====== Power Supplies ====== Equipment is useful... when it works. But a laser pistol without power may not even be a good club. Many ultratech devices need a power supply, as specified in the equipment description. Personal equipment uses power cells (see below). Larger devices typically use external power – plugging them into an building or vehicle power supply. Other options for powering gadgets are described as well. ===== POWER CELLS ===== Equipment, robots, and vehicles often use standardized power supplies, known as power cells. All power cells are assumed to be compact and relatively inexpensive. They may be advanced electrical batteries, micro fuel cells, or superconductor loops. Fuel cells combine hydrogen or methanol with oxygen (often in the form of water, which contains oxygen) in an electrochemical reaction. Fuel cells are more complex than batteries, incorporating a fuel tank and microelectronics to control fuel flow. Superconductor loops are made of materials that are electrical superconductors, storing electricity without any losses due to resistance. Ultra-tech superconductor loops can operate at or near room temperature. All power cells are assumed to store power without running down when not in use; they have an indefinite shelf life. === Sizes of Power Cells === There are several sizes of power cells, designated by letter from AA (the smallest) to F (the largest). Power cells increase in power exponentially. An A cell is 10 times as powerful as a modern AA cell, a B cell has 10 times the power of an A cell, and so on. AA cell: These tiny cells operate devices with minimal power requirements, like very small robots or brain implants. $1, 0.0005 lbs. (2,000 AA cells weigh 1 lb.) A cell: These small cells are often used in clothing or consumer goods that require low power outputs. They’re about the size of a watch battery, or postage stamp-sized for flexible cells (see below). $2, 0.005 lbs. (200 A cells weigh 1 lb.) B cell: These power wearable computers, tiny radios, small tools, and other devices with modest power requirements, including some low-powered weapons. A typical B cell is the same size as a pistol cartridge or an 2010-era AA battery. $3, 0.05 lbs. C cell: These are the most common energy source for personal beam weapons, tools and high-power electronics. Equipment designed for larger or smaller cells often has an adapter for C-cell operation. An ultra-tech battlefield may be littered with expended C cells. Each cell is about the same size as a pistol magazine. $10, 0.5 lbs. D cell: These power military beam weapons and heavy equipment. They are often worn as a separate power pack. They’re about the size of a thick paperback book. $100, 5 lbs. LC4. E cell: These power small vehicles, battlesuits, support weapons and other power-intensive systems. They’re about the size of a backpack. $2,000, 20 lbs. LC4. F cell: These power medium or large vehicles and cannon-sized beam weapons. They’re about the size of a compact car engine. $20,000, 200 lbs. LC4. ==== Flexible Power Cells ==== These flat polymer power cells are used for powering clothes, printed computers, and similar devices. They are attached like stamps and peeled off when exhausted. Gadgets noted as using flexible cells use them instead of normal power cells; they’re also embedded into smart labels, smart paper, and similar disposable items. AA and A flexible cells are the usual cost; others are 4 times the normal cost. ==== Non-Rechargeable Power Cells ==== Normal power cells are assumed to be rechargeable. Non-rechargeable cells are also available. They last twice as long, or provide twice as many shots, but may not be refueled or recharged. They are otherwise identical to normal or flexible power cells. ==== Power Slugs ==== These are essentially the dollar-store equivalent of power cells; non-rechargeable batteries with lower-than-average power storage, made and sold cheaply. These cost 1/5th as much as regular batteries, and are non-rechargeable. Also, manufacturer reliability varies widely; they tend to store roughly 50% + (1d-1 x 10%) as much charge as an ordinary rechargeable cell. ==== Specialty Power Cells ==== Steady-Rate: These standard power cells are designed to discharge and charge at a 'standard' rate. They do not lose power when in storage, can be recharged in roughly one hour from a standard-quality charger, can be discharged in up to one minute, and can be recharged an nigh-infinite amount of times without losing duration. However, they are insufficient to fire any weapon that gets fewer than 60 shots on a C cell (but see high-discharge options). 