The cost per kilowatt-hour and payback time for wind generated power. http://www.wind-power-program.com/costperkwhr.htm

2. The cost per kilowatt-hour and payback time for wind generated power.
Coins
The cost of the electricity generated by a wind turbine and the investment payback period are essential factors in determining whether a particular installation is worthwhile or not. These factors can be calculated in a number of ways depending on how the accounting is done and it is not really feasible to include all the possible methods that might be used in a general program. Instead, in the WindPower program, a fairly basic approach is adopted that nonetheless is sufficiently flexible to take account of grants, interest payments and so on. The expression for the costs of the electricity per kilowatt-hour is
Cost per kilowatt-hour
where Pm is the turbine mean power already calculated from the previous form and Lt is the turbine lifetime in hours.

When the option to calculate the cost per kilowatt-hour is selected from the menu bar, a form similar to the one shown below opens up. All that is necessary is to enter an estimate of the installation costs, any other fixed costs (such as decommisioning or an overhaul charge) and any annual charges such as maintenance payments. For small turbines, it is usually the installaation cost that dominates and so this may be the only figure that need be entered. For larger turbines, other costs and maintenance can be more significant. For example, annual maintenance costs for large turbines are concerned primarily with the infra-structure associated with the wind generated power and these can amount to around 20% of the fixed costs.

Cost per kwhr blank

Once the installations costs are entered, the 'Calculate costs per kilowatt-hour' button can be clicked and this results in a display similar to the one below for the cost per kilowatt-watt hour as a function of the mean wind speed and the expected turbine lifetime. The turbine lifetime can be adjusted with scroll bars and its influence on the costs instantly displayed. The monetary units of the costs per kilowatt-hour are one hundredth of the units used for the installation costs so that, for example, if the installations costs are in US dollars, the costs per kilowatt-hour will be in cents. For installation costs in British Pounds, the unit costs will be in pence. The example below is for a popular American designed small turbine - the Skystream 3.7 metre 1.9 kilowatt - and the installation cost is only a very rough estimate in pounds Sterling. Nonetheless, it serves to give an order of the costs per kilowatt-hour in pence but it should be stressed that the installation costs exclude grants and, more particularly, any interest payments involved if the installation costs were raised on the basis of a bank loan.

cost per kwhr (full)

Some users will also be interested in the time it takes to recover the cost of a wind turbine installation. This might be a somewhat more complicated calculation because it depends on the cash flows of meeting the various costs. However, for present purposes, a first estimate can be obtained by assuming that the installation costs are all met upfront (including any interest payments). Under these circumstances, an estimate of the payback period can be obtained from the expression
Payback formula
Pm is again the mean power from the turbine and Cr is the cost per kilowatt-hour of the electricity against which the payback period is being assessed. This might either be the cost of the electricity that the turbine is seeking to displace or, say, the cost of any payments that you receive from government incentive schemes for producing 'green' power - like the US Renewable Energy Credits or the UK's Renewable Obligations Certificates.

The payback period option is also available from the menu bar and, in this case, a form like the one below opens up. Once again, only installation costs have to be entered and then the 'Calculate payback period' button can be clicked.

Payback(blank)

The calculation of the payback period depends on the cost per kilowatt-hour of the electricity that the wind turbine is seeking to displace or, alternatively, the cost of the electricity that the user will receive through some government incentive scheme such as the US Renewable Energy Credits or the UK's Renewables Obligation Certificates. This reference cost can be adjusted by scroll bars and the impact of this on the payback period instantly displayed.

Both the cost per kilowatt hour results and the payback period results can be printed and/or saved in comma-separated-variable files so that they may be imported into spreadsheet programs like Excel.

Payback(full)


Next, the power-output profile menu option.