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A long-term commitment is unlikely to be obtained at this stage and information on existing costs may be limited, so a cautious approach may be needed. The situation is clearer in the residential sector where the costs of the conventional individual boiler systems are generally well established. The main options available in the residential sector are:

• sales to individual residents by means of a fixed charge related to size of dwelling

• sales to individual residents based on measuring the heat energy actually used (dwelling heat meters)

• sales to individual residents based on the measurement of actual energy used by a block of flats and an apportionment based on size of dwelling/occupancy.

Pre-payment systems can be used to collect either fixed or variable charges or a combination of both. Some consideration should be given to assessing the likely levels of bad debt where prepayment systems are not installed, and bad debt costs may need to be incorporated in the economic analysis.

3.7.2: Electricity sales

Where CHP plant is installed, it is vital to obtain the maximum income from the electricity produced. Typically, a 10% increase in electricity sales will improve the internal rate of return (IRR) of a project (see section 1.10) by 2%, whereas a 10% increase in heat sales will improve the IRR by 1%. 

The CHP/CH company may opt to sell electricity in bulk to the host public electricity supplier (PES), which will normally offer terms on a p/kWh basis for electricity generated at different times of the day and year seasonal time of day (STOD) tariff. However, if the CHP/CH company can supply electricity users directly (this may include residents themselves) a much better return can be obtained. Among the more favourable options that exist, (following the liberalisation of the electricity market in 1998) is the sale of electricity direct to residents and other customers. A summary of the options is as follows:

• sale to the host PES

• sale to a second tier supplier, i.e. other PES’s and other suppliers of electricity

• direct sale to customers as a second tier supplier. This implies pool membership for an aggregate supply of more than 500 kW

• sale under the non fossil-fuel obligation (NFFO) (only for energy-from-waste projects which have bid for this arrangement in advance).

• sale through the pool (this entails having pool membership and is more appropriate for projects in the range 30 MWe-50 MWe)

• sale as an on-site generator to other customers on the same site.

It will normally be helpful to use the conventional route of sale to the host PES for the base case analysis, with the other options considered as possible improvements that can be investigated, depending on the scale of the project and the resources of the study. An element of negotiation will be needed in most of these options. As a result, definite figures are not likely to be available at 本论文由英语论文网提供整理，提供论文代写，英语论文代写，代写论文，代写英语论文，代写留学生论文，代写英文论文，留学生论文代写相关核心关键词搜索。