any power not used within 4 hours is lost) but are used because they can discharge almost instantaneously. *Clockwork* (TL4) stores energy in compressed springs, giant rubber bands, or similar mechanical energy storage systems. Clockwork is rechargeable by rewinding. Add 5% to the weight, volume and cost of the clockwork for gearing and motors if this is to be done by a power plant. Otherwise it is rewound manually 0.02 x ST kWs per second of labor. *Compressed Air* (TL5) stores energy in a high pressure gas, usually air, but cylinders and cartridges of other gases may have special applications, and share the same statistics. Compressed air storage requires a compressor to recharge; this weighs 1.5 lb and costs $20 per kW, and occupied weight/50 cf. *Cosmic Cells* (TL16): Provide energy by means incomprehensible to science. Unlike Cosmic power plants, Cosmic Cells can produce any power level, but may only supply a fixed amount of energy. Standard cells supply the same amount each day, but non-recharging versions which appear limitless until they completely drain the microuniverse they tap are a common variation. In a sense powerstones are Cosmic Cells, weighing about 10 times as much. *Cryogen Storage* (TL7) recovers energy by operating a heat engine between the surrounding warm air and a stored cryogen, typically liquid air. This has been seriously proposed to meet tough anti-pollution laws, since the exhaust is the boiled cryogen if you use liquid air.... Half the system weight is the cryogen. It can be recharged by refilling the tank, if you have a source of cryogenic liquid. *Explosive Generators* (TL7) produce a short pulse of electrical power from the detonation of an explosive. They can only be fired once, and any energy not immediately used or stored elsewhere is lost. *Flywheels* (TL5) store energy kinetically, in a rapidly rotating ring. Kept in a mediocre vacuum a flywheel can spin for months. Note heavy flywheels don't provide the best energy densities, since stress on the rim at a given speed also increases with mass. Lighter materials allow faster speeds at the same stress, and energy storage increases with the square of speed. The earliest flywheels are cast iron, advanced alloys are used at TL6, glass or carbon fiber composites at TL7. Flywheels can be recharged. *High Capacity Storage Batteries* (TL8): are cheap rechargeable energy banks introduced in Autoduel. It is unclear how they work, though regenerative fuel cells seem the most plausible excuse. They are flammable (fire number 10) so a chemical fuel seems likely. *High Temperature Batteries* (TL7) use electrochemistry that runs only at high temperatures. They are inert at room temperature - so they have essentially infinite shelf life. A small pyrotechnic is fired to heat them to the working temperature, and they must be drained in a few hours or the stored energy is lost. Most applications are those you need a lot of power at once possibly a long time in the future - emergency gear, missiles, interplanetary probes. The TL7 systems are usually sodium sulfur. Lithium-iron sulfide and lithium tellurium fluoride are typical at TL8. High temperature batteries cannot be recharged. *Lead-Acid Batteries* (late TL5) are the standard lead-lead oxide batteries in sulfuric acid electrolyte found in every automobile engine. Though far from the best battery technology, they were developed early and use cheap chemistry, which keeps them in use where weight isn't critical. Many later applications use TL6 lead-acid batteries for the cost savings. The TL7 versions are sealed cells. All lead acid batteries can be recharged. *Metal-Air Batteries* (TL7) generate electricity by reacting a light metal (such as lithium or beryllium) with oxygen in the air. Weight triples by the time the battery is dead. They cannot be recharged, though light metals are expensive and so the metal oxide is normally recycled. *Metal-Water Batteries* (TL7) work similarly, storing energy as an active metal reacted with the environment, in this case surrounding water. They are popular for deep diving submersibles. Metal-water batteries generally use cheaper metals - magnesium or aluminum, since the reaction energy for more exotic metals with water is simply not enough better to be worth it. *Pulse Generators* (TL7) are devices delivering precisely