Fuel cells can be usefully installed alongside solar and wind power, and battery storage systems to provide highly reliable on-site energy, as well as to cut emissions and alleviate strain on the electricity grid. And it is already being done, writes Ryan Skukowski of US-based Fuel Cells 2000.
|Bloom Energy 100 kW fuel cell units at Adobeà¢€â„¢s headquarters in San Jose, California Source: Edelman|
Long considered a modern marvel of engineering, the US electricity grid à¢€“ the vast network of centralized power plants and transmission lines that power millions of homes and businesses across the country à¢€“ has recently seen its fair share of problems. Frequent blackouts, extreme weather disruptions, and even the occasional solar flare have all served to remind Americans of the gridà¢€â„¢s fragility, and have helped fuel a growing movement among businesses and homeowners to get à¢€Ëœoff the gridà¢€â„¢ and install renewable energy systems to lower their costs and emissions.
Fundamentally, people are starting to demand things that the grid cannot deliver, chief among them reliability, security and environmental cleanliness. For many companies in the US, this has meant shifting attention towards on-site renewable energy and combined heat and power (CHP) technology.
Fuel cells have emerged in this space as a more reliable, more secure, and much cleaner alternative to grid power, replacing megawatts of fossil fuel power capacity with cleaner, more localized energy. Fuel cells generate energy through an electrochemical reaction between hydrogen and oxygen, a process that is inherently clean and efficient. The only emissions from fuel cells are water and heat, both of which can be recovered and put to use.
Satisfied customers of fuel cells such as Coca-Cola, Google and Wal-Mart are experiencing significant emissions reductions and returns on their investment. But some companies are going a step further by choosing to co-locate fuel cells with other renewable energy technologies on-site, dramatically reducing or completely eliminating their dependency on the electricity grid for power. When combined with other renewable technologies such as wind turbines or solar photovoltaic (PV) arrays, fuel cells can provide a crucial helping hand, carrying a siteà¢€â„¢s electrical load through cloudy days and periods of intermittent wind.
WHY CO-LOCATED RENEWABLE SYSTEMS?
Co-located renewable energy systems harden a siteà¢€â„¢s reliability, and are ideally suited to places where critical power needs must be met. For any business, losing power for a prolonged period of time has a high cost, but for sites such as data centres and telecom stations, power interruptions of only a few minutes can spell financial doom. Companies that operate these critical-need sites are increasingly willing to pay the high initial cost of renewable energy technology to avoid even more costly power outages.
The 1 MW fuel cell installation at Santa Rita jail works together with PV,
wind and a battery storage system Source: FuelCell Energy
Other companies are pursuing co-located renewable energy as part of their sustainability goals. For large companies, in particular, installing wind, solar, or fuel cell capacity is not only smart on paper, but can also serve as striking visual proof of their commitment to the environment.
The declining cost of renewable energy technology is also contributing to the installation of these co-located systems. A recent analysis by the Lawrence Berkley National Laboratory (LBNL) found that the average installed cost of residential and commercial solar PV systems fell by 17% from 2009 to 2010. And, while costs vary widely between regions, the LBNL study estimated an average price of between $6.30/W and $8.40/W for systems less than 10 kW in size, and between $3.00/W and $4.00/W for large utility-sector systems.
The same trend is being realized in the cost of wind energy. The average turbine price fell 4% between 2010 and 2011, and is expected to fall another 2% this year, according to Bloombergà¢€â„¢s Wind Turbine Price Index. Continued research and a production ramp-up to achieve economies of scale are expected to drive costs down even further, but recent trends have already encouraged more companies to take a serious look at the technology.
In this new environment, fuel cells are ripe with potential and have made inroads over the last few years in several commercial markets, including large stationary power, forklifts and backup power for telecommunications. Fuel cells can be sited indoors, outdoors, below ground or on the roof, so they can go wherever wind turbines and PV panels go à¢€“ but with a smaller footprint à¢€“ ranging from remote and rugged terrain to urban environments. Fuel cells are also fuel-flexible, meaning they can run on natural gas or biogas.
When paired with another renewable technology, fuel cells are a reliable partner in providing on-site electricity. Fuel cells often provide a buildingà¢€â„¢s baseload power needs while solar and wind handle the peripheral loads. Collectively, such a co-located system achieves dramatic reductions in emissions and fuel use, and eliminates the risks associated with power delivery such as downed transmission lines and efficiency loss.
