Friday, May 23, 2008

Enjoying the Power

Yahoo! we are on line and making green electricity as of May 21, 2008.

For those of you interested in how we will be making electricity for our Lake Home here are the details:

We will have an on-grid PV system. The PV system will be connected to Cooperative Light and Power Association’s standard electrical grid system. In addition we will have 12 sealed lead acid batteries, (the type of battery that does not require regular maintenance), that will give us about a weeks worth of storage should the grid go down and the need for power becomes critical.

A special meter is installed to track and document how much kwh is being sent back to the grid. The billing or buyback is reconciled per billing period which usually is each month. The meter cost $800.00

All electrical work will be in full compliance with the MN State electrical code and best industry practices.

There will be two SMA Sunny Boy 6000U Inverters located in the mechanical room. The inverters change the Direct Current (DC) coming from the PV panels to Alternating Current (AC) at a voltage and frequency that is synchronized with the utility power. These inverters along with two SMA Sunny Islands 4248U units will allow us to interface with the sealed lead acid batteries. The addition of batteries to a grid inter-tie system allows our solar equipment to continue to operate during a utility power outage as well as store energy for nights and cloudy days.
There will be 42, Sanyo 200W PV modules each about 13 sq. ft. in surface area, for a total of about 540 sq. ft. of PV modules with a peak output of 8.4 KW. We should be able to generate an average of around 925 KWH per month or 11,000 KWH per year, and we are assuming that we should only need 200 to 500 kwh per month, which means we should be able to sell 5,000 KWH per year or more back to the grid.

Currently we are working with Cooperative Light and Power to determine the rate in which they will be buying back the electricity. This is a new customer agreement for them so we will be setting precedence with this agreement. Currently they are offering a 7 ½ cent per KWH buyback rate. Their standard buying rate for customers is 9 ½ cent KWH. We have to buy green power from them at a 1.5 cent per KWH if we were to purchase it from the Coop in lieu of making our own. State Statues in Chapter 3875 Public Utilities Commission regulates how to get paid for cogeneration and small power generation situations so we are researching this document and verifying with other utility companies their buyback rates. Stay tuned.

It costs about $7.00 per KWH, (after rebate it is $5.10 per KWH), to install this system. If you do that math, it indicates that yours and our grandchildren will be the ones reaping the benefits of this system, not John and I. We estimated we will be paid about $500 per year for electricity; we think we will be using that same amount, which means that it will take 40 years to pay for the system, this assumes some level of speculation regarding increase electrical costs. And who knows, with the increasing cost of energy these days, it’s anybodies guess how quickly we will ultimately see the return on our investment.

The reduction of CO2 emissions due to the installation of this system in lieu of getting it from a coal fire electric plant is estimated to be 22,000 pounds of CO2 per year.

Sanyo HIT (Heterojunction with Intrinsic Thin Layer) Photovoltaic modules are among the most efficient in the industry with a module efficiency of over 17% on the 200 watt version. Sanyo HIT cells are hybrids, made of thin mono crystal silicon surrounded by ultra-thin amorphous silicon layers.

We are confirmed to get a $16,800 rebate from the state for the PV system and a $4,000 rebate from Co-op Light and Power.