Friday, December 15, 2017

Advanced Wood Heating Can Flatten The Duck Curve

There is a pattern of power use and renewable power production that is putting pressure on electric utilities.  When power demand is highest- through the evening and overnight hours to morning- renewable electrical production is often at its lowest.  Power demand, when plotted over a 24 hour period can look like the silhouette of a duck. The graph below from the U.S. Office of Energy Efficiency and Renewable Energy illustrates power demand in California on a single day (March 31st) over several years. In the example it is possible to see the deeper "belly" and steeper "neck" that is caused by increased deployment of solar power and increased electrical demand in the evening. March 31st has a particularly steep "neck" because air conditioning is not greatly demanded during that season and solar power production is high. So, why does a steep duck neck put pressure on electric utilities? The utilities have a difficult time ramping up so steeply to meet evening demand. Further, during some days it is even possible to have too much power ("over-generation").

Scientists and planners often mention the need for electricity storage, better grid distribution of power, and altering consumer power consumption habits as means for "flattening" the duck.


The duck curve at this time is most impactful in California and Hawaii because of their high percentage of renewable power generation. Solar power contributed 40% of Californian power generation on March 31, 2017.

Forty percent of Vermont power is now also produced with renewables. What is interesting about Vermont and other New England States is that despite the known grid challenges created by renewable power generation and increasing nightly power consumption, state energy policies and the electric utilities that work with state incentive programs seem to be encouraging behavior that will only exacerbate the duck curve problem.

Consider cold climate air source heat pumps. Many tout these heat pumps as a renewable energy source, which of course they are not. They are basically highly efficient reverse refrigerators. Heat pumps can add heat in the winter and add cooling in the summer. Heat pumps are electric power consumers. The colder the air is outside our homes, the more power that air source heat pumps use. Also, what most people don't speak about is how much additional electrical demand will be created by air source heat pumps when those who previously had no air conditioning discover that a heat pump can also cool homes. Cold climate heat pumps promise to increase the duck curve whether in summer or winter. However, given reduced solar power production in winter the impact on the duck curve should be greater during cold months.

Advanced wood heat is a solution for the duck curve in the Northeast U.S. because wood heat is available any time of day. We tend to overlook the elegance of trees as solar storage. When burned in advanced wood boilers, decades of stored solar energy are released in a chemical conversion process that releases 80% or more of that stored energy into heat. By deploying advanced wood heat instead of heat pumps, States would not only flatten the duck's head, but reduce total power consumption and offset the use of other fossil fuels such as gas and oil.

Particularly in Vermont, which has been presented with a carbon tax plan called The ESSEX Plan (an Economy Strengthening Strategic Energy Exchange), the potential for exacerbating the duck curve has not been well addressed. The Essex Plan proposes to tax common fossil fuels such as gasoline, diesel, heating fuel, and propane and to use the tax income to lower electric rates, help with weatherization programs, encourage electric vehicles, and fund rebates through Green Mountain Power's Energy Assistance Program. Here is the problem: The ESSEX plan is completely electric power-centric. It seeks to encourage more heat pumps, more electric vehicles, and more conservation. These are reasonable goals, but why not encourage more biomass? Funds generated through the carbon tax should incentivize all forms of renewable energy.

It is amazing how much focus is put on renewable power and electric heat when advanced wood heat is being deployed now and helps solve several problems created by power-centric planning, such as the duck curve. Nature's solar battery is in ample supply. We know how to use it efficiently and in a way that supports not only the wealthy but also low income and rural populations. In fact, utilizing wood is an excellent tool for helping rural economics. Not only does wood harvest and processing produce jobs, but it increases land values and funds rural land owners through timbers sales. Let's not forget all of the benefits of advanced wood heat.

Thursday, July 27, 2017

Featured T4 Installation at the Marsh-Billings-Rockefeller National Historical Park

Boilers: Fröling T4 150 (500,000 Btu/r) wood pellet/wood chip boiler.
Previously installed Garn WH1500 (177,000 Btu/hr) with a water capacity of 1,420 gallons.
Thermal Storage: The Garn’s water capacity is used as the thermal buffer tank.
Fuel Storage: 20’ shipping container modified for fuel storage
Fuel Delivery: Modified P4 cyclone (day hopper) suction device.
Sold and Installed By: Sunwood Biomass of Waitsfield, VT | 802.583.9300 |
Location: Marsh-Billings-Rockefeller National Historical Park | 54 Elm Street | Woodstock, VT 05091 |

There is a mandate to invent an entirely new kind of park. It must be one where the human stories and the natural history are intertwined; where the relatively small acreage serves as an educational resource for the entire National Park Service and a seedbed for American environmental thought; and where the legacy of American conservation and its future enter into dialogue, generating a new environmental paradigm for our day. (John Elder, author and Middlebury College Professor Emeritus, From a speech at the opening of the Marsh-Billings-Rockefeller National Historical Park, June 5, 1998).

