Solar and Battery Backup Systems

Drews Solar does not offer battery backup systems at this time. Battery systems are currently a large investment without economic benefit for solar homeowners, and generators are still the top option for backup power. When the benefits or economics of battery systems change, they can be added to a residence and interconnected to an existing rooftop solar array at a later time.

Are Batteries the Right Investment for Your Home?

While battery backup systems are a good choice for some homes, they are currently a large investment for most homeowners. To give you a rough idea of what a battery backup system would look like with Tesla Powerwall batteries: Tesla Powerwall batteries cost about $12,000 to $14,000 installed and hold 13.5 kWh each. Depending on how much electricity your home uses on a daily basis, and how much power you would want available during a power outage, you would likely need between one and four Powerwalls to meet your needs. It is a large investment for the amount of power the batteries would make available in the event of an outage. For most customers, a generator would be a better investment until the cost of battery systems becomes more affordable. Generators also have the added benefit of continuing power supply during a power outage in inclement weather. If the power outage occurs during a winter storm, when snow covers the solar panels, or during a stretch of stormy, overcast weather, the solar panels may not be able to recharge the batteries enough to provide continuous power to the home.

Can Batteries Store my Solar Power for Nighttime Use?

You can, but fortunately, you don’t need to! All Wisconsin utilities bill and meter residential solar customers with net metering. Net metering is a utility billing policy that enables customers who generate electricity from their own solar systems to receive a credit for any energy they export to the grid for use at a later time, such as during the evening or night. When the customer generates more electricity than they use, the excess flows back to the grid and customer receives a credit on their bill for the excess electricity they export to the grid. This credit can be used to offset electricity the customer uses at other times during the billing cycle or year. Some utilities net meter on a monthly billing-cycle basis, others on an annual or indefinite basis, allowing residential solar customers to trade electricity with the grid in a one-for-one basis for a month, a year, or more. Net metering eliminates the economic incentive for homeowners to add battery storage for daily usage; excess solar electricity produced during the day will be used to offset any electricity pulled from the grid at night, essentially treating the utility like a battery.

Planning Ahead for Batteries in the Future

It is possible to install your solar array to be battery-ready. For a small additional cost, we can install a different SolarEdge inverter that can be connected to battery systems. But, we don’t recommend this option unless you plan on adding a battery system in the next couple of years. If you are planning on adding a battery system, in the next five to ten years or more, we recommend installing a new battery-ready inverter at the same time you install your battery system for the following reasons:

• Not all inverters and batteries are compatible. By installing a battery-ready inverter at the same time you install your batteries, you can choose from all the battery systems available, instead of being locked into choosing between a brand or two of batteries.

• Battery technology is quickly evolving. By waiting to install a battery-ready inverter at the same time you install your batteries, both your inverter and batteries will have the same level of technology and the most updated systems, so you can be sure your system has the highest levels of efficiency and communication.

If you are Ready to Install an Integrated Solar-and-Battery System Now

For homeowners who are ready to invest in battery systems now, we are able to offer a referral to a Wisconsin-based solar and electrical company with expertise in designing and installing integrated solar-and-battery-backup systems.  Contact us for a referral if you’re interested in further exploring if a battery backup system is right for you and your home.

MG&E Rate Changes May Be Coming For Future Solar Customers in 2024

November 2023 Update: MG&E’s proposed changes to solar billing and metering were rejected by the Wisconsin Public Service Commission.

MG&E has proposed rate changes for homeowners who add solar to their homes, and these changes would make going solar less economically beneficial than the current rate structures.

As proposed, the rate changes would go into effect on September 1st, 2024 for MG&E customers. All homeowners that apply for solar interconnection after that date would be subject to the new rate changes. All homeowners who have applied for solar interconnection with MG&E before September 1st, 2024, an have their installation complete before December 31st, 2025, will be “grandfathered in” to the current rate structure for 20 years.

If your utility is MG&E and you if you are hoping to add solar to your home, start the process now.

Current Monthly Net Metering

With net metering, homeowners with solar receive credits for all electricity they push onto the grid and can then use those credits when they pull electricity from the grid. The grid essentially acts as a virtual battery for the homeowner, allowing them to push-and-pull electricity freely and only paying for the difference at the end of each monthly billing cycle.

Madison Gas and Electric currently meters solar customers on a monthly basis. That means that at the end of each monthly billing cycle, any excess energy production is credited to your account at the full retail rate in the form of dollars, to be rolled over to later months. This is wonderful for solar customers because excess energy produced during the summer months can be rolled over to the lower-producing winter months. You can find additional details about MG&E Net Metering on our website here.

Here are some of the proposed changes:

• Loss of Monthly Net Metering: Instead of net metering on a monthly basis, both utilities propose metering throughout each day. MG&E proposes metering every 60 minutes, with the homeowner adding either charges or credit to their bill every hour. Homeowners would lose the ability to “bank” their energy over-production for later in the day, month, or year.