80% cost. Budget: These cheap 'dollar store' grade cells tend to hold less power, recharge more slowly, and/or suffer memory effects over time/are less reusable. If it matters, roll 1d: on 1-2, cell holds 50% normal power, on 3-4, cell takes twice as long to charge, on 5 cell has an effective Malf of 16 and stops recharging when it malfunctions, and on 6 the cell works normally. The user will not be made aware of this fact, although brands that always have the same problem will likely be determinable via a bit of market research. Cost is 50% normal. High-Capacity: These cells hold more power in the same space, due to technological advancements. Cost is 2x normal for 50% extra capacity, 3x normal for 100% extra capacity, or 5x normal for 150% extra capacity. High-Power: These cells are capable of discharging and recharging much more quickly than standard cells, but do not have a higher capacity. In short, these cells can be discharged in as little as one second if necessary, and recharge in 50% less time if used with an appropriate charger. Cost is normal; most batteries used by adventurers are 'High Power' varieties. Heavy Duty: These cells hold more power and can be used in High-Power discharge applications; however they recharge more slowly. In short, they can discharge entirely in one second, and hold 100% more power than standard cells, but take twice as long to recharge. Cost is 2x normal. Max Discharge: These cells are designed to be capable of discharging completely in a very low timeframe without affecting the battery's ability to be recharged, but have only 'standard' storage and recharge capacity. They can discharge completely in less than a second, which may be hazardous if done improperly (they make good impromptu explosives). Cost is 2x normal. Fast Charge: These cells have a high recharge rate, but standard capacity and discharge rates. Double cost for 2x normal charge rate, quadruple cost for 3x, and multiply cost by 10 for 4x. Premium: These cells combine high capacity and high recharge into an optimum performance package, but maintain 'standard' discharge rates. Quadruple cost for 2x charge rate and capacity, or multiply cost by 10 for triple charge rate and capacity. Hotshot: These cells are the budget equivalent of Max Discharge cells; they can empty rapidly, and capacity is normal, but their recharge rate is slow and they tend to suffer from memory effects. If it matters, they have an effective Malf rate of 16, recharge in double the normal time, and can discharge completely in one second. Cost is 80% normal. Bulk Capacity: These cells are the budget equivalent of high-capacity cells; they hold more power, but charge more slowly and may suffer from memory effects. Effective Malf is 16 and charging takes twice normal time, but double capacity costs only as much as a normal battery, and triple capacity costs only three times as much. Zapper: These cells are the budget equivalent of fast-charge cells; they can recharge quickly but tend to break down faster. This gives them a Malf of 16, normal capacity and discharge rates, and doubled recharge rate for only 80% of the cost of normal batteries. ==== Hydrogen Fuel Cells ==== Hydrogen fuel cells can be used to replace any size B or larger energy cell, and last five times as long; however, they cost twice as much as normal power cells, and they cannot be recharged. C cells and larger can be refueled (a hydrogen refuel kit costs approximately 20% of the cost of the hydrogen cell); otherwise, they need to be replaced. Hydrogen fuel cells are commonly used as primary power cells in vehicles and other large industrial machines where service interruptions are forgivable and long operating time is desired. ==== Standard Power Cartridges ==== Power cartridges are used in flamers and plasma guns, and combine a nonrechargeable power cell with a small hydrogen tank that contains the necessary fuel for the weapon. Advanced power cartridges hold more power and more hydrogen, allowing them to develop in a manner similar to normal power cells. ==== Refuelable Power Cartridges ==== Refuelable power cartridges cost twice as much as regular power cartridges, but the hydrogen component can be refueled and the battery component can be recharged. (A power cartridge refuel kit costs approximately 5% of the cost of the power cell.) ==== Capacitance Gel Cell ==== Any battery of size B or higher can be designed as a capacitance gel tank; these batteries use a viscous gel that can store extremely high quantities of energy for their size. These batteries can store up to ten times normal charge, but take five times as long to charge up (and are usually sold uncharged) and cost twenty times as much. They require a specific recharger to recharge properly and safely; attempting to use other rechargers may result in explosions or other unfortunateness. ====Paper Power Cell==== At the bleeding edge of the digital age, paper once again revolutionizes the world. Campaigns set in the microtech age and beyond often use generic power cells (Ultra-Tech p. 18). However, alternate means of power often coexist. Whether for realism, punch, or variety, one alternative is the paper cell. As a nanocomposite, paper cells store massive energy in minimal mass. One postage stamp slice powers a light diode for days. A sheaf of battery paper can drive an electric car. Power grains may be impregnated in muscle fibers to give them a boost, or supply artery-cleaning microbots. Biodegradable and even edible, the paper cell fits anywhere a sheet of construction paper will go. Paper cells may be portrayed as a catalyst for a TL9 society. ===Sizes of Paper Cells=== Paper cells fall under standard sizes, rated from AAA to F. (These sizes differ from regular power cell sizes; see p. 15 for two possible conversions.) One B paper cell provides the same power as a modern lithium AA battery. Each size category increases capacity nine times, and may be stacked or cut down accordingly (see Jury-Rigging, p. 14). Further stats are given in the boxed text on pp. 13 and 14. Paper cells are rechargeable. AAA Paper Cell: Sand-grain cells stimulate body tissue and micro-medical devices. AA Paper Cell: Rice cells power tiny devices, including: hearing aids, body implants, and insect-sized robots. A Paper Cell: Stamp cells power common small devices, including: wrist computers, pocket lights, and hideaway guns. B Paper Cell: Playing-card cells are the baseline unit, due to capacity and convenient handling. B cells power net phones, electronic binoculars, and various pistols. C Paper Cell: Letter-sheet cells are the largest retail size. They are mainly used in computers and power decks (see below). C cells may be fed into any standard printer. D Paper Cell: Newspaper sheet cells are the standard industrial unit, from which smaller cells are cut. They may be ordered factory direct or purchased in outlets. D cells are often built into the hulls of cars, small boats, aircraft, and powered armor! E Paper Cell: Large bed-sheet cells. These are medium industrial units, used in large piles or thick sheaves. They supply anti-air lasers, and truck-mounted radars, and are built into wind turbine and solar arrays. E cells are the largest size normally available at a factory-outlet store. F Paper Cell: Large tent cells. Intended for special and heavy operations, such as storing emergency power onboard space and sea vessels, or driving electric cargo trucks and trains. F cells are also built into the walls of collapsible structures, such as electronic tents for arctic explorers, search-and-rescue smart huts, and portable military buildings. ===Power Decks=== For large-scale needs, paper cells may be stacked into refillable containers called power decks (which also provide some protection from the elements). Many military, automotive, and industrial devices accept decks rather than individual cells. In turn, cells may be drawn from a deck. Thus, soldiers who find themselves outside an enemy bunker might be able to pop open their deck, draw a pair of A cells, and rig the control panel to enter. ====Paper Cell Stats==== “Charge” is the time to charge the cell. “Wt.” is weight in pounds. Cost is per unit. Reload is the time to reload a device in seconds. Paper cells have DR 1 and HT 10. Rugged paper cells are DR 2, HT 12 at the same weight, but double cost. ===Paper Cell Table=== ^ Size ^ Charge ^ Wt. (lb.) ^ Cost ($) ^ LC ^ HP ^ Reload ^ | AAA | 20 sec. | 0.000005 | 1/100 | – | 1 | 6 | | AA | 1 min. | 0.00005 | 1/10 | – | 1 | 6 | | A | 3 min. | 0.0005 | 1 | – | 1 | 3 | | B | 9 min. | 0.005 | 5 | – | 2 | 3 | | C | 27 min. | 0.05 | 10 | 4 | 4 | 3 | | D | 1.3 hrs. | 0.5 | 50 | 4 | 6 | 6 | | E | 4 hrs. | 5 | 250 | 3 | 14 | 12 | | F | 12 hrs. | 20 | 1250 | 3 | 22 | 24 | ==Sizes of Power Decks== Standard decks are sold in B sizes and up, providing