shaped electrical pulses with high voltages, currents or energies, such as electron accelerators or Marx generators. They lose power very quickly (assume a maximum of 10 minutes of storage) so are normally charged from another source which is not capable of either such rapid discharge or precise control. *Spinning Inductors* (TL7) store energy in a rotating mass coupled to an inductive load. Homopolar generators and compulsators are the most common examples. Spinning inductors can be recharged. *Superconducting Loop* (TL7) store energy in a magnetic field generated by a current flowing around a superconductive loop. The TL7 version is a rare metal alloy cooled in liquid helium. At TL8+ room temperature superconductors make this a possible explanation of rechargeable cells. *Thermal Storage* (TL5) stores energy as heat, normally the latent heat of a phase transition. At lower TLs it is recovered with a conventional heat engine, but at TL7+ some systems are thermoelectric. The main problem with thermal storage is shelf life, heat leakage dissipates any energy not used within 4 hours (TL5), 1 day (TL6) or 1 week (TL7+). Thermal storage was tried for light rail vehicles at the end of TL5, but appears to have been killed by the heat loss problem. Thermal storage can be recharged. *Thermal System* (TL6) is a vague name for a very specific kind of power plant, also known equally vaguely as a stored chemical energy unit. A highly exothermic chemical reaction with condensed products (so there is no exhaust or pressure buildup) boils the working fluid of a closed cycle vapor engine. The reactions used are not particularly friendly - active metals, halogens, sulfur, selenium and tellurium - a typical version reacts a lithium boiler lining with sulfur hexafluoride gas. Thermal systems are not rechargeable, but are controllable enough to shut off and restart a few times - assume each cycle wastes 5% of the stored energy. *Ultracapacitors* (TL8) are advanced capacitors storing charge in a the double layer of an electrolyte at the surface of a very high surface area electrode, typically a carbon aerogel. Energy Bank Design Table 6 Advanced Battery 0.01 $2.5 7 Advanced Battery 0.005 $10 8 Advanced Battery 0.001 $30 10 Anaerobic Biochemical 0.007 $75 10 Biochemical Cell 0.00015 $100 5 Capacitors 50.0 $1 6 Capacitors 6.0 $15 7 Capacitors 3.0 $30 4 Clockwork 0.25 $20 5+ Compressed Air 0.03 $0.5 16 Cosmic Cells 0.00000012 $10 7+ Cryogenic Storage 0.01 $20 7 Explosive Generator 0.005 $100 8 Explosive Generator 0.001 $100 5 Flywheel 0.8 $0.5 6 Flywheel 0.1 $6 7 Flywheel 0.01 $15 8 Flywheel 0.005 $15 8 Hi Cap Storage Btry 0.0005 $4 7 High Temp Battery 0.002 $50 8 High Temp Battery 0.0008 $50 5 Lead Acid Battery 0.03 $0.25 6 Lead Acid Battery 0.025 $0.5 7+ Lead Acid Battery 0.02 $1.25 7 Metal-Air Battery 0.0005 $100 8 Metal-Air Battery 0.0001 $200 7 Metal-Water Battery 0.0025 $5 8 Metal-Water Battery 0.0005 $5 7 Pulse Generator 3.0 $30 7 Spinning Inductor 0.15 $20 8+ Spinning Inductor 0.05 $20 7 Superconducting Loop 0.02 $25 5 Thermal Storage 0.012 $1 6 Thermal Storage 0.008 $2.5 7+ Thermal Storage 0.004 $5 6 Thermal System 0.004 $100 7 Thermal System 0.001 $100 8 Thermal System 0.0005 $100 8 Ultracapacitors 0.12 $15 9+ Ultracapacitors 0.04 $10 Volume: for most systems, volume is weight/50. For lead-acid batteries volume is weight/200. For advanced, high temperature, metal-air or metal-water batteries, explosive generators or cosmic cells, volume is weight/100. ________________________________________ Power and Fuel p87a Energy Banks - Power Cells ________________________________________ Power cells are the standard GURPS ultratech energy storage device, from GURPS Space onward. Unfortunately they weren't designed for consistency. TL8 power cells range from 7200 to 28800 kWs/lb, weight/316 to weight/880 cf and $100 to $16,000 per lb. Vehicles opted to use the E cell (18000 kJ/lb, $100/lb) as the standard, which was probably a mistake since most equipment uses B through D cells at 7200 kJ/lb. Selecting that as the standard changes the smallest number of equipment statistics. The specific energy of all power cells is multiplied by (TL-6)/2. Power cells and related technologies are capable of instant discharge - they have to be since their major game role is to allow beam weapons. *Power Cells - Nonrechargeable* (TL8) are the standard GURPS power cells, generally described as using an exotic fuel like californium or metastable helium. They are not rechargeable. *Power Cells - Rechargeable* (TL8) the standard GURPS rechargeable power cells are usually described as superconducting or photonic loops. They are identical to nonrechargeable power cells, except they store half as much energy and are rechargeable. *Power Slugs* (TL8) introduced in Cyberworld (CW94) as a transitional step to power cells. They also range all over the place, from 50 to 3000 kJ/lb, weight/120 to weight/2200 cf and $2.1 to $16 per lb. As written smaller power slugs actually under-perform conventional batteries. *Power Cartridges* (TL8) relatives of explosive generators introduced in UltraTech2. They weigh 0.72 times as much as an equivalent capacity power cell. Cost is likewise reduced (it is still $100 x weight). Like explosive generators they can only be used once, and any unused energy is lost. Power cells and realism. All energy storage technologies are fundamentally limited in energy storage density by the strength of the containing forces. For most the limiting energy density is set by the strength of the chemical bonds holding the storage system together - it equals the yield strength of the material divided by its density. A device storing more than that will explode. For high strength metal alloys this can be as high as 500 kJ/lb, for diamond it works out to 14430 kJ/lb, and even the theoretical limits aren't much more than twice that. _________________________________________ Power and Fuel p88a Alternative Solid Fuels _________________________________________ Most coal burning power plants can also burn other solid fuels: Solid Fuel lb/cf $/cf coal equivalent/cf Anthracite coal 70 $2.00 1.70 Bituminous coal 50 $1.00 1.00 Coke 27 $1.50 0.67 Wood (dense) 35 $0.30 0.42 Charcoal 15 $0.30 0.35 Dried algae 17 $0.20 0.33 Compressed straw 24 $0.25 0.30 Textile fiber 20 $0.50 0.30 Peat 25 $0.25 0.23 Dung 25 $0.25 0.20 Lignite 25 $0.30 0.18 Dried seaweed 20 $0.10 0.13 Loose straw 5 $0.05 0.07 ________________________________________ Power and Fuel p88a Fuel Tanks ________________________________________ *Collapsible Tanks* (TL5) are made of a light folding material - rubberized canvas at TL5, polymers at higher TLs - and typically erected in a cargo space or open deck. An empty collapsible tank can be folded into empty weight/40 cf for storage. A filled tank will rupture, spilling its contents, if the vehicle makes a maneuver above 1.5g (30mph/s). Cryogenic fuels can't be stored in such tanks until TL8, and no other weight reducing options can be combined with the collapsible option. *Cryogenic* (TL6) tanks built to contain cryogenic fuels must be specially designed to provide heat insulation, boil-off pressure release and resistance to large changes in temperature. *Excited State* (TL9) fuels require specialized stabilization technology to prevent the fuel from exploding spontaneously. The stabilization method for each fuel is different, so the tanks are not interchangeable. Excited state tanks consume power to maintain the fuel stabilization, but like Antimatter Bays this is integral to the tankage and independent of the vehicle powerplant. Fail safes can be installed just as for antimatter plants (p91). *Pressurized Gas* (TL5) store high density gases instead of cryogenic liquids. This requires significantly stronger and heavier tanks. It is most common in stationary hydrogen or hydrogen-oxygen burning generators where weight isn't very important. In this case a 'gallon' is an accounting unit for an equal mass of gas, about equal to 100 cf at STP (also a handy number for filling gasbags) *'Solid Hydrogen' Tank* (TL7) is a generalization of a variety of methods of storing hydrogen at room temperatures. The hydrogen is somehow immobilized, either in easily decomposed compounds (hydride storage) or physically on the molecular level (zeolite or carbon nanotube storage). This can also be used to represent the fictional 'hydrogel' from Terradyne. Again 'gallon' becomes something of an accounting unit. Fuel Tank Table 5 Pressurized Gas 50 3 $100 +4 6 Pressurized Gas 30 3 $30 +4 7 Pressurized Gas 30 1 $600 +2 7 Solid Hydrogen 7.0 0.15 $30 -7 *Options* 5 Collapsible x0.05 x1.0 x0.1 +1 6 Cryogenic x1 