The 21st century has highlighted a need for clean, efficient and economic energy, which has put Combined Heat & Power (CHP) into the limelight. By providing on-site power generation, waste heat recovery and system integration, CHP offers a realistic, near-term solution for exceptional energy efficiency and emission reduction. CHP systems can generate electricity locally while they recover heat to satisfy heating loads in buildings.
The UK is facing growing electricity demands, volatile fuel costs and power reliability issues, which is necessitating new technologies to provide greater levels of efficiency and further expand the use of this clean energy. Due to growing concern about climate change and a steep global rise in demand for petroleum products, the need for energy efficiency improvements are more urgent than ever.
There are several drivers, beside energy efficiency, for the growing interest in on-site generation. Historically, a major barrier for distributed generation (DG) development has been the high investment costs for small units compared to larger central stations. In recent years, the cost of small-scale power generating units has fallen, which allows for cost-effective installations in markets with high electricity prices. In addition customers are now demanding electricity with higher reliability than the grid can deliver.
CHP or co-generation, is the simultaneous production of electricity and heat from a single fuel source. A CHP system recovers the heat normally lost in electricity generation for use in heating, dehumidification and other processes even including cooling. Compared with separate generation of electricity and heat, CHP systems can operate at more than 85 percent efficiency.
CHP is not a single technology, but an integrated energy system that can be modified depending upon the needs of the energy end user. CHP can use a variety of fuels to provide reliable electricity, mechanical power or thermal energy for industrial plants, universities, hospitals or commercial buildings – wherever power is needed.
Energy efficiency: CHP systems recycle waste energy and use it for heating and cooling; enhance fuel use efficiency; and increase the benefit to the customer from each cubic meter of natural gas or propane consumed.
Emissions reduction: Efficient CHP technologies decrease emissions of pollutants and greenhouse gases. What's more, CHP can use clean, renewable fuels such as biomass or biogas to provide electrical and thermal energy.
Energy reliability and quality: CHP technologies deliver the high-quality power required by computer systems and sensitive manufacturing processes.
Energy security: CHP systems can operate independently of the grid to sustain critical services such as health care, communications, shelter, and public safety, after disasters.
Economic development: CHP systems directly relieve grid congestion, reduce or eliminate power purchases, and avoid the need to construct new power plants. In the case of alternate fuels, CHP systems enable the use of local energy resources and support high-tech manufacturing industries.
The main benefit of a CHP system is that the overall annual energy costs can be reduced. Buildings connected to communityheating networks can receive available hot water and chilled water for air conditioning use.
On site generation reduces the amount of electricity that has to be purchased from the grid. Although there will be a shift in gas electricity balance of a building's total fossil fuel consumption, any rise in gas costs will be more than offset by the savings in electricity costs. Advanced CHP technology can provide this. Many buildings often have sufficient demand for space heating and hot water to utilise a small CHP plant, such as powertherm. Some manufacturers, such as shentongroup, can synchronise multiple units together to create a very efficient on-site power station that can substantially reduce electricity bills.
A Whole Life cost analysis will help managers determine the full benefits of investing in CHP. This will include comparing the conventional provision of heat and power by boiler and electricity purchased from the local electricity network. When carrying out such an exercise it is important to take into account the capital expenditure as well as all operating and fuel costs. Although capital costs of CHP equipment are higher than a conventional boiler plant, the equipment usually has lower Whole Life costs when the annual expenditure on operation, maintenance, heating, ventilation and air conditioning as well as fuel costs become part of the equation.
Will CHP work for you?There are 3 important criteria to determine this.
1. The ability to use the heat, for heating or hot water, most of the year round.
2. Using a reasonable amount of electricity to start with. Savings come mostly from reductions in your electricity bill, so if you aren't spending much to start with then the potential will be reduced.
3. The difference in electricity & gas prices (known as the 'spark ratio'). CHP burns gas to produce cheap electricity, so the ratio in these costs is important.
Here's a yardstick. If your annual costs for electricity are in excess of £200,000, and you have a constant need for hot water, a CHP system may be the answer. Savings and Return On Investment are impressive. Some buildings are saving over £40,000 per year from a single small unit. For example, a medium size hotel with a swimming pool would be a classic case where CHP is likely to be very effective.
Energy industry leaders and Government Ministers agree that CHP will play a more prominent role in the United Kingdom's transition to a low-carbon economy. It is an integral part of its ambition to set the UK on the path to achieving a 60% reduction in carbon dioxide emissions by 2050.
Can CHP save you money? Wouldn't you like to find out?