A 4 kW ReliOn fuel cell backs up the PV power supply for this telecoms
tower in Ackley, Ohio Source: Cellcom
Co-locating different renewable energy tech-nologies at the same site is also a way for the entire industry to stand together à¢€“ a powerful statement of technological unity in a country that values choice and flexibility when it comes to virtually every other service it receives on a daily basis. As many customers of renewable energy technology have asked themselves already, why should power generation be any different?
WHOLE FOODS MARKET à¢€“ DEDHAM, MA
Whole Foods Market à¢€“ a national chain of natural and organic grocers à¢€“ is one company that has made renewable energy a top priority. The Whole Foods grocery store in Dedham, Massachusetts, is now almost completely grid-independent thanks to a 400 kW fuel cell from Connecticut-based manufacturer UTC Power and an 80 kW solar PV array from SunEdison, headquartered in California. In addition to generating electricity, the fuel cell produces waste heat that is captured to provide 100% of the storeà¢€â„¢s hot water needs and is run through absorption chillers for refrigeration. On the storeà¢€â„¢s rooftop, 460 PV panels handle most of the lighting needs around the store.
For a grocery store like Dedham Whole Foods, gaining renewable electricity as well as freedom from the grid is a worthwhile goal. A sustained loss of power can end up costing a company thousands of dollars due to spoiled food and lost business. The presence of two renewable technologies also provides major bragging rights for Whole Foods, which has made sustainability and environmental stewardship a major part of its brand.
ADOBE HEADQUARTERS à¢€“ SAN JOSE, CA
At software giant Adobeà¢€â„¢s corporate headquarters in San Jose, California, fuel cells are working in tandem with wind turbines to provide about 30% of the electricity needed to power the siteà¢€â„¢s three office towers and more than 90,000 m2 of office space. With 12 100 kW Bloom Energy fuel cell units, as well as 20 1.2 kW Windspire turbines in the buildingà¢€â„¢s central courtyard, Adobe is able to significantly reduce its dependency on the grid for power. The fuel cells, installed on Adobeà¢€â„¢s West Tower, convert natural gas into electricity at a rate of 9.5 GWh per year. Adobe purchases renewable biogas from a Pennsylvania landfill to offset the natural gas being converted in the fuel cells on site, making the system virtually carbon neutral.
Some 20 vertical, propeller-free wind turbines line the edges of the buildingà¢€â„¢s sixth-floor patio, which is located between the siteà¢€â„¢s three towers. Taking advantage of a wind tunnel effect between the buildings and sustained breezes off the Pacific Ocean, the turbines generate 2.4 MWh per year.
Like Whole Foods, Adobeà¢€â„¢s sustainability goals are especially ambitious. Prior to installing fuel cells and wind turbines at its San Jose site, completed in late 2010, Adobe set a company-wide goal of receiving half of its energy from renewable sources.
SANTA RITA JAIL à¢€“ DUBLIN, ALAMEDA COUNTY, CA
Jails are another example of sites that demand continuous power for their daily operations. At the Santa Rita Jail in Dublin, California, a statewide energy crisis in 2001 left the site disconnected from the grid for almost a month and reliant on diesel generators to ensure power for thousands of inmates at the site. This experience prompted Santa Rita Jail to seriously consider renewable energy technology. Over the following years the site slowly built its own electrical grid to make the main one virtually redundant.
That microgrid is now operational, and includes a 1 MW fuel cell, a 1.2 MW rooftop solar PV array, five 2.3 kW wind turbines, and a 2 MW battery storage system. Added in 2001, the solar PV panels on the roof generate some of their highest output during peak times, offsetting purchases of electricity from the grid at the most expensive rates.
The fuel cell, a DFC1500 power plant manufactured by FuelCell Energy, was installed in 2005 and now provides consistent baseload power to the jail, meeting about half of its overall electricity needs. In addition, 1.4 million BTU (0.41 MWh) of waste heat from the fuel cell is recovered and used to help heat the jailà¢€â„¢s water. In 2010, five wind turbines were added to the system, giving the site even more flexibility.
