Hybrid power

Early hybrid power system. The gasoline/kerosine engine drives the dynamo which charges the storage battery.

Hybrid power are combinations between different technologies to produce power.

In power engineering, the term 'hybrid' describes a combined power and energy storage system. It does not mean a "method," such as the popular use of hybrid to mean a hybrid electric vehicle like the Toyota Prius. Although the drive train in the Toyota Prius can accurately be described as a hybrid power system.

Examples of power producers used in hybrid power are photovoltaics, wind turbines, and various types of engine-generators – e.g. diesel gen-sets.

Hybrid power plants often contain a renewable energy component (such as PV) that is balanced via a second form of generation or storage such as a diesel genset, fuel cell or battery storage system. They can also provide other forms of power such as heat for some applications.

Hybrid power system

Hybrid systems, as the name implies, combine two or more modes of electricity generation together, usually using renewable technologies such as solar photovoltaic (PV) and wind turbines. Hybrid systems provide a high level of energy security through the mix of generation methods, and often will incorporate a storage system (battery, fuel cell) or small fossil fueled generator to ensure maximum supply reliability and security.

See also

• Hybrid renewable energy system
• Solar hybrid power systems
• Stand-alone power system
• Wind hybrid power systems

References

Hybrid renewable energy systems are becoming popular as stand-alone power systems for providing electricity in remote areas due to advances in renewable energy technologies and subsequent rise in prices of petroleum products. A hybrid energy system, or hybrid power, usually consists of two or more renewable energy sources used together to provide increased system efficiency as well as greater balance in energy supply.

Examples

Biomass-wind-fuel cell

For example, consider a load of 100% power supply and there is no renewable system to fulfill this need, so two or more renewable energy system can be combined. For example, 60% from a biomass system, 20% from wind system and the remainder from fuel cells. Thus combining all these renewable energy systems may provide 100% of the power and energy requirements for the load, such as a home or business.

Photovoltaic and wind

Block diagram of a SUV/wind hybrid energy system

Another example of a hybrid energy system is a photovoltaic array coupled with a wind turbine. This would create more output from the wind turbine during the winter, whereas during the summer, the solar panels would produce their peak output. Hybrid energy systems often yield greater economic and environmental returns than wind, solar, geothermal or trigeneration stand-alone systems by themselves.

Completely Renewable Idea

Completely Renewable Hybrid Power Plant (solar, wind, biomass, hydrogen) A hybrid power plant consisting of these four renewable energy sources can be made into operation by proper utilization of these resources in a completely controlled manner. Hybrid Energy Europe-USA. Caffese in Europe introduce hybridizing transmission with Marine hydro pumped Energy Storage via elpipes. The project of Caffese is 3 marine big lakes producing 1800 GW and transmission with elpipes. A part 1200 GW produce water fuels-wind fuels-solar fuels 210 billion liter year. (IEEE Power and Engineering Society-General Meeting Feb 9, 2011. Arpa-E, Doe USA, MSE Italy, European Commission-Energy-Caffese plan and Consortium Hybrid renewable energy systems are becoming popular as stand-alone power systems for providing electricity in remote areas due to advances in renewable energy technologies and subsequent rise in prices of petroleum products. A hybrid energy system, or hybrid power, usually consists of two or more renewable energy sources used together to provide increased system efficiency as well as greater balance in energy supply

Drawbacks of standalone renewable energy sources

Most of us already know how a solar/wind/biomass power generating system works, but, all these generating systems have drawbacks of some kind. Solar panels, for example, are expensive to set up, and are peak output is not obtained during the night or cloudy days. Similarly, Wind turbines can’t operate safely in high wind speeds, and low wind speeds produce little power. Biomass plants collapse at low temperatures.

How to overcome?

