Renewable energy: protecting the electronic equipment involved
01 September 2020
Renewable energy – that is energy collected or harnessed from the earth’s infinite, non-exhaustible or naturally replenished renewable resources on human timescales, rather than our traditional reliance upon the finite fossil fuel resources – is projected to account for more than half of global electricity production by 2035.
This article was originally featured in the September 2020 issue of EPDT magazine [read the digital issue]. Sign up to receive your own copy each month.
According to research firm, Allied Market Research, the renewable energy market is predicted to grow to more than $1.5 trillion by 2025, with biomass representing the leading form of energy. Here, Jade Bridges, Global Technical Support Manager at electro-chemical solutions expert, Electrolube explores the various forms of renewable energy sources – and explains how its solutions can help protect the electronic equipment involved from the elements...
Our discussion commences with a traditional source of renewable energy: water. Water-based power sources, including hydropower, tidal power and wave power, all rely on hydrokinetic potential: that is, the energy carried by bodies of water. Water-based power is sustainable and has a low carbon footprint. Typically known as hydropower, the energy generated by falling or fast moving water has been used for centuries for a variety of mechanical applications. Hydropower was first used for electricity generation in the late 19th century, and has since developed into an important source of renewable power.
Hydroelectricity is produced by passing flowing water through turbine generators, which consist of a number of electronic components, including alternators, inverters, control panels, and power switches or breakers. This type of power is incredibly versatile, and examples of its application can be seen around the world – one of the most famous being the Hoover Dam, in the USA. Run-in-river applications can also be utilised to harness power from flowing water, rather than falling water as seen in a reservoir-dam facility. While emissions from these plants may be low, they are not totally emission-free, and their effect on the environment must also be considered; protection of fish from turbines, appropriate use of land and evaluation of surrounding wildlife are just some criteria that should be addressed when developing new sites.
The two remaining water-based renewable energy sources sound similar, but are, in fact, very different. Tidal patterns are continuous, therefore energy generation from this source is predictable. Tidal generators can be situated on suitable shorelines to harness this power. Wave power, however, generated at sea, is more unpredictable and currently plays a minor role in the global mix of energy sources. In both cases, consideration needs to be given to the effects of any machinery or movement on the surrounding ecosystem.
It is in these demanding electronic applications where Electrolube products can assist, with protective compounds, such as encapsulation resins and conformal coatings, that aid the efficient and prolonged application of these electronics in challenging environmental conditions. Devices such as sensors and data loggers are important for gathering information both in and out of the plant, providing details such as water depth and wave acceleration to adjust systems and achieve maximum capability. Water protection for these devices is just one example of where encapsulation resins may help make these measurements possible, greatly reducing maintenance requirements and human interaction in data collection.
Moving on, solar energy has to be one of the most iconic forms of renewable energy, particularly prevalent in the domestic electricity market. Solar cells produce direct current (DC) electricity from sunlight via technology known as photovoltaics (PV) – and it is these solar cells that we have become accustomed to seeing in many different applications globally. However, the technology doesn’t stop at the solar cell alone. Inverters are used to convert the direct current into alternating current (AC) electricity, so that it can be fed from the solar panel into your home/building to operate standard appliances. In addition, capacitors are used to temporarily store electricity where required, or in off-grid applications, batteries may be required to store power for more widespread use.
In such cases, these electronic devices will require protection from the elements, but will also be required to operate at higher temperatures and offer some form of thermal dissipation, due to the heat emitted during operation. Depending on the design, thermal management products may be used to help dissipate heat away from devices; this could be in the form of thermal gap fillers (such as Electrolube GF400), for example. However, to offer both protection from the environment and thermal dissipation, specialist encapsulation resins, such as Electrolube’s ER2221, may be required.
In addition to capturing and converting the energy, there is a requirement for measuring performance and having some control over the solar panel. Measurements such as solar panel temperature can help to manage solar farms, ensuring the most efficient use of the technology is attained. Unfortunately, some of these system electronics can be relatively small and fragile; yet conversely, the average piece of solar equipment must be able to withstand extreme weather conditions, including direct exposure to the sun, heat and other environmental elements.
Electrolube has worked directly with organisations harnessing solar power. In one particular instance, a small device displaying information on the performance and connectivity of the solar panels in an array required protection from the external environment. Some issues had arisen with resins tested, where the hardness and Tg (glass transition temperature) of the material resulted in pressure on the LCD screen, leading to failures in operation. Initially silicone options were tested, due to this low stress requirement, but these did not perform to the high level achieved by Electrolube’s UR5044, which exhibited great stability and low hardness over a wide temperature range. In particular, adhesion of this polyurethane resin was greatly improved compared to the previous silicone resins tested, and thus, improved protection from external conditions was realised.