equivalent power. They fit a specific cell size in sets of 10. An empty deck is half the weight of the total number of cells that it can fit, and costs the same as a single cell. Energy is simply (the number of cells) times (the energy of one cell). See Paper Power for example energy values. Example: A CB deck holds 10 B cells, so 10 x 3 = 30 Ah. All cells within a power deck will recharge and discharge at the same time. Some common deck sizes are as follows: * BA Deck: Bottle cap sized. Holds 10 A cells. Common for cheap, portable devices. * CA Deck: Pistol magazine sized. Holds 80 A cells. Standard for pistols and carbines. * CB Deck: Small envelope sized. Holds 10 B cells. Common for computers and radios. * DB Deck: Thick card pack sized. Holds 80 B cells. Standard for infantry rifles and magnetic launchers. * DC Deck: Business envelope sized. Holds 10 C cells. Powers electric bikes and light drones. Most devices safely accommodate only one deck or cell size. Smart decks use microprocessors to detect and compensate for mismatched cells. They accommodate one size category smaller or larger, at double price. The best smart decks can also accommodate different voltages. ====Decay and Destruction==== Because the components are cellular and redundant, paper cells are homogenous for injury purposes (Basic Set, p. 380). They function in temperatures between -100° to 400° F. They will burn at temperatures above 420° and may be damaged by power surges or overcharging as the GM determines. Cells will lose 5% of their charge for every month in storage. However, they may be charged and discharged endlessly, under normal conditions. Paper cells are biodegradable. This is useful for implants, where the body is expected to absorb a microbot after completing its duty. Otherwise, paper cells become brittle over time when exposed to light, air, and bacteria. Power decks can preserve cells for decades or centuries, provided they aren’t left out in a desert or radioactive zone! For every HP a piece of battery paper loses from damage or decay, the cell loses a corresponding fraction of its energy capacity. Wet cells will rapidly discharge, and short out any device. However, they can be dried and reused if they haven’t fallen apart first. Paper cells are not suitable for devices that require long-term storage followed by sudden activation, such as guided missiles and bombs. ====Using Paper Cells==== Equipment quality bonuses (p. B345) apply to paper cells. Good-quality cells and higher may also have a modest bonus to capacity and shelf-life, up to 1.5 times. If a cell has to be rolled or folded first, the GM may specify an additional time or skill penalty for reloading. Fast-Draw (Ammo) skill applies. ====Paper Power==== The suggested paper-cell default is 3 Ah for one B cell, consistent with a top-quality modern AA battery. Capacity scales linearly with mass; each size category is roughly nine times larger, and so each carries nine times as much power. One pair of C cells provides 54 Ah, outperforming a commercial car battery! Voltages are based on equivalent real world batteries. These are all approximations, balanced between the plausible and the gameable. === Paper Cell Capacity === ^ Size ^ Ah ^ V ^ | AAA | 0.004 | 1 | | AA | 0.04 | 1 | | A | 0.3 | 1.2 | | B | 3 | 1.2 | | C | 27 | 12 | | D | 243 | 1-120* | | E | 2187 | 120-440† | | F | 21870 | 440+† | * Because D cells are cut into smaller sizes, they share the voltage of the target cell. Otherwise, whole D cells are 120V for powering domestic and small industrial appliances. † Heavy-duty E and F cells are customized for specific devices. ===Fabrication=== Basic paper cells are made from carbon fullerenes, roomtemperature liquid salt, and plant matter. Lithium and a variety of metals may be used in higher quality units. Cells cannot simply be mixed in the kitchen – they must be manufactured. The result resembles black construction paper, but they may be dyed to any color. Paper E cells are printed off like newspaper and cut to size. The standard shape is a square or rectangle, allowing cells to be arrayed. However, custom shapes may be created. Improvised and basic-quality power decks may be assembled in any electrician’s shop. Advanced decks require microprocessors to regulate voltage and discharge. ==Cell Capacity and Voltage== The exact capacity of paper cells is ultimately up to GM; see p. 15 for some suggestions and Paper Power (above) for an example. If specific capacity matters in a hard