Tarm Biomass has had the privilege of providing two boilers for Marsh-Billings-Rockefeller National Historical Park, in Woodstock, VT. We applaud the National Park Service for its efforts to prove the value of an environmentally sustainable National Park System. This post is about the most recent installation of a Fröling T4 150 automatically fed and fired wood pellet boiler for heating a 30,000 square foot mansion at the park.

There are two boilers housed in the Mansion’s garage, which are used to heat approximately 30,000 sq. ft. The Garn wood boiler was installed a few years ago and reduced the Mansion’s oil consumption by about 50%. With the new Fröling T4 150 boiler installed, there is no fossil fuel consumed at the Mansion. Previously, the Mansion consumed 33% of the oil used at the park.

There were two unique challenges with the installation of the new T4 150. Both challenges were caused by a lack of space for bulk wood pellet storage and for a thermal buffer tank in the garage. Yet, the Park Service could not allow for the construction of additional buildings.

With the help of National Park Asset Management, LN Consulting, and the installing contractor, Sunwood Biomass, a plan was developed. A portable 20’ cargo container was chosen for the wood pellet fuel storage. The storage container ingeniously includes sloped floors, a Fröling suction screw auger system, fuel level sensors, fill connections, and all necessary safety devices. Because the Park Service also did not want the wood pellet fuel container visible during the busy summer season, the wood pellet fuel container is removed between early spring and late fall. To remove the wood pellet container easily, quick disconnects for both fuel and electrical were installed. Normally the Fröling T4 150 is not equipped for pneumatic delivery of wood pellets, but a hybrid fuel delivery system was created using portions of the fuel delivery system from a Fröling P4 pellet boiler. Pneumatic fuel conveyance through small, flexible hoses makes disconnecting the fuel lines a snap. The fuel storage container was even painted forest green and adorned with Park Service emblems.

During the summer, the Garn wood boiler is used for domestic hot water and any small heating needs.

The second challenge, including an adequate thermal buffer tank to improve boiler performance, was met by utilizing the built-in water storage of the Garn wood boiler. The Fröling T4 operates best with approximately 1000 gallons of buffer, so the 1,500 gallons in the existing system was a perfect solution.

There is one other Fröling boiler installed in the park. In 2013, a Fröling P4 32/38 wood pellet boiler was installed in the Double Cottage building, which includes two staff housing units. The P4 replaced an aging oil boiler and furnace. The building is now entirely free of fossil fuel.


The Marsh-Billings-Rockefeller Mansion


Alternate view of boiler house and pellet container

A view of the Mansion’s garage that houses the boilers and the pellet fuel container

Pellet container being moved

Pellet container being off-loaded

Combination of container images

Three views of the pellet container showing fill and building connections

Photo of inside of pellet container

Inside view of the pellet container

Full view of boiler house with door open showing boilers

Front View of garage housing the boilers

Front view of boiler and feed system, Garn in background

A closer view of the Fröling T4 Boiler

Close up of cyclone on feed auger

A close-up view of the pellet suction and day hopper

Tuesday, February 14, 2017

Hydronics for High-Efficiency Biomass Boilers Training

Update! The correct date and information for the upcoming NYSERDA boiler training. It seems our email subscription feed hiccuped and sent out an old post from 2015.


Friday, January 6, 2017

Featured Installation: South Main Apartments-Waterbury, VT

36 State Drive, Waterbury
The historic Ladd Hall in Waterbury, VT has gone through a huge makeover. The building was sitting vacant since August 2011, when Tropical Storm Irene hit and flooded the basement. The original  building was bult in the 1890’s with a wing added in the 1950’s to house nurses working at the state hospital. The building was then later used for offices for the state.

Building Information:

The original front brick building was converted into 2 3-bedroom apartments and a one bedroom apartment on the third floor. The 1950’s addition was totally demolished and replaced with new construction to house 23 more apartments (twelve1-bedroom and eleven 2-bedroom). The new wing is where the new heating system is located and is built to high energy efficient standards. The total square footage is 28,000 Sq. Ft. Building owned and operated by Downstreet Housing and Community Developement located in Barre, VT.

ladd-hall1  Architectural Rendering
                                   Waterbury South Main Apartments
                                                                                                   Completed View of New Construction Wing 
Heating System:  IMG_3071
The new heating system comprises of two 350,000 Btu/hr Fröling P4 pellet boilers with 900 gallons of heat storage. Heat storage allows allows efficient heating of Domestic Hot Water year-round and efficient boiler. The building has NO fossil fuel back-up boiler. The pellet boilers are estimated to offset approximately 10,000 gallons of heating oil annually. The boilers are connected to a 20 ton interior pellet store room. Each boiler has it’s own suction auger delivery device.
Heating System was designed by Trevor Parson, Engineering Services of Vermont, and Sunwood Biomass. Installed and manitained by SunWood Biomass, Waitsfield, VT. 802-583-9300

Viewing window for the pellet store room. The squeegee looking device is actually using a magnet to keep the glass free from dust.
Pellet fill connections.
We like the placards.
The original building.
The new wing housing 23 apartments of Affordable Housing.

Which would you choose?