To cope with continuous growth in the world demand for gas, it is not enough to make simply continue investments on new gas field developments. At the same time the gas pipeline network has to be extended to new markets whenever a new gas producing region is created, since gas has no alternative transport measure from fields to market. The nature of pipelines is to form a "natural monopoly" because of the large investments required and the exclusiveness of competition. However, at the planning stage plans of cross-border gas pipelines are facing various types of competition. Russia, the largest gas producing country in the world, confronts competition of gas suppliers set by Turkmenistan and Azerbaijan for the market of China and the South Europe respectively, on the other hand Russia made China a gas-market competitor against the traditional European market, which allowed Russia to win a series of long-term sales and purchase agreements from European gas distributors. As the gas demand soars, Russia may notch a stronger position against both East and West due to its magnitude and flexibility of deliveries, which is being accomplished not through geopolitics but rather through competition in the market.
In this research biomass accounting framework, which summarizes economic and environmental performance data in the form of an accounting table, was suggested in order to provide the information on the biomass town achievements in general as well on the individual biomass-related activities. Differently from scenario analysis and simulation tools, developed to support biomass town planning process, biomass accounting is aimed at assisting evaluation of current situation and increasing transparency of biomass-related decision-making process.
The performance of a Stirling engine depends significantly on performance of heat exchanger. The heat exchanger of a Stirling engine comprises a heater, a cooler, and a regenerator. The heater and cooler perform heat transferring from high and low external heat sources to working gas, while the regenerator absorbs heat from the working gas when the gas flows from heater to cooler, and releases heat during the reverse process. These auxiliary devices increase the weight of the engine and reduce its specific power. In this study, in order to improve the performance of the compact Stirling engine, a new heat exchanger(hereafter called the prototype heat exchanger) with a heater that reduces the energy loss from combustion gas, and a cooling system that uses fuel gas were developed. The performances of these systems were then compared with that of a conventional multi-tube heat exchanger. The prototype heat exchanger capable of reducing the heat loss in a heat exchanger via conbusting in a tube. Additionally, the weight of the prototype heat exchanger is lighter than that of a conventional multi-tube heat exchanger. The prototype heat exchanger is advantageous for reducing the engine weight and improving the specific power. Experiments conducted on the prototype heat exchanger installed on the engine showed excellent results and its superior performance.