science or numberheavy campaign, use amp hours (Ah). Amps are the Standard International unit of electric current; amp-hours is one common method of rating real batteries. For bigger cells and more powerful gadgets, amp hours may convert to watthours as follows: (Amp-hours) times (voltage of the cell) equals watts, or Ah x V = Wh. The voltage (V) of a paper cell may vary between sizes, societies, and even species. GMs are free to set the value themselves, especially if they wish to specify a device’s running time or wattage. Most devices safely accommodate only one voltage, and require jury-rigging to use strange cells. Smart decks that can adjust voltage can be an uncommon but valuable solution. ==Advancing Paper Cells== Nanotech may improve all components at the molecular level, doubling energy and shelf life. Such advanced cells are also double the price and one quarter as available. At TL10, common nano-fabrication allows these advanced cells to become standard. ===Jury-Rigging=== Paper cells can be cut, pierced, folded and rolled to any shape. It’s possible to braid temporary power cables out of strips or feed sheets into a standard printer for desperate instructions or sly plans. Geometrically, paper cells may be cut into ninths to create smaller sizes (e.g., one B cell produces nine A cells). However, they may be trimmed to any size or shape if the user is willing to keep track! ==Voltaic Piles== Adventurers can stack reams of paper cells, creating a “voltaic pile.” Likewise, paper cells can be laid end-to-end in voltaic arrays. Nine cells equal one size category larger. Creating stacks should not require a skill check, unless the character is from a culture that has little knowledge of paper cells (a check is likely if their familiar TL is also lower). Rigging a device is another matter. A roll against Electrician or Electronics Repair is needed to fit smaller cells into any gadget, including a deck. Oversized cells, or those with different voltages, may require penalties set by the GM. Devices and cells of different tech levels also require modified rolls (p. B168). ==Bursting Paper Cells== Paper cells cannot normally explode, unless they contain a volatile electrolyte such as lithium. They will burn at temperatures above 423° F, and the liquid electrolyte will boil away. Loaded power decks may rupture, but will not burst like a frag grenade unless tightly sealed. Space operas and other cinematic campaigns may ignore these limits. ==Eating Paper Cells== Spies and smugglers faced with capture may //eat// paper cells. Basic cells have no nutritional value for humans; an advanced cell will be toxic! Fullerenes might also be carcinogenic. Otherwise, they are digestible. Explorers meeting a tribe of intelligent herbivores might gain their trust with a few paper-cell snacks. ===DB-52: The Covert Card Pack=== In the United Space Defense Force, it is known only by its designation, DB-52. To agents of the covert operations division, these “jack packs” are life-saving examples of poker power. Disguised as a fully playable deck of cards, the DB-52 contains 52 B cells, with deck electrodes imbedded into the package markings. They may fit into any military DB slot (and civilian gadgets at GM’s discretion) but are most often used in special-ops gadgets – or for smuggling cells into repressive societies. LC2. ===Integration=== Paper and power cells may coexist. In this case, assume 10 paper cells of the same size equal one power cell of the same size category. For example, 10 B paper cells equal one B power cell. Flexible power cells are used in niche applications, such as hardened military electronics and high-powered battlesuits. Paper cells take care of devices with lower power requirements, such as electronic textbooks and personal comm links. Flexible power cells might even be a competing technology from a rival megacorporation! In either case, paper cells are thinner, lighter, and easier to conceal or recharge. They are also easier to lose, and are both degradable and costly. In turn, power cells are mechanically complex and more likely to explode or fail. However, they are cheaper, more powerful per unit, and have indefinite storage life. Likewise, a challenge facing adventurers might be that one type of cell is incompatible – or possibly illegal – in a strange society or facility. ==== Replacing Power Cells ==== It takes three seconds to replace an A, B, or C cell with a new one, or 5 seconds to replace a tiny AA or hefty