Home fuel cell

A home fuel cell or a residential fuel cell is an electrochemical cell used for primary or backup power generation, similar to larger industrial stationary fuel cells, but built at a smaller scale for residential use. These fuel cells are usually based on combined heat and power (CHP) or micro combined heat and power (MicroCHP) technology, generating both power and heated water or air.

See also: Fuel cell

A commercially working cell is called Ene-Farm in Japan and is supported by the regional government which uses natural gas to power up the fuel cell to produce electricity and heated water.

Uses

Most home fuel cells fit either inside a mechanical room or outside a home or business, and can be discreetly sited to fit within a building's design. The system operates like a furnace, water heater, and electricity provider—all in one compact unit. Some of the newer home fuel cells can generate anywhere between 1–5 kW—optimal for larger homes (370 square metres [4,000 sq ft] or more), especially if pools, spas, and radiant floor heating are in plans. Other uses include sourcing of back-up power for essential loads like refrigerator/freezers and electronics/computers.

Deploying the system's heat energy efficiently to a home or business' hot water applications displaces the electricity or gas otherwise burned to create that heat, which further reduces overall energy bills. Retail outlets like fast food chains, coffee bars, and health clubs gain operational savings from hot water heating.

Since it is in general not possible for a fuel cell to produce at all times exactly the needed amount of both electricity and heat, home fuel cells are typically not standalone installations. Instead they may rely on the grid when the electricity production is above or below what is needed. Additionally, a home fuel cell may be combined with a traditional furnace that produces only heat. For example, the German company Viessmann produces a home fuel cell with an electric power of 0.75 kW and a thermal power of 1 kW, integrated with a traditional 19 kW heat producing furnace, using the grid for electricity need below and above the fuel cell production.[1]

PEMFC fuel cell mCHP operates at low temperature (50 to 100 °C) and requires high purity hydrogen. It is prone to contamination and changes can be made to operate at higher temperatures and improve upon the fuel reformer. SOFC fuel cell mCHP operates at a high temperature (500 to 1,000 °CP) and can handle different energy sources but the high temperature requires expensive materials to handle the temperature. Changes can be made to operate at a lower temperature. Because of the higher temperature, SOFC in general has a longer start-up time.

Environmental impact

Because the home fuel cell generates electricity and heat that are both used on site, theoretical efficiency approaches 100%. This is in contrast to traditional or fuel cell non-domestic electricity production with both a transmission loss and useless heat, requiring extra energy consumption for the domestic heating. As noted above however, the home fuel cell can in general not at all times generate exactly the needed amount of both heat and electricity, and is therefore typically not a standalone installation but rather combined with a traditional furnace and connected to the grid for electricity need above or below that produced by the fuel cell. As such, the overall efficiency is below 100%. The optimum efficiency of home fuels cell has caused some countries such as Germany to economically support their installation as part of a policy reacting to climate change.[2]

Installation

Home fuel cells are designed and built to fit in either an interior mechanical room or outside—running quietly in the background 24/7. Connected to the utility grid through the home's main service panel and using net metering, the home fuel cells easily integrate with existing electrical and hydronic systems and are compliant with utility interconnection requirements. In the event of grid interruption the system automatically switches to operate in a grid-independent mode to provide continuous backup power for dedicated circuits in the home while the grid is down. It can also be modified to run off-the-grid, if desired.

Current installations

Twenty companies have installed Bloom Energy fuel cells in their buildings, including Google, eBay, and FedEx.[3] The eBay CEO said to 60 Minutes, that they have saved $100,000 in electricity bills in the 9 months they have been installed.[4]

Oregon-based ClearEdge Power has installations of its 5 kW system at the home of Jackie Autry,[5] Bay Area Wealth Manager Bruce Raabe[6] and VC investor Gary Dillabough.[7]

Update – ClearEdge Power went out of business in 2014 and no longer supports any of the 5 kW units in the field.