• Lower Electricity Buyback Rates: With the new proposed rate changes and the loss of monthly net-metering, the hourly overproduction would be purchased back by MG&E at an estimated 4-7 cents per kWh (with a potential 5 cents per kWh additional “outflow adder”), significantly less than the current rate of about 15 cents per kWh. MG&E has also proposed rate increases for 2024 to 17 cents per kWh for MG&E, increasing the expected cost of electricity for all homeowners.

You can read the full transcript of the MG&E on the PSC website here.

What it will mean for homeowners:

• A Solar Rush: If rate changes are approved, there may be a rush for homeowners to go solar before the rate changes occur so they could be grandfathered in to the current rate structure. Waiting to go solar close to a rate change could mean long waits or difficulty finding a solar installer with availability.

• Longer Payback Periods: The decreased buyback rates and loss of monthly net metering would increase the amount of time it would take for a homeowner’s solar array to pay for itself.

• Challenges to Forecast Savings: With the loss of monthly net metering, it will be more challenging to predict how long it will take any given household to receive a return on investment for their rooftop solar array.  

• A Move to Batteries: Batteries would become more economically advantageous for homeowners, since they would allow homeowners to bank the solar-energy created during the day for their evening and morning hours without having to push it back onto the grid at lower buyback rates. Adding batteries significantly adds to the up-front cost of going solar but would reduce the return-on-investment time for a new solar array.

Bottom line: There is a very good chance at least part of these proposals will go through, and while it will still make economic and environmental sense to go solar even if all the proposed changes go through, the payback period for going solar will be shorter for those who get in on the current rate structure.

We expect to hear if these proposed rate changes are approved or not by the Public Service Commission sometime around Thanksgiving 2023.

Alliant Proposed Solar Rate Changes

November 2023 Update: Alliant’s proposed changes to solar billing and metering were rejected by the Wisconsin Public Service Commission.

Alliant has proposed a new system for billing and metering solar customers called Power Partnership that would begin January 1st, 2026. We are currently waiting to see if the new proposal is approved by the Public Service Commission, but we are almost certain it will pass. Here are some of the details of the new rate structure:

• A switch from monthly (billing cycle) metering to hourly metering. Instead of net metering on a monthly basis, Alliant will meter every 60 minutes, with the homeowner adding either charges or credit to their bill every hour. All solar homeowners with solar would automatically be switched to time-of-use billing.

• Significantly higher buyback rates of access energy production. Any excess energy production at the end of each hour will be purchased back by the utility at a rate of, roughly, the time-of-use wholesale rate plus a solar-value-rate adder of about $0.064/kWh.

• The base “wholesale” rate of electricity for 2024 will be $0.07057 from 11am to 7pm in the summer, so during the prime solar production hours, the hourly buyback rate of excess electricity would be $0.13457. This would build up a lot of credits that can be used to offset evening and winter electricity usage, which is why the new rate structure may actually be economically better for some homeowners. In comparison, the monthly buyback rate will be $0.04877 for Alliant customers in 2024.

• The solar-value adder will be “locked in” every two years, can only go up or down by 15% every-other-year, and must be PSC approved, so changes must clearly demonstrate why the value of additional solar energy has changed. Bottom line- the solar-value adder may change but it will be slow and predictable.

• Addition of a non-bypassable monthly charge of $10. Currently, Alliant customers can use their excess energy credits to pay for their monthly base charge, but under Power Partnership, a $10 monthly charge would be on your bill no matter what- credits could not be used to pay for it. Instead, all of your credits would roll over to subsequent months.

• Current net metering would remain until December 31, 2025. New customers with installations under 20 kW will be able to choose between net metering and Power Partnership until Dec. 31, 2025. Any homeowners who go solar before December 31, 2025 can lock-in the current rate structure and become legacy customers for about 10 years.

• Legacy treatment for about 10 years. Any homeowners who go solar before December 31, 2025 will not be moved into the new Power Partnership until January 1, 2033

Financing Your Solar Project

Drews Solar does not offer in-house financing. But based on our customers’ experience, we do have a few recommendations for financial institutions to consider:

Summit Credit Union

Many of our customers have had success obtaining loans through the locally-based Summit Credit Union. With many branches around our service area and extensive expertise in financing, they may be the right choice for your loan. 

Clean Energy Credit Union

The Clean Energy Credit Union is a national credit union that specializes in loans for renewable energy projects, including residential solar installations. Since they only provide loans for renewable projects, they make the process easy and straightforward for those going solar. Our customers who have chosen to obtain financing from the Clean Energy Credit Union have had a great experience.

Marine Credit Union

Marine Credit Union is a Wisconsin-based credit union that has been actively reaching out to homeowners who want to go solar. Marine Credit Union specializes in loaning to those who may not be able to easily qualify for a loan through other financial institutions. We recommend reaching out to Marine Credit Union’s solar loan specialist, Krist Poppe at krist.poppe@marinecu.com to get the process started.

It may take a bit of time, but by obtaining a solar loan from your own bank or credit union, or one of the options above, you may save a lot of money over the lifetime of your loan, making going solar an even better investment.