I think perfomance indicators as construction indicators are very important, but you may study social, environmental and economic indiators too.

Generation Performance Indicators

Generation Performance Indicators are the parameters that are related to the availability, service continuity or environmental impact of a generation plant or unit.

Development of common performance indicators is the first step in a process of creating large databases which would enable power plant operators to compare their own plant performances with others, and make improvements.

Plant Factor

The plant factor of a power plant is the ratio of the actual energy output of the power plant over a period of time to its potential output if it had operated at full nameplate capacity the entire time.

Plant Factors vary greatly depending on the type of power plants.

Running Plant Factor

The running plant factor of a generation unit is the ratio of the actual energy output of a generation unit over a period of time toits potential output if it had operated at full nameplate capacity during the period in which it has been operated.

Running Plant Factor shows the extent to which the generation units have been operated when they are running out of their nominal capacities.

Equivalent Full Load Hours

This gives the number of hours during one year,during which the generator would have to run at rated power in order to produce the energy delivered throughout a year.

Number of Equivalent Full Load Hours for a generator can be calculated using the formula given below.

Generation Unit Cost

Electricity generation is the process of generating electrical power from other sources of primary energy. Electricity is by electromechanical generators, primarily driven by heat engines fueled by chemical combustion or by other methods such as the kinetic energy of flowing water or wind.

Apart from that the other energy sources include solar photovoltaic and geothermal power.

However, there is a cost associated with power generation which mainly affects the electricity price.

This cost varies with the energy source incorporated with power generation and also could be classified as energy cost and maintenance cost.

The electricity generation cost of any power plant can be used to find the cost of generation per one unit (1kWh) of electricity.

Auxiliary Consumption

The auxiliary system facility is a major part of a power generation facility and the auxiliary consumption of a power plant depends on its configuration, age and related technical parameters. Purpose of an auxiliary system is to supply power for its own electricity requirements.

Auxiliary Consumption Percentage is a very important performance indicator to evaluate the productive output from a power plant.

Normally 0.5% -2% of power generated is consumed for the auxiliary system in hydro plants while the auxiliary consumption in fossil fuel power plants is 7% -15% since there are different equipment like feed pumps, cooling water pumps, air fan, etc.

Availability Factor

The evaluation of availability of a power plant is one of the most important tasks at any power station, which indicates the fraction of time that it is able to produce electricity over a certain period.

To analyze plant availability performance, generation unit outages should be scrutinized to identify the causes of unplanned or forced energy losses and to reduce the planned energy losses. Reducing outages increases the number of operating hours, therefore, increases the plant availability factor.

Availability Factor of a generation unit can be calculated using the formula given below.

Special Performance Indicators for Renewable Power Plants

Electricity generation using renewable energy sources is somewhat different from the other conventional methods. These energy sources are freely available in the environment unlimitedly.

Therefore, some special performance indicators can be defined in the technical, environmental, and sociological point of views.

Wind Power Generation

Noise from Wind Turbines.

The maximum noise of a wind turbine can be measured in dB from specifically defined distances from wind turbine such as;

• At the foot of the wind turbine

• 500m away from the foot of the wind turbine

•At a standard distance (H + D/2) from the foot of the turbine

Where;

H = Height of the turbine tower

D = Diameter of the circle swept by the turbine blades

Birds Fatalities

This is to measure the number of birds killed per wind turbine in the reported period

Up to now i found that, two parameters, the power coefficient and torque coefficient, are essential to validate the performance of a wind turbine.

the power coefficient(Cp) is used to estimate the capability of power generation for a wind turbine

Torque coefficient (CT) was used to assess the mechanical torque generated by the wind turbine. Wind turbines with higher value of CT could start and work at lower wind velocit

I work in the wind industry in Australia and some of the most important metrics we use are time based availability and energy based availability, this is often a contractual measure between the owner and the service provider. Traditionally OEMs who offer service contracts will guarantee a certainty number of hours a year a turbine will be down for servicing, this is reflected in a time based availability of 95-97%. However, time based availability doesn't give incentive to the service provider to undertake maintenance during lower wind periods so the industry is now wisening up to start a move to energy based availability, where the guarantee is about capturing the 95-97% of available energy. 

This is a fairly old question but if you or anyone wants further info on other metrics (such as yield, energy to downtime ratio etc) feel free to contact me, I'm doing research in this space for Renewable Energy mini-grids atm. 

wind technology sophistication indicator? capabilities indicator? the drawbacks to use turbine capacity? indicators that can be captured from normal statistical channels?