Congratulations, Maine: fantastic idea!
All the best, Susan (author)

With little demand for electricity between midnight and dawn, they were paid as little as four cents a kWh for their exported wind power, and with the distance to the mainland, the coop was incurring a 3% line loss. Developing a storage capability on the island itself was embraced as a better economic alternative to exporting the power at low rates.

Funds are becoming available nationwide under the Recovery Act for states to sponsor approved energy audits, weatherization and fuel switching to cleaner, more renewable forms of energy.Thermal Electric storage is one of the technologies to be sponsored by Efficiency Maine.

This new and exciting Smart Grid technology is being developed by a local company that enables remote control of the storage heaters, turning them on or off from a remote location, based on wind generator output, grid demand, and the spot price of power (that fluctuates with the demand on the grid).

Thermal Energy Storage of Maine is working with Steffes; the company making the units to replace the oil heaters in six of the island’s residents’ homes with wind powered electric heaters that can store and safely hold heat in extremely dense ceramic bricks – and slowly release the heat, on demand, for up to 24 hours.

Steffes technology has been around for decades.There are thousands of units like this in operation in Europe, and many in other states. But only now, as more excess renewable electricity is created at off-peak hours, has the need arisen to store that electricity somewhere, creating a new business opportunity for a new green technology.

The way that Steffes Electric Thermal Storage (ETS) units work is that electricity heats coils that radiate heat to extremely dense adjacent ceramic bricks, which are surrounded by a space-age insulation that keeps the exterior from heating above 160 degrees F. As heat is removed throughout the 24 hour period the bricks shed heat and the exterior eventually cools as well. They work no differently than other home heating systems: you set the temperature at whatever you desire and a fan circulates air over the bricks at a variable speed so that a steady temperature is maintained. Being charged with electricity from a Smart Grid controller does nothing to change the amount of heat being discharged into a space; the homeowner chooses that temperature.

Until recently, nobody has thought to use them specifically as a distributed energy storage option for wind power, by adding sensors to absorb excess grid power. When there is more wind electricity on the grid than can be used, it would be dispatched to these units, which provide distributed storage for electricity for use as heat later.

Once they reach their maximum core temperature, they won’t charge anymore. At that point, the heaters controls won’t accept more power from the grid. Inside; the electric thermal storage units can transform and store enough electricity to heat each unit up to 1,200 degrees F, storing 24 hours of heat. Commercial sized units can heat up to 1,600 degrees F. Of course, the homeowner doesn’t want a house that is suddenly hot at 2 in the morning while the wind is howling outside, and that doesn’t happen. The exterior of each unit never gets above 160 degrees F, like an old fashioned radiator.

ISOs are constantly monitoring the demand for electricity on the grid compared with their generation output. Power plants have to generate more, or less power, at any time, to keep things in balance. Sometimes wind farms have to be actually turned off at night because there is nobody using that electricity.

The test of the six units over the coming months will determine whether the technology is reliably able to divert excess wind power to the storage units. Using that extra wind power on the island to heat homes is the first step.

On a large scale this would enable wind power to be utilized not only during off-peak hours, but to be a flexible option for sudden needs for storage of excess power that can develop temporarily at any time during the day as well. A pilot program sponsored by New England grid operator ISO-NE will determine the feasibility of using remote-controlled thermal storage heaters to provide this regulation service that is currently only provided by generators, providing the “sink” needed to absorb this power on Maine’s grid, that is aiming to add 3,000 MW of wind by 2020 to meet state Renewable Energy Standards.

“This smart grid technology will allow “load-in” in the form of remote controlled electric thermal storage units to follow generation” said Sam Zaitlin.

“To use an automotive analogy: going down the highway at a steady 60 mph is more fuel efficient than ramping up to 70, down to 62, up to 68, etc. The same holds true for power plants. Now imagine you’ve got installed, say, 25 MW of storage capacity in X number of ETS units”.

“It’s a winter night in Maine when the wind is blowing hard and it’s very cold outside, but the grid doesn’t need the extra 17 MW of power that the turbines could produce,” he concluded. “What we’re talking about here is the ability to sense the capacity available in those heaters and automatically dispatch the power to them without curtailing the wind generation. So, we’d be matching the load to the generation that’s out there”.

With distributed storage, any community could simply add more storage units as needed, as local renewable energy resources grow, the number of these thermal electricity storage units in homes and businesses could also multiply – in tandem – so that there would always be a good match between dispatchable power and the needs of consumers.

In addition to being scalable, distributed individual units comprise a very inexpensive solution for energy storage when compared with centralized storage for renewable energy, such as pumped hydro or compressed air.

If it works it would have a wide application, nationally.The Obama administration is funding the development of many storage technologies for renewable energy in the Recovery Act, and California legislators just proposed the first legislation actually requiring a certain percentage of energy storage in tandem with renewable energy development, to meet the state RES for 33% renewable by 2020.

In the twenty nine states – including Maine – that have an RES, a storage requirement could well become the rule, as more renewable energy is added to the grid.
- Susan Kraemer