x1.0 x5 +0 9 Excited State x2 x1.2 x20 +0 ________________________________________ Power and Fuel p89a Types of Fuel ________________________________________ Rock Dust is typically powdered asteroid, sifted lunar regolith or something similar used as a mass driver reaction mass. It is a solid, stored in fuel bunkers, weighs 180lb/cf and costs $0.1/cf. Types of Liquid Fuel *Monopropellants* include nitromethane, hydrogen peroxide, ethylene oxide and hydrazines. All of them can explode spontaneously (use the rules for rocket fuel) and contact with any of them can cause serious chemical burns. *Storable liquids* are fuels (such as kerosene, hydrazines, alcohols, or benzene derivatives) and oxidizers (hydrogen peroxide, chlorine trifluoride, red fuming nitric acid, pentaborane, dinitrogen tetroxide) that are liquid at near room temperature. Several are explosive, many are toxic, and all oxidizers are corrosive on contact. *Cryogenic liquids* are liquids only at very low temperatures. In addition to freezing and fire hazards common to all of them, ozone can explode like rocket fuel, liquid fluorine can ignite almost anything including human flesh, and carbon monoxide is toxic in concentrations *far* lower than those found around a CO tank boil-off valve. *Cryogenic inert gases* include helium, neon, nitrogen, argon, carbon dioxide, and xenon. They present a cold hazard, but are chemically inert and non-toxic, and hence fairly safe. *Suspended Atomic Hydrogen* is liquid hydrogen, but 25% of it is somehow kept in atomic rather than diatomic form. Energy is released when the atomic radicals recombine into ordinary diatomic hydrogen. Should the stabilization technology fail, a tank of SAH explodes for 6d x 20 per gallon. *Free Radical Hydrogen* is liquid hydrogen in which all the hydrogen is monatomic. If the stabilization fails it explodes for 6d x 35 per gallon. *Metastable Helium* is liquid helium in which the atoms are somehow kept in the triplet excited state. Energy is released when they return to the singlet ground state, which under normal conditions takes a few milliseconds (longer than the microseconds for most atoms, thus the name 'metastable'). If the stabilization fails, metastable helium explodes for 6d x 215 per gallon! Rocket Fuels Table Weight Cost Fire Thrust Monopropellants Factor Hydrazine 8.4 $5 13 0.87 'Rocket Fuel'(R) 10.0 $2 13 1.00 90% Hydrogen Peroxide 12.0 $10 13 1.06 Nitromethane 9.4 $2 14 1.13 Storable Liquids Hydrazine/Pentaborane 6.6 $10 13 0.75 'Rocket Fuel' 10.0 $2 13 1.00 Hydrazine/N2O4 10.1 $5 13 1.00 Hydrazine/Nitric Acid 10.2 $3 13 1.00 Kerosene/Peroxide 10.8 $8 13 1.05 Kerosene/Nitric Acid 11.2 $1.5 13 1.05 Hydrazine/TFH 11.9 $10 13 1.38 Cryogenic Liquids Hydrogen/Oxygen (HO) 2.1 $0.1 13 1.00 Hydrogen/Ozone 2.5 $10.0 14 1.30 Hydrogen/Fluorine 2.9 $2.0 13 1.45 Carbon Monoxide/Oxygen 8.1 $1.0 13 2.87 Alcohol/Oxygen 8.4 $2.5 13 2.90 Kerosene/Oxygen 8.5 $1.0 13 3.05 Ammonia/Tetraflurohydrazine 10.6 $8 13 3.60 Metal Oxide Metal/LOX (MOX) 12.0 $15 13 1.00 Al/LOX 11.5 $20 13 1.23 AlMg/LOX 11.7 $20 13 1.25 Fe/LOX 14.2 $15 13 1.00 Si/LOX 11.2 $20 13 1.16 Ti/LOX 13.3 $30 13 1.28 BeH2/LOX * 10.7 $350 13 2.25 Excited State Suspended Atomic Hydrogen (SAH) 0.47 $5 32 1.00 Free Radical Hydrogen (FRH) 0.29 $20 34 1.28 Metastable Helium (MSH) 0.90 $30 34 6.31 *in addition to the high cost of beryllium, the use of this mixture is somewhat limited because the exhaust is a poisonous dust. Reaction Mass Table Material Weight Cost Fire Thrust Power Storable Liquids Factor Factor Water (H2O) 8.34 $0.1 - 4.82 1.61 Methanol (CH3OH) 6.59 $1.5 10 2.85 0.72 Hydrazine (N2H4) 8.38 $5.0 13 3.62 0.91 Ethanol (C2H5OH) 6.57 $2.0 10 2.37 0.50 Cadmium (Cd) 72 $860 - 15.52 2.08 Mercury (Hg) 113.45 $370 - 19.63 1.97 Cryogenic Gases Hydrogen (H2) 0.58 $0.1 13 1.00 1.00 Liquefied Gas Giant Atmosphere 0.64 $0.1 12 1.05 1.00 Helium (He) 1.04 $1.0 - 1.27 0.91 Methane (CH4) 3.54 $0.5 13 2.17 0.77 Ammonia (NH3) 5.69 $1.0 9 3.38 1.19 Neon (Ne) 10.01 $50.0 - 5.46 1.73 Carbon Monoxide (CO) 6.61 $0.8 9 3.06 0.82 Nitrogen (N2) 6.71 $0.1 - 3.11 0.84 Liquid Air 7.33 $0.1 8* 3.34 0.88 Oxygen (O2) 9.53 $0.1 9* 4.13 1.04 Argon (Ar) 11.60 $1.0 - 4.50 1.01 Carbon Dioxide (CO2) 9.19 $0.2 - 3.39 0.73 Nitrogen Dioxide (NO2) 12.1 $5.0 10* 4.34 0.91 Xenon (Xe) 25.87 $500 - 5.53 0.69 ________________________________________ Power and Fuel p90a Synthetic Fuels ________________________________________ When petroleum is in short supply (as it often is during a war or on worlds with small or depleted reserves) alternative sources can be very important. Alcohol can be distilled from fermenting biomass at TL3 for triple cost, 1.5 times cost at late TL7, standard cost thereafter. Biomass produced methane has triple cost at TL5, 1.5 times cost at TL7+. Several processes can convert water and carbon (coal, coke, charcoal or other types of pyrolyzed biomass) into diesel, alcohol, methane or propane at 4 times list cost at TL6, double list at TL7, list cost at TL8. Increase these multipliers by a factor of 1.5 for gasoline, aviation gas or kerosene/jet fuel. Standard hydrogen costs are for steam reforming of natural gas. Electrolysis of water multiplies the cost by 10 at TL 6 or 7, or 4 at TL8+, and of course consumes at least as much electricity as it produces fuel. Photolysis of water using sunlight, either by inorganic catalysis or modified biological photosynthesis can produce hydrogen for 100 times list cost at TL7, falling to standard cost by the end of TL8. A lot of TL7 research is aimed at producing cheap fuels from biomass. Most of the more successful attempts are lightly processed plant oils - assorted triglycerides, terpenes, latexs, esters, and carboxylic acids. Peanuts and Chinese tallow trees are the best candidates, but soybeans, castor beans, rapeseed and corn oils also show potential. Light biofuels are the lower density, more volatile such fuels, which can be burned in any multifuel engine, or any diesel or gasoline engine with small modifications (10% of engine cost). Heavy biofuels are denser, less volatile or more viscous materials like unprocessed plant oils and the products of wood distillation or the pyrolysis of garbage, which can only be burned in multifuel capable engines, and require twice the normal fuel volumes. Synthetic Fuels Table Light Biofuels 6.5 $3 10 Heavy Biofuels 8 $0.5 8 ________________________________________ Power and Fuel p90a Antimatter Storage ________________________________________ While not unreasonable, the standard antimatter storage systems are so heavy they negate any advantages of antimatter propulsion. Many settings using antimatter assume much more efficient storage. Some possible approaches: Antimatter Storage Fields (TL11): are very light storage units containing slightly pressurized antihydrogen gas. Statistics are per gram of antimatter stored. These are modeled on deflectors, but gravitics or stasis fields might be alternate enabling technologies. 11 Antimatter Storage Field 0.05 0.1 $200 12 Antimatter Storage Field 0.025 0.1 $100 13 Antimatter Storage Field 0.015 0.1 $50 Antimatter Converters (TL14): uses total conversion technology (which is the same process as antimatter generation under time reversal) to convert matter into an equal mass of antimatter. Converter weight is 0.25 lb x (micrograms produced/hour). Volume is weight/50, cost is $30 x weight. ________________________________________ Power and Fuel p90a Interstellar Ramscoops ________________________________________ A ramscoop is a magnetic or electromagnetic device for collecting interstellar hydrogen, usually for use as a fuel or reaction mass in a fusion engine. There are many different designs. Some have a minimum operating velocity, but most collect about the same amount of fuel per unit time at any speed relative to the medium. Select a fuel collection rate in lb/hour. The mass of the ramscoop is 7.5 million lbs x (lb/hr collected), at TL8, divided by 10 at TL9, 100 at TL10. Cost is $100/lb. Volume is usually irrelevant, all ramscoops require huge (kilometers long) cable structures, and like lightsails cannot approach an atmosphere too closely. If desired they can be retracted into weight/100 cf, but seldom are. Properly designed ramscoops require no power, any energy needed to collect the fuel is recovered from the exhaust stream, but it does require a lot of energy to activate them in the first place, building up large superconducting currents or separated charges. Energizing a ramscoop consumes 320 trillion kWs (10 gigawatt-years) x (lb/hr)^2, which must either be dissipated or stored elsewhere before the ramscoop can be retracted, one of the reasons it