So if all the three are combined into one hybrid power generating system the drawbacks can be avoided partially/completely, depending on the control units. As the one or more drawbacks can be overcome by the other, as in northern hemisphere it is generally seen that in windy days the solar power is limited and vice versa and in summer and rainy season the biomass plant can operate in a full flagged so the power generation can be maintained in the above stated condition. The cost of solar panel can be subsided by using glass lenses, mirrors to heat up a fluid, that can rotate the common turbine used by wind and other sources. Now the question arises what about the winter nights or cloudy winter days with very low wind speeds. Here comes the activity of the Hydrogen. As we know the process of electrolysis can produce hydrogen by breaking water into hydrogen and oxygen, it can be stored; hydrogen is also a good fuel and burns with oxygen to give water. Hydrogen can be used to maintain the temperature of the biomass reservoir in winter so that it can produce biogas in optimum amount for the power generation. As stated above biogas is a good source in summer; in this period the solar energy available is also at its peak, so if the demand and supply is properly checked and calculated the excess energy can be used in the production of hydrogen and can be stored. In sunny, windy &hot day, the turbine operates with full speed as the supply is maximum, and this excess power can be consumed for the process of manufacturing hydrogen. In winter, the power consumption is also low so the supply limit is low, and obtained with lesser consumption. Driving hybrid cars will disable this outcome.

Areas of research

• Amount of Hydrogen produce by amount of power utilized and reusing the hydrogen for maintaining the temperature. Is it cost efficient?
• Limited to areas near equatorial regions (23deg N-23deg S), at low altitudes.
• Infrastructure cost may be high.

Regulation

To get constant power supply, the output of the renewables may be connected to the rechargeable battery bank and then to the load. If the load is alternating current (AC), then an inverter is used to convert the direct current (DC) supply from the battery to the AC load. Consideration about voltage transition among modules starting from Wind Generator, Battery Charger Controller and Inverter should be subject to voltage standard which mainly focus about voltage compatibility.

Need for research

The key to cost reductions of this order is, of course, the right sort of support for innovation and development - something that has been lacking for the past and, arguably, is still only patchy at present. Research and development efforts in solar, wind, and other renewable energy technologies are required to continue for:

• improving their performance,
• establishing techniques for accurately predicting their output
• reliably integrating them with other conventional generating sources

Economic aspects of these technologies are sufficiently promising to include them in developing power generation capacity for developing countries.

See also

• List of energy storage projects
• Solar hybrid power systems
• Wind hybrid power systems

External links

• Demonstration of an integrated Hybrid Renewable Energy System with system sketch
• Professional Hybrid Renewable Energy Systems discussions on LinkedIn
• Project examples from the mining industry Project dadabase of THEnergy platform for "Renewables & Mining"

Hybrid solar and wind system

Solar hybrid power systems are hybrid power systems that combine solar power from a photovoltaic system with another power generating energy source. A common type is a photovoltaic diesel hybrid system, combining photovoltaics (PV) and diesel generators, or diesel gensets, as PV has hardly any marginal cost and is treated with priority on the grid. The diesel gensets are used to constantly fill in the gap between the present load and the actual generated power by the PV system.

As solar energy is fluctuating, and the generation capacity of the diesel genesets is limited to a certain range, it is often a viable option to include battery storage in order to optimize solar's contribution to the overall generation of the hybrid system.

The best business cases for diesel reduction with solar and wind energy can normally be found in remote locations because these sites are often not connected to the grid and transport of diesel over long distances is expensive. Many of these applications can be found in the mining sector and on islands

In 2015, a case-study conducted in seven countries concluded that in all cases generating costs can be reduced by hybridising mini-grids and isolated grids. However, financing costs for diesel-powered electricity grids with solar photovoltaics are crucial and largely depend on the ownership structure of the power plant. While cost reductions for state-owned utilities can be significant, the study also identified short-term economic benefits to be insignificant or even negative for non-public utilities, such as independent power producers, given historical costs at the time of the study.

Other solar hybrids include solar-wind systems. The combination of wind and solar has the advantage that the two sources complement each other because the peak operating times for each system occur at different times of the day and year. The power generation of such a hybrid system is more constant and fluctuates less than each of the two component subsystems.

The intermittent / non-dispatchable solar PV at the prevailing low tariffs clubbed with pumped-heat electricity storage can offer cheapest dispatchable power round the clock on demand.

