Tom Geist, a senior project manager at Electric Power Research Institute (EPRI), kicked off the session by announcing that the perfect power source doesn’t exist. However, there are lots of options, so it will be increasingly up to utilities to choose the one(s) that best fits the need.
EPRI explains DG
Distributed generation is often used interchangeably with distributed resources, but that is inaccurate. Distributed resources equal distributed generation plus energy storage plus controls (load management).
The importance of distributed generation for utilities is that it offers the opportunity to reduce transmission and distribution line loss, anywhere from a few percentage points up. Distributed generation gives system planners more flexibility, and allows utilities to make better ancillary services a worthy product. Most importantly, customers care about the improved power quality, reliability, efficiency and lower costs distributed generation can enhance. Utilities can create customized solutions for customers around distributed generation systems.
How EPRI picks the best
EPRI deals with products just out of the laboratory, test them and demonstrates the technology in the field. The reports from those tests are available to all utility subscribers.
To help utilities determine which technologies are the most valuable, EPRI takes the system view—every technology is a system composed of multiple technologies: source, conversion, storage, power electronics. Hence, comparison is difficult.
The metrics EPRI applies to technologies are price, size, weight, energy, power, efficiency, safety, reliability and life cycle. Any one of these can determine success or failure of application. People tend to focus on one of the sub-systems, sometimes at the expense of the entire system.
Proven technologies aplenty
There are lots of proven distributed generation technologies which meet some of the metrics but not others. Solar turbines from the Caterpillar Company have been operating commercially since the 1940s. This technology presents a golden opportunity for capturing waste heat. Typically, 25 percent of power is lost in conversion, but 42 percent can be recovered through combined heat and power (CHP) technology.
Conventional fuel cells are another proven technology. They usually provide a small amount of base load power, but are bulky, complex to operate, can be expensive and have short life cycles. The phosphoric acid fuel cell runs at a high temperature, offering CHP possibilities. It needs to be operated in parallel with the grid. The catalyst makes use of platinum, an expensive metal, so scaling up is costly. Solid oxide and proton exchange membrane fuel cells are similar to phosphoric acid types.
Micro turbines are based on turbocharger technology found in aircraft auxiliary power units. They usually generate less than a MW of base load power with CHP potential.
Flow batteries are similar to conventional batteries except that the electrodes are charged liquid. This technology has good energy density and cycle life; it is long-lasting, scalable with the potential for lower cost, but has failed to generate much interest.
Another type of battery familiar to everyone with a lap top or cell phone is the lithium ion battery. It has made tremendous advances in the past two decades, but the challenge is to scale up to larger applications. It has safety issues, one being the potential to catch fire during charging, especially the large batteries.
The advanced lead-acid battery is an improved version of the familiar lead carbon system. This technology has a very good cycle life and is good for large systems.
Utilities can use all of these technologies for peak shaving, load leveling and improved reliability.
Technologies on the way
The one emerging technology on every utility’s radar is the smart grid, with its promise of improved performance. It is evolutionary, not revolutionary, a matter of applying communications controls to existing technology. EPRI is conducting 11 regional smart grid demonstrations.
The future is not one size fits all. Invest in new technology – they are coming. Distributed generation is a customized solution with great potential.
Thin film solar comes to Florida
Julio Baroso from Keys Energy in Florida talked about a 30 kW thin-film solar project his utility installed on the Eco-Discovery Center.
It started with a cold call between the Keys Energy general manager and the National Oceanic and Atmospheric Administration (NOAA). The Florida Municipal Power Agency became involved later. Total project cost $235,928, with NOAA contributing about $90,000.
Advanced Green Technologies was only vendor who answered Keys’ RFP with a thin film solution. Keys wanted to try something new, since traditional panels are a problem in hurricanes. A system that lays flat on the roof is a better solution. Also, there are a lot of historic buildings in the Florida Keys, usually owned by the customers most likely to be interested in alternative energy, so the utility wanted to showcase a system designed to work with architecture in historic district.
Installation is simple—just peel off the adhesive backing and roll it down. All connections take place at peak of roof. The system was completed in about one day. It was only one year from the first phone call to powering up the system at end of 2009.
The system does not have backup a storage battery because its output does not exceed museum use.
The educational component, including a kiosk, is an important aspect of the project. Keys wanted to introduce customers to a different type of solar system. The Eco-Discovery Center is good fit with its focus on the environment of the Florida Keys.
And now, the Bloom Box
The final presentation came from Bloom Energy of 60 Minutes fame. The show put the company in the spotlight for its green attributes, but the Bloom Box is a total distributed generation solution.
The “old school” model the Bloom Box seeks to replace is “generation plus transmission.” The technology combines the two onsite. That may sound far-fetched, but computing and telephones are good examples of connected technology now gone distributed.
Bloom Box generators start at 100 kW, and can be scaled up to 1 MW. The modular design means that there is no need to shut the generator down entirely to service it. The company guarantees a 10-year performance, with ongoing service agreement.
The system doesn’t require water during operation, although it needs a little for start up. It is not suitable for customers who have an application for hot water, but if it is just electricity they need, the Bloom Box is for them. So far, it is only scaled for commercial applications.
What makes it marketable
For a new energy resource to move into the marketplace, it has to be more than reliable and affordable. It must be also be clean and easy. Legacy generators—coal, nuclear—are dirty, complicated and high maintenance or unreliable and intermittent—solar, wind. Legacy fuel cells are expensive, complicated.
Bloom has all four attributes. The first Bloom Box was installed in 2008, but the company waited to tell the story because fuel cells have baggage. A reliable affordable fuel cell has been five years away from market for last 25 years. This is an entirely different type of fuel cell, so the company waited to let customers announce their installations.
The Bloom Box works because of low-cost materials. The central component is a “flat, square piece of sand,” not platinum. It is an all-electric technology that approaches 50 percent efficiency, and is fuel-flexible—propane, ethanol, natural gas—it can run on anything with carbon and hydrogen. Electricity is generated by a direct electro-chemical reaction. It is a base load, not intermittent, solution with no waste heat.
The value propositions the technology offers to utilities are lower energy costs, clean power, pay-as-you-grow scalability, primary power, reliability, fuel flexibility and ease of installation.
With Federal and state incentives, a Bloom Box pays the owner back in less than five years. In California, it provides price stability and can help California emission reduction goals. Running on natural gas, it produces only 50 percent of the emissions of conventional generation. On biogas, it is a zero emissions power source.
Early adopters include ebay, Coca Cola, Fed Ex, Google, Staples and Walmart.
For utilities, the Bloom Box is a way to invest in the future. The technology provides superior customer service, power supply management and distribution performance. Working with customers to install a Bloom Box demonstrates environmental leadership to policy makers.
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