HPG 80.05 - FAQ -Efficiency

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Frequently Asked Questions - Efficiency

Why is efficiency important ?

Why is Yield important ?

Is Renewable Energy efficient ?

What's the difference between "Efficiency" and "Efficacy" ?

How can I increase the Yield of a Solar Array ?

Why is efficiency important ?

How efficient your equipment is will contribute directly to Annual energy capture and therefore the payback - as payback is a direct result of energy sold to the grid . Simply put, efficient equipment gives you more electricity for the same investment.

It is important to realize that ALL systems should be evaluated in terms of Annual Yield. Evaluation of 'nameplate rating' or 'price per kilowatt' usually results in a misleading result because such measurements are based on idealized conditions ( wind and sunshine ) which actually don't exist. The only reasonable measurement is how many kiloWatt Hours are generated per year. All Hybridyne calculations are based on Annual Yield.

Please be aware that not all systems are equal. A common misconception is that " all PV panels are the same" and that "all inverters are the same", and that all renewable energy systems operate with the same basic principal. The issues for Wind and Solar are somewhat parallel :

"Wind farms" use large, and often very expensive wind turbines and their ancillary equipment. They are designed for direct connection to the electrical grid as power utilities.

Older-technology turbines are intended to be located only in areas of constant high-velocity wind. They usually have gear reduction transmissions or some other mechanical means to keep the generator running at a specific velocity in variable wind conditions - these mechanical devices 'steal' or 'lose' some energy. Geared turbines are often very reluctant to start generating at low wind speeds, and do not gather much energy at the bottom end of the wind energy spectrum. At high wind speeds, these turbines are typically slowed down by mechanical braking systems which waste further available energy.
The newest technology in wind turbines is " Direct Drive " - direct connection of the blade to the generator which converts rotary motion into electricity. Eliminating the gearbox saves a lot of wasted energy, allows the turbine to produce electricity in less wind, and dramatically reduces expensive maintenance and 'down time'.
HPG uses Direct Drive turbines exclusively - and marries them to Hybridyne Power Electronics Conversion/Inversion Technology to efficiently convert 'raw' electricity to 'refined electricity' at unprecedented efficiency levels. As soon as the high wind-efficiency turbines start to turn ( even in light wind ) the HPE CIT starts gathering energy . ( Click here to see the difference ) . In very high winds, where normal control systems slow the turbines mechanically, ( with brakes, by feathering the blades, or with 'dump load' resistors ), the CIT uses the load (or the grid) as the brake - directing the extra energy into the storage system or the grid. This allows the turbine to continue to be utilized in higher than average wind speeds ( higher in the wind energy spectrum ) than would otherwise be expected.

Large solar arrays have a similar limitation - the control systems only start gathering energy when the illumination reaches a preset threshold value, and stop gathering energy when the illumination drops back to that threshold. This often saves money in power electronics but costs money by requiring more PV panels, more land area, and/or lost efficiency.

On the other hand, with the HPE CIT , as soon as the solar panels are illuminated, the CIT will gather whatever energy is available. ( Click here to see the difference ) Later in the day, as the sun's illumination decreases, the CIT still gathers whatever energy is available - producing electricity long after conventional 'inverters' have shut down.
By using HPE's CIT, HPG is able to gather much more electricity from the same sunshine - dramatically increasing the output yield ( measured as KiloWattHours per year and ultimately dollars ).

Why is Yield important ?

As previously mentioned, Yield is the accurate measurement of efficiency. You can talk about the theoretical ( or even measured ) efficiency of the various components of a Renewable Energy System, but since they are all interrelated, the only thing that really counts is " how much electricity is coming out the other end ? ".

One of the much-criticized limitations of Renewable Energy equipment is its reliance on the weather, which is literally variable from minute to minute :

sunlight varies over the course of a year as it rises later, sets earlier, and crosses the sky in a lower path ( during the winter )
the sunlight varies over the course of a day as the sun gets higher in the sky
the sunlight varies over the course of minutes as a cloud sweeps by
wind constantly fluctuates

The theoretically perfect conditions ( high noon on a cloudless but cool summer day, for example ) rarely happen. What happens 99.99% of the time is something less than perfect - it's early in the day, or it's partially cloudy, or it's a January day with fewer hours of sunlight, or it's fitfully windy.

Therefore, instantaneous measuremets are worthless - only measurements of days, weeks, and years of output tell the true story.

Because all Hybridyne technologies ( wind or solar ) gather more electricity during the 'less than perfect' conditions that generally prevail, the overall amount of electricity gathered per day/week/year/decade will be higher, and since more electricity means more revenue, that's why Yield is important.

Is Renewable Energy efficient ?

The efficiency of any system, including one which uses Renewable Energy to generate electricity, depends on the quality of engineering done on the equipment used.

Wind Turbine efficiency depends on blade design, alternator efficiency and mechanical efficiency. Hybridyne uses highly efficient turbines sized specifically for the application.

Solar Panel efficiency depends on ‘density” ( how much energy is generated per square metre ), and the technology of the collector. Traditional silicon-based Photo-voltaic ( PV ) cells are becoming more efficient and work best when pointed directly at the sun at an appropriate angle. Newer “DSC” cells can gather electricity like plants – whenever sunlight is available in any form.

Generally, when describing the efficiency of any generating system ( for example , coal-fired ) the efficiency is measured as the number of kilowatt hours generated per dollar of fuel burned. Since the ‘fuel’ for Renewable Energy systems is free, the efficiency is very high, and therefore much more efficient than any fuel-based generation system. Beyond that, is the question of how much electricity is returned for the cost of purchase and construction.

Often, the deciding factor on efficiency is the electronics which convert 'raw' electricity into 'refined' electricity which can be sold to the grid. HPG uses Hybridyne Power Electronics Conversion/Inversion Technology which delivers the highest 'yield' in the industry. Simply put, with the CIT, the Energy Park will generate much more income from the same wind and sun.

What's the difference between "Efficiency" and "Efficacy" ?

Efficiency is a measure of loss - in the case of a solar inverter or wind converter, the loss of electricity in the form of heat. A highly efficient device translates more of its input energy into output electricity and loses less in the form of heat.

Efficacy, on the other hand, is a measure of effectiveness - what can the device do with the constraints of the characteristics of the input energy?

A solar inverter is a perfect example, because the input energy varies in its characteristics over the duration of a day. The input to a solar inverter is the energy from a string of PV solar panels. That energy is expressed in both Volts and Amps ( current ). By Ohm's Law, the voltage and current will be reciprocal values - high voltage means low current, and low voltage means high current. Under low light conditions, a PV string will deliver low voltage/high current electricity.

All inverters 'turn on' at some voltage and off as some higher voltage ( the "Voltage Window") . An inverter that is ineffective, will have a narrow voltage window - it will wait until the voltage reaches, say, 300 Volts before it begins to convert the electricity. An inverter that is effective will turn on at an lower voltage, say, 90 Volts.

The voltage window, therefore is a measure of the Efficaciousness of the inverter. An invereter with a wider voltage window will be more Efficacious and will deliver more output energy , which is more yield, which is more revenue.