Solar thermal hybrid systems

Though Solar PV generates cheaper intermittent power during the day light time, it needs the support of sustainable power generation sources to provide round the clock power. Solar thermal plants with thermal storage are clean sustainable power generation to supply electricity round the clock. They can cater the load demand perfectly and work as base load power plants when the extracted solar energy is found excess in a day. Proper mix of solar thermal (thermal storage type) and solar PV can fully match the load fluctuations without the need of costly battery storage.

During the day time, the additional auxiliary power consumption of a solar thermal storage power plant is nearly 10% of its rated capacity for the process of extracting solar energy in the form of thermal energy. This auxiliary power requirement can be made available from cheaper solar PV plant by envisaging hybrid solar plant with a mix of solar thermal and solar PV plants at a site. Also to optimise the cost of power, generation can be from the cheaper solar PV plant (33% generation) during the day light whereas the rest of the time in a day is from the solar thermal storage plant (67% generation from Solar power tower and parabolic trough types) for meeting 24 hours base load operation. When solar thermal storage plant is forced to idle due to lack of sunlight locally during cloudy days in monsoon season, it is also possible to consume (similar to a lesser efficient, huge capacity and low cost battery storage system) the cheap surplus / infirm power from solar PV, wind and hydro power plants by heating the hot molten salt to higher temperature for converting stored thermal energy in to electricity during the peak demand hours when the electricity sale price is profitable.

Gallery

• 
  Typical wind and solar hybrid system
• 
  Hybrid on Žirje, Croatia
• 
  Small wind and solar hybrid system

See also

• Distributed generation
• Hybrid power
• Hybrid renewable energy system
• Stand-alone power system
• Wind hybrid power system
• Photovoltaic thermal hybrid solar collector

External links

• Wind, Solar, and Hybrid Plants used in the Mining Industry Project database "Renewables in Mining"
• Wind, Solar, and Hybrid Plants used on Islands Project database "Renewables on Islands"

A hybrid wind and solar power system

Wind hybrid power systems combines wind turbines with other storage and/or generation sources. One of the key issues with wind energy is its intermittent nature. This has led to numerous methods of storing energy.

Wind-hydro system

A wind-hydro system generates electric energy combining wind turbines and pumped storage. The combination has been the subject of long-term discussion, and an experimental plant, which also tested wind turbines, was implemented by Nova Scotia Power at its Wreck Cove hydro electric power site in the late 1970s, but was decommissioned within ten years. Since, no other system has been implemented at a single location as of late 2010.

Wind-hydro stations dedicate all, or a significant portion, of their wind power resources to pumping water into pumped storage reservoirs. These reservoirs are an implementation of grid energy storage.

Advantages

Wind and its generation potential is inherently variable. However, when this energy source is used to pump water into reservoirs at an elevation (the principle behind pumped storage), the potential energy of the water is relatively stable and can be used to generate electrical power by releasing it into a hydropower plant when needed. The combination has been described as particularly suited to islands that are not connected to larger grids.

Proposals

During the 1980s, an installation was proposed in the Netherlands. The IJsselmeer would be used as the reservoir, with wind turbines located on its dike. Feasibility studies have been conducted for installations on the island of Ramea (Newfoundland and Labrador) and on the Lower Brule Indian Reservation (South Dakota).

An installation at Ikaria Island, Greece, had entered the construction phase as of 2010.

The island of El Hierro is where the first world's first wind-hydro power station is expected to be complete. Current TV called this "a blueprint for a sustainable future on planet Earth". It was designed to cover between 80-100% of the island's power and was set to be operational in 2012. However, these expectations were not realized in practice, probably due to inadequate reservoir volume and persistent problems with grid stability.

100% renewable energy systems require an over-capacity of wind or solar power.

Wind-hydrogen system

One method of storing wind energy is the production of hydrogen through the electrolysis of water. This hydrogen is subsequently used to generate electricity during periods when demand can not be matched by wind alone. The energy in the stored hydrogen can be converted into electrical power through fuel cell technology or a combustion engine linked to an electrical generator.

Successfully storing hydrogen has many issues which need to be overcome, such as embrittlement of the materials used in the power system.

This technology is being developed in many countries. In 2007 there was an IPO of an Australian firm called Wind Hydrogen that aimed to commercialise this technology in both Australia and the UK. In 2008 the company changed its name and turned its operations to fossil fuel exploration.

