Low Co_2 EMISSION AND NEAR ZERO EMISSION POWER PLANTS AS FUTURE Co_2 CONTROL TECHNOLOGIES

摘要

In this paper, CO_2 control technologies like decarbonisation either of the flue gas or of the fuel as well as the use of oxyfuels in near zero emission cycles are investigated. Four existing technologies of CO_2 removal from flue gas are compared from the point of view of their penalties on performance and costs of fossil fuels fired power plants, namely the CO_2 chemical absorption using amines, membranes, cryogenic distillation and adsorption on solids. Using the first technique results in an overcost of the generated kWh of around 60%. From the four considered techniques, the chemical absorption is the most mature and the best suited to power plants. Decarbonisation of the fuel is also considered; it is much less penalising than chemical absorption (30% overcost of the kWh) and produces hydrogen. A new concept of near zero CO_2 emission power plant is presented, the so-called MATIANT cycle, using an oxyfuel with total recycling of the flue gas. The cost of its kWh is 50% to 100% higher than that of a current Combined Cycle. As a conclusion, when the external costs are internalised in the generating cost, the resulting social cost (generation + external costs) of the kWh in fossil fuels fired plants with capture and sequestration of CO_2 is of the same order of magnitude as that of on shore windmills and the social cost of the kWh generated in a MATIANT cycle is comparable to that of a Combined Cycle with capture and storage of CO_2 and in the range of social costs of windmills too.