D or E cell, or 20 seconds to replace an F cell. Cells can only be replaced if the user is strong enough to lift them out! Fast-Draw (Ammo) skill can be used to reduce the time for cells loaded into weapons. A successful skill roll reduces the replacement time by one second. Life-support systems, flying belts, and other items that cannot afford power interruptions often have two or more cells, so that if one is drained another takes over immediately. They are also usually equipped with a warning system to notify the user that one cell has been expended. ==== Jury-Rigging Power Cells ==== A device will usually be designed to use a specific size, type, and TL of cells. In an emergency, a device can use different cells or other power sources. Ten cells that are one size category smaller can substitute for a single larger cell, e.g., a D cell can be replaced by an array of 10 C cells (or 100 B cells, or 50 B cells and 5 C cells, etc.). Rigging this requires a roll against Electrician-2 and 10 minutes of work per attempt; critical failure damages the gadget. The GM may also rule that different nations or cultures use different voltages or sizes for their cells. This means an Electrician roll, at a penalty set by the GM, will be required to use familiar energy cells in strange equipment (or vice versa). Lower TL cells can be used to power a higher TL device, but this is always a jury-rig; be sure to apply TL modifiers. High-TL devices using lower TL cells will, at best, function like the lower-TL version of that same device. A bad roll on the jury-rig could result in failure to operate, or even damage the device. Low-TL devices can use higher-tech cells, getting increased operating time but no other improvement in efficiency. If the TL of the cells is more than 1 greater than the device's TL, the GM may require an Engineer roll, with appropriately cinematic results on a failure. ("The futuristic power cells just destroyed your flashlight, but before it melted, the beam went through the wall.") ==== Exploding Power Cells ==== Hydrogen fuel cells are fairly stable, but can explode if destroyed. Treat them as an explosive of the same weight as the cell but with a REF of 1/2. Capacitance gel cells are much more volatile, and are treated as having an REF of 2. ==== Psiwave Power Cells ==== Psiwave power cells are designed to extract energy from the unconscious psychic gestalt of the world and convert it into electrical energy. They are currently under development and no update on the progress exists at this time, but the potential seems great if they can be properly developed. ==== External Power ==== Many large items of equipment are described as using external power. This means they’re designed to be plugged into a building or vehicle's power system, or into a generator (see below) rather than using a power cell. They operate as long as the power is available. In addition, any device can be made to use a power adapter (same cost and weight as its usual power cell) which lets them run off the external power supply. ====Backpack Power Unit (TL9^)==== A solid-state portable nuclear battery unit, this device can charge an E cell in one hour and has connectors for any size power cell. It lasts one year, then should be replaced. It has DR 40, HP 15, and HT 15. Causes a radiation leak (1 rad/hour) if damaged and disabled (fails a HT check), but cannot explode. $50,000, 50 lbs. LC2. ====Solar Backups==== Explorers and frontier colonists might have uncertain access to power plants. Adding small solar panels to gadgets lets them trickle-charge in daylight. It costs 20% of the cost of the power cells. Recharging could take a few days to weeks, depending on the device’s surface area relative to power capacity ===== GENERATORS ===== A generator can be used to provide external power to equipment. Explorers, military units, and other expeditions use them for base camps, and they may be the only power supplies available for isolated habitations or anyone living "off the grid" (e.g., in a abandoned building). They're also used as emergency power supplies. ==== Diesel Generators ==== ==== Bio-Generators ==== ==== Fission Generators ==== === Fission Reactor === Fission reactors produce power by splitting the nucleus of heavy fissionable elements such as uranium. The reactor and electric generator designs available now are much more compact and far less expensive than 20th century reactors. (They are still heavy, due to the shielding required.) A typical