In our previous edition of Customer Insights, we introduced our integrated approach offered by the AEP family of companies. Together, AEP Energy and AEP OnSite Partners work with you to provide a complete behind-the-meter (BTM) energy solution package for your business.
Last month we described the various BTM systems available such as solar, battery storage, natural gas or diesel-fired generators, and fuel cells. Each type of asset is unique and tailored to your business’ goals and desire for energy management.
In this edition of Customer Insights, our experts from AEP OnSite Partners will focus on fuel cells: what they are, how they work, what types of fuel cells are offered, and the benefits of installing a fuel cell for your business.
First, let’s share a few facts about fuel cells with you.
The first fuel cells were invented in 1838 by Sir William Grove, a Wales native, who invented the Grove voltaic cell. It wasn’t until the 1960s that fuel cells were used commercially when the NASA space program used them to generate power for satellites and space capsules. In 2015, the U.S. Senate passed a bill recognizing October 8 as National Hydrogen and Fuel Cell Day, honoring America’s role in fuel cell development.
Today, fuel cells are used for a broad range of purposes including primary and backup distributed power generation for businesses, providing energy for our cars and buses, and even power for laptop computers.
What is a fuel cell?
A fuel cell uses chemical energy to produce electricity. Typically, hydrogen is the fuel which is often derived from natural gas. Hydrogen is the basic fuel, but fuel cells also require oxygen. A fuel cell produces electricity, water and heat. Fuel cells differ from batteries in that, unlike batteries, they require a constant external fuel source and supply of oxygen to produce the electricity. However, fuel cells do not need to be recharged like batteries.
Over a year ago, AEP OnSite Partners installed a 1.4 megawatt (MW) fuel cell at Trinity College in Connecticut. It features a single FuelCell Energy SureSource 1500™ power plant weighing nearly 110 tons on less than half an acre of land. In addition to the 1.4 MW of electricity capacity, the plant will also generate up to 2.2 million British thermal units (MMBtu) of useful thermal energy that is captured and used for steam, producing up to 1,500 pounds per hour. Below is a picture of the fuel cell owned by AEP OnSite Partners through a 15-year Power Purchase Agreement (PPA) with Trinity College.
How does a fuel cell work?
Fuel cells convert chemical energy into electricity through a reaction of hydrogen and oxygen. A fuel cell consists of an anode, an electrolyte which is in the center of the fuel cell, and a cathode. The anode is a negative electrode and the cathode is a positive electrode. Electricity is produced through the process of protons flowing from the anode to the cathode through the electrolyte.
A single fuel cell generates a small amount of direct current (DC) electricity. In order to create an amount of electricity that would be useful in a commercial setting, many fuel cells are usually assembled into a stack. If alternating current (AC) is needed, the DC output of the fuel cell can be converted to AC by installing an inverter.
There are several kinds of fuel cells with slight differences. In general terms, hydrogen atoms enter a fuel cell at the anode where a chemical reaction strips them of their electrons. The hydrogen atoms are now “ionized,” and carry a positive electrical charge. The negatively charged electrons provide the electrical current that creates the power.
Although there many differences in design, fuel cells can be placed into three categories by the type of electrolyte that is used. For distributed power generation application, there are three types of electrolytes used. These are molten carbonate, phosphoric, and solid oxide. We’ll explain each of these in more detail next.
What are the basic fuel cell types?
Molten carbonate fuel cells use high-temperature compounds of salt carbonates as the electrolyte. Their efficiency ranges from 60 to 80 percent, and the operating temperature is about 1,200 degrees Fahrenheit.
The waste heat produced from the fuel cell, which is hot water or steam, can be used for a thermal load at your site, or it can be recycled to make additional electricity.
Usually nickel is used for the electrode which is inexpensive compared to the platinum used in other cells.
Below is an example of a molten carbonate fuel cell.
FuelCell Energy produces carbonate fuel cells. Their smallest scalable fuel cell is the SureSource 1500™, a 1.4 MW fuel cell which provides up to 3.7 MMBtu per hour of thermal energy. Visit FuelCell Energy to learn more about their fuel cell products.
Phosphoric acid fuel cells utilize phosphoric acid as the electrolyte. These fuel cells tend to be larger than their counterparts that use different electrolytes. The efficiencies of phosphoric acid fuel cells average 40 to 50 percent and operate at temperatures around 300 to 400 degrees Fahrenheit.
Usually phosphoric acid fuel cells need a platinum catalyst at the electrodes which can be expensive. The first versions of modern fuel cells used phosphoric acid, making these fuel cells the most established technology. Molten carbonate and phosphoric acid both use liquid electrolytes.
Doosan produces phosphoric acid fuel cells. The Doosan PureCell® Model 400 operates on natural gas, generating 460 kW of electricity. To learn more about Doosan’s phosphoric acid fuel cells click here.
Solid oxide fuel cells use a hard, ceramic compound of metal oxides as the electrolyte. The efficiency is about 60 percent, and the operating temperatures are about 1,800 degrees Fahrenheit. Like molten carbonate fuel cells, waste heat can be utilized for local thermal needs, or recycled to make additional electricity. Because of the high operating temperature, solid oxide fuel cells tend to be larger than their counterparts.
Bloom Energy, headquartered in San Jose, CA, produces solid oxide fuel cells. Click here to learn more about Bloom Energy and the fuel cells they produce.
Below is an example of a solid oxide fuel cell.
What are the benefits of a fuel cell?
A fuel cell can be incorporated into a distributed generation strategy for commercial and industrial customers. Like most technologies, fuel cells offer advantages and disadvantages over other forms of on-site generation.
Because fuel cells employ a chemical reaction rather than combustion, they generate electricity with less pollution compared to reciprocating engines or micro turbines. Much of the hydrogen and oxygen used in generating electricity ultimately combine to form a harmless byproduct: water. The electricity produced by fuel cells is a drastically reduced carbon footprint compared to conventional power plants. Because fuel cells require natural gas, solar and wind generation would be considered more sustainable technologies.
Fuel cells are compact and require relatively small amounts of space. A ten-megawatt fuel cell system requires roughly one acre of land. An equivalent solar array would require nearly 25 acres.
Fuel cells are easily scalable for larger loads, and are an efficient choice, especially for combined heat and power (CHP) applications for customers with thermal loads. Another point to consider is that fuel cells often have high operating temperatures. While this may not be a concern in many applications, especially CHP, it could be a concern with some types of commercial and industrial businesses.
Fuel cells can also be grid independent, making them a good choice for customers that desire resiliency.
The cost of fuel cells is very high, especially when compared to the falling cost of solar. Usually it requires a subsidy to make a fuel cell an economic choice.
A fuel cell system is an ideal application for a commercial or industrial customer that has large power needs, has a thermal load, is land constrained, and has either available subsidies or places economic value on resiliency. AEP OnSite Partners has the experience and knowledge to find the right type of fuel cell system that fits your application and can help with finding available subsidies in your area.
Interested in learning more?
AEP OnSite Partners provides customers with turn-key offerings to design, own, maintain and operate behind-the-meter (BTM) generation. If you are interested in learning about a pathway to BTM generation to help reduce your utility costs, increase your sustainability, and increase your site resiliency to grid outages, contact Dean Naillon, Director of Business Development for AEP OnSite Partners, at email@example.com, or contact your AEP Energy sales representative to find out if BTM generation makes sense for your organization.