{"id":44584,"date":"2015-11-24T05:05:32","date_gmt":"2015-11-24T10:05:32","guid":{"rendered":"http:\/\/planetsave.com\/?p=44584"},"modified":"2015-11-30T06:26:53","modified_gmt":"2015-11-30T11:26:53","slug":"evs-pvs-driving-on-sunshine","status":"publish","type":"post","link":"https:\/\/planetsave.com\/articles\/evs-pvs-driving-on-sunshine\/","title":{"rendered":"EVs & PVs \u2014 Driving on Sunshine"},"content":{"rendered":"

Originally published on\u00a0CleanTechnica<\/a>.
\nby Kyle Field<\/em><\/p>\n

This is an overview for how to assess a solar installation for a residential property and pair the system with an EV or two to generate your own power and drive on sunshine. This is not an attempt to document every scenario, but rather to share the overall direction and flow from which you can, with your newfound knowledge, move forward with an installation of your own. Let’s get started!<\/p>\n

When we first put solar panels on the roof of our 2-story home here in sunny Southern California, I understood the concept but had some questions about how it all actually worked. It was quite the learning process, and since then, I have continued to add panels to the roof to offset our base usage while also adding more load to our system with the addition of 2 EVs in the last 12 months. With all this, we are now living the dream and effectively “driving on sunshine.” As there were so many learnings with both systems, this article will help frame both pieces of the puzzle in order to help others understand some of the nuances and how they work together.<\/p>\n

\"The<\/p>\n

The first step towards getting solar panels up on your roof is sizing the system. This is one of the first steps a solar installer will typically do for your site, but you can also go through it yourself to understand the details or for a DIY installation. Many factors dictate system size but the two big ones are the usage you want to offset with new solar generation and the\u00a0solar potential of the installation location.<\/p>\n

Calculating your estimated usage is very straightforward, as your utility has a vested interest in tracking usage accurately so it\u00a0can bill you for it. \ud83d\ude42 Look up the last 12 months of bills and capture the monthly usage in kWhs for each month. The resulting total is your starting point for annual usage. Next, take into account any big project that could impact your usage in the next few years — adding an EV (I’ll review estimating EV usage below), removing a hot tub, installing LED lighting<\/a>, etc., and either add or subtract those from the annual usage total. Finally, determine what % of that usage you would like to offset. Most installers will use 90% of the production, as any excess is typically not\u00a0a good investment for the homeowner. My personal goal is to continually generate at least 105% of my total usage.<\/p>\n

To understand the solar potential of your location, use an online solar production potential calculator like PVWatts<\/a>. You enter the key details of your system — some which take more work than others, like installation address, system size (from your work in the previous step), tilt, module type, etc., and the system spits out a nice annual chart of estimated production by month, including the value of the energy produced.<\/p>\n

\"PVWatts<\/p>\n

One of the first question folks normally ask about residential solar is “but, what about the batteries?” In most residential installations, the PV solar system will be connected to the grid, meaning that any excess energy produced will be sent to the grid. In a net metering arrangement, the utility will track how much the PV generation sends to the grid and keep a tally sheet, “netting out” usage vs generation at the end of the year. Why annually? This allows systems that generate more in the summer and less in the winter to level out over the year instead of the utility paying the customer in the summer and vice versa in the winter. This could be a whole separate article but I’ll leave it at that for now. \ud83d\ude42<\/p>\n

Now that we have our system sized up, let’s go get some bids from installers! I’m not going to go into full detail on how systems are priced out, but there are primarily 3 options:<\/p>\n