December 17, 2013 – Vol.18 No.40
Hybrid Systems – The Next Step in Power Generation
by Kord F. Christianson, President of TDX Power
Long-term promise and potential for renewable energy sources remains vast. But the reality of current renewable technologies and the plain fact that today’s utilities and their users demand constant availability means that fossil fuels are here to stay for a while longer as a base generation source.
However, that does not mean that renewables have to take a back seat in the evolving power-generation market. There are strategies for renewable integration that utilities and power-generators should consider implementing that expand the value and functionality of renewables. The advancements in hybrid configurations leverage renewable sources so they can make increased energy contributions far exceeding previously envisioned limits. The intelligent, strategic use of hybrid systems (fossil fuels and renewable energy) significantly lowers fuel consumption, which improves operating economics and curtails emissions.
At TDX Power, we’ve found that hybrid power systems are well suited for power generation in remote locations. These sites demonstrate the cost effectiveness of renewables. To date, we have installed three hybrid systems in remote Alaskan outposts – wind turbines integrated with diesel-generator systems. All three locations offer excellent wind-generation resources, and include existing diesel generators. These sites are also “must run” environments, requiring continuous energy access. Even short lapses in power availability can be extremely detrimental to equipment, livelihoods and lives.
In our experience, the keys to integrating renewables into existing fossil fuel power plants include:
As an example, in 2000 at our POSS Camp facility on St. Paul Island, Alaska, we created a hybrid system marrying diesel generators with wind-generated energy. The system powers our commercial installations as well as a hotel and airport terminal facilities on our property. Ten individual buildings in all are powered by the hybrid system.
Technically, installation of hybrid systems can be astonishingly straightforward. The core components of the original POSS Camp plant include one 225-kW Vestas V27 wind turbine, a pair of 150-kW Volvo diesel-engine generators, a 6,000-gallon hot water tank, a 300kVA synchronous condenser, and immersion water heating elements to manage integration of wind energy with the existing grid. The products required for integration are clearly affordable and readily available, maximizing return on investment (ROI).
Operation at POSS Camp can even be done without the diesel engine, one of the first demonstrations of this type of system architecture in the world. This was accomplished by building in a high amount of excess wind capacity, as opposed to employing energy-storage technologies, which were not commercially feasible at the time. Our installation takes advantage of low-cost thermal storage to maintain system stability. We created a thermal network in our ten buildings, redirecting excess wind energy – a “thermal dump” – to generate hot water for commercial and domestic use throughout more than 75,000 square feet on our site. Shunting excess wind energy to the thermal system via the automatic control system is nearly instantaneous and seamless.
POSS Camp diesel/wind hybrid system operated by TDX Power on St. Paul Island, Alaska.
The proprietary installation at POSS Camp runs 20 percent of the time on pure wind power, 20 percent of the time solely on diesel power, and 60 percent of the time on a combination of both energy sources. In 2011, the cost savings on diesel fuel was estimated at more than $26,000 per month, as wind energy replaced nearly 5,000 gallons of monthly diesel fuel usage.
By demonstrating power stability and proving the viability of our proprietary hybrid system, we’ve been able to enter a relationship with City of St. Paul Municipal Electric Utility, recently connecting one of POSS Camp’s three 225kW wind turbines to the city’s power grid. In the first three weeks of trial operation, we supplied 52,500 kWh, reducing fuel usage by approximately 3,800 gallons, and with an approved plan to add additional turbine capacity.
While we are still in the early phases of the project with City of St. Paul Municipal Electric Utility, the proven hybrid system performance has opened eyes of numerous parties who guide power-infrastructure decisions. As is typically the case, dependable systems that deliver demonstrable value will always be of interest to forward-thinking municipalities.
We at TDX Power are excited about the advancements we’re seeing in renewable technologies. But while we wait for renewable solutions that completely satisfy the needs of utilities and their customers, we’re aggressively pursuing integrated solutions that meld fossil fuels and renewable sources. By proving the reliability of hybrid systems in microgrids and isolated utilities, we’re confident that power generators and utilities of all sizes will become more comfortable in their assessments of hybrid systems for their organizations.
Kord F. Christianson is President of TDX Power, and a 30-year-veteran of the energy industry. Born in Sitka, Alaska and holding leadership positions with companies including Caterpillar and Wartsila, Kord has in-depth experience in development, finance, design and construction of wind, solar, oil, natural gas, and hybrid power plants. (907) 278-2312, info(at)tdxpower.com
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