A simplified double grade meteorological data model for the simulation of the annual performance of a domestic-size renewable energy system is proposed. With the model, only two representative days (clearest and cloudiest) during each season of the year are necessary to estimate annual energy balances, carbon emissions and the running costs. The model was chosen in preference to other simplified models based on the error distributions from the results of the continuous simulations in a test period. Detailed numerical simulation studies show that the carbon emissions from the renewable energy system are about 16% of a comparable conventional system. The thermal energy produced by a solar collector during the winter season, however, is insufficient to meet all the loads so that frequent heat pump operations and the auxiliary boiler are necessary in cold climate regions.

Five different kinds of domestic-size renewable energy system configurations for very cold climate regions were investigated. From detailed numerical modeling and system simulations, it was found that the consumption of fuel oil for the auxiliary boiler in residentialtype households can almost be eliminated with a renewable energy system that incorporates photovoltaic panel arrays for electricity generation and two storage tanks: a well-insulated electric water storage tank that services the hot water loads, and a compact boiler/geothermal heat pump tank for room heating during very cold seasons. A reduction of Greenhouse Gas Emissions (GHG) of about 28% was achieved for this system compared to an equivalent conventional system. The near elimination of the use of fuel oil in this system makes it very promising for very cold climate regions in terms of energy savings because the running cost is not so dependent on the unstable nature of global oil prices.

[1] Dissolved methane (DM) concentrations were measured in 17 lakes as part of the operations of the 45th Japanese Antarctic Research Expedition in ice-free rocky areas along the eastern coast of Lützow-Holm Bay (Syowa Oasis) in East Antarctica in the summer of [2003][2004]. DM at the surfaces of 14 lakes ranged from the atmospheric equilibrium concentration (about 4 nmol L −1 for freshwater) to 385 nmol L −1 . Relatively low DM of less than 50 nmol L −1 were observed in about 60% of the lakes. Many of the lakes (area fraction of 85%) were supersaturated and are thus sources of methane to the atmosphere. The exchange coefficient was calculated using wind speed data at Syowa Station. Area fraction frequency distributions with four surface DM ranges were applied to all lakes at Syowa Oasis (110 lakes, total lake area of 9 km 2 ). Extrapolation to the whole Syowa Oasis gives an estimate of total emission of about 1 t CH 4 yr. This is the first estimation of methane flux from the surfaces of thawed lakes to the atmosphere in Antarctica. Since a methane efflux of about 2 t CH 4 yr −1 was estimated in our previous study from frozen bubbles in lake ice, a total amount of 3 t CH 4 yr −1 would be released to the atmosphere from the lakes during the ice melting season (December-January) at Syowa Oasis.

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