KACO new energy Inc.

DC / AC Ratio Optimization Gordon Woodcock

SAM Virtual Conference 2013

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Contents

Introduction

Sources

Analysis Setup

Results

Applications

Next Steps

2 Contents

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𝑃𝑜𝑤𝑒𝑟 𝑟𝑎𝑡𝑖𝑜 =𝑅𝑎𝑡𝑒𝑑 𝐴𝑟𝑟𝑎𝑦 𝑃𝑜𝑤𝑒𝑟 (𝐷𝐶 𝑘𝑊)

𝑅𝑎𝑡𝑒𝑑 𝐼𝑛𝑣𝑒𝑟𝑡𝑒𝑟 𝑂𝑢𝑡𝑝𝑢𝑡 (𝐴𝐶 𝑘𝑊)

𝑁𝑃𝑉 𝑖, 𝑁 = 𝑅𝑡1 + 𝑖 𝑡

𝑁

𝑡=0

DC / AC ratio or power ratio compares the photovoltaic array power to the inverter capacity:

Net present value is the summation of a time series of cash flows brought into the present:

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As DC/AC ratio increases, the inverter is more likely to derate

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kW

25-Jun

Effect of DC / AC Ratio on AC Output (100 kW inverter)

DC kW (1.33 DC / AC)

AC kW (1.33 DC / AC)

DC kW (1.16 DC / AC)

AC kW (1.16 DC / AC)

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Choosing the ideal DC / AC ratio that maximizes net present value is a moving target

Max NPV

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What are the significant variables and how do they interact?

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The initial analysis is split into an up front cost block

DC / AC Ratio Optimization

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... and a financing block

DC / AC Ratio Optimization

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Several sources were used to approximate real world scenarios.

DC / AC Ratio Optimization

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LA, no financing

Bldr, no financing

ABQ, no financing

HSV, no financing

SLV, no financing

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Examining how NPV and DC / AC ratio interact provides the following benefits: • Inverter manufacturers can build a business case for new product

development around higher power ratios

• Developers and designers can optimize system size based on NPV while adhering to existing design rules

• Policy makers can see how taxes, incentives, and energy rates shift economic benefits

DC / AC Ratio Optimization

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Next steps: • Perform parametric analysis with additional variables (e.g, module

price, inverter price, discount rate)

• Rank variables by significance, identify correlated factors