Microgeneration is the small-scale production of heat or electric power from a "low carbon source," as an alternative or supplement to traditional centralized grid-connected power.
Microgeneration technologies include small-scale wind turbines, micro hydro, solar PV systems, microbial fuel cells, ground source heat pumps, and micro combined heat and power installations. These technologies are often combined to form a hybrid power solution that can offer superior performance and lower cost than a system based on one generator.
History In the United States, Microgeneration had its roots in the 1973 oil crisis and the Yom Kippur War which prompted innovation.
On June 20, 1979, 32 solar panels were installed at the White House. The solar cells were dismantled 7 years later during the Reagan administration, only to be replaced in the early 21st century.
The use of solar water heating dates back before 1900 with "the first practical solar cell being developed by Bell Labs in 1954." The "University of Delaware is credited with creating one of the first solar buildings, “Solar One,” in 1973. The construction ran on a combination of solar thermal and solar photovoltaic power. The building didn't use solar panels; instead, solar was integrated into the rooftop."
Technologies and set-up Power plant In addition to the electricity production plant (e.g. wind turbine and solar panel), infrastructure for energy storage and power conversion and a hook-up to the regular electricity grid is usually needed and/or foreseen. Although a hookup to the regular electricity grid is not essential, it helps to decrease costs by allowing financial recompensation schemes. In the developing world however, the start-up cost for this equipment is generally too high, thus leaving no choice but to opt for alternative set-ups.
Extra equipment needed besides the power plant
The whole of the equipment required to set up a working system and for an off-the-grid generation and/or a hookup to the electricity grid herefore is termed a balance of system and is composed of the following parts with PV-systems:
Energy storage apparatus A major issue with off-grid solar and wind systems is that the power is often needed when the sun is not shining or when the wind is calm, this is generally not required for purely grid-connected systems: a series of deep-cycle, stationary or sealed maintenance free batteries (the most common solution) or other means of energy storage (e.g. hydrogen fuel cells, flywheel energy storage, pumped-storage hydroelectricity, compressed-air tanks, ...) a charge controller for charging the batteries or other energy storage
For converting DC battery power into AC as required for many appliances, or for feeding excess power into a commercial power grid: an inverter or grid-interactive inverter. The whole is also sometimes referred to as "power conditioning equipment"
Safety equipment Groundings, transfer switches or isolator switches and surge protectors. The whole is also sometimes referred to as "safety equipment".
Usually, in microgeneration for homes in the developing world, prefabricated house-wiring systems (as wiring harnesses or prefabricated distribution units) are used instead. Simplified house-wiring boxes and cables, known as wiring harnesses, can simply be bought and mounted into the building without requiring much knowledge about the wiring itself. As such, even people without technical expertise are able to install them. They are also comparatively cheap and offer safety advantages. battery meters (for charging rate and voltage), and meters for power consumption and electricity provision to the regular power grid
Wind turbine specific
With wind turbines, hydroelectric plants, ... the extra equipment neededExtra equipment needed with wind turbines (EnergyAlternatives) is more or less the same as with PV-systems (depending on the type of wind turbine used),Schematic showing certain components as controllers built into the wind turbine itself yet also include: a manual disconnect switch foundation for the tower grounding system shutoff and/or dummy-load devices for use in high wind when power generated exceeds current needs and storage system capacity.
Vibro-wind power A new wind-energy technology is being developed that converts energy from wind energy vibrations to electricity. This energy, called Vibro-Wind technology, can use winds of less strength than normal wind turbines, and can be placed in almost any location.
A prototype consisted of a panel mounted with oscillators made out of pieces of foam. The conversion from mechanical to electrical energy is done using a piezoelectric transducer, a device made of a ceramic or polymer that emits electrons when stressed. The building of this prototype was led by Francis Moon, professor of mechanical and aerospace engineering at Cornell University. Moon's work in Vibro-Wind Technology was funded by the Atkinson Center for a Sustainable Future at Cornell. Vibro-wind power is not yet commercially viable and in early development stages. Significant progress will be needed to commercialize this early stage venture.
Possible set-ups Several microgeneration set-ups are possible. These are:
Off-the-grid set-ups which include: Off-the grid set-ups without energy storage (e.g., battery, ...) Off-the grid set-ups with energy storage (e.g., battery, ...) Battery charging stations Grid-connected set-ups which include: Grid connected with backup to power critical loads Grid-connected set-ups without financial recompensation scheme Grid-connected set-ups with net metering Grid connected set-ups with net purchase and sale
All set-ups mentioned can work either on a single power plant or a combination of power plants (in which case it is called a hybrid power system). For safety, grid-connected set-ups must automatically switch off or enter an "anti-islanding mode" when there is a failure of the mains power supply. For more about this, see the article on the condition of islanding.