seldom is. Collection rates assume a density of about 10^5 atoms/m^3. This is the average density of the galaxy; it's about the same both within and between the arms, in or out of the galactic plane. Intergalactic space is much lower, and star-forming clouds can be a thousand times higher. Unfortunately the Sol system sits in a hot plasma cloud with a density of about 10^3 atoms/m^3, a roughly 200 parsec radius sphere centered about 100 parsecs from Sol called the Local Bubble. It is probably a 100,000 year old supernova remnant. _______________________________________ Power and Fuel p90a Scale and Ultimate Energy Sources _______________________________________ So how much power is a lot? A low tech civilization consumes about 0.25 kW per capita, almost all of it as biomass - food or firewood. Industrial civilizations consume 3 kW per capita at late TL5, 6 kW at TL6, 10 kW at TL7. Based on the standard of living curves it is reasonable to continue doubling per capita consumption every TL, though the late TL7 trend is for energy use to actually drop slightly in the richest nations. World energy consumption at the end of TL7 is 11.5 TW (0.99 EJ/day), from which we can conclude a significant fraction of the population is not living at the standard of living of even a TL5 industrial civilization. A power utility - whether steam, nuclear, a hydroelectric dam, or bay barrier tidal plant usually generates at least several hundred MW, and few exceed a GW. In terms of reserves, the Earth's standing biomass is about 13,000 EJ. The original fossil fuels reserves were 300,000 EJ coal, 30,000 EJ petroleum and 30,000 EJ natural gas, so far humans have burned about 15% of the oil and gas, and 2% of the coal. Fissionable reserves are actually fairly modest, only 3500 EJ with current technology, though perhaps as much as 700,000 EJ with breeder reactors. Fusion resources from seawater are 18,000,000,000 EJ for Li-D fusion, 1,200,000,000,000,000 EJ for D-D, which should make it obvious why fusion is highly desirable for long term civilizations. Total output from the Sun is 3.9 x 10^14 TW, but only 175,000 TW of that touches the Earth. About 100,000 TW reaches ground level, 65% of which is immediately reflected to space. About 4000 TW dissipates in the atmosphere, perhaps 40 TW of it in near surface winds. About 10,000 TW end up in the water cycle and oceans - mostly in temperature gradients and heat driven currents, but also 10 TW in waves, 3 TW as the potential energy of rainfall onto land (potential hydropower) and 2.6 TW for the osmotic potential of mixing of that same fresh water. Solar flux at ground level depends on clouds, latitude, time of year and a host of other factors. For mid-latitude deserts 2.9 kWhr/day per square meter is typical, up to 10.8 kWhr/day at the best spots. For temperate climates the range is 1.9 to 6.4 kWhr/day per square meter, changing with the season. Recovery efficiency varies tremendously, hydropower routinely comes close to 100% at late TL7, while ocean thermal systems start bumping thermodynamic limits at less than 2%. Also, tapping more than a few percent of any solar flow probably has significant environmental consequences. Photosynthesis is the cheapest form of solar power by absolute costs. Coniferous forests are about 1% efficient (50 MJ/yr per sq meter), tropical forests are about 2% efficient and get more light (150 MJ/yr per sq m), tropical reed swamps can exceed 3% (250 MJ/yr per sq m). Some algae can reach 8% conversion, but drying it so it will burn uses much of the energy you can extract by burning it. Current forest could supply about 1 TW renewably, current cropland about 2 TW, increasing to 5 TW if all the planet's grasslands are converted to crops. Of other 'renewable' sources, currently tides dissipate about 2.4 TW, a third of it in near-shore shallow water, but redesign of the ocean floor could increase this considerably. Tidal energy comes from slowing the rotation of the Earth and the angular momentum mostly ends up increasing the distance to the Moon. Geothermal heat flow through the crust is 32 TW, 6.5 TW of it in hydrothermal discharges near mid-ocean ridges and 0.3 TW through volcanoes or hot springs. There is also a 400,000 EJ reserve in near surface hotspots, but tapping it kills most of the hydrothermal and volcanic sources and d