semi-portable system fits in a truck bed, and provides external power for five years before maintenance and refueling (50% of cost). $50,000, 500 lbs. LC2. ==== Fusion Generators ==== When fusion reactors first appeared, they were gigantic installations that required heavy radiation shielding and frequent maintenance. Nowadays, fusion reactors produce less radiation (due to the use of harder-to-ignite but more efficient aneutronic fusion reactions) and are significantly lighter. Semi-Portable Fusion Reactor: A small nuclear fusion reactor. It fuses hydrogen into helium, liberating energy in the process. $200,000, 100 lbs. Its internal fuel supply operates it for up to 20 years; refueling and maintenance is $20,000. LC3. ===== ENERGY COLLECTION ===== Energy collectors gather energy from natural sources. Major installations may use hydroelectric, solar, or geothermal power sources, but solar power is the most common means of energy collection. ==== Solar Panels ==== Solar panels convert light into electricity. They work in any environment where strong light (such as sunlight) is available. The primary development at ultra-tech TLs is in inexpensive production of thin-film solar cells. Solar Power Array: This semi-portable array of solar panels is a generator that provides external power. It takes a minute to deploy, and covers about 400 square feet. $5,000, 250 lbs. The size assumes an earthlike level of sunlight; multiply cost and weight by relative light levels for other environments. LC4. Solar Paint: These cheap plastic solar cells can be painted onto any surface, including clothing or rooftops. A coating of solar paint is only 20% of the cost and weight of regular solar panels, but it requires twice the surface area and has no DR. LC4. ===== BEAMED AND BROADCAST POWER ===== Devices may operate on power "beamed" or "broadcast" from a central station, as long as they remain within line of sight. Buildings may have receivers on the roof to turn beamed power into "wall power." There may be many beam stations on a civilized ultra-tech planet; a colony may have only a few, or just one. A satellite or spaceship can beam power to ground units in line of sight below it. This means that nobody has to worry about powering vehicles or devices... until something happens to the power station. A power company may send its customers a monthly bill. A customer’s bill is typically 1% of the cost of his power receivers (see below). ==== Beamed Power ==== These use microwave beams to carry the power. The receiver for beamed power weighs the same as the normal power cell it is replacing, but operates indefinitely as long as it is in line of sight of the transmitter, plus 1/10th as long as the power cell when outside line of sight (it has a stored power backup system). Cost is the same. Usually, only D cells and larger are designed to receive beamed power. Beamed power transmitters are usually 10 times the cost and double the weight of an equivalent power cell per mile or fraction of a mile of range; they power one system at a time. Solar Power Satellites: Large solar panels are sometimes placed in geostationary orbit, to capture sunlight before it has been filtered by the atmosphere. They beam power down to receivers on the ground or to other space stations. ===== Broadcast Power ===== Broadcast power works like beamed power, but does not require line of sight transmission. Broadcast power receivers are 10 times as expensive as normal power cells, and are available in any size, not just D and up. Broadcast power transmitters are generally double the cost and weight of an equivalent power cell per yard of radius. ===== Civilization and Power ===== Fossil fuels and nuclear fission continue to be a convenient source of power in rural environments, or regions that haven't upgraded. Power plants tapping renewable sources such as hydroelectric power, wind power, geothermal energy, or ocean currents will also continue to be used where local geography and climate makes them economical. Other developments in power: Hydrogen fuel cell power plants supplement or replace fossil-fueled generators, perhaps using renewable energy sources such as solar power to electrolyze water into hydrogen. Solar power stations in orbit beam microwave energy down to the planet. Building-sized fusion reactors are common. Cheap superconductor cables improve the efficiency of power distribution. Some antimatter power plants are available, but too expensive for widespread use.