The world’s population is expected to reach 9 billion by 2050, and energy consumption is predicted to increase by over 80 percent, according to the Organisation for Economic Co-operation and Development. With rising fuel costs and pressures to improve air quality and reduce carbon emissions, governments and business owners are seeking new methods for efficient and sustainable energy use.
Tri-generation could be an answer. Essentially a combined cooling, heat and power solution, gas-fired tri-generation is ideal as a self-contained (off the grid) energy source for an industrial park, for example. A property developer could offer tenants a compelling proposition. On top of other facilities management services, ready-made electricity, heating and cooling services could be provided at lower costs with reduced emissions.
How It Works
In a typical turbine, heat is used during fuel combustion to generate electricity. Excess heat is then expelled into the environment as waste heat. Energy is lost.
With cogeneration, by-product heat, in the form of steam, is emitted and put to further use for heating water or the surrounding space, or as process steam. Tri-generation takes the process one step further. Waste heat is put toward generating cooling via an absorption chiller. So, tri-generation produces electricity as well as heating and cooling.
In conventional fossil fuel power plants, less than 50 percent of input heat is converted to electricity. The remaining heat emerges from the turbines as low-grade waste heat with no significant local uses. This is mainly due to the typical transmission distance from the plant to customers. The waste heat is therefore usually lost to the environment.
Tri-Generation Has Many Potential Benefits:
When waste heat is used for heating and cooling, thermal efficiency can reach up to 90 percent. This high conversion rate suggests that tri-generation reaps its greatest benefits when scaled to fit facilities where electricity, heating and cooling are needed constantly. This is ideal for facilities such as 24-hour industrial parks, certain commercial building blocks, or even hospitals that operate all day.
Tri-generation is also useful in areas prone to brownouts. Operations can continue through erratic weather patterns that often would affect electricity transmission from a centralized power station.
Tri-generation can be an off-the-grid solution. This can help businesses scale back on the cost of electricity, as well as costs from heating and cooling requirements.
Localizing energy transmission means electricity does not need to be transported over a long distance to reach consumers. It reduces the burden on a utility’s transmission infrastructure.
Tri-generation also enables an opportunity for efficient repurposing of waste heat, producing heating and cooling for customers nearby.
Combining electricity, heating and cooling production from one source reduces carbon emissions significantly.
Exploring Tri-Generation Opportunities
It is little wonder, then, why countries like China are exploring tri-generation options.
China is the world’s largest user of coal – 4 billion tons will be used in 2012, according to the U.S. Department of Commerce. With electricity use soaring, the country recognizes the need for greener solutions. Hence, the government has reinforced the need for efficiency at all stages of the energy value chain.
Chinese Premier Wen Jiabao committed to a 7 percent economic growth target last year in a public address on the 12th Five-Year Plan. During his speech, he reiterated the importance of balancing growth with environmental sustainability. He said “(China) must not any longer sacrifice the environment for the sake of rapid growth . . . as that would result in unsustainable growth featuring industrial overcapacity and intensive resource consumption.”
To meet its targets, the Chinese government has begun developing smart electric power infrastructure. These are built to deliver power combining conventional grid components with new storage and information communication technology. To support its latest efforts, the Chinese government was awarded a grant from the U.S. Trade and Development Agency (USTDA), and Black & Veatch was selected by the National Energy Administration (NEA) of China to conduct a clean energy feasibility study.
Black & Veatch will work with NEA to assess the implementation of “distributed energy-combined cooling, heat and power” (DE-CCHP) tri-generation. This technology will be looked at across two model facilities in China. The study supports the U.S. – China Energy Cooperation Program, a public-private partnership to advance the development of clean energy in China.
This is a major bilateral cooperative program between the United States and China. It leverages private sector resources for clean energy project development in China. The aim is to increase awareness of technology, product standards, regulatory processes and services that can assist China in developing its clean energy sector.
DE-CCHP will allow China to generate reliable power and thermal energy by reducing its dependence on coal-fired power plants. Tri-generation also provides China with significant opportunities to improve energy efficiency and reduce greenhouse gas emissions.
Overcoming Barriers
Tri-generation faces roadblocks. Climate suitability is crucial. The solution is more suitable for temperate climates where there is a need for power, heat and cooling throughout the year. Another challenge is the need to convince utilities that the benefits outweigh the losses in revenue. Taking large facilities off the grid means losing customers. And without the buy-in of regulators who give the ultimate green light, adoption of tri-generation is slow.
The industry needs a leader to pave the way for this new technology.
When China identified wind power as a key component of the country’s growth, it stated ambitious claims to have 100 gigawatts (GW) of wind power generating capacity by the end of 2015 and to generate 190 billion kilowatt-hours (kWh) of wind power annually. According to the Global Wind Energy Council, wind power in China accounted for 62 GW of electrical generating capacity at the end of last year.
This is a good example of how government support can springboard the adoption of emerging energy solutions.
The DE-CCHP feasibility study represents the initial step the Chinese government is taking in approaching this relatively new development. At the rate Chinese cities are growing and the potential for top-down government and regulatory mandates, there is an opportunity for China to drive another sustainable energy solution.
Subject Matter Expert
Suqing Wang: WangS2@bv.com