Devices separate from the solar farm are also important. Measurements of solar radiation, incoming UV and infrared light spectrums give data to help correctly position and manage these solar plants. Such data must be transmitted, often by GPRS or perhaps Bluetooth, and any protection compound used must not interfere with these wireless signals. Encapsulation resins with a low dielectric constant are best suited, such as Electrolube’s UR5118, which also offers excellent water resistance. However, if the unit is well sealed by the outer casing and has a high IP rating, it may also be possible to use a conformal coating (such as Electrolube AFA) to prevent the effects of condensation on the electronics, and also minimise the weight of the device, in comparison to a potted unit.
Everywhere we look, solar panels can be seen, powering devices from decorative garden lighting to street lights and road signs. Smart street lights and solar benches are among the newest products to fully integrate numerous technologies, such as remote management control, wireless charging and Wi-Fi hotspots, all built in – and again, all requiring protection for the electronics used. The chemical industry is playing a strong part in novel developments in this industry, right up the development of solar paint. The possibilities here are seemingly endless.
The third renewable source for discussion is wind power, one of our most predominant sources, with the UK currently ranking as the sixth largest producer of wind power in the world. Wind farms capture the energy of wind flow through the use of turbines and convert it into electricity. Commercially-positioned wind farm systems can power many organisations, whereas single wind turbines are predominantly used as a method to supplement pre-existing energy sources.
Traditional turbines are huge structures, with very large blades, driven by wind power, which in turn powers a rotor. This rotor spins the shaft within the tall upright of the turbine and this powers a generator for harnessing electricity. Almost all wind turbines can contain up to 8,000 separate parts, including gearboxes, power systems, generators, sensors and devices for electronic control. One of the challenges is to assemble these enormous devices, to enable a long life and trouble-free operation. All electronics and components mounted in the tower must be able to withstand constant vibration, temperature changes and extremes, environmental conditions (these vary depending upon the location, but can include salt mist/spray) and limited accessibility. Longevity of component life, reduced maintenance and long term cost are all key drivers prompting reliable protection systems in the form of either conformal coatings, encapsulation resins or sometimes a combination of both.
There are also requirements for thermal management materials within the use of wind turbines, and Electrolube was faced with a particularly challenging problem when a ‘greener’ version of a standard thermal interface material (TIM) was required. It is encouraging that green energy developers are considering all aspects of environmental impact, including the materials used with the manufacture of their products. In this case, the thermal interface material had to be classed as completely non-hazardous, and since traditional TIMs contain zinc oxide, they were deemed unsuitable. Presented with the problem, Electrolube developed a bespoke solution, HTCX_ZF. This was developed using alternative thermally conductive fillers, which removed the zinc oxide and corresponding H410 hazard statement, representing toxicity to aquatic life. The product also offered increased thermal conductivity compared to the standard material, thus delivering greater efficiency of heat dissipation in customer testing.
The location of wind farms is as important as the location of any other renewable energy sites. In offshore wind farms, conditions are far more extreme, and corrosive elements, such as salt mist, can have a detrimental effect on both mechanical and electrical parts. With experience in electronic devices for marine applications, Electrolube is perfectly placed to offer support and advice on suitable protection compounds for such applications.
Like developers of integrated technology, Electrolube strives to utilise experience gained from multiple industries and from varying types of products offered in our range. Combining the understanding of protection levels required, with correct thermal management and suitability for applications such as LED technology, assists in the correct selection of products for complex and critical applications. For example, the use of Electrolube products to protect lighting arrays in outdoor applications, such as shopping centres, sports arenas and even aircraft runways, gives confidence and understanding of the potential use of these products to protect the warning lights used on the top of wind turbines. Combine that with our understanding of products in applications where wireless data transfer is required, and the smart management of such lighting technology can be successfully achieved, even in such harsh external conditions.
The most widely used form of renewable power in the UK today, however, is carbon-neutral and comes from bio-waste, making use of unwanted by-products of today’s way of life. Biomass is an alternative fuel made from organic materials, including wood, crops and plants, animal waste and more. Biomass products are burned within a boiler, generating a source of steam to turn a turbine, thereby producing electricity. Traditional coal-fired power stations can be converted to run entirely on biomass fuel. Biomass, hydroelectricity and wind power are the three resources on which we depend the most in order to achieve cleaner energy goals and the reduction of our carbon footprint.
While the most reliable and productive sources of renewable energy have a heavy reliance on harvesting equipment with a myriad of mechanical moving parts, it is clear that electronic developments have been key in the development and integration of these sources into our everyday lives. Over time, the harvesting of energy will likely become even more automated and entwined with the IoT, as we see trees fitted with PV cells and pressure power sensors fitted underneath high traffic roads. Efficiency and reliability will increase as the level of AI builds. Thermal management materials, conformal coatings and encapsulation resins all have a vital part to play in the protection, reliability and lifetime of devices throughout the planning and maintenance of renewable energy generation and harvesting technologies.
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