In 2013, 64% of global sales the fuel cell micro-combined heat and power passed the conventional mechanical rotary systems in sales in 2012.[8]

Life cycle

Fuel cells have an average lifetime of around 60,000 hours. For PEM fuel cell units, which shut down at night, this equates to an estimated lifetime of between ten and fifteen years.[9]

Cost

Most home fuel cells are comparable to residential solar energy photovoltaic systems on a dollar per watt-installed basis. Some natural gas driven home fuel cells can generate eight times more energy per year than the same size solar installation, even in the best solar locations. For example, a 5 kW home fuel cell produces about 80 MWh of annual combined electricity and heat, compared to approximately 10MWh generated by a 5 kW solar system. However, these systems are not directly comparable because solar power is a renewable resource with basically no operating cost while natural gas is neither.

Operating costs for home fuel cells can be as low as 6.0¢ per kWh based on $1.20 per therm for natural gas, assuming full electrical and heat load utilization.

Residential fuel cells can have high initial capital costs – As of December 2012, Panasonic and Tokyo Gas Co., Ltd. sold about 21,000 PEM Ene-Farm units in Japan for a price of $22,600 before installation.[10]

Incentives

In the U.S.A., home fuel cells are eligible for substantial incentives and rebates at both the state and federal levels as a part of renewable energy policy. For example, the California Self Generation Incentive Program (SGIP) rebate ($2,500 per kW) and Federal Tax Credits ($1,000 per kW residential and $3,000 per kW commercial) will significantly reduce the net capital cost to the customer. For businesses, additional cash advantages can be realized from bonus and accelerated depreciation of fuel cells.[11]

In addition, home fuel cells receive net metering credit in many service areas for any excess electricity generated, but not used, by putting it back on the utility grid.

The Database of State Incentives for Renewables & Efficiency (DSIRE) provides comprehensive information on state, local, utility, and federal incentives that promote renewable energy and energy efficiency.[12]

California

In California in particular, utilities charge higher per kWh rates as energy consumption rises above established baselines – with the top tier set at the highest rates to discourage consumption at those levels. Home fuel cells reduce customer exposure to the top tier rates, saving homeowners as much as 45% in reduced annual energy costs.[13]

Market status
Further information: Micro combined heat and power and Fuel cell

Home fuel cells is a new market and represents a fundamental shift in the sourcing of energy. An individual home fuel cell system installed in a US home becomes a part of the bigger picture of U.S. energy independence. An ultimate benefit of home fuel cells will be to eventually create networks of micro-CHP systems distributed throughout communities and business parks. This self-generation of energy in a distributed generation approach that will secure and increase US power generating capacity, enabling unused electricity to be sent back to the grids without having to add new power plants and transmission lines. Putting a home fuel cell system into homes has the potential to get people off-the-grid, play a significant role in energy efficiency, and reduce US dependence on foreign energy imports.

See also

References
  1. "Vitovalor.de – Brennstoffzellen-Heizgerät Vitovalor 300-P – die stromerzeugende Heizung" [Vitovalor.de – fuel cell-furnace Vitovalor 300-P – the electricity generating heater]. vitovalor.de (in German). Retrieved 29 July 2015.
  2. "Richtlinie zur Förderung von KWK-Anlagen bis 20 kWel (Mini-KWK-Richtlinie)" [Guide line for support for CHP-installations up to 20 kWel (Mini-CPH-guide line)]. klimaschutz.de (in German). Retrieved 28 July 2015.
  3. "Is K.R. Sridhar's 'magic box' ready for prime time? – Fortune". Archived from the original on 2010-04-08. Retrieved 2010-02-21.
  4. The Bloom Box: An Energy Breakthrough? – CBS News
  5. LaMonica, Martin. "ClearEdge touts home fuel cells over solar panels". CNET News. Retrieved 24 May 2011.
  6. Halstead, Richard. "Kent Woodlands resident becomes first in county to power home using fuel cell". Marin Independent Journal. Retrieved 18 February 2011.
  7. Schwab, Jennifer. "The cutting edge in green". Huffington Post. Retrieved 24 May 2011.
  8. The fuel cell industry review 2013
  9. Latest developments in the Ene-Farm scheme
  10. Launch of new 'Ene-Farm' home fuel cell product more affordable and easier to install
  11. California Energy Commission: Distributed Generation Archived May 13, 2008, at the Wayback Machine
  12. "Database of State Incentives for Renewables & Efficiency". Archived from the original on 2008-09-08. Retrieved 2008-10-15.
  13. California Energy Commission on Utility Energy Efficiency
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