A ‘How To’ for Grid-Tie PV on the Big Island of Hawaii

            

                          This site describes my experience in designing and installing a residential grid-tie PV system at my house (ele. 650ft) on the Kona side of the Big Island. Hopefully this site will help others down the same path. I was inspired to write this because at the current date (December 2006) there is a lot of information available on installing solar water heating, but almost nothing with sufficient detail to enable actually designing and installing a grid-tie PV system.

 

                          Why do this? It is the ‘green’ thing to do (reduced carbon footprint), and it is a step towards energy self sufficiency for the island. Or maybe it just appeals to my geek gene. My 2kW system cost about $10,500 including parts, shipping, labor, fees, taxes, and tax credits. The tax credits are substantial. The system is expandable to 3kW by adding extra panels.

 

                          It is hard to predict the future cost of electricity or the future cost of money, however I expect this system to pay for it’s self in 10 years or less and have a life of more than 20 years. Financially a PV system is equivalent to an energy price indexed immediate annuity.

 

                          This diagram from the Xantrex inverter manual shows an overview of the system:

 

 

How well does this work? This is my electricity bill:

 

 

 

 

 

 

 

 

 

 

 

                         

                          The PV equipment was installed in late December. The first full billing cycle was February 2007; the May billing cycle was cloudy and my HELCO usage was higher. The drop in usage seen on my bill beginning in July 2006 is due to installing solar water heating.

 

                          More detailed PV results are contained in the Generating Power section.

 

                          This web site contains PV implementation details, if you want the big picture your eyes will probably glaze over if you read the rest of this.

 

                          This information should still be broadly applicable on the smaller islands of Hawaii too (e.g. HELCO is the same company as HECO).

 

                          I would like to acknowledge the help of Arie, Alex, and Ron in enabling this project, each of them made critically important suggestions.