In 2007, technology test sites included:

Community	Country	Wind MW
Ramea, Newfoundland and Labrador	Newfoundland, Canada	0.3
Prince Edward Island Wind-Hydrogen Village	PEI, Canada
Lolland	Denmark
Bismarck	North Dakota, US
Koluel Kaike	Santa Cruz, Argentina
Ladymoor Renewable Energy Project (LREP)	Scotland
Hunterston Hydrogen Project	Scotland
RES2H2	Greece	0.50
Unst	Scotland	0.03
Utsira	Norway	0.60

Wind-diesel system

Wind Hydrogen system on Ramea in Canada

A wind-diesel hybrid power system combines diesel generators and wind turbines, usually alongside ancillary equipment such as energy storage, power converters, and various control components, to generate electricity. They are designed to increase capacity and reduce the cost and environmental impact of electrical generation in remote communities and facilities that are not linked to a power grid. Wind-diesel hybrid systems reduce reliance on diesel fuel, which creates pollution and is costly to transport.

History

Wind-diesel generating systems have been under development and trialled in a number of locations during the latter part of the 20th century. A growing number of viable sites have been developed with increased reliability and minimized technical support costs in remote communities.

Technology

The successful integration of wind energy with diesel generating sets relies on complex controls to ensure correct sharing of intermittent wind energy and controllable diesel generation to meet the demand of the usually variable load. The common measure of performance for wind diesel systems is Wind Penetration which is the ratio between Wind Power and Total Power delivered, e.g. 60% wind penetration implies that 60% of the system power comes from the wind. Wind Penetration figures can be either peak or long term. Sites such as Mawson Station, Antarctica, as well as Coral Bay and Bremer Bay in Australia have peak wind penetrations of around 90%. Technical solutions to the varying wind output include controlling wind output using variable speed wind turbines (e.g. Enercon, Denham, Western Australia), controlling demand such as the heating load (e.g. Mawson), storing energy in a flywheel (e.g. Powercorp, Coral Bay). Some installations are now being converted to wind hydrogen systems such as on Ramea in Canada which is due for completion in 2010.

Communities using wind-diesel hybrids

The following is an incomplete list of isolated communities utilizing commercial wind-diesel hybrid systems with a significant proportion of the energy being derived from wind.

Community	Country	Diesel (in MW)	Wind (in MW)	Population	Date Commissioned	Wind Penetration (peak)	Notes
Mawson Station	Antarctica	0.48	0.60		2003	>90%
Ross Island	Antarctica	3	1		2009	65%
Bremer Bay	Australia	1.28	0.60	240	2005	>90%
Cocos	Australia	1.28	0.08	628
Coral Bay	Australia	2.24	0.60		2007	93%
Denham	Australia	2.61	1.02	600	1998	>70%
Esperance	Australia	14.0	5.85		2003
Hopetoun	Australia	1.37	0.60	350	2004	>90%
King Island	Australia	6.00	2.50	2000	2005	100%	Currently (2013) expanding to include 2 MW Diesel-UPS, 3 MW / 1.6 MWh Advanced Lead Acid battery and dynamic load control through smart grid
Rottnest Island	Australia	0.64	0.60		2005
Thursday Island, Queensland	Australia		0.45	?
Ramea	Canada	2.78	0.40	600	2003		Being converted to Wind Hydrogen
Sal	Cape Verde	2.82	0.60		2001	14%
Mindelo	Cape Verde	11.20	0.90			14%
Alto Baguales	Chile	16.9	2.00	18,703	2002	20%	4.6 MW hydro
Dachen Island	China	1.30	0.15			15%
San Cristobal, Galapagos Island	Ecuador		2.4		2007		Expanding to cover 100% of island's energy needs by 2015
Berasoli	Eritrea	0.08	0.03				Under tender
Rahaita	Eritrea	0.08	0.03				Under tender
Heleb	Eritrea	0.08	0.03				Under tender
Osmussaar	Estonia	?	0.03		2002
Kythnos	Greece	2.77	0.31
Lemnos	Greece	10.40	1.14
La Désirade	Guadeloupe	0.88	0.14			40%
Sagar Island	India	0.28	0.50
Marsabit	Kenya	0.30	0.15			46%
Frøya	Norway	0.05	0.06			100%
Batanes	Philippines	1.25	0.18		2004
Flores Island	Portugal		0.60			60%
Graciosa Island	Portugal	3.56	0.80			60%
Cape Clear	Ireland	0.07	0.06	100	1987	70%
Chukotka	Russia	0.5	2.5
Fuerteventura	Spain	0.15	0.23
Saint Helena	UK		0.48		1999–2009	30%
Foula	UK	0.05	0.06	31		70%
Rathlin Island	UK	0.26	0.99			100%
Toksook Bay, Alaska	United States	1.10	0.30	500	2006
Kasigluk, Alaska	United States	1.10	0.30	500	2006
Wales, Alaska	United States		0.40	160	2002	100%
St. Paul, Alaska	United States	0.30	0.68			100%
Kotzebue, Alaska	United States	11.00			1999	35%
Savoonga, Alaska	United States		0.20		2008
Tin City, Alaska	United States		0.23		2008
Nome, Alaska	United States		0.90		2008
Hooper Bay, Alaska	United States		0.30		2008

