The Tribune

By JOSHUA KEY

Does it make sense to add batteries to your solar system?

In two previous articles we talked about some battery basics and benefits and then discussed situations in which solar batteries can now be a practical addition to your home or business. Today, we look at two areas where batteries can bring big benefits in the future.

First, batteries will be able to let us buy power from the electricity company when it is cheap, and sell it back when it is high. Barry Cinnamon (who founded the largest US residential solar installer in the middle of the last decade) calls this Energy Arbitrage. The motto: buy low, and sell high.

How does Energy Arbitrage work?

In many places around the world, electricity costs different rates at different times of the day. You want to buy it when it’s cheap and and sell it back to the grid when it’s expensive.

To over-simplify, let’s say the electric company charges 42 cents per kilowatt for power during the early evening, but only 11 cents in the middle of the night. With battery backup, you could charge the batteries at night from the grid (when it’s cheap), and sell that power back during the expensive evening time for 31 cents profit per kilowatt. You could even use your solar system to reduce the power you need from the company during the day.

Why can’t

we do this now?

We do provide hybrid systems that let you determine when to buy and sell power. However, as a larger-scale money-making plan, many utilities don’t allow this - and the Bahamas is behind other areas in setting this up.

Also, looking at the limits of current technology, Energy Arbitrage would cycle the batteries too often and wear them out sooner. By the time you crunch the figures to work out how much money you gain from Energy Arbitrage versus how much extra money you will have to spend to replace the batteries more often, it’s not economic. It doesn’t work out in your favour.

That said, as battery technology improves, this will likely become a more viable option in the future. Instead of paying Bahamas Power and Light at the end of the month, you could end up with a negative electric bill. That’s good for your pocket and can help the environment. If you install a solar system today, you may want one that is capable of reaping this benefit for you in the future, so be sure to ask your solar professional.

Second after Energy Arbitrage is Grid Support. This will occur when we reach the point where a significant number of homes and businesses have solar systems with some batteries to supplement their power.

How does Grid Support work?

Today, we have power surges (too much power), brown outs (too little power), and black outs (no power). In the future, with the right software and the right safeties on the power lines (similar to what is used now), the public will be able to help the grid provide power.

We see this on a small scale today with microgrids - groups of homes that use renewable energy to power each other without real need for the electric company.

Why don’t we do Grid Support services now?

The incentives have not been worked out - for example, who should get paid for supporting the grid? And how much should they get paid? Linked to that, utilities don’t want to spend the money to add the extra safeties, and they might lose revenue if power is coming from your building instead of from their power plant! However, your solar system today can be designed to contribute when this does become a reality.

What will all

this result in?

We will need to burn less oil, we will have a healthier environment for ourselves and our children, we will save more money, and we will have more reliable electricity.

Isn’t that something you want to be part of? Professional services are available in the Bahamas to help you find out how you can. Just ask.

• Joshua Key is General Manager for SuperGreen Solutions Bahamas, on Wullf Road next to FYP. SuperGreen Solutions leads the market as one of the premier advisors, suppliers and installers of domestic and commercial energy efficient solutions. Established over 19 years and with a reputation spanning five continents, SuperGreen Solutions looks at energy creation and energy saving from a holistic point of view, to provide clients with total solutions.