Renewable energy has always been part of our diverse energy mix. Hydroelectric dams, wind farms, and solar arrays are all part of America’s effort to keep power clean and affordable. The recent drop in the price of solar panels, and developments in solar efficiency and micro-inverters make solar generation more accessible to homeowners. A properly sized solar array that can utilize all of the energy when it is being produced can be a smart investment.
Heartland has a handful of members with wind and solar resources connected to our system, all benefiting from our net metering policy. Because their electric meters run forward and backward, it's currently possible for members to "bank" excess power generated and offset power consumption later in the monthly billing cycle.
Heartland's net metering policy has a monthly sweep, so any "banked" power is lost at the end of the billing cycle. Therefore, when deciding how big a wind or solar system to install, it's important to compare the system's expected power generation to your home's monthly power use
Heartland's policy of sweeping excess generation at the end of the month, and our policy on limiting solar installations to what is appropriately sized helps address 2 issues. First, it ensures that large solar arrays don’t feed excess power onto Heartland’s infrastructure and cause power quality issues. The policies also protect members from installing over-sized arrays and limit the subsidies that can happen between members that do not have solar and those that do. Our policy is designed so that everyone has access to the benefits of affordable solar power.
Every electric provider is different. Heartland’s service area is almost entirely rural, with very few members per mile of line. That makes our issues unique when compared to most power providers. Heartland’s net metering policy and monthly sweep is the same policy as the other rural electric cooperatives in Kansas. In fact, the state’s cooperatives all adopted the same policy to make installation uniform for those who install wind and solar systems. And as a cooperative, our philosophy of carefully addressing the needs of all of our members is a priority for us.
The Skystream 3.7 wind turbine that Heartland helped install at Greenbush has a rated output of 1.8 kilowatts. Because this part of Kansas is considered Class 2 with average wind speeds of 12 to 14 mph, that turbine averages about 300 kilowatt-hours per month.
A 5 kilowatt PV solar array will generate between 300 and 700 kilowatt-hours each month in this part of Kansas. Solar and wind systems will have high months and low months and predicting those will be important to a successful installation. The PVWatts Calculator from the National Renewable Energy Laboratory can help you find out how much power a PV solar array will generate at your location.
The best way to determine your home's maximum solar array size is to call our office and have us determine the best size by looking at your home's electric usage data. You can get a rough idea of what size solar you can install by using the formula below. Keep in mind, the formula just gives you a "back of the napkin" estimate of your best solar installation size.
In this formula, Minimum kilowatt-hours (kWh) is your home's lowest monthly kWh usage from the previous 12 months. This month is frequently April, May, September or October, when the weather is nice and HVAC systems run the least. Divide this number by 720 (which is the number of hours in a month). Then divide this number by your home's load factor. For most homes, the load factor is .2 but for businesses with more consistent power use the load factor will be .5 or even .8 if a large electrical load is turned on and runs most of the time.
Please call our office for an examination of your electrical use, and a more accurate calculation of your ideal solar array size.
For members who install renewable generation significantly more than they expect to use during a typical month, an alternate parallel generation rider can be chosen which pays members for their power generated at a rate of 150% of the cooperative's monthly system average cost of energy.
In the "Properly sized vs oversized solar" graph shown here, we show a home's monthly kWh consumption (blue bars), along with the monthly output of two possible solar arrays. The 6kW solar installation (orange bars) is properly sized. The 10kW array (gray bars) is too big, and overproduces more electricity than the home needs on seven months of the year. Under our net metering policy, Heartland does not purchase this excess generation.
For members who install renewable generation, but aren’t a good fit with our Net Metering policy, an alternate parallel generation rider can be chosen. This pays members for their power generated at a rate of 150% of the cooperative's monthly system average cost of energy. No energy is banked, and there is no monthly sweep.
If you are interested in installing a renewable generation system, your first step is to work with an installer and Heartland to determine what size solar array is right for you. The formula above can help with that. Our staff can help look at your usage to help refine your right size solar array. When you and your installer have determined what will be installed, you’ll need to submit an interconnection proposal to Heartland. An application form and $100 fee are required for systems 10 kilowatts or smaller. Systems larger than 10 kilowatts have a more complicated approval process due to concerns about the produced power on the cooperative's infrastructure. For very large systems, members will be required to cover the costs of an analysis conducted by an independent engineer.
Any wind or solar systems installed by Heartland members must be inspected by our staff before they can be interconnected to the power grid. All wind and solar systems interconnected with the power grid must have safety measures in place to make sure power is not put back on the grid during a power outage. An accessible manual disconnect switch must also be included so that Heartland crews can disconnect the system when working in the area. A separate meter on your solar array will help you and Heartland monitor your system’s output.
No. Member solar arrays that are interconnected into Heartland’s grid are designed to automatically stop producing power during an outage. This is necessary to prevent backfeeds and ensure the safety of our line workers working to restore power during an outage. The only way a solar array can provide power during an outage is if it is paired with a dedicated battery storage system.
No. Heartland does not purchase power from members under our net metering agreement. Your renewable installation helps you by reducing the amount of electricity you purchase from the cooperative.
If you're like the majority of our consumer-members and are on the Peak Savers rate, your monthly utility bill from Heartland is made up of 3 parts. The first is the energy charge, which is based on how many kWh Heartland provides your home, farm or business throughout the course of a month. Our rates are designed so that this charge covers the cost of wholesale power, its delivery, and equipment related to the delivery of that power. The second part of your bill is the Service Availability Charge. This is a fixed monthly amount that primarily goes toward the daily operations of Heartland and everything that it takes to keep the co-op running, including the trucks, employee salaries, and some basic infrastructure. It’s the price you pay to have power available, whether you need lots of electricity or almost no electricity. It’s necessary for everyone to pay this fee, because even members with large solar arrays rely on Heartland staff to properly maintain our poles, wires, and substations.
If Heartland needs to make upgrades to the cooperative’s distribution system in order to accommodate the power produced by a consumer-member's distributed generation equipment, the consumer-member will be expected to cover those costs. When a member’s solar array pushes power back onto Heartland’s system, it is critical that the system be able to handle that backfed power. This is more likely to be required with very large, commercial installations. Heartland’s equipment needs to be able to handle those situations when the sun is shining, and you are not using power yourself.
We have found that many of our members who have installed wind and solar systems want to know just how much power their equipment is producing. A second meter monitoring the wind or solar array will help you know how much power is being produced by your system and help Heartland with future planning for future electric system infrastructure upgrades.
Storing power for later use is helpful for many reasons. For those on time-of-use rates, and commercial rates with demand charges, energy storage can help members use less power during those times of day when power is expensive. Members who add battery storage to a solar array installation reduce the need for the cooperative to serve as a virtual battery. And many battery storage systems can provide power during an outage.
Similar to a whole-house generator, a battery storage system can be installed by a member on their side of the meter. Like a generator, a battery storage system must be installed with proper disconnections to ensure that power is not backfed onto Heartland’s system during a power outage.
Any wind or solar systems installed by Heartland members must be inspected by our staff before they can be interconnected to the power grid. A simple application form and $100 fee are required for systems 10 kilowatts or smaller. All wind and solar systems interconnected with the power grid must have safety measures in place to make sure power is not put back on the grid during a power outage. An accessible manual disconnect switch must also be included so that Heartland crews can disconnect the system when working in the area.
Systems larger than 10 kilowatts have a more complicated approval process due to concerns about the produced power on the cooperative's infrastructure. For very large systems, members will be required to cover the costs of an analysis conducted by an independent engineer.
For more information, call our office at (800) 835-9586.