66 MAKALE / ARTICLE inside view of the new energy center at North Staffs Hospital in the UK, which includes a 1,4 MWe gas-fired CHP unit. WHO CAN BENEFIT FROM CHP? There is strong desire by governments in a number of countries around the world for CHP to be adopted. This is because good quality CHP plants achieve a reduction of between 30-50% in carbon dioxide emissions, compared with generation from coal-fired power stations, and over 10% in comparison with gas-fired combined cycle gas turbines. The encouragement of CHP may be part of a government energy strategy or commitment to carbon dioxide reduction, and financial incentives may be available. Some progressive companies may consider CHP as 'a good thing' to adopt as it is perceived to be economical. There may also be a marketing benefit that the company is publicly seen to adopt current best practice across the range of its operations. However, there must be a strong business case to invest in any new plant and it is often the case that payback periods for CHP may exceed company expectations for investment in the core business process. ENERJi & KOJENERASYON DÜNYASI CHP may not, therefore, be good for every company but with careful analysis of the real benefits, many will find it a viable option to pursue. As a general rule, the simultaneous supply of power and heat is required over a sufficient time-base to gain good utilization of new plant. A 'nine to five', five-day working week does not generaliy favor CHP. Typical industries that benefit from CHP include breweries, refineries, pharmaceutical plants, paper milis and water desalination plants - ali of which operate for extended hours. Where there is a large amount of steam or hot water use relative to the electricity use, the displaced cost of heating, using traditional boiler plant, may favor CHP. The sensible ratio of heat to power may vary, season to season or even during each working day, but the typical ratio determines the type of prime mover. The ratio of fuel and power prices is one of the most significant factors. Again, this may vary, season to season, and wili almost certainly change over a number of years, perhaps with little certainty as to future trends. A low fuel price relative to purchased electricity will generaliy be required to justify CHP. As stated above, a company operating a process that requires the simultaneous supply of power and heat, and where the plant operates continuously or on shift working may benefit by installing CHP. Whilst natura! gas is an ideal fuel, CHP is also suited to a range of fuel types, limited by the capability of the prime mover. Part or fuli firing on biomass or a by-product from an industrial process can improve economic performance. The prime mover at North Staffs Hospital CHP plant
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