As already noted, storing power for the 14 days of darkness each lunar month is a serious problem. It will NOT be dark, for the initial “nearside” camps, because Earthshine is quite bright! The “half Earth” conditions near sunset and sunrise will be about 10 times as bright as a “Full Moon”, with no clouds to reduce the light. “Full Earth” at the middle of the lunar night will be at least 30 times as bright as a conventional “Full Moon” in Earth's clear sky. You won't need lights outside, but you will certainly need them in the habitat! Since the brightness mentioned is more than 1000 times dimmer than direct sunlight, solar power production is effectively zero. Power will have to be stored. Since all such processes have inefficiencies, it will be good to double my initial Solar Power plan, using 6 kg of thin cells, rather than only 3kg. More than 10KW peak power will be produced, with an ample 3kw Day/Night average. This also provides insurance against solar cell damage and degradation. Battery power storage of course springs to mind, but it is virtually useless, except for short time emergency use! The sun will be down 336 hours each cycle. Very good Lithium Ion cells can hold about 170 Watt Hours per kg mass. But this barely provides ½ watt average power output, per Kilogram, for the 14 days of darkness. A modest 500 Watt average power would require One Ton of lithium cells, even if the full capacity could be tapped each cycle for one hundred cycles (8 year desired life). A much better power storage system is needed. An interesting possibility would be to store heat in a buried volume of lunar rock. The lunar “crust” has modest thermal conductivity (as shown by the lack of thermal cycling 80 cm below the surface). Heat transfer is even lower under loose regolith fill. The heat could be recaptured when the sun is down with a variety of heat engines. But that will wait for later. A good short term solution is to adapt the needed “Life Support” processes for power handling as well. The “Sabatier Reaction” (so loved by Robert Zubrin) -- CO2 + 4H2 => CH4 + 2H2O -- converts CO2 to Methane by forcing Hydrogen gas to combine with it under high pressure. As usual, this reaction is also promoted by quickly capturing the water (H2O) produced. The water from the listed reaction is electrolytically dissociated to produce more hydrogen, as is water from metabolic food oxidation in the astronauts. This is one of the few reactions that can completely recover the used respiratory Oxygen. When a surplus of Methane has been accumulated, it can be dissociated at high temperature and low pressure to produce useful “Pyrolytic Graphite” and release the Hydrogen for reuse. (Graphite electrodes are usually used for electrolytic production of Aluminum.) But the Methane can be “burned” with Oxygen in a very practical fuel cell. This of course regenerates the Carbon Dioxide and adds more water for recycling. But 15,470 Wh of energy is released for each kilogram of methane used. This is almost 100 times the energy/mass ratio of Lithium Ion cells and has an essentially unlimited cycle life! The materials listed here are unavoidable in the life support system of a manned outpost and most of the chemical reactions are already necessary in that system. Twenty Kilograms of Methane can produce my target 500 watts of electrical power, at practical efficiency, for each 14 day dark cycle on the Moon! The best fuel cell for this purpose is the Solid Oxide Fuel Cell (SOFC) running continuously at 600 to 900 degrees C. These cells are in active use at remote industrial and residential sites. Their efficiency converting the chemical energy to electric power is also unusually high, at 60%, and the high temperature waste heat can also be used. They have set records for longevity, with 8 years of continuous operation, and 50,000 hours as a typical expectation. Similar tests on PEM, room temperature fuel cells, averaged 3000 hours. The use of any hydrocarbon is challenging with both Alkaline and PEM fuel cells, as one will not tolerate CO2, and the catalysts of the other are poisoned by CO. The SOFC, on the other hand, has unlimited tolerance for both gases, and will run very well with Methane (not just Hydrogen) as feedstock. Note that the SOFC process works equally well in reverse, to split water and release Hydrogen and Oxygen. This can be accomplished with simple equipment on the Moon, but the SOFC based electrolysis system is very attractive for Zero G, Mars Expedition use! The fuel cells and other systems, of course, also add mass. Current materials seem to offer an SOFC stack to produce my 500 Watts sustained power with 1 kg mass. Methane is significantly easier to liquefy than Oxygen, with the 10 kg mass then occupying about 20 liters (less than 1 cubic foot) in an insulated tank. The minimum temperature at the Apollo 15 landing site (92 K) is well below the normal boiling point of Methane, and below the boiling point of Oxygen at 150 kPa = 22 psia. Liquid storage of both gases is feasible and can use similar equipment. Only 7 liters of LOX is needed for breathing by each astronaut over the 14 day period, so that the reserve for a three person crew requires a similar storage tank. With total system losses, 1000 to 2000 watts of electrical power (up to 1/3 my enhanced 10 KW peak supply) will drive this process and guarantee 500 average Watts through the dark half cycle. A small group of Lithium ion cells can handle short term peaks. High energy processes – CO2 conversion, water electrolysis, desiccant regeneration, LOX and LNG generation and regolith processing - will occur during the 14 day, sun up half cycle, with many kilowatts of available power.