Costs Depending on the set-up chosen (financial recompensation scheme, power plant, extra equipment), prices may vary. According to Practical Action, microgeneration at home which uses the latest in cost saving-technology (wiring harnesses, ready boards, cheap DIY-power plants, e.g. DIY wind turbines) the household expenditure can be extremely low-cost. In fact, Practical Action mentions that many households in farming communities in the developing world spend less than $1 on electricity per month. However, if matters are handled less economically (using more commercial systems/approaches), costs will be dramatically higher. In most cases however, financial advantage will still be done using microgeneration on renewable power plants; often in the range of 50–90% as local production has no electricity transportation losses on long distance power lines or energy losses from the Joule effect in transformers where in general 8–15% of the energy is lost.
In the UK, the government offers both grants and feedback payments to help businesses, communities and private homes to install these technologies. Businesses can write the full cost of installation off against taxable profits whilst homeowners receive a flat-rate grant or payments per kWh of electricity generated and paid back into the national grid. Community organizations can also receive up to £200,000 in grant funding.UK Grant Funding information
In the UK, the Microgeneration Certification Scheme provides approval for Microgeneration Installers and Products which is a mandatory requirement of funding schemes such as the Feed in Tariffs and Renewable Heat Incentive.
Grid parity Grid parity (or socket parity) occurs when an alternative energy source can generate electricity at a levelized cost of energy (LCOE) that is less than or equal to the price of purchasing power from the electricity grid. Reaching grid parity is considered to be the point at which an energy source becomes a contender for widespread development without subsidies or government support. It is widely believed that a wholesale shift in a generation to these forms of energy will take place when they reach grid parity.
Grid parity has been reached in some locations with on-shore wind power around 2000, and with solar power it was achieved for the first time in Spain in 2013.
Comparison with large-scale generation microgeneration large-scale generation notes Other names Distributed generation Centralized generation Economy of scale Necessitates mass production of generators which will create an associated environmental impact. Systems are less expensive when produced in quantity. Depends on power source – generally more economical given the larger scale of the generators. Photovoltaics, similar panels are used in all applications are affected less by this whilst wind power, where power scales approximately as the square of size is affected greatly. Ability to meet needs supply within the limits of the installed generation or storage For wind and solar energy, the actual production is only a fraction of nameplate capacity. Fuel based systems are fully dispatchable Solar panels are simple and reliable, they can provide a little electricity at a reasonable cost. generally more flexible supply within the limits of local transmission as long as the grid is effectively maintained Environmental impact larger number of smaller devices may lead to greater impact from device production especially with the wind. larger generators can have more local impact, transmission equipment can also disrupt areas, however, the overall impact is likely reduced due to economies of scale. Commentators claim that householders who buy their electricity with green energy tariffs can reduce their carbon usage further than with microgeneration and at a lower cost. Transmission losses Proximity to end user typically closer resulting in potentially fewer losses. (Potentially, because the lack of scale at each individual installation may lead to use of less efficient transmission technologies.) A significant proportion of electrical power is lost during transmission (approximately 8% in the United Kingdom according to BBC Radio 4 Today programme in March 2006). Changes to Grid reduces the transmission load, and thus reduces the need for grid upgrades increases the power transmitted, and thus increases the need for grid upgrades Grid failure event Electricity may still be available to local area in many circumstances Electricity may be not available due to grid Generator failure event Electricity will not be available except in hybrid scenario Electricity is very likely to be available due to grid redundancy Consumer choices May choose to purchase any legal system May choose to purchase offerings of the power companies depending on market Reliability and maintenance requirements Photovoltaics, Stirling engines, and certain other systems, are usually extremely reliable , and can generate electric power continuously for many thousands of hours with little or no maintenance. However, unreliable systems will incur additional maintenance labor and costs. Managed by power company. Grid reliability varies with location. Waste Heat by-product Can be used for heating purposes in cold climates, thus greatly increasing efficiency and offsetting energy total costs. This method is known as micro combined heat and power (microCHP).Used in some privately owned industrial combined heat and power (CHP) installations. It is also used in large-scale applications where it's called district heating and uses the heat that is normally exhausted by inefficient powerplants.Milieu Centraal, 29 April 2009 -- Stadsverwarming en blokverwarming