Let's combine our energy for a smarter, more efficient tomorrow. DTE Energy has the technology, expertise and resources to assist customers with a variety of solar and renewable energy initiatives.
If you are installing 20 kW (kilowatt) or less of renewable resource capacity, please see our Interconnection Process for connecting customer-owned generation to the electrical system. Please follow all the steps to ensure the safety and reliability of your renewable generation.
We also strongly recommend that you start by consulting the approved equipment list and apply for interconnection prior to major equipment purchases.
If you have any questions, please call the interconnection hotline at 313.235.4333.
How can I estimate how large a wind or solar generator I can install and still qualify for net metering?
The first step is to estimate the energy you expect to produce annually. For wind generators, the estimate is determined from available wind at the installed height and the unit performance characteristics for units you are considering. This calculation is very sensitive to local conditions, equipment performance and installation height. Your vendor may be able to assist in estimating the output.
A term commonly used in the industry is capacity factor, which is expected output divided by theoretical output. For example, if you were considering a 5 kW (kilowatt) unit and site and unit conditions indicated it would produce 6,570 kWh (kilowatt hours) per year, the capacity factor would be 6,570 kWh divided by 8,760 hours (5 kW) or 15 percent.
The second step would be to total the amount of electricity that you use from your last 12 electric bills to get your annual use and divide that number by 8,760 to get your average hourly use. For example, if your 12 electric bills showed you used 14,450 kWh per year that would be 1.65 kW per hour on average.
The third step would be to determine the size needed by dividing the 1.65 kW per hour on average use by the capacity factor of 15 percent. This would indicate you would need to install an 11 kW unit to produce your annual needs.
The sensitivity of output to location and unit specific characteristics is demonstrated by units in the net metering program in place from late 2007 through mid 2009. Wind units in that program have operated at annual capacity factors ranging from 4 to 24 percent. A 5 kW unit operating at these extremes would produce 1,752 kWh per year at the low end to 10,512 kWh per year at the high end. Consequently, to properly size your unit it is essential that your specific conditions be considered.
The same procedure would be used to size a solar installation. However, solar units are less sensitive to site conditions (assuming all installations are located in unshaded areas with the proper inclination and directional placement).
The lack of sensitivity for solar installations is demonstrated by units in the net metering program in place from late 2007 through mid 2009. Solar units in that program have operated at annual capacity factors of 14 to 15.5 percent. A 5 kW unit operating at these extremes would produce 6,132 kWh per year at the low end to 6,789 kWh per year at the high end.
I own or am considering purchasing an emergency generator for my business. Can I sell back the energy I don't use?
No. Emergency generators are not a qualified source of energy for the net metering rate. If you have a generator that is greater than 250 kW, then you could qualify for dispersed generation (Rider 13).
What is a REC?
An REC is a Renewable Energy Credit, a tradable environmental commodity that represents that 1 MWh (megawatt-hour) of electricity generated from a renewable source.
Do I need a DTE Electric meter on my generator to sell my RECs?
Yes. Even if you do not sell them to DTE Electric, the purchaser will likely want a billing quality meter to measure generator output. If you choose to sell your RECs to another party, DTE Electric will allow you to use its billing quality meter, maintained to company standards, for the purpose of billing the person purchasing your RECs.