Finally, the lithium-ion battery system allows the jail to store electricity purchased from the grid at low rates and use that electricity when needed. All of these systems work in tandem with each other via the batteryà¢€â„¢s control system, which automatically draws power from the battery or stores it for later use.
The jail remains connected to the grid and operates in parallel with it, disconnecting in the event of a grid disturbance and reconnecting once the grid is back online. According to the projectà¢€â„¢s engineers, the system is scalable, meaning Santa Rita Jail could see the installation of more solar panels, wind turbines or fuel cells with no impact on the main grid.
HYBRID SYSTEMS FOR TELECOM STATIONS
Though the emergence of co-located renewable energy technologies is a relatively new phenomenon for large commercial buildings such as stores, offices and data centres, hybrid renewable systems have been active for several years at remote off-grid sites such as telecom stations.
IdaTech of Bend, Oregon, and ReliOn of Spokane, Washington, are two US companies with experience in operating off-grid power sites that employ two or more renewable energy technologies. Fuel cells are a key component at these sites, carrying the electrical load when solar panels and wind turbines lose their free fuel or when the batteries lose voltage.
Telecommunications, in particular, has benefited from hybrid renewable energy solutions. Orange UK, the largest wireless provider in the UK, currently relies on a system that combines wind, solar, and IdaTechà¢€â„¢s 5 kW fuel cell to provide backup power to a radio transmission and base transceiver station at its Elan Valley site in Wales. A battery bank stores the energy generated by all three systems, and a liquid-fuelled reformer converts a methanol-water solution into hydrogen on-site, vastly simplifying the fuel logistics. This configuration ensures constant power to the site, as well as low noise and emissions for the surrounding area, along with assurance for Orange UK that critical public safety communications will not be interrupted.
ReliOnà¢€â„¢s 4 kW T-2000 unit has supported a similar function at an off-grid cellular tower since 2008 in Ackley, Wisconsin. The tower, owned by wireless giant Cellcom, sits on a remote patch of Ackleyà¢€â„¢s designated wildlife area, a place that truly defines à¢€Ëœoff grid.à¢€â„¢ An array of 6.3 kW solar panels provides the siteà¢€â„¢s primary power, which is stored in batteries, and a wind turbine supports the solar array on dark days. Providing crucial backup to both systems is ReliOnà¢€â„¢s fuel cell. The combination of all three technologies creates a reliable power solution in a place previously thought unreachable, and saves Cellcom the expense of lengthening the grid, which at the time was estimated to be about $90,000.
Integrated renewable backup systems like these are scalable, and have given end users great flexibility in meeting their site needs.
Building a microgrid that integrates fuel cells with other renewable energy technology is also the approach Apple is taking for the latest renovation to its data centre in Maiden, North Carolina. The 46,000 m2 data centre already hosts the companyà¢€â„¢s iCloud services, and will soon be home to the USà¢€â„¢s largest end user-owned solar PV array, as well as its largest non-utility fuel cell system. When completed, the fuel cell system will run on biogas and deliver 40 GWh of baseload power per year. The solar panels will provide an additional 42 GWh over the same period of time.
Apple puts the data centreà¢€â„¢s peak demand at 20 MW, a demand that cannot be met through the combination of fuel cells and solar alone. But the associated emissions reductions and ability to displace even a small fraction of grid electricity will be worth the investment for Apple.
Each renewable energy technology has its own set of benefits and limitations. When co-located at the same site, these systems complement each other and provide added benefits that could not be achieved with merely one system. Reliability in the event of a grid disruption along with fuel efficiency and dramatic emission reductions are just a few of the reasons why companies in the US are considering this option.
For companies that operate critical-needs facilities such as grocery stores, data centres and jails, the added reliability that comes from a co-located renewable system more than justifies the initial high cost of installation. Those who seek a à¢€Ëœgreenà¢€â„¢ business image have also been satisfied with this configuration, and have left the door open for scaling up their renewable energy systems in the future. Fuel cells play a critical role in keeping these sites powered, quiet, and space efficient. In many cases, they provide the critical push over the hill towards grid independence.
As interest in co-located renewable energy systems continues to grow, fuel cells will remain a reliable partner for solar, wind, and battery systems, and will help sites achieve a crucial energy mix that results in lower emissions and a far less strained electric grid.
Ryan Skukowski is a policy analyst with Fuel Cells 2000, Washington, DC, US. www.fuelcells.org