WHAT, WHY, HOW, WHERE AND WHEN
CHP means Cogeneration of Heat and Power. This means the use of any kind of fuel to produce simultaneously power and useful heat. To achieve this purpose, the combination of different technologies is required. Among such technologies we find reciprocating engines, gas turbines, steam turbines, heat recovery boilers, absorption chillers, cooling towers etc.
Inevitably any non-renewable power generation is involving the release of waste heat. CHP is transforming this into useful heat, using transfer fluids such as steam, hot water, thermal oil directly to the consumption point.
One simple example: exhaust combustion gases of a gas turbine, after power production, are converted into steam that is used in machinery in many textile mills all over the world. Another example: exhaust heat of a reciprocating genset is turned into hot water in hospitals and hotels.
CHP is the most efficient way of producing power based on the use of fossil fuels. Indeed, while the Rankine coal cycles cannot achieve 50% efficiency in real operation, and most developed combined cycles cannot achieve more than 55%, many real CHP plants are achieving efficiencies higher than 80% on fuel spent.
Following European Directive 2012/27/EU, only the high-efficiency cogeneration is worth some kind of promotion by the State Members. The condition to fulfill is having a Primary Energy Savings, compared to a modern combined cycle, above 10%. Can a law be more exigent than that? Thousands of CHP plants meet this target today.
CHP delivers to owner reliable onsite power and abatement of energy bill. For the local system country it means reduction of grid losses, reduction in grid investment, primary energy savings and reduction of greenhouse gases emissions.
Three factors are key for success
- Customer-oriented design, as every cogen installation is taylor made. After 18 years of experience in designing and auditing CHP we have not seen 2 identical plants. Design engineer must master the art of creating ideal CHP for a certain site, depending on power and heat demand (quantity and shape), wise lay-out and cost-effective investment. Wrong equipment choice or incorrect heat recovery arrangement will sure mean a missed opportunity of a successful project. Fuel type, whether natural gas, HFO, LFO, biomass, biogas.. will depend on local most convenient and cheap resource.
- Operation and maintenance costs require tough surveillance, in order to keep economy of the business profitable while plant reliability is well preserved.
- Intense surveillance of operational data. A set of proper KPI is required in your control board. Good decissions are better made when proper information is available.
Above 90% of cogeneration all over the world is implemented in industrial sites. Sectors like paper making, board, food, mining, chemicals, refining and beverages are ideal for implementation of a CHP plant. CHP can abate the energy bill of power purchase and fuel spent in conventional boilers. Also in big DHC systems and large buildings like hospitals or hotels CHP has been implemented for good.
CHP is convenient and profitable in economies with a ratio of electricity price and fuel price above 1:3, as a rule of thumb. An easy way to check this is to convert fuel price to $/MWhLHV. If, for instance, fuel price is 10 $/MMBtu (i.e. 38 $/MWhLHV) then electricity price shall be at least 110-120 $/MWh.
Power shortages and scarce access to reliable power also is a typical scenario for successful CHP.
Energy engineer must have in mind that CHP is not always most convenient power technology. It all depends on local electricity and fuel market price, and the availability of alternative easy cheap local resources as, for instance, high water resource in the rivers available for hydropower. Each particular case must be analized properly, no standard solutions are good in distributed energy systems.
Right now!, as long as you have basic conditions for its implementation. Always bear in mind that there are not good or bad technologies, only exist good or bad applications of a certain tehnology.
In EFITEKNA we are devotely dedicated to energy efficiency, because
- It will help you to reduce energy bill
- We make this world better and more environmentally friendly
We are looking forward to assist you in building up your successful energy project