December 3, 2013
Up take of solar energy in New Zealand
The main source of energy in New Zealand comes from Gas, Geothermal and Hydro. However solar energy has gained popularity because of the low cost of production and the low cost of acquiring solar panels.
Solar energy is abundantly available in New Zealand with immense potential of generating a huge amount of primary energy. New Zealand has technologies that can convert this type of energy to electricity at a lower cost. Solar energy has the potential to supply energy for the foreseeable future in commercial, industrial and residential areas.
Solar energy can help the country to greatly diversify her current energy sources with the aim of growing the manufacturing sector. As a result, the country has initiatives and mechanisms to overcome the market barriers and the cost facing the technology of producing this energy.
What is the current situation and the market contribution of solar energy in New Zealand?
Solar energy contributes to over 3 percent of total energy in New Zealand. Around 2200 units of solar are installed per year particularly in residential places spurred by the government initiative in the savings of the energy.
Solar energy is slowly replacing the thermal generation of electricity and has created employment of over five thousand people. More importantly, solar energy is mitigating the risk of carbon emission to the atmosphere produced from thermal generation.
The production of solar is well established in remote areas and often done on stand alone applications. The cost of producing energy using solar ranges between 35 – 60 c/kWh. Solar energy from the rooftops of buildings generates around 40GWh of electricity per year.
Solar energy is distributed across the country by use of retail companies or power lines. The distribution trend continues to increase. The use of solar energy has become a common phenomenon in the country since around 1.6 percent of home-owners in the country have installed solar water heating systems. Presently, over 3500 new installations of water systems are witnessed in the country each year. The number is expected to continue at a rate of around 40 percent per year.
What has made the country to embrace the use of solar energy?
One of the reasons is the cost of production. The cost of producing solar energy in the country is cheap when comparing it to other sources such as hydro;
Another reason is that solar is a clean energy with no effects on the environment. Solar energy does emit any carbon to the atmosphere hence ensuring a clean environment;
Further, New Zealand has over 2000 hours of sunshine in the whole year that is not utilized.
Overall; statistics on the uptake of solar energy in New Zealand continue to grow at a rate of 40 percent per year.
December 3, 2013
The use of inverters in energy connection to the grid requires a standard procedure that must be followed to realize desirable results. Generally, AS/NZ 4777 standard for power inverters requires that it should support a maximum of 100kVA. It also requires balancing for systems with over 20A – making its largest installation to be 4.8kVA. Throughout its lifespan it needs liaison with electricity distributor. It also involves inclusion of micro inverters such as AC modules; and with the use of inverters with multiple modes, a new definition is added. Consideration of standards such as IEC 62109 is essential. Vitally important, it is worth noting that the word shall denotes a mandatory statement and should refers to a recommendation on the basis of industry’s best practice. Failure to comply requires a justification.
It consists of inverter(s), source(s) of energy, wiring, metering, control, and safety devices – all connected to a specific point within an installation. Household installations shall have a maximum of 600V d.c. while non-household areas shall have restrictions on the wiring and equipment and permission shall only be granted to authorized persons. Also, systems with currents in excess of 20A shall have the output balanced among its three phases. It is also recommended that the gross output be metered. The system connection of MSB or DSB is compulsory. The use of connectors as well as couplers is acceptable but not the a.c. standard type. Also, cable ties made of plastic are not acceptable. The voltage drop as well as voltage rise should be by a margin of 1 percent between the inverter and main switch of the inverter, and 1 percent between main switch of inverter and connection point. In the event that a single inverter fails to meet the requirements of a multiple inverter then there shall be need for more central protection outside the IES. Balance protection of phases is essential at the inverter supply, that is, the main switch if: The unbalance in current is higher than 20A and that in voltage higher than 2 percent. There is need for voltage protection as well as frequency protection of integrated inverter for IES greater than 30kVA. This additional safety offers a coordination level between supply point, single inverters, as well as consumer installation equipment. The protection of mechanical cable is facilitated by RCDs which must be specified by the manufacturer. There is need for special consideration of UPS or Multiple Mode. These will be critical for the operation of the inverter.
December 3, 2013
How does one look at transformer power inverters vs transformerless power inverters? For starters, one must look at three basic points namely power distribution efficiency, system complexity or simplicity and of course, its costs.
Power inverters work to convert direct current, such as the power coming from a car battery, into alternating current, such as those needed by cell phones to charge, vacuum cleaners to work, and lamps to turn on. In other words, they are the means by which large primary input current is converted to manageable output current. These are indispensable tools in aiding with the measurement of alternating current.
The ‘transformer’ in transformer power inverters refers to a device which has two circuits partnered by a magnetic field that is both linked to each. The change in one circuit affects the other. They are used for the conversion of large primary currents into smaller, easy to measure, secondary currents. Most of these products have different sizes and shapes but are usually used in the same manner which is as an interfacing solution that will bridge the gap between high currents and instrumentation devices.
On the other hand, transformerless power inverters are a more current innovation. It is considered to be one of the biggest advancements in inverter technology. This design offers integrators, independent power-producers, and it maximizes power distribution while simplifying the system for installation. It is also important to note that it is greatly beneficial for large scale installations. As they say, less is more.
With the absence of a transformer, the inverter becomes more compact or around 50% to 70% smaller and lighter than its transformer-based counterpart with similar output, making integrators freer to install and design as they wish. As with most advancement, the resulting technology is usually more efficient as with the case of this inverter. In terms of generating energy, it is proven to be more capable. It also removes the necessity for inverter-centric transformers and balance-of-system costs. It is also cheaper to produce because it no longer needs unnecessary wiring such as copper wiring made up of iron or steel core. However, as with all the things in life and work, it still has its drawbacks. Most important is its requirement of having the DC wiring to be ungrounded. Because of this, they must meet more standard rules as per regulations. These are just some of the main differences of transformer power inverters vs transformerless power inverters.