I’m a simple man, and I’m not too good at math, but here are my simple numbers for your return on a solar system if you’re a commercial building owner.
Let’s make some assumptions. First, forget about your usage numbers. Let’s just consider that you want to take the roof of your commercial building and turn it into a cash-cow solar generating plant. Let’s say SRECs are trading at a conservative $400/1mWh.
OK, you have a big enough roof to put up a 40kW system. That’s going to cost you around $350,000. After rebates and such that gets down to around $224,000. It’s going to earn you around 6 SRECs a month. At $400, you’re making $2400/month on SREC sales. That’s a payoff of around 8 years.
Let’s look at a best-case scenario. SRECs trade at $600, you’re now making $3600/month, and your payoff is now 5 years.
After the initial payoff period, it’s like adding a tenant. One that doesn’t need parking spaces.