Wind-diesel hybrids at mining sites

Recently, in Northern Canada wind-diesel hybrid power systems were built by the mining industry. In remote locations at Lac de Gras, in Canada's Northwest Territories, and Katinniq, Ungava Peninsula, Nunavik, two systems are used to save fuel at mines. There is another system in Argentina.

Wind-compressed air systems

At power stations that use compressed air energy storage (CAES), electrical energy is used to compress air and store it in underground facilities such as caverns or abandoned mines. During later periods of high electrical demand, the air is released to power turbines, generally using supplemental natural gas. Power stations that make significant use of CAES are operational in McIntosh, Alabama, Germany, and Japan. System disadvantages include some energy losses in the CAES process; also, the need for supplemental use of fossil fuels such as natural gas means that these systems do not completely make use of renewable energy.

The Iowa Stored Energy Park, projected to begin commercial operation in 2015, will use wind farms in Iowa as an energy source in conjunction with CAES.

Wind-solar systems

Horizontal axis wind-turbine, combined with a solar panel on a lighting pylon at Weihai, Shandong province, China

A combine use of wind-solar systems results, in many places, to a smoother power output since the resources are anti-correlated. Therefore, the combined use of wind and solar systems is crucial for a large-scale grid integration.[1].

See also: Solar hybrid power systems

Wind-solar grid supply

In 2019 in western Minnesota, a $5m hybrid system was installed. It runs 500 kW of solar power through the inverter of a 2 MW wind turbine, increasing the capacity factor and reducing costs by $150,000 per year. Purchase contracts limits the local distributor to a 5% maximum of self-generation.

Wind-solar building

The Pearl River Tower in Guangzhou, China, will mix solar panel on its windows and several wind turbines at different stories of its structure, allowing this tower to be energy positive.

Wind-solar lighting

In several parts of China & India, there are lighting pylons with combinations of solar panels and wind-turbines at their top. This allows space already used for lighting to be used more efficiently with two complementary energy productions units. Most common models use horizontal axis wind-turbines, but now models are appearing with vertical axis wind-turbines, using a helicoidal shaped, twisted-Savonius system.

Solar panels on turbines

Solar panels on the already existing wind turbines has been tested, but produced blinding rays of light that posed a threat to airplanes. A solution was to produce tinted solar panels that do not reflect as much light. Another proposed design was to have a vertical axis wind turbine coated in solar cells that are able to absorb sunlight from any angle.

See also

• Hybrid power
• Hybrid renewable energy system
• Solar hybrid power system
• Stand-alone power system

External links

• HAMILTON SPECTATOR - Integrating fuel cell technology into wind turbine structure that can produce cryo-compressed hydrogen and oxygen that is stored on-site, and used to generate electrical power when there is no wind
• International Association for Hydrogen Energy
• European Hydrogen Association
• RES2H2
• NREL Wind Hydrogen
• THEnergy platform "Renewables & Mining"